Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2016	Oct. 20, 2016
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Entity Registrant Name	Employers Holdings, Inc.
Entity Central Index Key	0001379041
Current Fiscal Year End Date	--12-31
Entity Well Know Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock Shares Outstanding		32,087,739
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	Q3

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Available for sale:
Fixed maturity securities at fair value (amortized cost $2,273,100 at September 30, 2016 and $2,221,100 at December 31, 2015)	$ 2,383,900	$ 2,288,500
Equity securities at fair value (cost $114,400 at September 30, 2016 and $137,500 at December 31, 2015)	184,500	198,700
Short-term investments at fair value (amortized cost $14,000 at September 30, 2016)	14,000	0
Total investments	2,582,400	2,487,200
Cash and cash equivalents	84,100	56,600
Restricted cash and cash equivalents	2,700	2,500
Accrued investment income	20,300	20,600
Premiums receivable (less bad debt allowance of $10,700 at September 30, 2016 and $12,200 at December 31, 2015)	317,100	301,100
Reinsurance recoverable for:
Paid losses	8,300	7,700
Unpaid losses	591,500	628,200
Deferred policy acquisition costs	46,800	44,300
Deferred income taxes, net	41,100	67,900
Property and equipment, net	22,600	24,900
Intangible assets, net	8,300	8,500
Goodwill	36,200	36,200
Contingent commission receivable—LPT Agreement	31,100	29,200
Other assets	31,800	40,900
Total assets	3,824,300	3,755,800
Claims and policy liabilities:
Unpaid losses and loss adjustment expenses	2,330,000	2,347,500
Unearned premiums	325,600	308,900
Total claims and policy liabilities	2,655,600	2,656,400
Commissions and premium taxes payable	50,500	52,500
Accounts payable and accrued expenses	17,500	24,100
Deferred reinsurance gain—LPT Agreement	177,800	189,500
Notes payable	32,000	32,000
Other liabilities	40,800	40,500
Total liabilities	2,974,200	2,995,000
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 56,124,974 and 55,589,454 shares issued and 32,109,976 and 32,216,480 shares outstanding at September 30, 2016 and December 31, 2015, respectively	600	600
Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued	0	0
Additional paid-in capital	368,600	357,200
Retained earnings	744,500	682,000
Accumulated other comprehensive income, net	117,600	83,600
Treasury stock, at cost (24,014,998 shares at September 30, 2016 and 23,372,974 shares at December 31, 2015)	(381,200)	(362,600)
Total stockholders’ equity	850,100	760,800
Total liabilities and stockholders’ equity	$ 3,824,300	$ 3,755,800

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Available for sale:
Fixed maturity securities, amortized cost	$ 2,401,500	$ 2,358,600
Available for sale, short-term investments, at amortized cost	14,000	0
Premiums receivable, bad debt allowance	10,700	12,200
Reinsurance Recoverables on Unpaid Losses, Allowance	$ 0	$ 0
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	56,124,974	55,589,454
Common stock, shares outstanding (in shares)	32,109,976	32,216,480
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	0	0
Treasury stock, at cost (in shares)	24,014,998	23,372,974
Debt Securities [Member]
Available for sale:
Fixed maturity securities, amortized cost	$ 2,273,100	$ 2,221,100
Equity Securities [Member]
Available for sale:
Fixed maturity securities, amortized cost	114,400	$ 137,500
Short-term Investments [Member]
Available for sale:
Fixed maturity securities, amortized cost	$ 14,000

Consolidated Statements of Income - USD ($)	3 Months Ended		9 Months Ended
Consolidated Statements of Income - USD ($)	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues
Net premiums earned	$ 173,300,000	$ 179,000,000	$ 522,800,000	$ 508,600,000
Net investment income	17,900,000	18,500,000	54,100,000	53,800,000
Net realized gains on investments	1,600,000	2,000,000	9,100,000	5,100,000
Other income	0	0	600,000	100,000
Total revenues	192,800,000	199,500,000	586,600,000	567,600,000
Expenses
Losses and loss adjustment expenses	109,000,000	115,800,000	328,000,000	323,500,000
Commission expense	21,300,000	21,000,000	63,500,000	62,600,000
Underwriting and other operating expenses	31,700,000	31,600,000	101,600,000	97,600,000
Interest expense	400,000	700,000	1,200,000	2,100,000
Total expenses	162,400,000	169,100,000	494,300,000	485,800,000
Net income before income taxes	30,400,000	30,400,000	92,300,000	81,800,000
Income tax expense	7,800,000	5,900,000	21,100,000	14,100,000
Net income	22,600,000	24,500,000	71,200,000	67,700,000
Comprehensive income
Unrealized (losses) gains during the period (net of tax (benefit) expense of $(2,300) and $(5,900) for the three months ended September 30, 2016 and 2015, respectively, and $21,500 and $(14,200) for the nine months ended September 30, 2016 and 2015, respectively)	(4,200,000)	(11,100,000)	39,900,000	(26,500,000)
Reclassification adjustment for realized gains in net income (net of taxes of $600 and $700 for the three months ended September 30, 2016 and 2015, respectively, and $3,200 and $1,800 for the nine months ended September 30, 2016 and 2015, respectively)	(1,000,000)	(1,300,000)	(5,900,000)	(3,300,000)
Other comprehensive (loss) income, net of tax	(5,200,000)	(12,400,000)	34,000,000	(29,800,000)
Total comprehensive income	17,400,000	12,100,000	105,200,000	37,900,000
Net realized gains on investments
Net realized gains on investments before credit related impairments	1,600,000	2,100,000	14,400,000	5,300,000
Other than temporary impairment recognized in earnings	0	(100,000)	(5,300,000)	(200,000)
Net realized gains on investments	$ 1,600,000	$ 2,000,000	$ 9,100,000	$ 5,100,000
Earnings per common share (Note 11):
Basic	$ 0.70	$ 0.76	$ 2.19	$ 2.12
Diluted	0.69	0.75	2.16	2.08
Cash dividends declared per common share	$ 0.09	$ 0.06	$ 0.27	$ 0.18

Conolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement Parenthetical [Abstract]
Other comprehensive income (loss), unrealized holding gain (loss) on securities arising during period, tax	$ (2,300)	$ (5,900)	$ 21,500	$ (14,200)
Other comprehensive income (loss), reclassification adjustment for sale of securities included in net income, tax	$ 600	$ 700	$ 3,200	$ 1,800

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities
Net income	$ 71,200	$ 67,700
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6,400	5,900
Stock-based compensation	4,300	3,200
Amortization of premium on investments, net	11,400	9,500
Allowance for doubtful accounts	(1,500)	3,700
Deferred income tax expense	8,500	4,500
Realized gains on investments, net	(9,100)	(5,100)
Excess tax benefits from stock-based compensation	0	(800)
Other	(200)	(100)
Change in operating assets and liabilities:
Premiums receivable	(14,500)	(14,300)
Reinsurance recoverable for paid and unpaid losses	36,100	38,000
Federal income taxes	3,000	2,200
Unpaid losses and loss adjustment expenses	17,500	11,800
Unearned premiums	16,700	16,300
Accounts payable, accrued expenses and other liabilities	(6,200)	2,400
Deferred reinsurance gain—LPT Agreement	(11,700)	(14,600)
Contingent commission receivable—LPT Agreement	(1,900)	(2,800)
Other	2,000	(9,900)
Net cash provided by operating activities	97,000	94,000
Investing activities
Purchase of fixed maturity securities	(325,200)	(365,600)
Purchase of equity securities	(38,800)	(77,700)
Purchase of short-term investments	(8,000)	(18,500)
Proceeds from sale of fixed maturity securities	111,700	87,000
Proceeds from sale of equity securities	70,200	21,400
Proceeds from maturities and redemptions of investments	145,100	214,000
Capital expenditures	(3,900)	(7,400)
Change in restricted cash and cash equivalents	(200)	7,700
Net cash used in investing activities	(49,100)	(139,100)
Financing activities
Acquisition of treasury stock	(18,600)	0
Cash transactions related to stock-based compensation	7,100	3,100
Dividends paid to stockholders	(8,800)	(5,800)
Payments on notes payable and capital leases	(100)	(400)
Excess tax benefits from stock-based compensation, financing activities	0	800
Net cash used in financing activities	(20,400)	(2,300)
Net increase (decrease) in cash and cash equivalents	27,500	(47,400)
Cash and cash equivalents at the beginning of the period	56,600	103,600
Cash and cash equivalents at the end of the period	$ 84,100	$ 56,200

Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2016
Basis of Presentation [Abstract]
Basis of Presentation	Basis of Presentation and Summary of Operations Employers Holdings, Inc. (EHI) is a Nevada holding company. Through its wholly owned insurance subsidiaries, Employers Insurance Company of Nevada (EICN), Employers Compensation Insurance Company (ECIC), Employers Preferred Insurance Company (EPIC), and Employers Assurance Company (EAC), EHI is engaged in the commercial property and casualty insurance industry, specializing in workers' compensation products and services. Unless otherwise indicated, all references to the “Company” refer to EHI, together with its subsidiaries. The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities Exchange Act of 1934, as amended. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal, recurring adjustments) necessary for a fair presentation of the Company’s consolidated financial position and results of operations for the periods presented have been included. The results of operations for an interim period are not necessarily indicative of the results for an entire year. These financial statements have been prepared consistent with the accounting policies described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015. The Company considers an operating segment to be any component of its business whose operating results are regularly reviewed by the Company’s chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance based on discrete financial information. Currently, the Company has one operating segment, workers’ compensation insurance and related services. Use of Estimates The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. As a result, actual results could differ from these estimates. The most significant areas that require management judgment are the estimate of unpaid losses and loss adjustment expenses (LAE), evaluation of reinsurance recoverables, recognition of premium revenue, deferred income taxes, and investments. Reclassifications Certain prior period information has been reclassified to conform to the current period presentation.

Changes in Estimates Level 1 (Notes)

9 Months Ended

Sep. 30, 2016

Changes in Estimates [Abstract]

Change in Estimates

The Company reduced its estimated reserves ceded under the Loss Portfolio Transfer Agreement (LPT Reserve Adjustment) as a result of the determination that an adjustment was necessary to reflect observed favorable paid loss trends during the second quarter of 2016. The following table shows the financial statement impact related to the reduction in estimated reserves ceded under the Loss Portfolio Transfer Agreement (LPT Agreement).



	Nine Months Ended
	September 30, 2016
	(in millions, except per share data)
Change in estimated reserves ceded under the LPT Agreement	$	(5.0	)
Cumulative adjustment to the Deferred Gain⁽¹⁾	(3.1		)
Net income impact of change in estimate	3.1
EPS impact of change in estimate
Basic	0.10
Diluted	0.09


(1)	The cumulative adjustment to the Deferred reinsurance gain–LPT Agreement (Deferred Gain) was also recognized in losses and LAE incurred in the Consolidated Statement of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised reserves been recognized at the inception of the LPT Agreement.

The Company increased its estimate of contingent commission receivable – LPT Agreement (LPT Contingent Commission Adjustment) as a result of the determination that an adjustment was necessary to reflect observed favorable paid loss trends during the second quarter of 2016. The following table shows the financial statement impact related to these changes in estimates.



	Nine Months Ended
	September 30, 2016
	(in millions, except per share data)
Change in estimate of contingent commission receivable – LPT Agreement	$	1.9
Cumulative adjustment to the Deferred Gain⁽¹⁾	(1.8		)
Net income impact of change in estimate	1.8
EPS impact of change in estimate
Basic	0.06
Diluted	0.05


(1)	The cumulative adjustment to the Deferred Gain was also recognized in losses and LAE incurred in the Consolidated Statement of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised reserves been recognized at the inception of the LPT Agreement.

- Definition

The entire disclosure for reporting accounting changes and error corrections. It includes the conveyance of information necessary for a user of the Company's financial information to understand all aspects and required disclosure information concerning all changes and error corrections reported in the Company's financial statements for the period.

+ References + Details

New Accounting Standards Level 1 (Notes)

9 Months Ended

Sep. 30, 2016

New Accounting Standards [Abstract]

New Accounting Standards

Recently Adopted Accounting Standards

In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) Number 2016-09, Compensation - Stock Compensation (Topic 718). This update simplifies several aspects of the accounting for share-based payment award transactions, including income taxes and classification of awards on the balance sheet and on the statement of cash flows. This update becomes effective for annual reporting periods, including interim periods within those annual periods, beginning after December 15, 2016 and early adoption is permitted. The Company elected to early adopt this standard in the quarter ended September 30, 2016 with an effective date of January 1, 2016. Adoption of this standard had the following impacts on the Company's consolidated financial statements:

•

Consolidated Statements of Comprehensive Income – This standard requires that the tax effects of stock-based compensation be recognized in the income tax expense. Net tax benefits related to stock-based compensation of $0.1 million and $1.4 million were recognized as reductions to Income tax expense and increases to Net income in the Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2016, respectively. These changes had no impact on the Company's basic and diluted earnings per share for the three months ended September 30, 2016, but increased basic and diluted earnings per share by $0.04 for the nine months ended September 30, 2016. This standard also requires that assumed proceeds under the treasury stock method be modified to exclude the excess tax benefits that would have been recognized in Additional paid-in capital. These changes were applied on a prospective basis.

•

Consolidated Statements of Cash Flows – This standard requires that the excess tax benefits from stock-based compensation be reported as cash flows from operating activities rather than the previous requirement to present the excess tax benefits from stock-based compensation as an inflow from financing activities and an outflow from operating activities. This update resulted in a change in presentation that was applied on a prospective basis and prior periods have not been adjusted.

This standard allows the Company to make a policy election as to whether it will include an estimate of stock-based compensation awards expected to be forfeited or whether it will account for forfeitures as they occur. The Company has elected to continue to estimate forfeitures in the computation of its stock-based compensation, consistent with previous guidance, and had no impact on the Company's consolidated financial statements.

Finally, this standard allows the Company to withhold an amount in excess of the supplemental rate from an employee’s stock-based compensation for federal tax withholding purposes without triggering liability accounting. It also clarifies that all cash payments made to tax authorities on an employee’s behalf should be presented as cash flows from financing activities in the Consolidated Statements of Cash Flows. This update related to tax withholding and presentation of cash flows had no impact on the Company's consolidated financial statements.

Recently Issued Accounting Standards – Not Yet Adopted

In January 2016, the FASB issued ASU Number 2016-01, Financial Instruments - Overall (Subtopic 825-10). This update replaces the guidance to classify equity securities with readily determinable fair values into different categories (trading or available-for-sale) and requires equity securities to be measured at fair value with changes in fair value recognized through net income. Additionally, this update eliminates the method and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost. It requires financial instruments to be measured at fair value using the exit price notion. Furthermore, this update clarifies that an evaluation of deferred tax assets related to available-for-sale securities is needed, in combination with an evaluation of other deferred tax assets, to determine if a valuation allowance is required. This update becomes effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. This update will result in a reclassification adjustment, net of tax, to retained earnings from accumulated other comprehensive income, which will be determined based on the fair value of securities at the effective date of adoption.

In February 2016, the FASB issued ASU Number 2016-02, Leases (Topic 842). This update provides guidance on a new lessee model that includes the recognition of assets and liabilities arising from lease transactions on the balance sheet. Additionally, the update provides clarity on the definition of a lease and the distinction between finance and operating leases. Furthermore, the update requires certain qualitative and quantitative disclosures pertaining to the amounts recorded in the financial statements. This update becomes effective for annual reporting periods, including interim periods within those annual periods, beginning after December 15, 2018 and early adoption is permitted. The Company has not yet estimated the full impact that the adoption will have on its consolidated financial condition and results of operations.

In June 2016, the FASB issued ASU Number 2016-13, Financial Instruments - Credit Losses (Topic 326). This update replaces the incurred loss impairment methodology for recognizing credit losses on financial instruments with a methodology that reflects an entity's current estimate of all expected credit losses. This update requires financial assets measured at amortized cost to be presented net of an allowance for credit losses. Additionally, this update requires credit losses on available-for-sale debt securities to be presented as an allowance rather than as a write-down, allowing an entity to also record reversals of credit losses in current period net income. This update becomes effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted as of fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company has not yet estimated the full impact that the adoption will have on its consolidated financial condition and results of operations.

In August 2016, the FASB issued ASU Number 2016-15, Statement of Cash Flows (Topic 230). This update provides guidance and clarification on eight specific cash flow issues due to diversity in practice of how certain cash receipts and cash payments are presented and classified in the statement of cash flows. The cash flow issues affected are debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments or other debt instruments with coupon rates that are insignificant in relation to the effective interest rate of the borrowing, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies, distributions received from equity method investees, beneficial interest in securitization transactions, and separately identifiable cash flows and application of the predominance principle. This update becomes effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company has not yet estimated the full impact that the adoption will have on its consolidated financial condition and results of operations.

- Definition

The entire disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6507316

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Direct Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=66092750

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22583-107794

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Indirect Effects of a Change in Accounting Principle
-URI http://asc.fasb.org/extlink&oid=6515603

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22580-107794

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.10-01.(b)(6))
-URI http://asc.fasb.org/extlink&oid=27015980&loc=d3e46468-122699

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Accounting Change
-URI http://asc.fasb.org/extlink&oid=6503790

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Retrospective Application
-URI http://asc.fasb.org/extlink&oid=6523989

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=68064558&loc=d3e765-108305

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=68064558&loc=d3e725-108305

+ Details

Fair Value of Financial Instruments

9 Months Ended

Sep. 30, 2016

Fair Value of Financial Instruments [Abstract]

Fair Value of Financial Instruments

The carrying value and the estimated fair value of the Company’s financial instruments were as follows:



	September 30, 2016				December 31, 2015
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
	(in millions)
Financial assets
Investments	$	2,582.4	$	2,582.4	$	2,487.2	$	2,487.2
Cash and cash equivalents	84.1		84.1		56.6		56.6
Restricted cash and cash equivalents	2.7		2.7		2.5		2.5
Financial liabilities
Notes payable	$	32.0	$	35.0	$	32.0	$	36.6

Assets and liabilities recorded at fair value on the consolidated balance sheets are categorized based upon the levels of judgment associated with the inputs used to measure their fair value. Level inputs are defined as follows:


•	Level 1 - Inputs are unadjusted quoted market prices for identical assets or liabilities in active markets at the measurement date.


•	Level 2 - Inputs other than Level 1 prices that are observable for similar assets or liabilities through corroboration with market data at the measurement date.


•	Level 3 - Inputs that are unobservable that reflect management's best estimate of what willing market participants would use in pricing the assets or liabilities at the measurement date.

Fair values of available-for-sale fixed maturity and equity securities are based on quoted market prices, where available. If quoted market prices and an estimate determined by using objectively verifiable information are unavailable, the Company produces an estimate of fair value based on internally developed valuation techniques, which, depending on the level of observable market inputs, will render the fair value estimate as Level 2 or Level 3. The Company bases all of its estimates of fair value for assets on the bid price, as it represents what a third-party market participant would be willing to pay in an arm's length transaction.

These methods of valuation will only produce an estimate of fair value if there is objectively verifiable information to produce a valuation. If objectively verifiable information is not available, the Company would be required to produce an estimate of fair value using some of the same methodologies, making assumptions for market-based inputs that are unavailable.

The Company's estimates of fair value for financial liabilities are based on the interest rates for notes with similar durations to discount the projection of future payments on notes payable. The fair value measurements for notes payable have been determined to be Level 2.

The following table presents the items on the accompanying Consolidated Balance Sheets that are stated at fair value and the corresponding fair value measurements.



	September 30, 2016						December 31, 2015
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
	(in millions)
Fixed maturity securities
U.S. Treasuries	$	—	$	127.9	$	—	$	—	$	120.2	$	—
U.S. Agencies	—		13.0		—		—		24.4		—
States and municipalities	—		897.2		—		—		854.5		—
Corporate securities	—		996.5		—		—		925.3		—
Residential mortgage-backed securities	—		235.0		—		—		237.9		—
Commercial mortgage-backed securities	—		86.5		—		—		80.3		—
Asset-backed securities	—		27.8		—		—		45.9		—
Total fixed maturity securities	$	—	$	2,383.9	$	—	$	—	$	2,288.5	$	—
Equity securities
Corporate equity securities	$	179.6	$	—	$	—	$	198.7	$	—	$	—
Federal Home Loan Bank stock	—		—		4.9		—		—		—
Total equity securities	$	179.6	$	—	$	4.9	$	198.7	$	—	$	—
Short-term investments	$	—	$	14.0	$	—	$	—	$	—	$	—

The following table provides a reconciliation of the beginning and ending balances that are measured using Level 3 inputs for the nine months ended September 30, 2016.



	Equity Securities
	(in millions)
Beginning balance, January 1, 2016	$	—
Purchases	4.9
Ending balance, September 30, 2016	$	4.9

Each of the Company's insurance operating subsidiaries is a member of the Federal Home Loan Bank (FHLB) of San Francisco. Members are required to purchase stock in the FHLB in addition to maintaining collateral deposits that back any funds advanced. Investment in FHLB stock is recorded at cost, as purchases and sales of these securities are at par value with the issuer. The stock is considered a restricted security and is periodically evaluated for impairment based on the ultimate recovery of par value. Due to the nature of FHLB stock, its carrying value approximates fair value.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Investments

9 Months Ended

Sep. 30, 2016

Investments [Abstract]

Investments

The cost or amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the Company’s investments were as follows:



	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in millions)
At September 30, 2016
Fixed maturity securities
U.S. Treasuries	$	122.9	$	5.0	$	—		$	127.9
U.S. Agencies	11.9		1.1		—			13.0
States and municipalities	842.9		54.6		(0.3		)	897.2
Corporate securities	957.9		39.4		(0.8		)	996.5
Residential mortgage-backed securities	225.3		9.7		—			235.0
Commercial mortgage-backed securities	84.5		2.0		—			86.5
Asset-backed securities	27.7		0.1		—			27.8
Total fixed maturity securities	2,273.1		111.9		(1.1		)	2,383.9
Equity securities
Corporate equity securities	109.5		71.4		(1.3		)	179.6
Federal Home Loan Bank stock	4.9		—		—			4.9
Total equity securities	114.4		71.4		(1.3		)	184.5
Short-term investments	14.0		—		—			14.0
Total investments	$	2,401.5	$	183.3	$	(2.4	)	$	2,582.4



At December 31, 2015
Fixed maturity securities
U.S. Treasuries	$	116.4	$	3.9	$	(0.1	)	$	120.2
U.S. Agencies	23.0		1.4		—			24.4
States and municipalities	809.4		45.1		—			854.5
Corporate securities	913.4		19.9		(8.0		)	925.3
Residential mortgage-backed securities	231.8		7.1		(1.0		)	237.9
Commercial mortgage-backed securities	81.1		0.2		(1.0		)	80.3
Asset-backed securities	46.0		—		(0.1		)	45.9
Total fixed maturity securities	2,221.1		77.6		(10.2		)	2,288.5
Equity securities
Corporate equity securities	137.5		65.8		(4.6		)	198.7
Total equity securities	137.5		65.8		(4.6		)	198.7
Total investments	$	2,358.6	$	143.4	$	(14.8	)	$	2,487.2

The amortized cost and estimated fair value of fixed maturity securities at September 30, 2016, by contractual maturity, are shown below. Expected maturities differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.



	Amortized Cost		Estimated Fair Value
	(in millions)
Due in one year or less	$	149.6	$	151.2
Due after one year through five years	920.1		958.6
Due after five years through ten years	600.6		641.2
Due after ten years	265.3		283.6
Mortgage and asset-backed securities	337.5		349.3
Total	$	2,273.1	$	2,383.9

The following is a summary of investments that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 months or greater as of September 30, 2016 and December 31, 2015.



	September 30, 2016						December 31, 2015
	Estimated Fair Value		Gross Unrealized Losses			Number of Issues	Estimated Fair Value		Gross Unrealized Losses			Number of Issues
	(in millions, except number of issues data)
Less than 12 months:
Fixed maturity securities
U.S. Treasuries	$	—	$	—		—	$	27.4	$	(0.1	)	20
States and municipalities	44.3		(0.3		)	12	—		—			—
Corporate securities	—		—			—	328.4		(4.7		)	122
Residential mortgage-backed securities	—		—			—	50.5		(0.8		)	24
Commercial mortgage-backed securities	—		—			—	51.5		(1.0		)	22
Asset-backed securities	—		—			—	34.1		—			27
Total fixed maturity securities	44.3		(0.3		)	12	491.9		(6.6		)	215
Equity securities	13.5		(1.1		)	30	35.8		(4.6		)	45
Total less than 12 months	$	57.8	$	(1.4	)	42	$	527.7	$	(11.2	)	260

12 months or greater:
Fixed maturity securities
Corporate securities	$	24.4	$	(0.8	)	10	$	34.6	$	(3.3	)	15
Residential mortgage-backed securities	—		—			—	7.1		(0.2		)	25
Asset-backed securities	—		—			—	11.1		(0.1		)	4
Total fixed maturity securities	24.4		(0.8		)	10	52.8		(3.6		)	44
Equity securities	2.2		(0.2		)	7	—		—			—
Total 12 months or greater	$	26.6	$	(1.0	)	17	$	52.8	$	(3.6	)	44

Total available-for-sale:
Fixed maturity securities
U.S. Treasuries	$	—	$	—		—	$	27.4	$	(0.1	)	20
States and municipalities	44.3		(0.3		)	12	—		—			—
Corporate securities	24.4		(0.8		)	10	363.0		(8.0		)	137
Residential mortgage-backed securities	—		—			—	57.6		(1.0		)	49
Commercial mortgage-backed securities	—		—			—	51.5		(1.0		)	22
Asset-backed securities	—		—			—	45.2		(0.1		)	31
Total fixed maturity securities	68.7		(1.1		)	22	544.7		(10.2		)	259
Equity securities	15.7		(1.3		)	37	35.8		(4.6		)	45
Total available-for-sale	$	84.4	$	(2.4	)	59	$	580.5	$	(14.8	)	304

Based on reviews of the fixed maturity securities, the Company determined that unrealized losses for the nine months ended September 30, 2016 were primarily the result of changes in prevailing interest rates and not the credit quality of the issuers. The fixed maturity securities whose total fair value was less than amortized cost were not determined to be other-than-temporarily impaired given the severity and duration of the impairment, the credit quality of the issuers, the Company’s intent to not sell the securities, and a determination that it is not more likely than not that the Company will be required to sell the securities until fair value recovers to above amortized cost, or principal value upon maturity.

Based on reviews of the equity securities, the Company recognized a total impairment of $5.3 million in the fair value of 32 equity securities for the nine months ended September 30, 2016, as a result of the Company's intent to sell and/or the severity and duration of the change in fair value of the securities. The remaining unrealized losses on equity securities were not considered to be other-than-temporary due to the financial condition and near-term prospects of the issuers. The other-than-temporary impairment of equity securities was primarily due to the Company's intent to sell certain securities and the downturn in the energy sector that continued through the first quarter of 2016.

Net realized gains on investments and the change in unrealized gains (losses) on fixed maturity and equity securities are determined on a specific-identification basis and were as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2016			2015			2016			2015
	(in millions)
Net realized gains on investments
Fixed maturity securities
Gross gains	$	—		$	0.2		$	1.3		$	0.5
Gross losses	—			(0.2		)	(0.5		)	(0.4		)
Net realized gains on fixed maturity securities	$	—		$	—		$	0.8		$	0.1
Equity securities
Gross gains	$	1.6		$	2.2		$	14.3		$	5.6
Gross losses	—			(0.2		)	(6.0		)	(0.6		)
Net realized gains on equity securities	$	1.6		$	2.0		$	8.3		$	5.0
Total	$	1.6		$	2.0		$	9.1		$	5.1

Change in unrealized gains (losses)
Fixed maturity securities	$	(10.2	)	$	8.0		$	43.4		$	(11.0	)
Equity securities	2.1			(27.0		)	8.9			(34.8		)
Total	$	(8.1	)	$	(19.0	)	$	52.3		$	(45.8	)

Net investment income was as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2016			2015			2016			2015
	(in millions)
Fixed maturity securities	$	16.9		$	17.3		$	50.8		$	51.6
Equity securities	1.7			1.7			5.4			4.0
Cash equivalents and restricted cash	0.1			0.1			0.2			0.1
Gross investment income	18.7			19.1			56.4			55.7
Investment expenses	(0.8		)	(0.6		)	(2.3		)	(1.9		)
Net investment income	$	17.9		$	18.5		$	54.1		$	53.8

The Company is required by various state laws and regulations to keep securities or letters of credit in depository accounts with certain states in which it does business. Securities having a fair value of $1.0 billion and $881.2 million were on deposit as of September 30, 2016 and December 31, 2015, respectively. These laws and regulations govern not only the amount, but also the types of securities that are eligible for deposit.

Certain reinsurance contracts require Company funds to be held in trust for the benefit of the ceding reinsurer to secure the outstanding liabilities assumed by the Company. The fair value of fixed maturity securities and restricted cash and cash equivalents held in trust for the benefit of ceding reinsurers was $27.7 million and $32.7 million at September 30, 2016 and December 31, 2015, respectively.

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Income Taxes

9 Months Ended

Sep. 30, 2016

Income Taxes [Abstract]

Income Taxes

Income tax expense for interim periods is measured using an estimated effective tax rate for the annual period. The following is a reconciliation of the federal statutory income tax rate to the Company’s effective tax rates for the periods presented.



	Nine Months Ended
	September 30,
	2016		2015
Statutory tax rate	35.0	%	35.0	%
Dividends received deduction and tax-exempt interest	(7.1	)	(7.6	)
LPT deferred gain amortization	(3.3	)	(4.3	)
LPT reserve adjustment	(1.5	)	(2.0	)
Pre-privatization reserve adjustment, excluding LPT	—		(4.6	)
Stock based compensation	(1.1	)	—
Other	0.9		0.7
Effective tax rate	22.9	%	17.2	%

Liability for Unpaid Losses and Loss Adjustment Expenses

9 Months Ended

Sep. 30, 2016

Liability for Unpaid Losses and Loss Adjustment Expenses [Abstract]

Liability for Unpaid Losses and Loss Adjustment Expenses

The following table represents a reconciliation of changes in the liability for unpaid losses and LAE.



	Nine Months Ended
	September 30,
	2016			2015
	(in millions)
Unpaid losses and LAE, gross of reinsurance, at beginning of period	$	2,347.5		$	2,369.7
Less reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	628.2			669.5
Net unpaid losses and LAE at beginning of period	1,719.3			1,700.2
Losses and LAE, net of reinsurance, incurred during the period related to:
Current period	343.1			339.7
Prior periods	(1.5		)	1.3
Total net losses and LAE incurred during the period	341.6			341.0
Paid losses and LAE, net of reinsurance, related to:
Current period	42.8			43.9
Prior periods	279.6			274.2
Total net paid losses and LAE during the period	322.4			318.1
Ending unpaid losses and LAE, net of reinsurance	1,738.5			1,723.1
Reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	591.5			634.8
Unpaid losses and LAE, gross of reinsurance, at end of period	$	2,330.0		$	2,357.9

Total net losses and LAE included in the above table excludes the impact of the aggregate of amortization of the deferred reinsurance gain—LPT Agreement, LPT Reserve Adjustments, and LPT Contingent Commission Adjustments, which totaled $13.6 million and $17.5 million for the nine months ended September 30, 2016 and 2015, respectively (Note 8).

The changes in the estimates of incurred losses and LAE attributable to insured events for prior periods were related to the Company's assigned risk business.

LPT Agreement	9 Months Ended
LPT Agreement	Sep. 30, 2016
LPT Agreement [Abstract]
LPT Agreement	LPT Agreement The Company is party to a 100% quota share retroactive reinsurance agreement (LPT Agreement) under which $1.5 billion in liabilities for losses and LAE related to claims incurred by EICN prior to July 1, 1995 were reinsured for consideration of $775.0 million. The LPT Agreement provides coverage up to $2.0 billion. The initial Deferred Gain resulting from the LPT Agreement was recorded as a liability in the accompanying consolidated balance sheets as Deferred reinsurance gain–LPT Agreement. The Company is also entitled to receive a contingent profit commission under the LPT Agreement. The contingent profit commission is an amount based on the favorable difference between actual paid losses and LAE and expected paid losses and LAE as established in the LPT Agreement. The Company records its estimate of contingent profit commission in the accompanying consolidated balance sheets as Contingent commission receivable–LPT Agreement and a corresponding liability is recorded in the accompanying consolidated balance sheets in Deferred reinsurance gain–LPT Agreement. The Deferred Gain is being amortized using the recovery method. Amortization is determined by the proportion of actual reinsurance recoveries to total estimated recoveries over the life of the LPT Agreement, except for the contingent profit commission, which is amortized through June 30, 2024, the date through which the Company is entitled to receive a contingent profit commission under the LPT Agreement. The amortization is recorded in losses and LAE incurred in the accompanying consolidated statements of comprehensive income. Any adjustments to the Deferred Gain are recorded in losses and LAE incurred in the accompanying consolidated statements of comprehensive income. The Company amortized $8.7 million and $8.5 million of the Deferred Gain for the nine months ended September 30, 2016 and 2015, respectively. Additionally, the Deferred Gain was reduced by $3.1 million and $6.4 million for the nine months ended September 30, 2016 and 2015, respectively, due to favorable LPT Reserve Adjustments and by $1.8 million and $2.6 million for the nine months ended September 30, 2016 and 2015, respectively, due to favorable LPT Contingent Commission Adjustments. The remaining Deferred Gain was $177.8 million and $189.5 million as of September 30, 2016 and December 31, 2015, respectively. The estimated remaining liabilities subject to the LPT Agreement were $472.3 million and $498.0 million as of September 30, 2016 and December 31, 2015, respectively. Losses and LAE paid with respect to the LPT Agreement totaled $715.9 million and $695.2 million from inception through September 30, 2016 and December 31, 2015, respectively.

Accumulated Other Comprehensive Income

9 Months Ended

Sep. 30, 2016

Accumulated Other Comprehensive Income [Abstract]

Accumulated Other Comprehensive Income, Net

Accumulated Other Comprehensive Income, net

Accumulated other comprehensive income, net, is comprised of unrealized gains on investments classified as available-for-sale, net of deferred tax expense. The following table summarizes the components of accumulated other comprehensive income, net:



	September 30, 2016			December 31, 2015
	(in millions)
Net unrealized gain on investments, before taxes	$	180.9		$	128.6
Deferred tax expense on net unrealized gains	(63.3		)	(45.0		)
Total accumulated other comprehensive income, net	$	117.6		$	83.6

- Definition

The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=66004124&loc=SL7669619-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e640-108580

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e716-108580

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e709-108580

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e637-108580

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e681-108580

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Reclassification Adjustments
-URI http://asc.fasb.org/extlink&oid=6522872

+ Details

Stock-Based Compensation

9 Months Ended

Sep. 30, 2016

Stock-Based Compensation [Abstract]

Stock-Based compensation

Stock-Based Compensation

The Company awarded stock options, restricted stock units (RSUs) and performance share units (PSUs) to certain officers of the Company as follows:



	Number Awarded	Weighted Average Fair Value on Date of Grant		Weighted Average Exercise Price		Aggregate Fair Value on Date of Grant
						(in millions)
March 2016
Stock options⁽¹⁾	67,431	$	8.38	$	27.72	$	0.6
RSUs⁽¹⁾	80,816	27.72		—		2.2
PSUs⁽²⁾	97,236	27.72		—		2.7

May 2016
RSUs⁽¹⁾	17,892	30.18		—		0.5

(1)

The stock options and RSUs awarded in March 2016 were awarded to certain officers of the Company and vest 25% on March 15, 2017, and each of the subsequent three anniversaries of that date. The stock options and RSUs are subject to accelerated vesting in certain circumstances, including but not limited to: death, disability, retirement, or in connection with change of control of the Company. The stock options expire seven years from the date of grant.

The RSUs awarded in May 2016 were awarded to non-employee Directors of the Company and have a service vesting period of one year from the date of grant.


(2)	The PSUs awarded in March 2016 were awarded to certain officers of the Company and have a performance period of two years followed by an additional one year vesting period. The PSU awards are subject to certain performance goals with payouts that range from 0% to 200% of the target awards. The value shown in the table represents the aggregate number of PSUs awarded at the target level.

A total of 484,829 and 463,466 stock options were exercised during the nine months ended September 30, 2016 and the year ended December 31, 2015, respectively.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Earnings Per Share

9 Months Ended

Sep. 30, 2016

Earnings Per Share [Abstract]

Earnings Per Share

Basic earnings per share excludes dilution and is computed by dividing income applicable to stockholders by the weighted average number of shares outstanding for the period. Diluted earnings per share reflects the potential dilutive impact of all convertible securities on earnings per share. Diluted earnings per share includes shares assumed issued under the “treasury stock method,” which reflects the potential dilution that would occur if outstanding RSUs and PSUs had vested and options were to be exercised. The following table presents the net income and the weighted average number of shares outstanding used in the earnings per common share calculations.



	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2016		2015		2016		2015
	(in millions, except share data)
Net income available to stockholders—basic and diluted	$	22.6	$	24.5	$	71.2	$	67.7
Weighted average number of shares outstanding—basic	32,449,617		32,184,143		32,497,478		32,000,142
Effect of dilutive securities:
PSUs	238,633		72,612		196,898		161,335
Stock options	192,827		245,708		251,068		289,348
RSUs	67,885		21,877		70,429		47,268
Dilutive potential shares	499,345		340,197		518,395		497,951
Weighted average number of shares outstanding—diluted	32,948,962		32,524,340		33,015,873		32,498,093

Diluted earnings per share excludes outstanding options and other common stock equivalents in periods where the inclusion of such options and common stock equivalents would be anti-dilutive. The following table presents options, PSUs, and RSUs that were excluded from diluted earnings per share.



	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2016	2015	2016	2015
Options excluded as the exercise price was greater than the average market price	—	80,800	—	26,933
Options, PSUs and RSUs excluded under the treasury method as the potential proceeds on settlement or exercise price were greater than the value of shares acquired	67,431	336,006	98,021	316,273

Changes in Estimates (Tables)

9 Months Ended

Sep. 30, 2016

Changes in Estimates [Abstract]

Change due to estmated reserves ceded under the LPT Agreement table

The following table shows the financial statement impact related to the reduction in estimated reserves ceded under the Loss Portfolio Transfer Agreement (LPT Agreement).



	Nine Months Ended
	September 30, 2016
	(in millions, except per share data)
Change in estimated reserves ceded under the LPT Agreement	$	(5.0	)
Cumulative adjustment to the Deferred Gain⁽¹⁾	(3.1		)
Net income impact of change in estimate	3.1
EPS impact of change in estimate
Basic	0.10
Diluted	0.09


(1)	The cumulative adjustment to the Deferred reinsurance gain–LPT Agreement (Deferred Gain) was also recognized in losses and LAE incurred in the Consolidated Statement of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised reserves been recognized at the inception of the LPT Agreement.

Change to contingent profit commission table

The following table shows the financial statement impact related to these changes in estimates.



	Nine Months Ended
	September 30, 2016
	(in millions, except per share data)
Change in estimate of contingent commission receivable – LPT Agreement	$	1.9
Cumulative adjustment to the Deferred Gain⁽¹⁾	(1.8		)
Net income impact of change in estimate	1.8
EPS impact of change in estimate
Basic	0.06
Diluted	0.05


(1)	The cumulative adjustment to the Deferred Gain was also recognized in losses and LAE incurred in the Consolidated Statement of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised reserves been recognized at the inception of the LPT Agreement.

Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2016

Fair Value of Financial Instruments [Abstract]

Estimated fair value of financial instruments table

The carrying value and the estimated fair value of the Company’s financial instruments were as follows:



	September 30, 2016				December 31, 2015
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
	(in millions)
Financial assets
Investments	$	2,582.4	$	2,582.4	$	2,487.2	$	2,487.2
Cash and cash equivalents	84.1		84.1		56.6		56.6
Restricted cash and cash equivalents	2.7		2.7		2.5		2.5
Financial liabilities
Notes payable	$	32.0	$	35.0	$	32.0	$	36.6

Fair value, assets and liabilities measured on recurring basis table

The following table presents the items on the accompanying Consolidated Balance Sheets that are stated at fair value and the corresponding fair value measurements.



	September 30, 2016						December 31, 2015
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
	(in millions)
Fixed maturity securities
U.S. Treasuries	$	—	$	127.9	$	—	$	—	$	120.2	$	—
U.S. Agencies	—		13.0		—		—		24.4		—
States and municipalities	—		897.2		—		—		854.5		—
Corporate securities	—		996.5		—		—		925.3		—
Residential mortgage-backed securities	—		235.0		—		—		237.9		—
Commercial mortgage-backed securities	—		86.5		—		—		80.3		—
Asset-backed securities	—		27.8		—		—		45.9		—
Total fixed maturity securities	$	—	$	2,383.9	$	—	$	—	$	2,288.5	$	—
Equity securities
Corporate equity securities	$	179.6	$	—	$	—	$	198.7	$	—	$	—
Federal Home Loan Bank stock	—		—		4.9		—		—		—
Total equity securities	$	179.6	$	—	$	4.9	$	198.7	$	—	$	—
Short-term investments	$	—	$	14.0	$	—	$	—	$	—	$	—

Fair value, assets measured on recurring basis, unobservable input reconciliation table

The following table provides a reconciliation of the beginning and ending balances that are measured using Level 3 inputs for the nine months ended September 30, 2016.



	Equity Securities
	(in millions)
Beginning balance, January 1, 2016	$	—
Purchases	4.9
Ending balance, September 30, 2016	$	4.9

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Investments (Tables)

9 Months Ended

Sep. 30, 2016

Investments [Abstract]

Available-for-sale securities table

The cost or amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the Company’s investments were as follows:



	Cost or Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(in millions)
At September 30, 2016
Fixed maturity securities
U.S. Treasuries	$	122.9	$	5.0	$	—		$	127.9
U.S. Agencies	11.9		1.1		—			13.0
States and municipalities	842.9		54.6		(0.3		)	897.2
Corporate securities	957.9		39.4		(0.8		)	996.5
Residential mortgage-backed securities	225.3		9.7		—			235.0
Commercial mortgage-backed securities	84.5		2.0		—			86.5
Asset-backed securities	27.7		0.1		—			27.8
Total fixed maturity securities	2,273.1		111.9		(1.1		)	2,383.9
Equity securities
Corporate equity securities	109.5		71.4		(1.3		)	179.6
Federal Home Loan Bank stock	4.9		—		—			4.9
Total equity securities	114.4		71.4		(1.3		)	184.5
Short-term investments	14.0		—		—			14.0
Total investments	$	2,401.5	$	183.3	$	(2.4	)	$	2,582.4



At December 31, 2015
Fixed maturity securities
U.S. Treasuries	$	116.4	$	3.9	$	(0.1	)	$	120.2
U.S. Agencies	23.0		1.4		—			24.4
States and municipalities	809.4		45.1		—			854.5
Corporate securities	913.4		19.9		(8.0		)	925.3
Residential mortgage-backed securities	231.8		7.1		(1.0		)	237.9
Commercial mortgage-backed securities	81.1		0.2		(1.0		)	80.3
Asset-backed securities	46.0		—		(0.1		)	45.9
Total fixed maturity securities	2,221.1		77.6		(10.2		)	2,288.5
Equity securities
Corporate equity securities	137.5		65.8		(4.6		)	198.7
Total equity securities	137.5		65.8		(4.6		)	198.7
Total investments	$	2,358.6	$	143.4	$	(14.8	)	$	2,487.2

Investments classified by contractual maturity date table



	Amortized Cost		Estimated Fair Value
	(in millions)
Due in one year or less	$	149.6	$	151.2
Due after one year through five years	920.1		958.6
Due after five years through ten years	600.6		641.2
Due after ten years	265.3		283.6
Mortgage and asset-backed securities	337.5		349.3
Total	$	2,273.1	$	2,383.9

Unrealized loss on investments table



	September 30, 2016						December 31, 2015
	Estimated Fair Value		Gross Unrealized Losses			Number of Issues	Estimated Fair Value		Gross Unrealized Losses			Number of Issues
	(in millions, except number of issues data)
Less than 12 months:
Fixed maturity securities
U.S. Treasuries	$	—	$	—		—	$	27.4	$	(0.1	)	20
States and municipalities	44.3		(0.3		)	12	—		—			—
Corporate securities	—		—			—	328.4		(4.7		)	122
Residential mortgage-backed securities	—		—			—	50.5		(0.8		)	24
Commercial mortgage-backed securities	—		—			—	51.5		(1.0		)	22
Asset-backed securities	—		—			—	34.1		—			27
Total fixed maturity securities	44.3		(0.3		)	12	491.9		(6.6		)	215
Equity securities	13.5		(1.1		)	30	35.8		(4.6		)	45
Total less than 12 months	$	57.8	$	(1.4	)	42	$	527.7	$	(11.2	)	260

12 months or greater:
Fixed maturity securities
Corporate securities	$	24.4	$	(0.8	)	10	$	34.6	$	(3.3	)	15
Residential mortgage-backed securities	—		—			—	7.1		(0.2		)	25
Asset-backed securities	—		—			—	11.1		(0.1		)	4
Total fixed maturity securities	24.4		(0.8		)	10	52.8		(3.6		)	44
Equity securities	2.2		(0.2		)	7	—		—			—
Total 12 months or greater	$	26.6	$	(1.0	)	17	$	52.8	$	(3.6	)	44

Total available-for-sale:
Fixed maturity securities
U.S. Treasuries	$	—	$	—		—	$	27.4	$	(0.1	)	20
States and municipalities	44.3		(0.3		)	12	—		—			—
Corporate securities	24.4		(0.8		)	10	363.0		(8.0		)	137
Residential mortgage-backed securities	—		—			—	57.6		(1.0		)	49
Commercial mortgage-backed securities	—		—			—	51.5		(1.0		)	22
Asset-backed securities	—		—			—	45.2		(0.1		)	31
Total fixed maturity securities	68.7		(1.1		)	22	544.7		(10.2		)	259
Equity securities	15.7		(1.3		)	37	35.8		(4.6		)	45
Total available-for-sale	$	84.4	$	(2.4	)	59	$	580.5	$	(14.8	)	304

Net realized gains and change in unrealized gains (losses), available for sale securities table

ealized gains on investments and the change in unrealized gains (losses) on fixed maturity and equity securities are determined on a specific-identification basis and were as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2016			2015			2016			2015
	(in millions)
Net realized gains on investments
Fixed maturity securities
Gross gains	$	—		$	0.2		$	1.3		$	0.5
Gross losses	—			(0.2		)	(0.5		)	(0.4		)
Net realized gains on fixed maturity securities	$	—		$	—		$	0.8		$	0.1
Equity securities
Gross gains	$	1.6		$	2.2		$	14.3		$	5.6
Gross losses	—			(0.2		)	(6.0		)	(0.6		)
Net realized gains on equity securities	$	1.6		$	2.0		$	8.3		$	5.0
Total	$	1.6		$	2.0		$	9.1		$	5.1

Change in unrealized gains (losses)
Fixed maturity securities	$	(10.2	)	$	8.0		$	43.4		$	(11.0	)
Equity securities	2.1			(27.0		)	8.9			(34.8		)
Total	$	(8.1	)	$	(19.0	)	$	52.3		$	(45.8	)

Investment income table

Net investment income was as follows:



	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2016			2015			2016			2015
	(in millions)
Fixed maturity securities	$	16.9		$	17.3		$	50.8		$	51.6
Equity securities	1.7			1.7			5.4			4.0
Cash equivalents and restricted cash	0.1			0.1			0.2			0.1
Gross investment income	18.7			19.1			56.4			55.7
Investment expenses	(0.8		)	(0.6		)	(2.3		)	(1.9		)
Net investment income	$	17.9		$	18.5		$	54.1		$	53.8

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Income Taxes (Tables)

9 Months Ended

Sep. 30, 2016

Income Taxes [Abstract]

Reconciliation of federal staturoty income tax rates to the effective tax rates table

The following is a reconciliation of the federal statutory income tax rate to the Company’s effective tax rates for the periods presented.



	Nine Months Ended
	September 30,
	2016		2015
Statutory tax rate	35.0	%	35.0	%
Dividends received deduction and tax-exempt interest	(7.1	)	(7.6	)
LPT deferred gain amortization	(3.3	)	(4.3	)
LPT reserve adjustment	(1.5	)	(2.0	)
Pre-privatization reserve adjustment, excluding LPT	—		(4.6	)
Stock based compensation	(1.1	)	—
Other	0.9		0.7
Effective tax rate	22.9	%	17.2	%

Liability for Unpaid Losses and Loss Adjustment Expenses (Tables)

9 Months Ended

Sep. 30, 2016

Liability for Unpaid Losses and Loss Adjustment Expenses [Abstract]

Changes in the liability for unpaid losses and LAE table

The following table represents a reconciliation of changes in the liability for unpaid losses and LAE.



	Nine Months Ended
	September 30,
	2016			2015
	(in millions)
Unpaid losses and LAE, gross of reinsurance, at beginning of period	$	2,347.5		$	2,369.7
Less reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	628.2			669.5
Net unpaid losses and LAE at beginning of period	1,719.3			1,700.2
Losses and LAE, net of reinsurance, incurred during the period related to:
Current period	343.1			339.7
Prior periods	(1.5		)	1.3
Total net losses and LAE incurred during the period	341.6			341.0
Paid losses and LAE, net of reinsurance, related to:
Current period	42.8			43.9
Prior periods	279.6			274.2
Total net paid losses and LAE during the period	322.4			318.1
Ending unpaid losses and LAE, net of reinsurance	1,738.5			1,723.1
Reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	591.5			634.8
Unpaid losses and LAE, gross of reinsurance, at end of period	$	2,330.0		$	2,357.9

Stock-Based Compensation Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Stock-Based Compensation [Abstract]

Share-based compensation arrangements by share-based payment award table

The Company awarded stock options, restricted stock units (RSUs) and performance share units (PSUs) to certain officers of the Company as follows:



	Number Awarded	Weighted Average Fair Value on Date of Grant		Weighted Average Exercise Price		Aggregate Fair Value on Date of Grant
						(in millions)
March 2016
Stock options⁽¹⁾	67,431	$	8.38	$	27.72	$	0.6
RSUs⁽¹⁾	80,816	27.72		—		2.2
PSUs⁽²⁾	97,236	27.72		—		2.7

May 2016
RSUs⁽¹⁾	17,892	30.18		—		0.5

(1)

The RSUs awarded in May 2016 were awarded to non-employee Directors of the Company and have a service vesting period of one year from the date of grant.


(2)	The PSUs awarded in March 2016 were awarded to certain officers of the Company and have a performance period of two years followed by an additional one year vesting period. The PSU awards are subject to certain performance goals with payouts that range from 0% to 200% of the target awards. The value shown in the table represents the aggregate number of PSUs awarded at the target level.

Earnings Per Share (Tables)

9 Months Ended

Sep. 30, 2016

Earnings Per Share [Abstract]

Net income and weighted average common shares outstanding used in earnings per share calculations table

The following table presents the net income and the weighted average number of shares outstanding used in the earnings per common share calculations.



	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2016		2015		2016		2015
	(in millions, except share data)
Net income available to stockholders—basic and diluted	$	22.6	$	24.5	$	71.2	$	67.7
Weighted average number of shares outstanding—basic	32,449,617		32,184,143		32,497,478		32,000,142
Effect of dilutive securities:
PSUs	238,633		72,612		196,898		161,335
Stock options	192,827		245,708		251,068		289,348
RSUs	67,885		21,877		70,429		47,268
Dilutive potential shares	499,345		340,197		518,395		497,951
Weighted average number of shares outstanding—diluted	32,948,962		32,524,340		33,015,873		32,498,093

Antidilutive securities excluded from computation of earnings per share table

The following table presents options, PSUs, and RSUs that were excluded from diluted earnings per share.



	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2016	2015	2016	2015
Options excluded as the exercise price was greater than the average market price	—	80,800	—	26,933
Options, PSUs and RSUs excluded under the treasury method as the potential proceeds on settlement or exercise price were greater than the value of shares acquired	67,431	336,006	98,021	316,273

Changes in Estimates (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Change in Accounting Estimate [Line Items]
Net income	$ 22,600	$ 24,500	$ 71,200	$ 67,700
Basic	$ 0.70	$ 0.76	$ 2.19	$ 2.12
Diluted	$ 0.69	$ 0.75	$ 2.16	$ 2.08
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Member]
Change in Accounting Estimate [Line Items]
Change to estimated reserves ceded under the LPT agreement			$ (5,000)
Cumulative adjustment to the Deferred Gain			(3,100)	$ (6,400)
Net income			$ 3,100
Basic			$ 0.10
Diluted			$ 0.09
Change to Contingent Profit Commission [Member]
Change in Accounting Estimate [Line Items]
Change in estimate of contingent commission receivable			$ 1,900
Cumulative adjustment to the Deferred Gain			(1,800)	$ (2,600)
Net income			$ 1,800
Basic			$ 0.06
Diluted			$ 0.05

New Accounting Standards Adopted ASU (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income	$ 22,600	$ 24,500	$ 71,200	$ 67,700
Income tax expense	7,800	$ 5,900	21,100	$ 14,100
Accounting Standards Update No 2016-09 [Member]
Net income	100		1,400
Income tax expense	$ (100)		$ (1,400)
Basic and Diluted			$ 0.04

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 2,582,400	$ 2,487,200
Investments, fair value	2,582,400	2,487,200
Cash and cash equivalents	84,100	56,600	$ 56,200	$ 103,600
Cash and cash equivalents, estimated fair value	84,100	56,600
Restricted cash and cash equivalents	2,700	2,500
Notes payable	32,000	32,000
Notes Payable, fair value	35,000	36,600
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	27,700	32,700
Restricted cash and cash equivalents	$ 2,700	$ 2,500

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

+ Details

Fair Value of Financial Instruments Fair Value of Financial Instruments, Reconciliation of Level 3 Securities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments	$ 2,582.4	$ 2,487.2
Purchases, Issuances, Settlements, net	4.9
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments	184.5	198.7
Equity Securities [Member] \| Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments	$ 4.9	$ 0.0

Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 2,401,500	$ 2,358,600
Gross unrealized gain	183,300	143,400
Gross unrealized loss	(2,400)	(14,800)
Investments	2,582,400	2,487,200
Deposit Assets
Investments	2,582,400	2,487,200
Assets Held-in-trust
Investments	2,582,400	2,487,200
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	2,273,100	2,221,100
Gross unrealized gain	111,900	77,600
Gross unrealized loss	(1,100)	(10,200)
Investments	2,383,900	2,288,500
Deposit Assets
Investments	2,383,900	2,288,500
Assets Held-in-trust
Investments	2,383,900	2,288,500
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	122,900	116,400
Gross unrealized gain	5,000	3,900
Gross unrealized loss	0	(100)
Investments	127,900	120,200
Deposit Assets
Investments	127,900	120,200
Assets Held-in-trust
Investments	127,900	120,200
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	11,900	23,000
Gross unrealized gain	1,100	1,400
Gross unrealized loss	0	0
Investments	13,000	24,400
Deposit Assets
Investments	13,000	24,400
Assets Held-in-trust
Investments	13,000	24,400
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	842,900	809,400
Gross unrealized gain	54,600	45,100
Gross unrealized loss	(300)	0
Investments	897,200	854,500
Deposit Assets
Investments	897,200	854,500
Assets Held-in-trust
Investments	897,200	854,500
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	957,900	913,400
Gross unrealized gain	39,400	19,900
Gross unrealized loss	(800)	(8,000)
Investments	996,500	925,300
Deposit Assets
Investments	996,500	925,300
Assets Held-in-trust
Investments	996,500	925,300
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	225,300	231,800
Gross unrealized gain	9,700	7,100
Gross unrealized loss	0	(1,000)
Investments	235,000	237,900
Deposit Assets
Investments	235,000	237,900
Assets Held-in-trust
Investments	235,000	237,900
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	84,500	81,100
Gross unrealized gain	2,000	200
Gross unrealized loss	0	(1,000)
Investments	86,500	80,300
Deposit Assets
Investments	86,500	80,300
Assets Held-in-trust
Investments	86,500	80,300
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	27,700	46,000
Gross unrealized gain	100	0
Gross unrealized loss	0	(100)
Investments	27,800	45,900
Deposit Assets
Investments	27,800	45,900
Assets Held-in-trust
Investments	27,800	45,900
Corporate equity securities [Domain]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	109,500	137,500
Gross unrealized gain	71,400	65,800
Gross unrealized loss	(1,300)	(4,600)
Investments	179,600	198,700
Deposit Assets
Investments	179,600	198,700
Assets Held-in-trust
Investments	179,600	198,700
Federal Home Loan Bank Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	4,900
Gross unrealized gain	0
Gross unrealized loss	0
Investments	4,900
Deposit Assets
Investments	4,900
Assets Held-in-trust
Investments	4,900
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	114,400	137,500
Gross unrealized gain	71,400	65,800
Gross unrealized loss	(1,300)	(4,600)
Investments	184,500	198,700
Deposit Assets
Investments	184,500	198,700
Assets Held-in-trust
Investments	184,500	198,700
Short-term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	14,000
Gross unrealized gain	0
Gross unrealized loss	0
Fair Value Measurement [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments	27,700	32,700
Deposit Assets
Investments	27,700	32,700
Assets Held-in-trust
Investments	27,700	32,700
Fair Value Measurement [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments	1,044,200	881,200
Deposit Assets
Investments	1,044,200	881,200
Assets Held-in-trust
Investments	$ 1,044,200	$ 881,200

Investments, Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less, amortized cost	$ 149,600
Due after one year through five years, amortized cost	920,100
Due after five years through ten years, amortized cost	600,600
Due after ten years, amortized cost	265,300
Mortgage and asset-backed securities, amortized cost	337,500
Total, amortized cost	2,273,100
Estimated Fair Value
Due in one year or less, fair value	151,200
Due after one year through five years, fair value	958,600
Due after five years through ten years, fair value	641,200
Due after ten years, fair value	283,600
Mortgage and asset-backed securities, fair value	349,300
Total, fair value	$ 2,383,900	$ 2,288,500

Investments, Continuous Loss Position (Details)	3 Months Ended		9 Months Ended
Investments, Continuous Loss Position (Details)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Estimated Fair Value
Estimated fair value, less than 12 months	$ 57,800,000		$ 57,800,000		$ 527,700,000
Estimated fair value, 12 months or greater	26,600,000		26,600,000		52,800,000
Estimated fair value, total	84,400,000		84,400,000		580,500,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(1,400,000)		(1,400,000)		(11,200,000)
Gross unrealized losses, 12 months or greater	1,000,000		1,000,000		3,600,000
Estimated unrealized losses, total	$ (2,400,000)		$ (2,400,000)		$ (14,800,000)
Number of issues in loss position, less than 12 months	42		42		260
Number of Issues in loss position, 12 months or greater	17		17		44
Number of issues loss position, aggregate	59		59		304
Other than temporary impairment, credit losses recognized in earnings	$ 0	$ 100,000	$ 5,300,000	$ 200,000
Total impairments, number of securities	32		32
Debt Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 44,300,000		$ 44,300,000		$ 491,900,000
Estimated fair value, 12 months or greater	24,400,000		24,400,000		52,800,000
Estimated fair value, total	68,700,000		68,700,000		544,700,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(300,000)		(300,000)		(6,600,000)
Gross unrealized losses, 12 months or greater	800,000		800,000		3,600,000
Estimated unrealized losses, total	$ (1,100,000)		$ (1,100,000)		$ (10,200,000)
Number of issues in loss position, less than 12 months	12		12		215
Number of Issues in loss position, 12 months or greater	10		10		44
Number of issues loss position, aggregate	22		22		259
US Treasury Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 0		$ 27,400,000
Estimated fair value, total	0		0		27,400,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		0		(100,000)
Estimated unrealized losses, total	$ 0		$ 0		$ (100,000)
Number of issues in loss position, less than 12 months	0		0		20
Number of issues loss position, aggregate	0		0		20
US States and Political Subdivisions Debt Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 44,300,000		$ 44,300,000		$ 0
Estimated fair value, total	44,300,000		44,300,000		0
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(300,000)		(300,000)		0
Estimated unrealized losses, total	$ (300,000)		$ (300,000)		$ 0
Number of issues in loss position, less than 12 months	12		12		0
Number of issues loss position, aggregate	12		12		0
Corporate Debt Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 0		$ 328,400,000
Estimated fair value, 12 months or greater	24,400,000		24,400,000		34,600,000
Estimated fair value, total	24,400,000		24,400,000		363,000,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		0		(4,700,000)
Gross unrealized losses, 12 months or greater	800,000		800,000		3,300,000
Estimated unrealized losses, total	$ (800,000)		$ (800,000)		$ (8,000,000)
Number of issues in loss position, less than 12 months	0		0		122
Number of Issues in loss position, 12 months or greater	10		10		15
Number of issues loss position, aggregate	10		10		137
Residential Mortgage Backed Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 0		$ 50,500,000
Estimated fair value, 12 months or greater	0		0		7,100,000
Estimated fair value, total	0		0		57,600,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		0		(800,000)
Gross unrealized losses, 12 months or greater	0		0		200,000
Estimated unrealized losses, total	$ 0		$ 0		$ (1,000,000)
Number of issues in loss position, less than 12 months	0		0		24
Number of Issues in loss position, 12 months or greater	0		0		25
Number of issues loss position, aggregate	0		0		49
Commercial Mortgage Backed Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 0		$ 51,500,000
Estimated fair value, total	0		0		51,500,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		0		(1,000,000)
Estimated unrealized losses, total	$ 0		$ 0		$ (1,000,000)
Number of issues in loss position, less than 12 months	0		0		22
Number of issues loss position, aggregate	0		0		22
Asset-backed Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 0		$ 34,100,000
Estimated fair value, 12 months or greater	0		0		11,100,000
Estimated fair value, total	0		0		45,200,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		0		0
Gross unrealized losses, 12 months or greater	0		0		100,000
Estimated unrealized losses, total	$ 0		$ 0		$ (100,000)
Number of issues in loss position, less than 12 months	0		0		0
Number of Issues in loss position, 12 months or greater	0		0		4
Number of issues loss position, aggregate	0		0		0
Equity Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 13,500,000		$ 13,500,000		$ 35,800,000
Estimated fair value, 12 months or greater	2,200,000		2,200,000		0
Estimated fair value, total	15,700,000		15,700,000		35,800,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(1,100,000)		(1,100,000)		(4,600,000)
Gross unrealized losses, 12 months or greater	200,000		200,000		0
Estimated unrealized losses, total	$ (1,300,000)		$ (1,300,000)		$ (4,600,000)
Number of issues in loss position, less than 12 months	30		30		45
Number of Issues in loss position, 12 months or greater	7		7		0
Number of issues loss position, aggregate	37		37		45

Investments, Net Realized Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net realized gains (losses)
Net realized gains (losses) on fixed maturity and equity securities	$ 1.6	$ 2.0	$ 9.1	$ 5.1
Change in unrealized gains (losses)
Change in unrealized gains (losses) on fixed maturity and equity securities	(8.1)	(19.0)	52.3	(45.8)
Debt Securities [Member]
Net realized gains (losses)
Gross gains from sales	0.0	0.2	1.3	0.5
Gross losses from sales	0.0	0.2	0.5	0.4
Net realized gains (losses) on fixed maturity and equity securities	0.0	0.0	0.8	0.1
Change in unrealized gains (losses)
Change in unrealized gains (losses) on fixed maturity and equity securities	(10.2)	8.0	43.4	(11.0)
Equity Securities [Member]
Net realized gains (losses)
Gross gains from sales	1.6	2.2	14.3	5.6
Gross losses from sales	0.0	0.2	6.0	0.6
Net realized gains (losses) on fixed maturity and equity securities	1.6	2.0	8.3	5.0
Change in unrealized gains (losses)
Change in unrealized gains (losses) on fixed maturity and equity securities	$ 2.1	$ (27.0)	$ 8.9	$ (34.8)

Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Net Investment Income (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	$ 18.7	$ 19.1	$ 56.4	$ 55.7
Investment expenses	0.8	0.6	2.3	1.9
Net investment income	17.9	18.5	54.1	53.8
Debt Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income related to fixed maturity securities and short-term investments and cash equivalents	16.9	17.3	50.8	51.6
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income related to equity securities	1.7	1.7	5.4	4.0
Short-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income related to fixed maturity securities and short-term investments and cash equivalents	$ 0.1	$ 0.1	$ 0.2	$ 0.1

Income Taxes (Details)	9 Months Ended
Income Taxes (Details)	Sep. 30, 2016	Sep. 30, 2015
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Statutory tax rate	35.00%	35.00%
Dividends received deduction and tax-exempt interest	(7.10%)	(7.60%)
LPT deferred gain amortization	(3.30%)	(4.30%)
LPT reserve adjustment	(1.50%)	(2.00%)
Pre-privatization reserve adjustment, excluding LPT	0.00%	(4.60%)
Stock based compensation	(1.10%)	0.00%
Other	0.90%	0.70%
Effective tax rate	22.90%	17.20%

Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Unpaid losses and LAE, gross of reinsurance, at beginning of period	$ 2,347,500	$ 2,369,700
Less reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	628,200	669,500
Net unpaid losses and LAE at beginning of period	1,719,300	1,700,200
Losses and LAE, net of reinsurance, incurred during the period related to:
Current period	343,100	339,700
Prior periods	(1,500)	1,300
Total net losses and LAE incurred during the period	341,600	341,000
Deduct payments for losses and LAE, net of reinsurance, related to:
Current period	42,800	43,900
Prior periods	279,600	274,200
Total net paid losses and LAE during the period	322,400	318,100
Ending unpaid losses and LAE, net of reinsurance	1,738,500	1,723,100
Reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	591,500	634,800
Unpaid losses and LAE, gross of reinsurance, at end of period	2,330,000	2,357,900
LPT Agreement [Abstract]
Impact of the LPT Agreement	$ 13,600	$ 17,500

LPT Agreement LPT Agreement (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Reinsurance Agreement [Line Items]
Reinsurance quota share, percentage	100.00%
Liabilities for the incurred but unpaid losses and LAE related to claims prior to July 1, 1995	$ 1,500,000
Ceded premiums written	775,000
Amortization of deferred gain	8,700	$ 8,500
Deferred reinsurance gain—LPT Agreement	177,800		$ 189,500
Estimated remaining liabilities - LPT Agreement	472,300		498,000
Paid losses and LAE claims related to LPT	715,900		$ 695,200
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Member]
Reinsurance Agreement [Line Items]
Cumulative adjustment to the Deferred Gain	3,100	6,400
Change to Contingent Profit Commission [Member]
Reinsurance Agreement [Line Items]
Cumulative adjustment to the Deferred Gain	1,800	$ 2,600
Indemnification Agreement [Member]
Reinsurance Agreement [Line Items]
Coverage provided under LPT Agreement	$ 2,000,000

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized gain on investments, before taxes	$ 180,900	$ 128,600
Deferred tax expense on net unrealized gains	(63,300)	(45,000)
Accumulated other comprehensive income, net	$ 117,600	$ 83,600

Stock-Based Compensation (Details) - USD ($)
$ / shares in Units, $ in Millions

1 Months Ended

9 Months Ended

12 Months Ended

May 31, 2015

Sep. 30, 2016

Dec. 31, 2015

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Stock-options exercised

484,829

463,466

Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Vesting rights for options awarded

vest 25% on March 15, 2017, and each of the subsequent three anniversaries of that date

Performance share awards performance period

two years

Performance share awards, minimum payout

0.00%

Performance share awards, maximum payout

200.00%

Stock Option [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based compensation award, shares issued

^[1]

67,431

Share-based compensation options, exercise price on grant date

^[1]

$ 8.38

Share-based compensation award, fair value assumptions, exercise price

^[1]

$ 27.72

Fair value of awards awarded on grant date

^[1]

$ 0.6

Stock Option [Member] | Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based compensation arrangement by share-based payment award, expiration period

7 years

Restricted Stock Units (RSUs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based compensation award, shares issued

^[1]

17,892

80,816

Share-based compensation options, exercise price on grant date

$ 30.18

^[1]

$ 27.72

^[2]

Share-based compensation award, fair value assumptions, exercise price

$ 0

Fair value of awards awarded on grant date

^[1]

$ 0.5

$ 2.2

Restricted Stock Units (RSUs) [Member] | Director [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based compensation arrangement by share-based payment award, award vesting period

1 year

Performance Shares [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based compensation award, shares issued

^[2]

97,236

Share-based compensation options, exercise price on grant date

^[2]

$ 27.72

Share-based compensation award, fair value assumptions, exercise price

$ 0

Fair value of awards awarded on grant date

^[2]

$ 2.7

Performance Shares [Member] | Officer [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Share-based compensation arrangement by share-based payment award, award vesting period

1 year

[1]

[2]

The PSUs awarded in March 2016 were awarded to certain officers of the Company and have a performance period of two years followed by an additional one year vesting period. The PSU awards are subject to certain performance goals with payouts that range from 0% to 200% of the target awards. The value shown in the table represents the aggregate number of PSUs awarded at the target level.

Earnings Per Share (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Earnings Per Share (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income available to stockholders - basic and diluted	$ 22,600	$ 24,500	$ 71,200	$ 67,700
Weighted average number of shares outstanding - basic	32,449,617	32,184,143	32,497,478	32,000,142
Effect of dilutive securities:
Dilutive securities	499,345	340,197	518,395	497,951
Weighted average number of shares outstanding - diluted	32,948,962	32,524,340	33,015,873	32,498,093
Antidilutive securities excluded from computation of earnings per share	0	80,800	0	26,933
Antidilutive securites excluded under the treasury method from computation of earnings per share	67,431	336,006	98,021	316,273
Employee Stock Option [Member]
Effect of dilutive securities:
Dilutive securities	192,827	245,708	251,068	289,348
Restricted Stock Units (RSUs) [Member]
Effect of dilutive securities:
Dilutive securities	67,885	21,877	70,429	47,268
Performance Shares [Member]
Effect of dilutive securities:
Dilutive securities	238,633	72,612	196,898	161,335

Basis of Presentation (Details)	9 Months Ended
Basis of Presentation (Details)	Sep. 30, 2016
Basis of Presentation [Abstract]
Number of Operating Segments	1

Fair Value of Financial Instruments, Fair Value Inputs (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 2,582.4	$ 2,487.2
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	2,383.9	2,288.5
Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	2,383.9	2,288.5
Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	127.9	120.2
US Treasury Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
US Treasury Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	127.9	120.2
US Treasury Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	13.0	24.4
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	13.0	24.4
US Government Agencies Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	897.2	854.5
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	897.2	854.5
US States and Political Subdivisions Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	996.5	925.3
Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	996.5	925.3
Corporate Debt Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	235.0	237.9
Residential Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Residential Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	235.0	237.9
Residential Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	86.5	80.3
Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	86.5	80.3
Commercial Mortgage Backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	27.8	45.9
Asset-backed Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Asset-backed Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	27.8	45.9
Asset-backed Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Corporate equity securities [Domain]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	179.6	198.7
Corporate equity securities [Domain] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	179.6	198.7
Corporate equity securities [Domain] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Corporate equity securities [Domain] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Federal Home Loan Bank Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4.9
Federal Home Loan Bank Stock [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Federal Home Loan Bank Stock [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Federal Home Loan Bank Stock [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4.9	0.0
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	184.5	198.7
Equity Securities [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	179.6	198.7
Equity Securities [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Equity Securities [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	4.9	0.0
Short-term Investments [Member] \| Fair Value, Inputs, Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0.0	0.0
Short-term Investments [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	14.0	0.0
Short-term Investments [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 0.0	$ 0.0