Employers (EIG) 10-Q 28 Apr 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 21, 2016
Document and Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Entity Registrant Name	Employers Holdings, Inc.
Entity Central Index Key	1,379,041
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		32,441,521
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Available for sale:
Fixed maturity securities at fair value (amortized cost $2,215,900 at March 31, 2016 and $2,221,100 at December 31, 2015)	$ 2,312,600	$ 2,288,500
Equity securities at fair value (cost $145,200 at March 31, 2016 and $137,500 at December 31, 2015)	207,600	198,700
Total investments	2,520,200	2,487,200
Cash and cash equivalents	70,800	56,600
Restricted cash and cash equivalents	4,200	2,500
Accrued investment income	19,600	20,600
Premiums receivable (less bad debt allowance of $9,600 at March 31, 2016 and $12,200 at December 31, 2015)	315,100	301,100
Reinsurance recoverable for:
Paid losses	7,900	7,700
Unpaid losses	621,400	628,200
Deferred policy acquisition costs	47,000	44,300
Deferred income taxes, net	55,500	67,900
Property and equipment, net	23,000	24,900
Intangible assets, net	8,400	8,500
Goodwill	36,200	36,200
Contingent commission receivable—LPT Agreement	29,200	29,200
Other assets	38,300	40,900
Total assets	3,796,800	3,755,800
Claims and policy liabilities:
Unpaid losses and loss adjustment expenses	2,341,900	2,347,500
Unearned premiums	323,700	308,900
Total claims and policy liabilities	2,665,600	2,656,400
Commissions and premium taxes payable	47,500	52,500
Accounts payable and accrued expenses	19,700	24,100
Deferred reinsurance gain—LPT Agreement	186,400	189,500
Notes payable	32,000	32,000
Other liabilities	41,900	40,500
Total liabilities	$ 2,993,100	$ 2,995,000
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 55,894,288 and 55,589,454 shares issued and 32,483,983 and 32,216,480 shares outstanding at March 31, 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	363,200	357,200
Retained earnings	700,100	682,000
Accumulated other comprehensive income, net	103,400	83,600
Treasury stock, at cost (23,410,305 shares at March 31, 2016 and 23,372,974 shares at December 31, 2015)	(363,600)	(362,600)
Total stockholders’ equity	803,700	760,800
Total liabilities and stockholders’ equity	$ 3,796,800	$ 3,755,800

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Available for sale:
Fixed maturity securities, amortized cost	$ 2,361,100	$ 2,358,600
Available for sale, short-term investments, at amortized cost	0	0
Premiums receivable, bad debt allowance	9,600	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)	55,894,288	55,589,454
Common stock, shares outstanding (in shares)	32,483,983	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)	23,410,305	23,372,974
Debt Securities [Member]
Available for sale:
Fixed maturity securities, amortized cost	$ 2,215,900	$ 2,221,100
Equity Securities [Member]
Available for sale:
Fixed maturity securities, amortized cost	$ 145,200	$ 137,500

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Net premiums earned	$ 172,600,000	$ 159,000,000
Net investment income	17,800,000	16,900,000
Net realized gains on investments	1,500,000	1,200,000
Other income	100,000	100,000
Total revenues	192,000,000	177,200,000
Expenses
Losses and loss adjustment expenses	107,300,000	106,200,000
Commission expense	20,300,000	18,700,000
Underwriting and other operating expenses	36,300,000	33,500,000
Interest expense	400,000	700,000
Total expenses	164,300,000	159,100,000
Net income before income taxes	27,700,000	18,100,000
Income tax expense	6,700,000	4,100,000
Net income	21,000,000	14,000,000
Comprehensive income
Unrealized gains during the period (net of tax expense of $11,200 and $5,000 for the three months ended March 31, 2016 and 2015, respectively)	20,800,000	9,200,000
Reclassification adjustment for realized gains in net income (net of taxes of $500 and $400 for the three months ended March 31, 2016 and 2015, respectively)	(1,000,000)	(800,000)
Other comprehensive income, net of tax	19,800,000	8,400,000
Total comprehensive income	40,800,000	22,400,000
Net realized gains on investments
Net realized gains on investments before credit related impairments	6,800,000	1,200,000
Other than temporary impairment recognized in earnings	(5,300,000)	0
Net realized gains on investments	$ 1,500,000	$ 1,200,000
Earnings per common share (Note 10):
Basic	$ 0.65	$ 0.44
Diluted	0.64	0.43
Cash dividends declared per common share	$ 0.09	$ 0.06

Conolidated Statements of Compr

Conolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement Parenthetical [Abstract]
Other comprehensive income (loss), unrealized holding gain (loss) on securities arising during period, tax	$ 11,200	$ 5,000
Other comprehensive income (loss), reclassification adjustment for sale of securities included in net income, tax	$ 500	$ 400

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities
Net income	$ 21,000	$ 14,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,200	1,700
Stock-based compensation	1,800	1,800
Amortization of premium on investments, net	3,700	3,200
Allowance for doubtful accounts	(2,600)	1,200
Deferred income tax expense	1,700	1,800
Realized gains on investments, net	(1,500)	(1,200)
Excess tax benefits from stock-based compensation	(800)	(600)
Other	100	400
Change in operating assets and liabilities:
Premiums receivable	(11,400)	(1,600)
Reinsurance recoverable for paid and unpaid losses	6,600	9,300
Federal income taxes	4,100	(1,600)
Unpaid losses and loss adjustment expenses	5,600	(600)
Unearned premiums	14,800	13,800
Accounts payable, accrued expenses and other liabilities	(4,000)	(1,400)
Deferred reinsurance gain—LPT Agreement	(3,100)	(2,900)
Contingent commission receivable—LPT Agreement	0	(200)
Other	(6,200)	(13,400)
Net cash provided by operating activities	20,800	24,900
Investing activities
Purchase of fixed maturity securities	(102,500)	(168,000)
Purchase of equity securities	(32,600)	(8,000)
Proceeds from sale of fixed maturity securities	42,400	0
Proceeds from sale of equity securities	26,300	8,200
Proceeds from maturities and redemptions of investments	61,500	85,100
Capital expenditures	(200)	(900)
Change in restricted cash and cash equivalents	(1,700)	2,400
Net cash used in investing activities	(6,800)	(81,200)
Financing activities
Acquisition of treasury stock	(1,000)	0
Cash transactions related to stock-based compensation	3,400	(300)
Dividends paid to stockholders	(2,900)	(1,900)
Payments on notes payable and capital leases	(100)	(100)
Excess tax benefits from stock-based compensation, financing activities	800	600
Net cash provided by (used in) financing activities	200	(1,700)
Net increase (decrease) in cash and cash equivalents	14,200	(58,000)
Cash and cash equivalents at the beginning of the period	56,600	103,600
Cash and cash equivalents at the end of the period	$ 70,800	$ 45,600

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 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.

New Accounting Standards (Notes

New Accounting Standards (Notes)	3 Months Ended
	Mar. 31, 2016
New Accounting Standards [Abstract]
New Accounting Standards	New Accounting Standards 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. The Company has determined that at March 31, 2016 , adoption of this guidance would result in a $62.4 million reclassification adjustment, net of tax, between retained earnings and accumulated other comprehensive income. The Company has not yet estimated the full impact that the adoption will have on its consolidated statement of comprehensive income. 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 March 2016, the FASB issued 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 has not yet estimated the full impact that the adoption will have on its consolidated financial condition and results of operations.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2016
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying value and the estimated fair value of the Company’s financial instruments were as follows: March 31, 2016 December 31, 2015 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) Financial assets Investments $ 2,520.2 $ 2,520.2 $ 2,487.2 $ 2,487.2 Cash and cash equivalents 70.8 70.8 56.6 56.6 Restricted cash and cash equivalents 4.2 4.2 2.5 2.5 Financial liabilities Notes payable $ 32.0 $ 32.2 $ 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. March 31, 2016 December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities U.S. Treasuries $ — $ 130.6 $ — $ — $ 120.2 $ — U.S. Agencies — 24.4 — — 24.4 — States and municipalities — 863.3 — — 854.5 — Corporate securities — 940.1 — — 925.3 — Residential mortgage-backed securities — 244.0 — — 237.9 — Commercial mortgage-backed securities — 80.1 — — 80.3 — Asset-backed securities — 30.1 — — 45.9 — Total fixed maturity securities $ — $ 2,312.6 $ — $ — $ 2,288.5 $ — Equity securities Corporate equity securities $ 202.3 $ — $ — $ 198.7 $ — $ — Federal Home Loan Bank stock $ — $ — $ 5.3 $ — $ — $ — Total equity securities $ 202.3 $ — $ 5.3 $ 198.7 $ — $ — The following table provides a reconciliation of the beginning and ending balances that are measured using Level 3 inputs for the three months ended March 31, 2016 . Equity Securities (in millions) Beginning balance, January 1, 2016 $ — Purchases, issuances, settlements, net 5.3 Ending balance, March 31, 2016 $ 5.3 Each of the Company's 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.

Investments

Investments	3 Months Ended
	Mar. 31, 2016
Investments [Abstract]
Investments	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 March 31, 2016 Fixed maturity securities U.S. Treasuries $ 125.1 $ 5.5 $ — $ 130.6 U.S. Agencies 23.0 1.4 — 24.4 States and municipalities 810.8 52.5 — 863.3 Corporate securities 912.9 32.4 (5.2 ) 940.1 Residential mortgage-backed securities 235.2 8.9 (0.1 ) 244.0 Commercial mortgage-backed securities 78.9 1.3 (0.1 ) 80.1 Asset-backed securities 30.0 0.1 — 30.1 Total fixed maturity securities 2,215.9 102.1 (5.4 ) 2,312.6 Equity securities Corporate equity securities 139.9 63.9 (1.5 ) 202.3 Federal Home Loan Bank stock 5.3 — — 5.3 Total equity securities 145.2 63.9 (1.5 ) 207.6 Total investments $ 2,361.1 $ 166.0 $ (6.9 ) $ 2,520.2 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 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 March 31, 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 $ 132.8 $ 134.4 Due after one year through five years 869.8 902.0 Due after five years through ten years 612.3 647.1 Due after ten years 256.9 274.9 Mortgage and asset-backed securities 344.1 354.2 Total $ 2,215.9 $ 2,312.6 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 March 31, 2016 and December 31, 2015 . March 31, 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 Corporate securities 67.2 (2.5 ) 28 328.4 (4.7 ) 122 Residential mortgage-backed securities — — — 50.5 (0.8 ) 24 Commercial mortgage-backed securities 7.3 (0.1 ) 2 51.5 (1.0 ) 22 Asset-backed securities — — — 34.1 — 27 Total fixed maturity securities 74.5 (2.6 ) 30 491.9 (6.6 ) 215 Equity securities 30.3 (1.5 ) 39 35.8 (4.6 ) 45 Total less than 12 months $ 104.8 $ (4.1 ) 69 $ 527.7 $ (11.2 ) 260 12 months or greater: Fixed maturity securities Corporate securities $ 33.5 $ (2.7 ) 17 $ 34.6 $ (3.3 ) 15 Residential mortgage-backed securities 20.9 (0.1 ) 23 7.1 (0.2 ) 25 Asset-backed securities — — — 11.1 (0.1 ) 4 Total fixed maturity securities 54.4 (2.8 ) 40 52.8 (3.6 ) 44 Total 12 months or greater $ 54.4 $ (2.8 ) 40 $ 52.8 $ (3.6 ) 44 Total available-for-sale: Fixed maturity securities U.S. Treasuries $ — $ — — $ 27.4 $ (0.1 ) 20 Corporate securities 100.7 (5.2 ) 45 363.0 (8.0 ) 137 Residential mortgage-backed securities 20.9 (0.1 ) 23 57.6 (1.0 ) 49 Commercial mortgage-backed securities 7.3 (0.1 ) 2 51.5 (1.0 ) 22 Asset-backed securities — — — 45.2 (0.1 ) 31 Total fixed maturity securities 128.9 (5.4 ) 70 544.7 (10.2 ) 259 Equity securities 30.3 (1.5 ) 39 35.8 (4.6 ) 45 Total available-for-sale $ 159.2 $ (6.9 ) 109 $ 580.5 $ (14.8 ) 304 Based on reviews of the fixed maturity securities, the Company determined that unrealized losses for the three months ended March 31, 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 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 three months ended March 31, 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 during the first quarter of 2016 was primarily due to the continued downturn in the energy sector. 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 March 31, 2016 2015 (in millions) Net realized gains on investments Fixed maturity securities Gross gains $ 0.2 $ — Gross losses (0.1 ) — Net realized gains on fixed maturity securities $ 0.1 $ — Equity securities Gross gains $ 7.2 $ 1.5 Gross losses (5.8 ) (0.3 ) Net realized gains on equity securities $ 1.4 $ 1.2 Total $ 1.5 $ 1.2 Change in unrealized gains (losses) Fixed maturity securities $ 29.3 $ 14.1 Equity securities 1.2 (1.2 ) Total $ 30.5 $ 12.9 Net investment income was as follows: Three Months Ended March 31, 2016 2015 (in millions) Fixed maturity securities $ 16.7 $ 16.4 Equity securities 1.9 1.1 Gross investment income 18.6 17.5 Investment expenses (0.8 ) (0.6 ) Net investment income $ 17.8 $ 16.9 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. As of March 31, 2016 and December 31, 2015 , securities having a fair value of $1,032.3 million and $881.2 million , respectively, were on deposit. 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 at March 31, 2016 and December 31, 2015 was $32.9 million and $32.7 million , respectively.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
Income Taxes [Abstract]
Income Taxes	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. Three Months Ended March 31, 2016 2015 Expense computed at statutory rate 35.0 % 35.0 % Dividends received deduction and tax-exempt interest (8.2 ) (8.8 ) LPT deferred gain amortization (3.2 ) (4.2 ) Other 0.6 0.5 Effective tax rate 24.2 % 22.5 %

Liability for Unpaid Losses and

Liability for Unpaid Losses and Loss Adjustment Expenses	3 Months Ended
	Mar. 31, 2016
Liability for Unpaid Losses and Loss Adjustment Expenses [Abstract]
Liability for Unpaid Losses and Loss Adjustment Expenses	Liability for Unpaid Losses and Loss Adjustment Expenses The following table represents a reconciliation of changes in the liability for unpaid losses and LAE. Three Months Ended March 31, 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 110.7 107.6 Prior periods (0.3 ) 1.7 Total net losses and LAE incurred during the period 110.4 109.3 Paid losses and LAE, net of reinsurance, related to: Current period 4.7 4.1 Prior periods 104.5 98.1 Total net paid losses and LAE during the period 109.2 102.2 Ending unpaid losses and LAE, net of reinsurance 1,720.5 1,707.3 Reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE 621.4 663.0 Unpaid losses and LAE, gross of reinsurance, at end of period $ 2,341.9 $ 2,370.3 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 $3.1 million for the three months ended March 31, 2016 and 2015 (Note 7 ). The change in the estimates of incurred losses and LAE attributable to insured events for prior periods was related to the Company's assigned risk business.

LPT Agreement

LPT Agreement	3 Months Ended
	Mar. 31, 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 $3.1 million and $2.9 million of the Deferred Gain for the three months ended March 31, 2016 and 2015 , respectively. Additionally, the Deferred Gain was reduced by $0.2 million for the three months ended March 31, 2015 , due to a favorable LPT Contingent Commission Adjustment. The remaining Deferred Gain was $186.4 million and $189.5 million as of March 31, 2016 and December 31, 2015 , respectively. The estimated remaining liabilities subject to the LPT Agreement were $490.8 million and $498.0 million as of March 31, 2016 and December 31, 2015 , respectively. Losses and LAE paid with respect to the LPT Agreement totaled $702.4 million and $695.2 million from inception through March 31, 2016 and December 31, 2015 , respectively.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 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: March 31, 2016 December 31, 2015 (in millions) Net unrealized gain on investments, before taxes $ 159.1 $ 128.6 Deferred tax expense on net unrealized gains (55.7 ) (45.0 ) Total accumulated other comprehensive income, net $ 103.4 $ 83.6

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 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 (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. (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 262,239 and 463,466 stock options were exercised during the three months ended March 31, 2016 and the year ended December 31, 2015 , respectively.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	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 March 31, 2016 2015 (in millions, except share data) Net income available to stockholders—basic and diluted $ 21.0 $ 14.0 Weighted average number of shares outstanding—basic 32,413,818 31,740,923 Effect of dilutive securities: PSUs 139,033 322,850 Stock options 238,582 310,899 RSUs 71,517 79,392 Dilutive potential shares 449,132 713,141 Weighted average number of shares outstanding—diluted 32,862,950 32,454,064 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 March 31, 2016 2015 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 80,800 267,444

Fair Value of Financial Instr17

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 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: March 31, 2016 December 31, 2015 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) Financial assets Investments $ 2,520.2 $ 2,520.2 $ 2,487.2 $ 2,487.2 Cash and cash equivalents 70.8 70.8 56.6 56.6 Restricted cash and cash equivalents 4.2 4.2 2.5 2.5 Financial liabilities Notes payable $ 32.0 $ 32.2 $ 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. March 31, 2016 December 31, 2015 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities U.S. Treasuries $ — $ 130.6 $ — $ — $ 120.2 $ — U.S. Agencies — 24.4 — — 24.4 — States and municipalities — 863.3 — — 854.5 — Corporate securities — 940.1 — — 925.3 — Residential mortgage-backed securities — 244.0 — — 237.9 — Commercial mortgage-backed securities — 80.1 — — 80.3 — Asset-backed securities — 30.1 — — 45.9 — Total fixed maturity securities $ — $ 2,312.6 $ — $ — $ 2,288.5 $ — Equity securities Corporate equity securities $ 202.3 $ — $ — $ 198.7 $ — $ — Federal Home Loan Bank stock $ — $ — $ 5.3 $ — $ — $ — Total equity securities $ 202.3 $ — $ 5.3 $ 198.7 $ — $ —
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following table provides a reconciliation of the beginning and ending balances that are measured using Level 3 inputs for the three months ended March 31, 2016 . Equity Securities (in millions) Beginning balance, January 1, 2016 $ — Purchases, issuances, settlements, net 5.3 Ending balance, March 31, 2016 $ 5.3

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2016 Fixed maturity securities U.S. Treasuries $ 125.1 $ 5.5 $ — $ 130.6 U.S. Agencies 23.0 1.4 — 24.4 States and municipalities 810.8 52.5 — 863.3 Corporate securities 912.9 32.4 (5.2 ) 940.1 Residential mortgage-backed securities 235.2 8.9 (0.1 ) 244.0 Commercial mortgage-backed securities 78.9 1.3 (0.1 ) 80.1 Asset-backed securities 30.0 0.1 — 30.1 Total fixed maturity securities 2,215.9 102.1 (5.4 ) 2,312.6 Equity securities Corporate equity securities 139.9 63.9 (1.5 ) 202.3 Federal Home Loan Bank stock 5.3 — — 5.3 Total equity securities 145.2 63.9 (1.5 ) 207.6 Total investments $ 2,361.1 $ 166.0 $ (6.9 ) $ 2,520.2 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 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	The amortized cost and estimated fair value of fixed maturity securities at March 31, 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 $ 132.8 $ 134.4 Due after one year through five years 869.8 902.0 Due after five years through ten years 612.3 647.1 Due after ten years 256.9 274.9 Mortgage and asset-backed securities 344.1 354.2 Total $ 2,215.9 $ 2,312.6
Unrealized loss on investments table	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 March 31, 2016 and December 31, 2015 . March 31, 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 Corporate securities 67.2 (2.5 ) 28 328.4 (4.7 ) 122 Residential mortgage-backed securities — — — 50.5 (0.8 ) 24 Commercial mortgage-backed securities 7.3 (0.1 ) 2 51.5 (1.0 ) 22 Asset-backed securities — — — 34.1 — 27 Total fixed maturity securities 74.5 (2.6 ) 30 491.9 (6.6 ) 215 Equity securities 30.3 (1.5 ) 39 35.8 (4.6 ) 45 Total less than 12 months $ 104.8 $ (4.1 ) 69 $ 527.7 $ (11.2 ) 260 12 months or greater: Fixed maturity securities Corporate securities $ 33.5 $ (2.7 ) 17 $ 34.6 $ (3.3 ) 15 Residential mortgage-backed securities 20.9 (0.1 ) 23 7.1 (0.2 ) 25 Asset-backed securities — — — 11.1 (0.1 ) 4 Total fixed maturity securities 54.4 (2.8 ) 40 52.8 (3.6 ) 44 Total 12 months or greater $ 54.4 $ (2.8 ) 40 $ 52.8 $ (3.6 ) 44 Total available-for-sale: Fixed maturity securities U.S. Treasuries $ — $ — — $ 27.4 $ (0.1 ) 20 Corporate securities 100.7 (5.2 ) 45 363.0 (8.0 ) 137 Residential mortgage-backed securities 20.9 (0.1 ) 23 57.6 (1.0 ) 49 Commercial mortgage-backed securities 7.3 (0.1 ) 2 51.5 (1.0 ) 22 Asset-backed securities — — — 45.2 (0.1 ) 31 Total fixed maturity securities 128.9 (5.4 ) 70 544.7 (10.2 ) 259 Equity securities 30.3 (1.5 ) 39 35.8 (4.6 ) 45 Total available-for-sale $ 159.2 $ (6.9 ) 109 $ 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 March 31, 2016 2015 (in millions) Net realized gains on investments Fixed maturity securities Gross gains $ 0.2 $ — Gross losses (0.1 ) — Net realized gains on fixed maturity securities $ 0.1 $ — Equity securities Gross gains $ 7.2 $ 1.5 Gross losses (5.8 ) (0.3 ) Net realized gains on equity securities $ 1.4 $ 1.2 Total $ 1.5 $ 1.2 Change in unrealized gains (losses) Fixed maturity securities $ 29.3 $ 14.1 Equity securities 1.2 (1.2 ) Total $ 30.5 $ 12.9
Investment income table	Net investment income was as follows: Three Months Ended March 31, 2016 2015 (in millions) Fixed maturity securities $ 16.7 $ 16.4 Equity securities 1.9 1.1 Gross investment income 18.6 17.5 Investment expenses (0.8 ) (0.6 ) Net investment income $ 17.8 $ 16.9

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 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. Three Months Ended March 31, 2016 2015 Expense computed at statutory rate 35.0 % 35.0 % Dividends received deduction and tax-exempt interest (8.2 ) (8.8 ) LPT deferred gain amortization (3.2 ) (4.2 ) Other 0.6 0.5 Effective tax rate 24.2 % 22.5 %

Liability for Unpaid Losses a20

Liability for Unpaid Losses and Loss Adjustment Expenses (Tables)	3 Months Ended
	Mar. 31, 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. Three Months Ended March 31, 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 110.7 107.6 Prior periods (0.3 ) 1.7 Total net losses and LAE incurred during the period 110.4 109.3 Paid losses and LAE, net of reinsurance, related to: Current period 4.7 4.1 Prior periods 104.5 98.1 Total net paid losses and LAE during the period 109.2 102.2 Ending unpaid losses and LAE, net of reinsurance 1,720.5 1,707.3 Reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE 621.4 663.0 Unpaid losses and LAE, gross of reinsurance, at end of period $ 2,341.9 $ 2,370.3

Accumulated Other Comprehensi21

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2016
Accumulated Other Comprehensive Income [Abstract]
Schedule of accumulated other comprehensive income (loss) table	The following table summarizes the components of accumulated other comprehensive income, net: March 31, 2016 December 31, 2015 (in millions) Net unrealized gain on investments, before taxes $ 159.1 $ 128.6 Deferred tax expense on net unrealized gains (55.7 ) (45.0 ) Total accumulated other comprehensive income, net $ 103.4 $ 83.6

Stock-Based Compensation Stock-

Stock-Based Compensation Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 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 (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. (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)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2016 2015 (in millions, except share data) Net income available to stockholders—basic and diluted $ 21.0 $ 14.0 Weighted average number of shares outstanding—basic 32,413,818 31,740,923 Effect of dilutive securities: PSUs 139,033 322,850 Stock options 238,582 310,899 RSUs 71,517 79,392 Dilutive potential shares 449,132 713,141 Weighted average number of shares outstanding—diluted 32,862,950 32,454,064
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 March 31, 2016 2015 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 80,800 267,444

FInancial Statement Notes DEI D

FInancial Statement Notes DEI Deferred reinsurance gain—LPT Agreement, LPT Reserve Adjustments, and LPT Contingent Commission Adjustments (Details) - USD ($) $ in Millions	Mar. 31, 2016	Mar. 31, 2015
Losses and LAE Note [Abstract]
Impact of the LPT Agreement	$ 3.1	$ 3.1

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2016
Basis of Presentation [Abstract]
Number of Operating Segments	1

FInancial Statement Notes DEI F

FInancial Statement Notes DEI FASB Issued (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accumulated other comprehensive income, net	$ 103,400	$ 83,600
Reclassification between AOCI and Retained earnings [Member]
Accumulated other comprehensive income, net	$ 64,200

New Accounting Standards Issued

New Accounting Standards Issued FASB (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Retained earnings	$ 700,100	$ 682,000
Reclassification between AOCI and Retained earnings [Member]
Retained earnings	$ 62,400

Fair Value of Financial Instr28

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	$ 2,520,200	$ 2,487,200
Investments, fair value	2,520,200	2,487,200
Cash and cash equivalents	70,800	56,600	$ 45,600	$ 103,600
Cash and cash equivalents, estimated fair value	70,800	56,600
Restricted cash and cash equivalents	4,200	2,500
Notes payable	32,000	32,000
Notes Payable, fair value	32,200	36,600
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments	32,900	32,700
Restricted cash and cash equivalents	$ 4,200	$ 2,500

Fair Value of Financial Instr29

Fair Value of Financial Instruments, Fair Value Inputs (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 2,520.2	$ 2,487.2
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	2,312.6	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
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	2,312.6	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
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	130.6	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
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	130.6	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
US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	24.4	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
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	24.4	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
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	863.3	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
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	863.3	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
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	940.1	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
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	940.1	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
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	244	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
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	244	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
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	80.1	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
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	80.1	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
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	30.1	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
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	30.1	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
Corporate equity securities [Domain]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	202.3	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	202.3	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
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
Federal Home Loan Bank Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	5.3
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
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
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	5.3	0
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	207.6	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	202.3	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
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	$ 5.3	$ 0

Fair Value of Financial Instr30

Fair Value of Financial Instruments Fair Value of Financial Instruments, Reconciliation of Level 3 Securities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments	$ 2,520.2	$ 2,487.2
Purchases, Issuances, Settlements, net	5.3
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments	207.6	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	$ 5.3	$ 0

Investments (Details)

Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 2,361,100	$ 2,358,600
Gross unrealized gain	166,000	143,400
Gross unrealized loss	(6,900)	(14,800)
Investments	2,520,200	2,487,200
Deposit Assets
Investments	2,520,200	2,487,200
Assets Held-in-trust
Investments	2,520,200	2,487,200
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	2,215,900	2,221,100
Gross unrealized gain	102,100	77,600
Gross unrealized loss	(5,400)	(10,200)
Investments	2,312,600	2,288,500
Deposit Assets
Investments	2,312,600	2,288,500
Assets Held-in-trust
Investments	2,312,600	2,288,500
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	125,100	116,400
Gross unrealized gain	5,500	3,900
Gross unrealized loss	0	(100)
Investments	130,600	120,200
Deposit Assets
Investments	130,600	120,200
Assets Held-in-trust
Investments	130,600	120,200
US Government Agencies Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	23,000	23,000
Gross unrealized gain	1,400	1,400
Gross unrealized loss	0	0
Investments	24,400	24,400
Deposit Assets
Investments	24,400	24,400
Assets Held-in-trust
Investments	24,400	24,400
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	810,800	809,400
Gross unrealized gain	52,500	45,100
Gross unrealized loss	0	0
Investments	863,300	854,500
Deposit Assets
Investments	863,300	854,500
Assets Held-in-trust
Investments	863,300	854,500
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	912,900	913,400
Gross unrealized gain	32,400	19,900
Gross unrealized loss	(5,200)	(8,000)
Investments	940,100	925,300
Deposit Assets
Investments	940,100	925,300
Assets Held-in-trust
Investments	940,100	925,300
Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	235,200	231,800
Gross unrealized gain	8,900	7,100
Gross unrealized loss	(100)	(1,000)
Investments	244,000	237,900
Deposit Assets
Investments	244,000	237,900
Assets Held-in-trust
Investments	244,000	237,900
Commercial Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	78,900	81,100
Gross unrealized gain	1,300	200
Gross unrealized loss	(100)	(1,000)
Investments	80,100	80,300
Deposit Assets
Investments	80,100	80,300
Assets Held-in-trust
Investments	80,100	80,300
Asset-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	30,000	46,000
Gross unrealized gain	100	0
Gross unrealized loss	0	(100)
Investments	30,100	45,900
Deposit Assets
Investments	30,100	45,900
Assets Held-in-trust
Investments	30,100	45,900
Corporate equity securities [Domain]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	139,900	137,500
Gross unrealized gain	63,900	65,800
Gross unrealized loss	(1,500)	(4,600)
Investments	202,300	198,700
Deposit Assets
Investments	202,300	198,700
Assets Held-in-trust
Investments	202,300	198,700
Federal Home Loan Bank Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	5,300
Gross unrealized gain	0
Gross unrealized loss	0
Investments	5,300
Deposit Assets
Investments	5,300
Assets Held-in-trust
Investments	5,300
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	145,200	137,500
Gross unrealized gain	63,900	65,800
Gross unrealized loss	(1,500)	(4,600)
Investments	207,600	198,700
Deposit Assets
Investments	207,600	198,700
Assets Held-in-trust
Investments	207,600	198,700
Fair Value Measurement [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments	32,900	32,700
Deposit Assets
Investments	32,900	32,700
Assets Held-in-trust
Investments	32,900	32,700
Fair Value Measurement [Member] | Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments	1,032,300	881,200
Deposit Assets
Investments	1,032,300	881,200
Assets Held-in-trust
Investments	$ 1,032,300	$ 881,200

Investments, Amortized Cost and

Investments, Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less, amortized cost	$ 132,800
Due after one year through five years, amortized cost	869,800
Due after five years through ten years, amortized cost	612,300
Due after ten years, amortized cost	256,900
Mortgage and asset-backed securities, amortized cost	344,100
Total, amortized cost	2,215,900
Estimated Fair Value
Due in one year or less, fair value	134,400
Due after one year through five years, fair value	902,000
Due after five years through ten years, fair value	647,100
Due after ten years, fair value	274,900
Mortgage and asset-backed securities, fair value	354,200
Total, fair value	$ 2,312,600	$ 2,288,500

Investments, Continuous Loss Po

Investments, Continuous Loss Position (Details)	3 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)
Estimated Fair Value
Estimated fair value, less than 12 months	$ 104,800,000		$ 527,700,000
Estimated fair value, 12 months or greater	54,400,000		52,800,000
Estimated fair value, total	159,200,000		580,500,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(4,100,000)		(11,200,000)
Gross unrealized losses, 12 months or greater	2,800,000		3,600,000
Estimated unrealized losses, total	$ (6,900,000)		$ (14,800,000)
Number of issues in loss position, less than 12 months	69		260
Number of Issues in loss position, 12 months or greater	40		44
Number of issues loss position, aggregate	109		304
Other than temporary impairment, credit losses recognized in earnings	$ 5,300,000	$ 0
Total impairments, number of securities	32
Debt Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 74,500,000		$ 491,900,000
Estimated fair value, 12 months or greater	54,400,000		52,800,000
Estimated fair value, total	128,900,000		544,700,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(2,600,000)		(6,600,000)
Gross unrealized losses, 12 months or greater	2,800,000		3,600,000
Estimated unrealized losses, total	$ (5,400,000)		$ (10,200,000)
Number of issues in loss position, less than 12 months	30		215
Number of Issues in loss position, 12 months or greater	40		44
Number of issues loss position, aggregate	70		259
US Treasury Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 27,400,000
Estimated fair value, total	0		27,400,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		(100,000)
Estimated unrealized losses, total	$ 0		$ (100,000)
Number of issues in loss position, less than 12 months	0		20
Number of issues loss position, aggregate	0		20
Corporate Debt Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 67,200,000		$ 328,400,000
Estimated fair value, 12 months or greater	33,500,000		34,600,000
Estimated fair value, total	100,700,000		363,000,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(2,500,000)		(4,700,000)
Gross unrealized losses, 12 months or greater	2,700,000		3,300,000
Estimated unrealized losses, total	$ (5,200,000)		$ (8,000,000)
Number of issues in loss position, less than 12 months	28		122
Number of Issues in loss position, 12 months or greater	17		15
Number of issues loss position, aggregate	45		137
Residential Mortgage Backed Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 50,500,000
Estimated fair value, 12 months or greater	20,900,000		7,100,000
Estimated fair value, total	20,900,000		57,600,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		(800,000)
Gross unrealized losses, 12 months or greater	100,000		200,000
Estimated unrealized losses, total	$ (100,000)		$ (1,000,000)
Number of issues in loss position, less than 12 months	0		24
Number of Issues in loss position, 12 months or greater	23		25
Number of issues loss position, aggregate	23		49
Commercial Mortgage Backed Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 7,300,000		$ 51,500,000
Estimated fair value, total	7,300,000		51,500,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(100,000)		(1,000,000)
Estimated unrealized losses, total	$ (100,000)		$ (1,000,000)
Number of issues in loss position, less than 12 months	2		22
Number of issues loss position, aggregate	2		22
Asset-backed Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 0		$ 34,100,000
Estimated fair value, 12 months or greater	0		11,100,000
Estimated fair value, total	0		45,200,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	0		0
Gross unrealized losses, 12 months or greater	0		100,000
Estimated unrealized losses, total	$ 0		$ (100,000)
Number of issues in loss position, less than 12 months	0		0
Number of Issues in loss position, 12 months or greater	0		4
Number of issues loss position, aggregate	0		0
Equity Securities [Member]
Estimated Fair Value
Estimated fair value, less than 12 months	$ 30,300,000		$ 35,800,000
Estimated fair value, total	30,300,000		35,800,000
Gross Unrealized Losses
Gross unrealized losses, less than 12 months	(1,500,000)		(4,600,000)
Estimated unrealized losses, total	$ (1,500,000)		$ (4,600,000)
Number of issues in loss position, less than 12 months	39		45
Number of issues loss position, aggregate	39		45

Investments, Net Realized Gains

Investments, Net Realized Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net realized gains (losses)
Net realized gains (losses) on fixed maturity and equity securities	$ 1.5	$ 1.2
Change in unrealized gains (losses)
Change in unrealized gains (losses) on fixed maturity and equity securities	30.5	12.9
Debt Securities [Member]
Net realized gains (losses)
Gross gains from sales	0.2	0
Gross losses from sales	0.1	0
Net realized gains (losses) on fixed maturity and equity securities	0.1	0
Change in unrealized gains (losses)
Change in unrealized gains (losses) on fixed maturity and equity securities	29.3	14.1
Equity Securities [Member]
Net realized gains (losses)
Gross gains from sales	7.2	1.5
Gross losses from sales	5.8	0.3
Net realized gains (losses) on fixed maturity and equity securities	1.4	1.2
Change in unrealized gains (losses)
Change in unrealized gains (losses) on fixed maturity and equity securities	$ 1.2	$ (1.2)

Net Investment Income (Details)

Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	$ 18.6	$ 17.5
Investment expenses	0.8	0.6
Net investment income	17.8	16.9
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	16.7	16.4
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income related to equity securities	$ 1.9	$ 1.1

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Expense computed at statutory rate	35.00%	35.00%
Dividends received deduction and tax-exempt interest	(8.20%)	(8.80%)
LPT deferred gain amortization	(3.20%)	(4.20%)
Other	0.60%	0.50%
Effective tax rate	24.20%	22.50%

Liability for Unpaid Losses a37

Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 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	110,700	107,600
Prior periods	(300)	1,700
Total net losses and LAE incurred during the period	110,400	109,300
Deduct payments for losses and LAE, net of reinsurance, related to:
Current period	4,700	4,100
Prior periods	104,500	98,100
Total net paid losses and LAE during the period	109,200	102,200
Ending unpaid losses and LAE, net of reinsurance	1,720,500	1,707,300
Reinsurance recoverable, excluding bad debt allowance, on unpaid losses and LAE	621,400	663,000
Unpaid losses and LAE, gross of reinsurance, at end of period	2,341,900	2,370,300
LPT Agreement [Abstract]
Impact of the LPT Agreement	$ 3,100	$ 3,100

LPT Agreement LPT Agreement (De

LPT Agreement LPT Agreement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 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	3,100	$ 2,900
Deferred reinsurance gain—LPT Agreement	186,400		$ 189,500
Estimated remaining liabilities - LPT Agreement	490,800		498,000
Paid losses and LAE claims related to LPT	702,400		$ 695,200
Change to Contingent Profit Commission [Member]
Reinsurance Agreement [Line Items]
Cumulative adjustment to the Deferred Gain		$ 200
Indemnification Agreement [Member]
Reinsurance Agreement [Line Items]
Coverage provided under LPT Agreement	$ 2,000,000

Accumulated Other Comprehensi39

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized gain on investments, before taxes	$ 159,100	$ 128,600
Deferred tax expense on net unrealized gains	(55,700)	(45,000)
Accumulated other comprehensive income, net	$ 103,400	$ 83,600

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-options exercised		262,239	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]	80,816
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	[1]	$ 2.2
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]	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.(2)
[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)

Earnings Per Share (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income available to stockholders - basic and diluted	$ 21,000	$ 14,000
Weighted average number of shares outstanding - basic	32,413,818	31,740,923
Effect of dilutive securities:
Dilutive securities	449,132	713,141
Weighted average number of shares outstanding - diluted	32,862,950	32,454,064
Antidilutive securites excluded under the treasury method from computation of earnings per share	80,800	267,444
Employee Stock Option [Member]
Effect of dilutive securities:
Dilutive securities	238,582	310,899
Restricted Stock Units (RSUs) [Member]
Effect of dilutive securities:
Dilutive securities	71,517	79,392
Performance Shares [Member]
Effect of dilutive securities:
Dilutive securities	139,033	322,850