Employers (EIG) 10-K 28 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 14, 2019	Jun. 30, 2018
Document and Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
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 Emerging Growth Company	false
Entity Small Business	false
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Common Stock Shares Outstanding		32,829,863
Entity Public Float			$ 1,109,698,729
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Investments:
Fixed maturity securities at fair value (amortized cost $2,513.7 at December 31, 2018 and $2,421.0 at December 31, 2017)	$ 2,496,400	$ 2,463,400
Equity securities at fair value (cost $131.9 at December 31, 2018)	199,900	0
Equity securities, at fair value (cost $116.7 at December 31, 2017)	0	210,300
Equity securities at cost	6,400
Short-term investments at fair value (amortized cost $25.0 at December 31, 2018 and $4.0 at December 31, 2017)	25,000	4,000
Total investments	2,727,700	2,677,700
Cash and cash equivalents	101,400	73,300
Restricted cash and cash equivalents	600	1,000
Accrued investment income	18,000	19,600
Premiums receivable (less bad debt allowance of $6.7 at December 31, 2018 and $10.0 at December 31, 2017)	333,100	326,700
Reinsurance recoverable for:
Paid losses	6,700	7,200
Unpaid losses	504,400	537,000
Deferred policy acquisition costs	48,200	45,800
Deferred income taxes, net	26,900	28,700
Property and equipment, net	18,200	13,900
Intangible assets, net	7,700	7,900
Goodwill	36,200	36,200
Contingent commission receivable–LPT Agreement	32,000	31,400
Cloud computing arrangements	26,000	0
Other assets	32,100	33,700
Total assets	3,919,200	3,840,100
Liabilities and stockholders’ equity
Unpaid losses and loss adjustment expenses	2,207,900	2,266,100
Unearned premiums	336,300	318,300
Commissions and premium taxes payable	57,300	55,300
Accounts payable and accrued expenses	37,100	23,700
Deferred reinsurance gain—LPT Agreement	149,600	163,600
Notes payable	20,000	20,000
Non-cancellable obligations	18,800	2,700
Other liabilities	74,000	42,700
Total liabilities	2,901,000	2,892,400
Commitments and contingencies (Note 12)
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 56,975,675 and 56,695,174 shares issued and 32,765,792 and 32,597,819 shares outstanding at December 31, 2018 and 2017, respectively	600	600
Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued	0	0
Additional paid-in capital	388,800	381,200
Retained earnings	1,030,700	842,200
Accumulated other comprehensive (loss) income, net of tax	(13,700)	107,400
Treasury stock, at cost (24,209,883 shares at December 31, 2018 and 24,097,355 shares at December 31, 2017)	(388,200)	(383,700)
Total stockholders’ equity	1,018,200	947,700
Total liabilities and stockholders’ equity	$ 3,919,200	$ 3,840,100

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Dec. 31, 2018		Dec. 31, 2017
Investments:
Amortized cost	$ 0		$ 2,541.7
Debt securities, available-for-sale, amortized cost	2,513.7		0
Equity Securities, available for sale	0		210.3
Equity Securities, FV-NI, Cost	131.9		0
Premiums receivable, bad debt allowance	$ 6.7		$ 10
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)	56,975,675		56,695,174
Common stock, shares outstanding (in shares)	32,765,792		32,597,819
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)	24,209,883		24,097,355
Debt Securities [Member]
Investments:
Amortized cost	$ 0		$ 2,421
Equity Securities [Member]
Investments:
Amortized cost	0		116.7
Short-term Investments [Member]
Investments:
Amortized cost	0		4
Total AFS, amortized cost	$ 25	[1]	$ 0
[1]	Other securities within fixed maturity securities consist of bank loans, which are classified as AFS and reported at fair value.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net premiums earned	$ 731.1	$ 716.5	$ 694.8
Net investment income	81.2	74.6	73.2
Net realized and unrealized (losses) gains on investments	(13.1)	7.4	11.2
Gain on redemption of notes payable	0	2.1	0
Other income	1.2	0.8	0.6
Total revenues	800.4	801.4	779.8
Expenses
Losses and loss adjustment expenses	376.7	417.2	417.9
Commission expense	94.2	91.4	83.5
Underwriting and other operating expenses	158.5	139.9	136.1
Interest and financing expenses	1.5	1.4	1.6
Other expenses	0	7.5	0
Total expenses	630.9	657.4	639.1
Net income before income taxes	169.5	144	140.7
Income tax expense	28.2	42.8	34
Net income	141.3	101.2	106.7
Comprehensive income
Unrealized AFS investment (losses) gains during the period (net of tax benefit (expense) of $12.9, $(8.9), and $1.0 for the years ended December 31, 2018, 2017, and 2016, respectively)	(48.5)	19.9	(1.8)
Reclassification adjustment for realized AFS investment losses (gains) in net income (net of tax benefit (expense) of $0.4, $(2.6), and $(3.9) for the years ended December 31, 2018, 2017, and 2016, respectively)	1.4	(4.8)	(7.3)
Other comprehensive (loss) income, net of tax	(47.1)	15.1	(9.1)
Total comprehensive income	94.2	116.3	97.6
Net realized and unrealized (losses) gains on investments
Net realized and unrealized (losses) gains on investments before impairments	(9.8)	8.8	17
Other than temporary impairments recognized in earnings	(3.3)	(1.4)	(5.8)
Net realized and unrealized (losses) gains on investments	$ (13.1)	$ 7.4	$ 11.2
Earnings per common share (Note 18):
Basic	$ 4.30	$ 3.11	$ 3.29
Diluted	4.24	3.06	3.24
Cash dividends declared per common share and eligible RSUs and PSUs	$ 0.80	$ 0.60	$ 0.36

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Comprehensive Income Parenthetical [Abstract]
Other comprehensive income (loss), unrealized holding gain (loss) on securities arising during period, tax	$ 12.9	$ (8.9)	$ 1
Other comprehensive income (loss), reclassification adjustment for sale of securities included in net income, tax	$ 0.4	$ (2.6)	$ (3.9)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income, Net	Treasury Stock at Cost
Stockholders' equity, shares at Dec. 31, 2015		55,589,454
Stockholders' equity, value at Dec. 31, 2015	$ 760,800	$ 600	$ 357,200	$ 682,000	$ 83,600	$ (362,600)
Stock-based compensation (Note 14), shares		0
Stock-based compensation (Note 14), value	5,800	$ 0	5,800	0	0	0
Stock-options exercised, shares		586,132
Stock options exercised, value	9,600	$ 0	9,600	0	0	0
Vesting of restricted stock units, net of shares withheld to satisfy minimum tax withholding (Note 14), shares		50,691
Vesting of restricted stock units, net of shares withheld to satisfy minimum tax withholding (Note 14), value	(600)	$ 0	(600)	0	0	0
Acquisition of treasury stock (Note 13), shares		0
Acquisition of treasury stock (Note 13), value	(21,100)	$ 0	0	0	0	(21,100)
Dividend to common stockholders, shares		0
Dividend to common stockholders, value	11,500	$ 0	0	11,500	0	0
Stockholders' equity, shares at Dec. 31, 2016		56,226,277
Net income for the period	106,700	$ 0	0	106,700	0	0
Change in net unrealized gains on investments, net of taxes	(9,100)	0	0	0	(9,100)	0
Stockholders' equity, value at Dec. 31, 2016	840,600	$ 600	372,000	777,200	74,500	(383,700)
Stock-based compensation (Note 14), shares		0
Stock-based compensation (Note 14), value	6,900	$ 0	6,900	0	0	0
Stock-options exercised, shares		307,076
Stock options exercised, value	6,000	$ 0	6,000	0	0	0
Vesting of restricted stock units, net of shares withheld to satisfy minimum tax withholding (Note 14), shares		161,821
Vesting of restricted stock units, net of shares withheld to satisfy minimum tax withholding (Note 14), value	(2,200)	$ 0	(2,200)	0	0	0
Grant date fair value adjustment	200	$ 0	1,500	1,300	0	0
Dividend to common stockholders, shares		0
Dividend to common stockholders, value	$ 19,700	$ 0	0	19,700	0	0
Stockholders' equity, shares at Dec. 31, 2017	56,695,174	56,695,174
Net income for the period	$ 101,200	$ 0	0	101,200	0	0
Net impact of tax enactment on net unrealized gains on investments	0	0	0	(17,800)	17,800	0
Change in net unrealized gains on investments, net of taxes	15,100	0	0	0	15,100	0
Stockholders' equity, value at Dec. 31, 2017	947,700	$ 600	381,200	842,200	107,400	(383,700)
Stock-based compensation (Note 14), shares		0
Stock-based compensation (Note 14), value	9,400	$ 0	9,400	0	0	0
Stock-options exercised, shares		57,091
Stock options exercised, value	1,100	$ 0	1,100	0	0	0
Vesting of restricted stock units, net of shares withheld to satisfy minimum tax withholding (Note 14), shares		223,410
Vesting of restricted stock units, net of shares withheld to satisfy minimum tax withholding (Note 14), value	(2,900)	$ 0	(2,900)	0	0	0
Acquisition of treasury stock (Note 13), shares		0
Acquisition of treasury stock (Note 13), value	(4,600)	$ 0	0	0	0	(4,600)
Dividend to common stockholders, shares		0
Dividend to common stockholders, value	$ 26,700	$ 0	0	26,700	0	0
Stockholders' equity, shares at Dec. 31, 2018	56,975,675	56,975,675
Net income for the period	$ 141,300	$ 0	0	141,300	0	0
Change in net unrealized gains on investments, net of taxes	(47,100)	0	0	0	(47,100)	0
Stockholders' equity, value at Dec. 31, 2018	1,018,200	600	388,800	1,030,700	(13,700)	(388,200)
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 0	$ 0	$ 0	$ 74,000	$ (74,000)	$ 0

Consolidated Stockholders Equit

Consolidated Stockholders Equity (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stockholders Equity Parenthetical [Abstract]
Change in net unrealized gains on investments, net of tax of	$ 12.5	$ (6.3)	$ 4.9

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 141.3	$ 101.2	$ 106.7
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	6.3	8.2	8.5
Stock-based compensation	9.4	6.8	5.8
Amortization of premium on investments, net	8.4	14.3	14.6
Allowance for doubtful accounts	(3.3)	0.2	(2.4)
Deferred income tax expense	14.4	24.2	13.4
Net realized and unrealized losses (gains) on investments	13.1	(7.4)	(11.2)
Gain on redemption of notes payable	0	(2.1)	0
Write-off of previously capitalized costs	0	7.5	0
Change in operating assets and liabilities:
Premiums receivable	(3.1)	(22.2)	(1.2)
Reinsurance recoverable on paid and unpaid losses	33.1	44.5	47.2
Cloud Computing Arrangements CF	(26)	0	0
Current federal income taxes	8.6	(2.7)	7.7
Unpaid losses and loss adjustment expenses	(58.2)	(34.9)	(46.5)
Unearned premiums	18	8	1.4
Accounts payable, accrued expenses and other liabilities	19.1	(7)	(4.2)
Deferred reinsurance gain–LPT Agreement	(14)	(11.3)	(14.6)
Non Cancellable Obligations CF	16.1	2.7	0
Other	(3)	12.3	(2.4)
Net cash provided by operating activities	180.2	142.3	122.8
Investing activities
Purchases of fixed maturity securities	(636.7)	(592.3)	(466.8)
Purchases of equity securities	(79.3)	(36.8)	(49.1)
Purchases of short-term investments	(59.7)	(8.2)	(10)
Proceeds from sale of fixed maturity securities	204.8	249.8	132.4
Proceeds from sale of equity securities	70.7	41.2	80.4
Proceeds from maturities and redemptions of fixed maturity securities	329.4	215.7	230.6
Proceeds from maturities of short-term investments	39	20.2	0
Net change in unsettled investment purchases and sales	22.4	5.8	0
Capital expenditures and other	(10.2)	(8.2)	(5)
Net cash used in investing activities	(119.6)	(112.8)	(87.5)
Financing activities
Acquisition of common stock	(4.2)	0	(21.1)
Cash transactions related to stock-based compensation	(1.8)	3.8	9
Dividends paid to stockholders	(26.7)	(19.7)	(11.5)
Redemption of notes payable	0	(9.9)	0
Payments on capital leases	(0.2)	(0.2)	0
Net cash used in financing activities	(32.9)	(26)	(23.6)
Net increase in cash, cash equivalents, and restricted cash	27.7	3.5	11.7
Cash, cash equivalents, and restricted cash at the beginning of the period	74.3	70.8	59.1
Cash, cash equivalents, and restricted cash at the end of the period	102	74.3	70.8
Non-cash transactions
Financed property and equipment purchases	0.3	0.4	0.7
Non-cash exchange of fixed maturity investments for short-term investments	0	0	6
Cash, cash equivalents, and restricted cash
Total cash, cash equivalents, and restricted cash	$ 74.3	$ 70.8	$ 59.1

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2018
Basis of Presentation [Abstract]
Basis of Presentation	Basis of Presentation and Summary of Operations Nature of Operations and Organization 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. In 1999, the Nevada State Industrial Insurance System (the Fund) entered into a retroactive 100% quota share reinsurance agreement (the LPT Agreement) through a loss portfolio transfer transaction with third party reinsurers. The LPT Agreement commenced on June 30, 1999 and will remain in effect until all claims under the covered policies have closed, the LPT Agreement is commuted or terminated, upon the mutual agreement of the parties, or the reinsurers' aggregate maximum limit of liability is exhausted, whichever occurs first. The LPT Agreement does not provide for any additional termination terms. On January 1, 2000, EICN assumed all of the assets, liabilities and operations of the Fund, including the Fund's rights and obligations associated with the LPT Agreement. See Notes 3 and 10 . The Company accounts for the LPT Agreement as retroactive reinsurance. Upon entry into the LPT Agreement, an initial deferred reinsurance gain (the Deferred Gain) was recorded as a liability on the Company’s Consolidated Balance Sheets. The Company is entitled to receive a contingent profit commission under the LPT Agreement. The contingent profit commission is estimated based on both actual paid results to date and projections of expected paid losses under the LPT Agreement and is recorded as an asset on the Company's Consolidated Balance Sheets. Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). All intercompany transactions and balances have been eliminated in consolidation. The Company operates as a single operating segment, workers’ compensation insurance, through its wholly owned subsidiaries. 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. 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, recoverability of deferred income taxes, and valuation of investments. Reclassifications Certain prior period information has been reclassified to conform to the current period presentation. Pending Acquisition On August 11, 2017, the Company entered into a stock purchase agreement (Purchase Agreement), as amended on October 25, 2018, with Partner Reinsurance Company of the U.S. (PRUS) with respect to the acquisition (Acquisition) of all of the outstanding shares of capital stock of PartnerRe Insurance Company of New York (PRNY). The purchase price is equal to the sum of: (i) the amount of statutory capital and surplus of PRNY at closing (which is currently estimated to be approximately $40.0 million ); and (ii) $5.8 million . The Company expects to fund the Acquisition with cash on hand. Pursuant to the Purchase Agreement, all liabilities and obligations of PRNY existing as of the closing date, whether known or unknown, will be indemnified by PRUS. In addition, PartnerRe Ltd., the parent company of PRUS, has provided the Company with a Guaranty that unconditionally, absolutely and irrevocably guarantees the full and prompt payment and performance by PRUS of all of its obligations, liabilities and indemnities under the Purchase Agreement and the transactions contemplated thereby. The Company will not be acquiring any employees or ongoing business operations pursuant to the Acquisition. The Acquisition is subject to certain closing conditions, including, among other things, approval from the Department of Financial Services of the State of New York.

Changes in Estimates Level 1 (N

Changes in Estimates Level 1 (Notes)	12 Months Ended
	Dec. 31, 2018
Changes in Estimates [Abstract]
Accounting Changes and Error Corrections	Changes in Estimates The Company reduced its estimated loss and LAE reserves ceded under the LPT Agreement (LPT Reserve Adjustments) in each of the years 2018 and 2016 as a result of the determination that adjustments were necessary to reflect observed favorable paid loss trends in each of these years. There were no LPT Reserve Adjustments in 2017. The following table shows the financial statement impact related to the LPT Reserve Adjustments. 2018 2016 (in millions, except per share data) LPT Reserve Adjustments $ (6.3 ) $ (5.0 ) Cumulative adjustment to the Deferred Gain (1) (2.2 ) (3.1 ) Net income impact from this change in estimate 2.2 3.1 Earnings per common share impact from this change in estimate: Basic 0.07 0.10 Diluted 0.07 0.09 (1) The cumulative adjustments to the Deferred Gain were also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised loss and LAE reserves been recognized at the inception of the LPT Agreement. The Company increased its estimate of Contingent commission receivable – LPT Agreement (LPT Contingent Commission Adjustments) in each of 2018 , 2017 , and 2016 as a result of the determination that adjustments were necessary to reflect observed favorable paid loss trends in each of those years. The following table shows the impact to the Consolidated Statements of Comprehensive Income related to these changes in estimates. 2018 2017 2016 (in millions, except per share data) LPT Contingent Commission Adjustments $ 0.5 $ 0.3 $ 1.9 Net income impact from this change in estimate 0.5 0.3 1.8 Earnings per common share impact from this change in estimate: Basic 0.02 0.01 0.06 Diluted 0.02 0.01 0.05

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Significant Accounting Policies	Summary of Significant Accounting Policies Cash and Cash Equivalents The Company considers all liquid investments with maturities of less than three months, as measured from the date of purchase, to be cash equivalents. Restricted Cash and Cash Equivalents Restricted cash and cash equivalents represent cash and cash equivalents held in trust in order to secure certain of the Company's obligations and, accordingly, are restricted as to withdrawal or usage. As of December 31, 2018 and 2017 the Company held $23.2 million and $24.5 million , respectively, in cash and investments in trust for reinsurance obligations, of which $0.6 million and $1.0 million , respectively, represented restricted cash and cash equivalents. Short-Term Investments The Company considers all liquid investments with maturities of between three and twelve months, as measured from the date of purchase, to be short-term investments. Investment Securities The Company's investments in fixed maturity securities, equity securities at fair value (prior to 2018), and short-term investments are classified as available-for-sale (AFS) and are reported at fair value with unrealized gains and losses excluded from earnings and reported as a separate component of stockholders' equity, net of deferred taxes, in Accumulated other comprehensive (loss) income on the Company’s Consolidated Balance Sheets. Beginning in 2018, with the adoption of ASU Number 2016-01, Financial Instruments - Overall (Subtopic 825-10) , the Company's investments in equity securities at fair value are no longer classified as AFS and changes in fair value are included in Net realized and unrealized (losses) gains on investments on the Company's Consolidated Statements of Comprehensive Income. Effective January 1, 2018, the Company's investment in FHLB stock is presented within Equity securities at cost on the Company's Consolidated Balance Sheets. As of December 31, 2017, the Company's investment in FHLB stock was presented within Equity securities at fair value on the Company's Consolidated Balance Sheet. The adoption of ASU 2016-01 also removed the impairment assessment for equity securities at fair value beginning in 2018 and changes in fair value are included in Net realized and unrealized (losses) gains on investments on the Company's Consolidated Statements of Comprehensive Income. Prior to adoption of this standard, when, in the opinion of management, a decline in the fair value of an equity security below its cost was considered to be “other-than-temporary,” the equity security's cost was written down to its fair value at the time the other-than-temporary decline is identified. The determination of an other-than-temporary decline for fixed maturity securities includes, in addition to other relevant factors, a presumption that if the market value is below cost by a significant amount for a period of time, a bifurcation of the write-down may be necessary based on the portion of the loss that is deemed to be a “credit loss”, which is considered a realized loss, and the portion that is deemed to be an “other than credit loss”, which is considered to be an unrealized loss. If management has the intent to sell the fixed maturity security or more likely than not will be required to sell the fixed maturity security before its anticipated recovery, the investment is written down to its fair value and the entire impairment is recorded as a realized loss in the Company's Consolidated Statements of Comprehensive Income. If management does not have the intent to sell or will not be required to sell the fixed maturity security but does not expect to recover the amortized cost basis of the fixed maturity security, the amount of the other-than-temporary impairment is bifurcated (see Note 6 ). Investment income consists primarily of interest and dividends generated by investment securities. Interest is recorded as earned on an accrual basis and dividends are recorded as earned at the ex-dividend date. Interest income on mortgage-backed and asset-backed securities is determined using the effective-yield method based on estimated principal repayments. Mortgage-backed securities are adjusted for the effects of changes in prepayment assumptions on the related accretion of discount or amortization of premium of such securities using the retrospective method. Realized gains and losses on investments are determined on a specific-identification basis. Recognition of Revenue and Expense Revenue Recognition Premiums written are recognized as revenues, net of any applicable underlying reinsurance coverage, and are earned over the term of the related policy. At the end of the policy term, payroll-based premium audits are performed on substantially all policyholder accounts to determine the actual amount of net premiums earned for that policy year. Earned but unbilled premiums include estimated future audit premiums based on the Company's historical experience. These estimates are subject to changes in policyholders' payrolls, economic conditions, and seasonality, and are continually reviewed and adjusted as experience develops or new information becomes known. Any such adjustments are included in current operations; however, they are partially offset by the resulting changes in losses and LAE, commission expenses, and premium taxes. The Company's premiums receivable on its Consolidated Balance Sheets included $63.7 million and $64.2 million of additional premiums expected to be received from policyholders for final audits at December 31, 2018 and 2017 , respectively. The Company establishes a bad debt allowance on its premiums receivable through a charge included in underwriting and other operating expenses in its Consolidated Statements of Comprehensive Income. This bad debt allowance is determined based on estimates and assumptions to project future experience. After all collection efforts have been exhausted, the Company reduces the bad debt allowance for write-offs of premiums receivable that have been deemed uncollectible. The Company's bad debt allowance was $6.7 million and $10.0 million at December 31, 2018 and 2017 , respectively. The Company had write offs, net of recoveries of amounts previously written off, of $8.2 million , $3.2 million , and $6.0 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. Deferred Policy Acquisition Costs Policy acquisition costs, those costs that relate directly to the successful acquisition of new or renewal insurance contracts, including underwriting, policy issuance and processing, medical and inspection, and sales force contract selling are deferred and amortized as the related premiums are earned. Amortization of deferred policy acquisition costs for the years ended December 31, 2018 , 2017 , and 2016 , was $112.0 million , $108.2 million , and $104.5 million , respectively. If the sum of a policy’s expected losses and LAE and deferred policy acquisition costs exceeds the related unearned premiums and projected investment income, a premium deficiency is determined to exist. In this event, deferred policy acquisition costs are immediately expensed to the extent necessary to eliminate the premium deficiency. If the premium deficiency exceeds deferred acquisition costs, a liability is accrued for the excess deficiency. There were no premium deficiency adjustments recognized during the years ended December 31, 2018 , 2017 , and 2016 . Unpaid Loss and LAE Reserves Unpaid loss and LAE reserves represent management's best estimate of the ultimate net cost of all reported and unreported losses incurred for the applicable periods, less payments made. The estimated reserves for losses and LAE include the accumulation of estimates for all claims reported prior to the balance sheet date, estimates of claims incurred but not reported, and estimates of expenses for investigating and adjusting all incurred and unadjusted claims (based on projections of relevant historical data). Amounts reported are subject to the impact of future changes in economic, regulatory and social conditions. Management believes that, subject to the inherent variability in any such estimate, the reserves are within a reasonable and acceptable range of adequacy. Estimates for claims prior to the balance sheet date are continually monitored and reviewed, and as settlements are made or reserves adjusted, the differences are reported in current operations. Salvage and subrogation recoveries are estimated based on a review of the level of historical salvage and subrogation recoveries. Reinsurance In the ordinary course of business, the Company purchases excess of loss reinsurance in order to protect it against the impact of large and/or catastrophic losses. Additionally, the Company is a party to the LPT Agreement (see Note 10 ). These reinsurance arrangements reduce the Company's exposure to such losses since its reinsurers are liable to the Company to the extent of the reinsurance protection provided. However, the Company remains liable for all losses it incurs to the extent that any reinsurer is unable or unwilling to make timely payments under its reinsurance agreements. Balances due from reinsurers on unpaid losses, including an estimate of such recoverables related to reserves for incurred but not reported losses, are reported as reinsurance recoverables on the Company’s Consolidated Balance Sheets. Reinsurance recoverables on paid losses represents amounts currently due from reinsurers. Reinsurance recoverables on unpaid losses represents amounts that will be collectible from reinsurers once the losses are paid. Reinsurance recoverables on unpaid losses and LAE amounted to $504.4 million and $537.0 million at December 31, 2018 and 2017 , respectively. Ceded reinsurance premiums are accounted for on a basis consistent with those used in accounting for the underlying premiums, and are reported as reductions to arrive at net premiums written and earned. Ceded losses and LAE are also accounted for on a basis consistent with those used in accounting for the original policies issued and the terms of the relevant reinsurance agreement, and are recorded as reductions to losses and LAE incurred. Pursuant to the LPT Agreement, LAE is deemed to be 7% of total losses paid and is payable to the Company as compensation for management of the claims under the LPT Agreement. The Deferred Gain is amortized using the recovery method, whereby the amortization is determined by the proportion of actual reinsurance recoveries to total estimated recoveries through the life of the LPT Agreement, and is recorded in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income. Any adjustment to the estimated loss and LAE reserves ceded under the LPT Agreement results in a cumulative adjustment to the Deferred Gain, which is also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, such that the Deferred Gain reflects the balance that would have existed had the revised reserves been recognized at the inception of the LPT Agreement. Additionally, the Company is entitled to receive a contingent profit commission under the LPT Agreement. The contingent profit commission is equal to 30% of the favorable difference between actual paid losses and LAE and expected paid losses and LAE as established in the LPT Agreement based on losses paid through June 30, 2024. The contingent profit commission is paid every five years beginning June 30, 2004 for the first 25 years of the agreement. The Company could be required to return any previously received contingent profit commission, plus interest, in the event of unfavorable differences through June 30, 2024. The Company records an estimate of contingent profit commission in its Consolidated Balance Sheets as Contingent commission receivable–LPT Agreement and a corresponding liability is recorded as Deferred reinsurance gain–LPT Agreement. The Contingent commission receivable–LPT Agreement is reduced as amounts are received from participating reinsurers. The Deferred reinsurance gain–LPT Agreement is amortized using the recovery method. The amortization of the contingent profit commission is determined by the proportion of actual reinsurance recoveries to total estimated recoveries over the life of the contingent profit commission (through June 30, 2024), and is recorded in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income. Any adjustment to the contingent profit commission under the LPT Agreement results in a cumulative adjustment to the Deferred Gain, which is also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, such that the Deferred Gain reflects the balance that would have existed had the revised contingent profit commission been recognized at the inception of the LPT Agreement. Property and Equipment Property and equipment are stated at cost less accumulated depreciation (see Note 7 ). Expenditures for maintenance and repairs are charged against operations as incurred. Electronic data processing equipment, software, furniture and equipment, and automobiles are depreciated using the straight-line method over three to seven years . Leasehold improvements are carried at cost less accumulated amortization. The Company amortizes leasehold improvements using the straight-line method over the lesser of the useful life of the asset or the remaining original lease term, excluding options or renewal periods. Leasehold improvements are generally amortized over three to eight years . Cloud Computing Arrangements The Company capitalizes software license fees and implementation costs associated with hosting arrangements that are service contracts. These amounts are included in Cloud computing arrangements on the Company's Consolidated Balance Sheets. Amortization of the software license fees is calculated using the straight-line method over the term of the service contract or based on the expected utilization of the asset. Amortization of the implementation costs are calculated using the straight-line method based on the term of the service contract and commence once the module or component is ready for its intended use, regardless of whether the hosted software has been placed into service, and will be recognized over the remaining life of the service contract. Obligations Held Under Capital Leases Leased property and equipment meeting capital lease criteria are capitalized at the lower of the present value of the related lease payments or the fair value of the leased asset at the inception of the lease. Amortization is calculated using the straight-line method based on the term of the lease and is included in the depreciation expense of property and equipment. See Note 12 for additional disclosures related to capital leases. Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company's financial statements. Under this method, the Company determines deferred tax assets and liabilities on the basis of the differences between the financial statement and tax bases of assets and liabilities by using enacted tax rates in effect for the year in which the differences are expected to reverse. As of December 22, 2017, the date that the Tax Cuts and Jobs Act was enacted (Enactment), the effect of the change in tax rates on the Company's deferred tax assets and liabilities was recognized in income and created stranded tax effects within accumulated other comprehensive income that did not reflect the newly enacted tax rate. The Company reclassified the net tax effects from Accumulated other comprehensive income, net of tax, to Retained earnings as of the date of Enactment. The Company records uncertain tax positions in accordance with ASC 740, Income Taxes , on the basis of a two-step process. Recognition (Step 1) occurs when the Company concludes that a tax position, based solely on its technical merits, is more likely than not to be sustained upon examination. Measurement (Step 2) is addressed only if Step 1 has been satisfied. Under Step 2, the tax benefit is measured as the largest amount of benefit, determined on a cumulative probability basis, that is more likely than not to be realized upon ultimate settlement. The Company recognizes deferred tax assets when it determines that such assets are more likely than not to be realized in future periods. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, tax-planning strategies, projected future taxable income, projected future tax rates, and results of recent operations. If the Company determines that it is not more likely than not that it could realize its deferred tax assets in future periods, it would establish a deferred tax asset valuation allowance that would increase the Company's provision for income taxes. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of its net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash and cash equivalents (including restricted cash equivalents), short-term investments, investment securities, premiums receivable, and reinsurance recoverable balances. The Company’s cash equivalents and short-term investments include investments in money market securities and securities backed by the U.S. government. The Company's investment securities are diversified throughout many industries and geographic regions and include investments in U.S. government and U.S. government-sponsored enterprises. The Company believes that it has no significant concentrations of credit risk from a single issue or issuer within its cash equivalents, short-term investments and investment securities other than concentrations in U.S. government and U.S. government-sponsored enterprises. The Company's premiums receivable are generally diversified due to the large number of entities composing the Company's policyholder base and their dispersion across many different industries. The Company monitors the financial condition of its reinsurers to minimize its exposure to significant losses from reinsurer insolvencies. The Company also obtains collateral from its reinsurers in order to mitigate the risks related to insolvencies. At December 31, 2018 , $2.0 million of the Company's reinsurance recoverables were collateralized by cash or letters of credit and an additional $311.6 million was in trust accounts for reinsurance recoverables specifically related to the LPT Agreement. Fair Value of Financial Instruments The fair values of the Company's financial instruments have been determined using available market information and other appropriate valuation methodologies. Judgment is required in developing fair value estimates where quoted market prices are not available. Accordingly, these estimates are not necessarily indicative of the amounts that could be realized in a current market exchange. The use of different market assumptions or estimating methodologies may have an effect on the estimated fair value amounts. The following methods and assumptions were used by the Company in estimating the fair value of its financial instruments: Cash and cash equivalents, short-term investments, premiums receivable, accounts payable and accrued expenses, and other liabilities. The carrying amounts for each of these financial instruments as reported in the Company's Consolidated Balance Sheets approximate their fair values. Investment securities. The Company’s investment securities are predominantly valued on the basis of actual market transactions or observable inputs. A small portion of the Company’s investment securities are valued on the basis of pricing models with significant unobservable inputs or nonbinding broker quotes. See Note 5 . Goodwill and Other Intangible Assets The Company tests for impairment of goodwill and non-amortizable intangible assets in the fourth quarter of each year. At the end of each quarter, management considers the results of the previous analysis as well as any recent developments that may constitute triggering events requiring the impairment analysis of goodwill and other intangible assets to be updated. The Company has assessed the effects of current economic conditions on the Company's financial condition and results of operations and changes in the Company's stock price and determined that there were no impairments of these assets as of December 31, 2018 and 2017 . Intangible assets related to state licenses are not subject to amortization. Intangibles related to insurance relationships were amortized in proportion to the expected period of benefit and were fully amortized as of December 31, 2018 . The gross carrying value, accumulated amortization, and net carrying value for the Company's intangible assets, by major class, as of December 31, were as follows: 2018 2017 Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value (in millions) State licenses $ 7.7 $ — $ 7.7 $ 7.7 $ — $ 7.7 Insurance relationships 9.4 $ (9.4 ) — 9.4 $ (9.2 ) 0.2 Total $ 17.1 $ (9.4 ) $ 7.7 $ 17.1 $ (9.2 ) $ 7.9 During the years ended December 31, 2018 , 2017 , and 2016 , the Company recognized $0.2 million , $0.3 million , and $0.3 million in amortization expense associated with its intangible assets, respectively. These amortization expenses are included in the Company's Consolidated Statements of Comprehensive Income in underwriting and other operating expenses. Stock-Based Compensation The Company provides stock-based compensation to its directors and certain of its employees, which is recognized in its Consolidated Statements of Comprehensive Income based on estimated fair values over the relevant service period (see Note 14 ).

New Accounting Standards

New Accounting Standards	12 Months Ended
	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Standards	New Accounting Standards Recently Issued Accounting Standards In August 2018, the Financial Accounting Standards Board (FASB) issued ASU Number 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This update removes the disclosure requirements for the amounts of and the reasons for transfers between Level 1 and Level 2 and disclosure of the policy for timing of transfers between levels. This update also removes disclosure requirements for the valuation processes for Level 3 fair value measurements. Additionally, this update adds disclosure requirements for the changes in unrealized gains and losses for recurring Level 3 fair value measurements and quantitative information for certain unobservable inputs in Level 3 fair value measurements. This update becomes effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company has determined that the impact of this new standard will not be material to the Company's financial statements. In July 2018, the FASB issued ASU Number 2018-09, Codification Improvements . This update provides clarification, corrects errors in and makes minor improvements to the Codification within various ASC topics. Many of the amendments in this update have transition guidance with effective dates for annual periods beginning after December 15, 2018 and some amendments in this update do not require transition guidance and are effective upon issuance of this update. The Company will adopt amendments as they become applicable and has determined that the impact of these improvements will not be material to its consolidated financial condition and results of operations. In July 2018, the FASB issued ASU Number 2018-11, Leases (Topic 842): Targeted Improvements . This update provides entities with an additional and optional transition method to adopt ASU Number 2016-02 with a cumulative-effect adjustment in the period of adoption. This update also provides guidance for a practical expedient that permits lessors to not separate non-lease components from the associated lease components. Additionally, in July 2018, the FASB issued ASU Number 2018-10, Codification Improvements to Topic 842, Leases . This update provides additional guidance on the new lease model with improvements in numerous aspects of the guidance in ASC 842 including, but not limited to, implicit rates, reassessment of lease classification, terms and purchase options, investment tax credits, and various other transition guidance. In December 2018, the FASB issued ASU 2018-20, Leases (Topic 842): Narrow-Scope Improvements for Lessors . This update provides amendments to various lease topics including sales taxes collected from lessees, certain lessor costs paid to third parties, and variable payments for contracts with lease and non-lease components. These updates will be adopted concurrently with ASU Number 2016-02 . The Company has determined that the impact of these new standards will not be material to the Company's financial statements. In January 2017, the FASB issued ASU Number 2017-04, Intangibles-Goodwill and Other (Topic 350) . This update simplifies the measurement of goodwill by eliminating the performance of Step 2 in the goodwill impairment testing. This update allows the testing to be performed by comparing the fair value of a reporting unit with its carrying amount and recognizing an impairment charge when the carrying amount exceeds fair value. Additionally, this update eliminates the requirements of any reporting unit with a zero or negative carrying value to perform Step 2, but requires disclosure of the amount of goodwill allocated to a reporting unit with zero or negative carrying amount of net assets. This update becomes effective for fiscal years beginning after December 15, 2019. The Company does not expect that this update will have a material impact to 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 fixed maturity 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 for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Additionally, in December 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses. This update provides clarification on the effective and transition dates and the exclusion of operating lease receivables from Topic 326. The Company is currently evaluating the impact that the adoption of these updates will have on its consolidated financial condition and results of operations. In February 2016, the FASB issued ASU Number 2016-02, Leases (Topic 842). This update provides guidance on a new lease 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 determined that the impact of this new standard will be equal to the present value of the Company's lease obligations under various non-cancellable operating lease contracts, which amounted to approximately $18.4 million at December 31, 2018 , and will be recognized as right-of-use assets and $20.2 million at December 31, 2018 , will be recognized as lease liabilities on the Company's Consolidated Balance Sheets upon adoption. Recently Adopted Accounting Standards In August 2018, the FASB issued ASU Number 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract. This update clarifies certain aspects of ASU 2015-05 and aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software and hosting arrangements that include an internal-use software license. This update becomes effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years and early adoption is permitted. The Company elected to adopt this standard as of July 1, 2018 using the retrospective method of adoption. Prior to adoption, the Company's accounting policy for capitalization of implementation costs followed the existing guidance for internal use software and therefore this update had no impact on the amounts previously capitalized. In accordance with ASU Number 2018-15 , $4.8 million of capitalized costs included on the Company's June 30, 2018 Consolidated Balance Sheets were reclassified from Property and equipment to Cloud computing arrangements on the date of adoption. Amortization under the new guidance will commence once the module or component is ready for its intended use, regardless of whether the hosting arrangement has been placed into service and will be recognized over the remaining life of the service contract. In March 2018, the FASB issued ASU Number 2018-05, Income Taxes (Topic 740) . This update provides guidance regarding the application of ASC Topic 740 for the income tax effects of the Tax Cuts and Jobs Act. This update allowed companies to report provisional amounts of the effects of the Tax Cuts and Jobs Act in their financial statements in the first reporting period they are able to determine a reasonable estimate and any adjustments to provisional amounts should be included in income from continuing operations as an adjustment to tax expense or benefit in the reporting period the amounts are determined. The Company adopted this update in the fourth quarter of 2017 and included an estimate of the income tax effects on its financial statements for the year ended December 31, 2017. In accounting for certain tax effects of Enactment in accordance with SAB 118, the Company made a final adjustment in 2018 of $(0.4) million . In February 2018, the FASB issued ASU Number 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220) . The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from Enactment. This update becomes effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted for reporting periods for which financial statements have not yet been issued and should be applied in the period of adoption or retrospectively to each period (or periods) in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act is recognized. The Company elected to early adopt this update and, accordingly, reclassified $17.8 million of net tax effects resulting from Enactment from Accumulated other comprehensive (loss) income, net of tax, to Retained earnings at December 31, 2017 . In March 2017, the FASB issued ASU Number 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) . This update shortens the amortization period on callable debt securities held at a premium to the earliest call date, which now closely aligns the amortization period of premiums and discounts to expectations incorporated in the market pricing on callable debt securities. This update becomes effective for fiscal years beginning after December 15, 2018 and interim periods within those fiscal years, and early adoption is permitted. The Company's current accounting practices align with this standard and the adoption had no impact on its consolidated financial condition or results of operations. In January 2016, the FASB issued ASU Number 2016-01, Financial Instruments - Overall (Subtopic 825-10) . This update replaced the guidance to classify equity securities with readily determinable fair values into different categories (trading or available-for-sale) and requires those equity securities to be measured at fair value with changes in fair value recognized through net income. Additionally, this update eliminates the disclosure of 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 did not apply to the Company’s investment in Federal Home Loan Bank (FHLB) stock. Rather, it specified that FHLB stock shall be carried at cost and evaluated periodically for impairment; furthermore, it specified that, beginning January 1, 2018, FHLB stock shall not be shown with securities accounted for under ASC 321, which provides detailed guidance on, among other things, accounting and reporting of investments in equity securities that have readily determinable fair values. As a result, the Company’s investment in FHLB stock is presented within Equity securities at cost on the Company's Consolidated Balance Sheet at March 31, 2018. In all periods prior to January 1, 2018, the Company's investment in FHLB stock is presented within Equity securities at fair value on the Company's Consolidated Balance Sheets. This update became effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The Company adopted this update effective January 1, 2018. Adoption of this accounting standard resulted in a $74.0 million reclassification adjustment, net of tax, from accumulated other comprehensive income to retained earnings. In November 2016, the FASB issued ASU Number 2016-18, Statement of Cash Flows (Topic 230) . This update provides guidance for the classification and presentation of restricted cash and restricted cash equivalents in the statement of cash flows. This update requires amounts generally described as restricted cash and restricted cash equivalents to be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. It requires the disclosure of information about the nature of restrictions on its cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. This update also requires the entity to disclose, on the face of the statement of cash flows or in the notes to the financial statements, any restricted cash or restricted cash equivalents disaggregated by the line item in which they appear within the statement of financial position. The adoption of this standard had no financial impact on the Company's consolidated financial condition, results of operations, or statement of cash flows. In May 2014, the FASB issued ASU Number 2014-09, Revenue from Contracts with Customers (Topic 606). This update clarifies the principles for recognizing revenue and develops revenue standards to improve revenue recognition guidance. This update requires an entity to recognize revenue as performance obligations are met in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. In applying this guidance companies are required to: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract(s); (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract(s); and (5) recognize revenue when, or as, the entity satisfies a performance obligation. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which deferred the effective date of ASU 2014-09 to annual reporting periods beginning after December 15, 2017, and interim reporting periods within that annual reporting period. Insurance contracts are not within the scope of this updated guidance. The Company has analyzed revenue streams within the current business operation and determined the adoption of this standard did not have an impact on its consolidated financial condition and results of operations.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2018
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 at fair value were as follows as of December 31 : 2018 2017 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Financial assets (in millions) Investments at fair value (Note 6) $ 2,721.3 $ 2,721.3 $ 2,677.7 $ 2,677.7 Cash and cash equivalents 101.4 101.4 73.3 73.3 Restricted cash and cash equivalents 0.6 0.6 1.0 1.0 Financial liabilities Notes payable (Note 11) $ 20.0 $ 23.5 $ 20.0 $ 23.6 Assets and liabilities recorded at fair value on the Company's 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. The Company uses third party pricing services to assist with its investment accounting function. The ultimate pricing source varies depending on the investment security and pricing service used, but investment securities valued on the basis of observable inputs (Levels 1 and 2) are generally assigned values on the basis of actual transactions. Securities valued on the basis of pricing models with significant unobservable inputs or nonbinding broker quotes are classified as Level 3. The Company performs quarterly analyses on the prices it receives from third parties to determine whether the prices are reasonable estimates of fair value, including confirming the fair values of these securities through observable market prices using an alternative pricing source, as it is ultimately management’s responsibility to ensure that the fair values reflected in the Company’s consolidated financial statements are appropriate. If differences are noted in these analyses, the Company may obtain additional information from other pricing services to validate the quoted price. The Company bases all of its estimates of fair value for assets on the bid price, when available, as it represents what a third-party market participant would be willing to pay in an arm's length transaction. For securities not actively traded, third party pricing services may use quoted market prices of similar instruments or discounted cash flow analyses, incorporating inputs that are currently observable in the markets for similar securities. Inputs that are often used in the valuation methodologies include, but are not limited to, broker quotes, benchmark yields, credit spreads, default rates, and prepayment speeds. There were no material adjustments to prices obtained from third party pricing services as of December 31, 2018 and 2017 . 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 its financial liabilities are based on a combination of the variable 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 at each of the periods presented. Each of the Company's insurance operating subsidiaries is a member of the Federal Home Loan Bank of San Francisco (FHLB). Members are required to purchase stock in the FHLB in addition to maintaining collateral deposits that back any funds advanced. The Company's investment in FHLB stock is recorded at cost, which approximates fair value, as purchases and sales of these securities are at par value with the issuer. FHLB stock is considered a restricted security and is periodically evaluated by the Company for impairment based on the ultimate recovery of par value. The following table presents the Company's investments at fair value and the corresponding fair value measurements. December 31, 2018 December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities U.S. Treasuries $ — $ 106.4 $ — $ — $ 137.0 $ — U.S. Agencies — 11.4 — — 11.8 — States and municipalities — 528.0 — — 642.5 — Corporate securities — 1,090.4 — — 1,118.0 — Residential mortgage-backed securities — 451.5 — — 389.3 — Commercial mortgage-backed securities — 94.3 — — 106.0 — Asset-backed securities — 64.5 — — 58.8 — Other securities — 149.9 — — — — Total fixed maturity securities $ — $ 2,496.4 $ — $ — $ 2,463.4 $ — Equity securities at fair value Industrial and miscellaneous $ 174.8 $ — $ — $ 181.7 $ — $ — Non-redeemable preferred (FHLB stock) — — — — — 4.7 Other 25.1 — — 23.9 — — Total equity securities at fair value $ 199.9 $ — $ — $ 205.6 $ — $ 4.7 Short-term investments $ — $ 25.0 $ — $ — $ 4.0 $ — Total investments at fair value $ 199.9 $ 2,521.4 $ — $ 205.6 $ 2,467.4 $ 4.7 Certain cash equivalents, principally money market securities, are measured at fair value using the net asset value (NAV) per share. The following table presents cash equivalents at NAV and total cash and cash equivalents carried at fair value on the Company's Consolidated Balance Sheets. December 31, 2018 December 31, 2017 Cash and cash equivalents at fair value $ 43.9 $ 34.3 Cash equivalents measured at NAV, which approximates fair value 57.5 39.0 Total cash and cash equivalents $ 101.4 $ 73.3 The following table provides a reconciliation of the beginning and ending balances that are measured using Level 3 inputs for the years ended December 31, 2018 and 2017 . Level 3 Securities 2018 2017 (in millions) Beginning balance, January 1 $ 4.7 $ 11.9 Transfers out of Level 3 (1) (4.7 ) (7.0 ) Purchases and sales, net — (0.2 ) Ending balance, December 31 $ — $ 4.7 (1) The transfer during the year ended December 31, 2018 was the result of adoption of ASU 2016-01, which specified that FHLB stock shall be carried at cost and is no longer measured at fair value. Transfers during the year ended December 31, 2017 were from Level 3 to Level 2 because observable market data became available for the securities.

Investments

Investments	12 Months Ended
	Dec. 31, 2018
Investments [Abstract]
Investments	Investments The cost or amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the Company’s AFS investments were as follows: Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value At December 31, 2018 (in millions) Fixed maturity securities U.S. Treasuries $ 106.7 $ 0.9 $ (1.2 ) $ 106.4 U.S. Agencies 11.3 0.1 — 11.4 States and municipalities 513.4 15.3 (0.7 ) 528.0 Corporate securities 1,106.2 5.8 (21.6 ) 1,090.4 Residential mortgage-backed securities 459.1 2.2 (9.8 ) 451.5 Commercial mortgage-backed securities 96.7 0.1 (2.5 ) 94.3 Asset-backed securities 64.7 0.2 (0.4 ) 64.5 Other securities (1) 155.6 — (5.7 ) 149.9 Total fixed maturity securities 2,513.7 24.6 (41.9 ) 2,496.4 Short-term investments 25.0 — — 25.0 Total AFS investments $ 2,538.7 $ 24.6 $ (41.9 ) $ 2,521.4 At December 31, 2017 Fixed maturity securities U.S. Treasuries $ 135.8 $ 2.0 $ (0.8 ) $ 137.0 U.S. Agencies 11.3 0.5 — 11.8 States and municipalities 617.0 25.5 — 642.5 Corporate securities 1,103.4 18.0 (3.4 ) 1,118.0 Residential mortgage-backed securities 388.3 3.6 (2.6 ) 389.3 Commercial mortgage-backed securities 106.5 0.4 (0.9 ) 106.0 Asset-backed securities 58.7 0.3 (0.2 ) 58.8 Total fixed maturity securities 2,421.0 50.3 (7.9 ) 2,463.4 Equity securities at fair value Industrial and miscellaneous 100.8 81.5 (0.6 ) 181.7 Non-redeemable preferred (FHLB stock) 4.7 — — 4.7 Other 11.2 12.7 — 23.9 Total equity securities at fair value 116.7 94.2 (0.6 ) 210.3 Short-term investments 4.0 — — 4.0 Total AFS investments $ 2,541.7 $ 144.5 $ (8.5 ) $ 2,677.7 (1) Other securities within fixed maturity securities consist of bank loans, which are classified as AFS and reported at fair value. The cost and estimated fair value of the Company's equity securities recorded at fair value at December 31, 2018 were as follows: Cost Estimated Fair Value (in millions) At December 31, 2018 Equity securities at fair value Industrial and miscellaneous $ 114.6 $ 174.8 Other 17.3 25.1 Total equity securities at fair value $ 131.9 $ 199.9 The amortized cost and estimated fair value of the Company's fixed maturity securities at December 31, 2018 , 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 $ 141.8 $ 142.1 Due after one year through five years 856.9 856.3 Due after five years through ten years 794.3 784.3 Due after ten years 100.2 103.4 Mortgage and asset-backed securities 620.5 610.3 Total $ 2,513.7 $ 2,496.4 The following is a summary of AFS 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 December 31, 2018 and 2017 . December 31, 2018 December 31, 2017 Estimated Fair Value Gross Unrealized Losses Number of Issues Estimated Fair Value Gross Unrealized Losses Number of Issues Less than 12 months: (dollars in millions) Fixed maturity securities U.S. Treasuries $ 12.2 $ (0.1 ) 7 $ 86.0 $ (0.5 ) 28 States and municipalities 70.1 (0.7 ) 21 — — — Corporate securities 624.4 (13.4 ) 205 307.6 (2.3 ) 113 Residential mortgage-backed securities 156.9 (2.5 ) 59 165.0 (0.8 ) 45 Commercial mortgage-backed securities 30.9 (0.5 ) 13 41.8 (0.2 ) 19 Asset-backed securities 25.1 (0.2 ) 18 29.3 (0.2 ) 25 Other securities 137.1 (5.7 ) 215 — — — Total less than 12 months $ 1,056.7 $ (23.1 ) 538 $ 629.7 $ (4.0 ) 230 12 months or greater: Fixed maturity securities U.S. Treasuries $ 72.7 $ (1.1 ) 25 $ 23.4 $ (0.3 ) 10 Corporate securities 193.7 (8.2 ) 69 53.2 (1.1 ) 17 Residential mortgage-backed securities 199.8 (7.3 ) 72 77.1 (1.8 ) 32 Commercial mortgage-backed securities 55.0 (2.0 ) 22 25.1 (0.7 ) 8 Asset-backed securities 16.5 (0.2 ) 17 — — — Total 12 months or greater $ 537.7 $ (18.8 ) 205 $ 178.8 $ (3.9 ) 67 At December 31, 2017 , the Company also had $0.6 million of gross unrealized losses on twenty-four equity securities that were in a continuous loss position for less than 12 months. The Company recognized impairments on fixed maturity securities of $3.3 million (consisting of sixty-six securities) and $0.5 million (consisting of nine securities) during the years ended December 31, 2018 and 2017 , respectively, as a result of the Company's intent to sell these securities and/or the severity of the change in fair values of these securities. There were no other-than-temporary impairments recognized on fixed maturity securities during the year ended December 31, 2016 . The Company determined that the remaining unrealized losses on fixed maturity securities at December 31, 2018 , 2017 , and 2016 were primarily the result of changes in prevailing interest rates and not the credit quality of the issuers. The fixed maturity securities whose fair value was less than amortized cost were not determined to be other-than-temporarily impaired given the lack of 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 at an amount less than their amortized cost. The adoption of ASU 2016-01 removed the impairment assessment for equity securities at fair value, and, beginning in 2018, changes in fair value are included in net realized and unrealized gains and losses on investments on the Company's Consolidated Statements of Comprehensive Income. Prior to adoption of this standard, the Company recognized impairments on equity securities of $0.9 million (consisting of seven securities) and $5.8 million (consisting of thirty-seven securities) during the years ended December 31, 2017 and 2016 , respectively. The other-than-temporary impairments recognized during these years were the result of the Company's intent to sell the securities and/or the severity and duration of the change in fair values of these securities. The impairments on equity securities in 2016 were primarily due to the downturn in the energy sector that occurred during the first quarter of 2016. Certain unrealized losses on equity securities during the years ended December 31, 2017 and 2016 were not considered to be other-than-temporary due to the financial condition and near-term prospects of the issuers, and the Company's intent to hold the securities until fair value recovers to above cost. Realized gains and losses on investments include the gain or loss on a security at the time of sale compared to its original or adjusted cost (equity securities) or amortized cost (fixed maturity securities). Realized losses on fixed maturity securities are also recognized when securities are written down as a result of an other-than-temporary impairment. Net realized gains on investments and the change in unrealized gains (losses) on the Company's investments recorded at fair value are determined on a specific-identification basis and were as follows: Gross Realized Gains Gross Realized Losses Change in Net Unrealized Gains (Losses) Changes in Fair Value Reflected in Earnings Changes in Fair Value Reflected in AOCI, before tax (in millions) Year Ended December 31, 2018 Fixed maturity securities $ 2.2 $ (4.0 ) $ (59.7 ) $ (1.8 ) $ (59.7 ) Equity securities 15.9 (1.6 ) (25.6 ) (11.3 ) — Total investments $ 18.1 $ (5.6 ) $ (85.3 ) $ (13.1 ) $ (59.7 ) Year Ended December 31, 2017 Fixed maturity securities $ 4.7 $ (2.2 ) $ 3.9 $ 2.5 $ 3.9 Equity securities 9.3 (4.4 ) 17.5 4.9 17.5 Total investments $ 14.0 $ (6.6 ) $ 21.4 $ 7.4 $ 21.4 Year Ended December 31, 2016 Fixed maturity securities $ 1.9 $ (0.7 ) $ (28.9 ) $ 1.2 $ (28.9 ) Equity securities 16.6 (6.6 ) 14.9 10.0 14.9 Total investments $ 18.5 $ (7.3 ) $ (14.0 ) $ 11.2 $ (14.0 ) Net investment income was as follows: Years Ended December 31, 2018 2017 2016 (in millions) Fixed maturity securities $ 76.0 $ 70.4 $ 68.5 Equity securities 6.5 6.9 7.4 Short-term investments 0.3 0.1 — Cash equivalents and restricted cash 2.0 0.6 0.4 Gross investment income 84.8 78.0 76.3 Investment expenses (3.6 ) (3.4 ) (3.1 ) Net investment income $ 81.2 $ 74.6 $ 73.2 The Company is required by various state laws and regulations to hold securities or letters of credit in depository accounts with certain states in which it does business. These laws and regulations govern not only the amount but also the types of securities that are eligible for deposit. As of December 31, 2018 and 2017 , securities having a fair value of $867.7 million and $1,009.7 million , respectively, were on deposit. Additionally, standby letters of credit from the FHLB were in place in lieu of $140.0 million of securities on deposit as of December 31, 2018 (see Note 11 ). Certain reinsurance contracts require the Company's 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 December 31, 2018 and 2017 was $23.2 million and $24.5 million , respectively.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property and Equipment [Abstract]
Property, Plant and Equipment Disclosure	Property and Equipment Property and equipment consists of the following: As of December 31, 2018 2017 (in millions) Furniture and equipment $ 3.3 $ 1.7 Leasehold improvements 3.2 2.9 Computers and software 61.9 54.2 Automobiles 1.1 1.1 Property and equipment, gross 69.5 59.9 Accumulated depreciation (51.3 ) (46.0 ) Property and equipment, net $ 18.2 $ 13.9 Depreciation expenses related to property and equipment for the years ended December 31, 2018 , 2017 , and 2016 were $6.1 million , $7.9 million , and $8.2 million , respectively. Internally developed software costs of $2.9 million and $2.1 million were capitalized during each of the years ended December 31, 2018 and 2017 , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes [Abstract]
Income Taxes	Income Taxes The Company files a consolidated federal income tax return. The insurance subsidiaries pay premium taxes on premiums in lieu of some states' income or franchise taxes. The Tax Cuts and Jobs Act significantly revised U.S. corporate income tax law by, among other things, reducing the corporate statutory income tax rate from 35% to 21% , beginning January 1, 2018 . This reduction in the corporate statutory income tax rate required the Company to re-evaluate certain of its deferred tax assets and liabilities, as of the date of Enactment, to reflect the revised income tax rates applicable to future periods. The Company's provision for income taxes consisted of the following: Years Ended December 31, 2018 2017 2016 Current tax expense: (in millions) Federal $ 13.2 $ 17.9 $ 20.3 State 0.6 0.7 0.3 Total current tax expense 13.8 18.6 20.6 Deferred federal tax expense: Impact of tax Enactment (0.4 ) 7.0 — Other 14.8 17.2 13.4 Total deferred federal tax expense 14.4 24.2 13.4 Income tax expense $ 28.2 $ 42.8 $ 34.0 The differences between the statutory federal tax rate of 21% for 2018 and 35% for 2017 and 2016 and the Company's effective tax rate on net income before income taxes as reflected in the Consolidated Statements of Comprehensive Income were as follows: Years Ended December 31, 2018 2017 2016 (in millions) Expense computed at statutory rate $ 35.6 $ 50.4 $ 49.3 Tax-advantaged investment income (2.9 ) (7.6 ) (8.5 ) LPT deferred gain amortization (2.6 ) (4.0 ) (4.7 ) Stock based compensation (1.4 ) (3.4 ) (1.6 ) LPT Reserve Adjustment (0.5 ) — (1.1 ) Impact of tax Enactment (0.4 ) 7.0 — Other 0.4 0.4 0.6 Income tax expense $ 28.2 $ 42.8 $ 34.0 The LPT Reserve Adjustments for the years ended December 31, 2018 and 2016 increased GAAP net income by $2.2 million and $3.1 million , respectively, but did not affect taxable income. There were no LPT Reserve Adjustments in 2017. The LPT Contingent Commission Adjustments increased net income by $0.5 million , $0.3 million , and $1.8 million during 2018 , 2017 , and 2016 , respectively, but did not increase taxable income. As of December 31, 2018 and 2017 , 2016 the Company had no material unrecognized tax benefits. The Company made cash payments of $4.2 million , $21.3 million and $13.7 million for income taxes during the years ended December 31, 2018 , 2017 , and 2016 , respectively. Tax years 2015 through 2018 remained open and are subject to full examination by the federal taxing authority. The significant components of deferred income taxes, net, were as follows as of December 31: 2018 2017 Deferred Tax Deferred Tax Assets Liabilities Assets Liabilities (in millions) Unrealized capital gains, net $ — $ 10.6 $ — $ 28.5 Deferred policy acquisition costs — 10.3 — 9.7 Intangible assets — 1.6 — 1.7 Loss reserve discounting for tax reporting 31.1 — 29.0 — Unearned premiums 13.3 — 12.8 — Allowance for bad debt 1.4 — 2.1 — Stock-based compensation 2.9 — 2.5 — Accrued liabilities 4.9 — 4.2 — Minimum tax credit — — 20.0 — Other 2.6 6.8 2.8 4.8 Total $ 56.2 $ 29.3 $ 73.4 $ 44.7 Deferred income taxes, net $ 26.9 $ 28.7 Enactment had no impact on the amount of the Company's minimum tax credit as of December 31, 2018 . Despite a repeal of the corporate alternative minimum tax, the Company's minimum tax credit was fully recognized in the year ended December 31, 2018. Deferred tax assets are required to be reduced by a valuation allowance if it is more likely than not that all or some portion of the deferred tax asset will not be realized. Realization of the deferred income tax asset is dependent on the Company generating sufficient taxable income in future years as the deferred income tax charges become deductible for tax reporting purposes. Although realization is not assured, management believes that it is more likely than not that the net deferred income tax asset will be realized.

Liability for Unpaid Losses and

Liability for Unpaid Losses and Loss Adjustment Expenses	12 Months Ended
	Dec. 31, 2018
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 Accounting for workers' compensation insurance requires the Company to estimate the liability for the expected ultimate cost of unpaid losses and LAE (loss reserves) as of a balance sheet date. Loss reserve estimates are inherently uncertain because the ultimate amount the Company will pay for many of the claims it has incurred as of the balance sheet date will not be known for many years. The estimate of loss reserves is intended to equal the difference between the expected ultimate losses and LAE of all claims that have occurred as of a balance sheet date and amounts already paid. The Company establishes loss reserves based on its own analysis of emerging claims experience and environmental conditions in its markets and review of the results of various actuarial projections. The Company's aggregate carried reserve for unpaid losses and LAE is the sum of its reserves for each accident year and represents its best estimate of outstanding loss reserves. The amount by which estimated losses in the aggregate differ from those previously estimated for a specific time period is known as reserve “development.” Reserve development is unfavorable when losses ultimately settle for more than the amount reserved or subsequent estimates indicate a basis for reserve increases on open claims, causing the previously estimated loss reserves to be ''deficient.'' Reserve development is favorable when estimates of ultimate losses indicate a decrease in established reserves, causing the previously estimated loss reserves to be ''redundant.'' Development is reflected in the Company's operating results through an adjustment to incurred losses and LAE during the period in which it is recognized. Although claims for which reserves are established may not be paid for several years or more, the Company does not discount loss reserves in its financial statements for the time value of money, in accordance with GAAP. The three main components of reserves for unpaid losses and LAE are case reserves, incurred but not reported (IBNR) loss reserves, and LAE reserves. When claims are reported, the Company establishes individual estimates of the ultimate cost of each claim (case reserves). These case reserves are continually monitored and revised in response to new information and for amounts paid. IBNR is an actuarial estimate of future payments on claims that have occurred but have not yet been reported. In addition to this provision for late reported claims, the Company also estimates and makes a provision for the extent to which the case reserves on known claims may develop and for additional payments on closed claims, known as “reopening.” IBNR reserves apply to the entire body of claims arising from a specific time period, rather than a specific claim. Most of the Company's IBNR reserves relate to estimated future claim payments on recorded open claims. LAE reserves are the Company's estimate of the future expenses of investigating, administering, and settling claims that will be paid to manage claims that have occurred, including legal expenses. LAE reserves are established in the aggregate, rather than on a claim-by-claim basis. LAE reserves are categorized between defense and cost containment, and adjusting and other. A portion of the Company's obligations for losses and LAE are ceded to unaffiliated reinsurers. The amount of reinsurance that will be recoverable on its losses and LAE reserves includes both the reinsurance recoverable from excess of loss reinsurance contracts, as well as reinsurance recoverable under the terms of the LPT Agreement. The Company uses actuarial methods to analyze and estimate the aggregate amount of unpaid losses and LAE. Management considers the results of various actuarial projection methods and their underlying assumptions, among other factors, in establishing reserves for unpaid losses and LAE. Judgment is required in the actuarial estimation of loss reserves, including the selection of various actuarial methodologies to project the ultimate cost of claims. Specifically, judgment is required in the following areas: the selection of projection parameters based on historical company data; the use of industry data and other benchmarks; the identification and quantification of potential changes in parameters from historical levels to current and future levels due to changes in future claims development expectations; and the weighting of differing reserve indications resulting from alternative methods and assumptions. The Company's Internal Actuary prepares reserve estimates for all accident years using our own historical claims data, industry data and many of the generally accepted actuarial methodologies for estimating loss reserves, such as paid loss development methods, incurred loss development methods, and Bornhuetter-Ferguson methods. These methods vary in their responsiveness to different information, characteristics, and dynamics in the data, and the results assist the actuary in considering these characteristics and dynamics in the historical data. The methods employed for each segment of claims data, and the relative weight accorded to each method, vary depending on the nature of the claims segment and on the age of the claims. Each actuarial methodology requires the selection and application of various parameters and assumptions. The key parameters and assumptions include: the pattern with which our aggregate claims will be paid or emerge over time; the magnitude and changes in claim settlement activity, claims cost inflation rates; the effects of legislative benefit changes and/or judicial changes; and trends in the frequency of claims, both overall and by severity of claim. The Company believes the pattern with which our aggregate data will be paid or emerge over time, claim settlement activity, claims cost inflation rates, and claim frequencies are the most important parameters and assumptions. The following table represents a reconciliation of changes in the liability for unpaid losses and LAE. Years Ended December 31, 2018 2017 2016 (in millions) Unpaid losses and LAE at beginning of period $ 2,266.1 $ 2,301.0 $ 2,347.5 Less reinsurance recoverable on unpaid losses and LAE 537.0 580.0 628.2 Net unpaid losses and LAE at beginning of period 1,729.1 1,721.0 1,719.3 Losses and LAE, net of reinsurance, incurred during the period related to: Current year 457.5 447.3 452.9 Prior years (1) (66.2 ) (18.5 ) (18.4 ) Total net losses and LAE incurred during the period (1) 391.3 428.8 434.5 Paid losses and LAE, net of reinsurance, related to: Current year 93.0 76.9 78.7 Prior years (2) 323.9 343.8 354.1 Total net paid losses and LAE during the period (2) 416.9 420.7 432.8 Ending unpaid losses and LAE, net of reinsurance 1,703.5 1,729.1 1,721.0 Reinsurance recoverable on unpaid losses and LAE 504.4 537.0 580.0 Unpaid losses and LAE at end of period $ 2,207.9 $ 2,266.1 $ 2,301.0 (1) Losses and LAE, net of reinsurance, incurred during the period related to prior years and Total net losses and LAE incurred during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10 ). Including these amounts, Losses and LAE, net of reinsurance, incurred during the period related to prior years was $(80.8) million , $(30.1) million , and $(35.0) million and Total net losses and LAE incurred during the period was $376.7 million , $417.2 million , and $417.9 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. (2) Paid losses and LAE, net of reinsurance, related to prior years and Total net paid losses and LAE during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10 ). Including these amounts, Paid losses and LAE, net of reinsurance, related to prior years was $309.3 million , $332.2 million , and $337.5 million and Total net paid losses and LAE during the period was $402.4 million , $409.1 million , and $416.2 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. In 2018, the Company had $66.2 million of favorable prior accident year loss development, which included $65.5 million of favorable development on its voluntary risk business and $0.7 million of favorable development related to its assigned risk business. In 2017, the Company had $18.5 million of favorable prior accident year loss development, which included $17.4 million of favorable development on its voluntary risk business and $1.1 million of favorable development related to its assigned risk business. In 2016, the Company had $18.4 million of favorable prior accident year loss development, which included $17.0 million of favorable development on its voluntary risk business and $1.4 million of favorable development related to its assigned risk business. The favorable prior accident year loss development on voluntary business in these years was the result of the Company's determination that adjustments were necessary to reflect observed favorable paid loss trends. Paid loss trends have been impacted by cost savings associated with accelerated claims settlement activity that began in 2014 and continued through 2018. In California, where the Company's operations began in 2002, the actuaries' and management's initial expectations of ultimate losses and patterns of loss emergence and payment were based on benchmarks derived from analyses of historical insurance industry data in California. No historical data from the Company's California insurance subsidiary existed prior to July 1, 2002; however, some historical data was available for the prior years for some of the market segments the Company entered in California, but was limited as to the number of loss reserve evaluation points available. The industry-based benchmarks were judgmentally adjusted for the anticipated impact of significant environmental changes, specifically the enactment of major changes to the statutory workers' compensation benefit structure and the manner in which claims are administered and adjudicated in California. The actual emergence and payment of claims by the Company's California insurance subsidiary have been more favorable than those initial expectations through 2008, due in part to the enactment of the major changes in the California workers' compensation environment. The Company's recent loss experience, from 2010 through 2016, indicates an upward trend in medical and indemnity costs that are reflected in its loss reserves. Loss experience in 2017 indicated a slight downward movement in medical and indemnity costs per claim. The Company's indemnity claims frequency (the number of claims expressed as a percentage of payroll) continued to decrease year-over-year for the past three years; however, in 2018, the Company saw an upward movement in medical and indemnity costs per claim that is reflected in the Company's current accident year loss estimate. The Company's reserve estimates assume that increasing medical cost trends will continue and will impact the Company's long-term claims costs and loss reserves. The Company continues to develop its own loss experience in California and will rely more on its experience and less on historical industry data in projecting its reserve requirements as such data becomes available. As the actual experience of the Company emerges, it will continue to evaluate prior estimates, which may result in additional adjustments in reserves. In Nevada, the Company has compiled a lengthy history of workers' compensation claims payment patterns based on the business of the Fund and EICN, but the emergence and payment of claims in recent years has been more favorable than in the long-term history in Nevada with the Fund. The expected patterns of claim payments and emergence used in the projection of the Company's ultimate claim payments are based on both the long and short-term historical paid data. In recent evaluations, claim patterns have continued to emerge in a manner consistent with short-term historical data. Consequently, the Company has relied more heavily on claim projection patterns observed in recent years in Nevada. Loss reserves shown in the Company's Consolidated Balance Sheets are net of $34.4 million and $35.0 million for anticipated subrogation recoveries as of December 31, 2018 and 2017 , respectively. The Company compiles and aggregates its claims data by grouping the claims according to the year in which the claim occurred (“accident year”) when analyzing claim payment and emergence patterns and trends over time. For the purposes of defining claims frequency, the number of reported claims includes any claim that has case reserves and/or loss and LAE payments associated with them. The Company analyzed the usefulness of disaggregation of its results and determined the characteristics associated with the policies and the related unpaid loss reserves, incurred losses, and payment patterns are similar in nature. As such, the following tables show the Company's historical incurred and cumulative paid losses and LAE development, net of reinsurance, as well as IBNR loss reserves and the number of reported claims on an aggregated basis as of December 31, 2018 for each of the previous 10 accident years. Incurred Losses and LAE, Net of Reinsurance Years Ended December 31, As of December 31, 2018 Accident Year 2009 (1) 2010 (1) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 IBNR Cumulative number of reported claims (in millions, except claims counts) 2009 $ 255.4 $ 266.9 $ 279.0 $ 280.1 $ 283.6 $ 283.7 $ 291.2 $ 290.5 $ 290.5 $ 287.9 $ 11.0 22,681 2010 204.9 224.4 228.1 246.1 250.2 262.0 259.9 258.8 255.2 16.7 18,540 2011 253.7 267.3 272.0 277.4 296.3 292.6 288.8 287.8 24.0 19,578 2012 348.8 359.9 360.9 386.4 388.2 382.8 379.8 41.1 25,989 2013 452.6 460.6 478.6 472.6 468.9 464.6 61.2 28,869 2014 463.4 445.8 432.9 434.6 430.5 72.2 28,524 2015 422.2 425.8 423.9 419.6 78.7 27,135 2016 419.0 414.6 395.4 94.4 25,621 2017 412.4 391.3 145.1 24,746 2018 422.5 220.0 23,617 Total $ 3,734.7 Cumulative Paid Losses and LAE, Net of Reinsurance Years Ended December 31, Accident Year 2009 (1) 2010 (1) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 (in millions) 2009 $ 59.0 $ 130.6 $ 174.1 $ 202.0 $ 219.3 $ 232.1 $ 242.3 $ 249.5 $ 255.1 $ 258.7 2010 47.1 105.6 143.8 171.7 190.7 206.2 215.4 221.3 226.5 2011 47.4 115.1 162.6 193.8 217.5 230.1 238.2 243.8 2012 58.6 148.3 214.2 261.4 289.9 305.0 316.9 2013 68.5 184.4 263.8 317.4 346.1 365.9 2014 65.3 172.7 248.9 297.2 323.4 2015 65.5 174.5 246.9 290.5 2016 65.6 166.8 227.7 2017 63.5 160.2 2018 77.9 Total $ 2,491.6 All outstanding liabilities for unpaid losses and LAE prior to 2009, net of reinsurance 371.5 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 1,614.6 (1) Data presented for these calendar years is required supplementary information, which is unaudited. The following table represents a reconciliation of claims development to the aggregate carrying amount of the liability for unpaid losses and LAE: December 31, 2018 (in millions) Liabilities for unpaid losses and LAE, net of reinsurance $ 1,614.6 Reinsurance recoverable on unpaid losses 504.4 Unallocated LAE (adjusting and other) 88.9 Total liability for unpaid losses and LAE $ 2,207.9 The following table presents the average annual percentage payout of incurred claims by age, net of reinsurance, as of December 31, 2018 and is presented as required supplementary information, which is unaudited: Average Annual Percentage Payout of Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 16.8 % 24.6 % 16.4 % 11.0 % 6.9 % 4.6 % 3.3 % 2.3 % 2.0 % 1.3 %

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2018
Reinsurance [Abstract]
Reinsurance	Reinsurance The Company purchases reinsurance from third parties in the normal course of its business in order to manage its exposures. The Company's reinsurance coverage is provided on both a quota share and excess of loss basis. The effects of reinsurance on the Company's written and earned premiums and on its losses and LAE incurred were as follows: Years Ended December 31, 2018 2017 2016 Written Earned Written Earned Written Earned (in millions) Direct premiums $ 739.0 $ 727.2 $ 719.5 $ 712.5 $ 691.0 $ 691.0 Assumed premiums 9.9 10.0 10.2 10.0 10.4 10.6 Gross premiums 748.9 737.2 729.7 722.5 701.4 701.6 Ceded premiums (6.1 ) (6.1 ) (6.0 ) (6.0 ) (6.8 ) (6.8 ) Net premiums $ 742.8 $ 731.1 $ 723.7 $ 716.5 $ 694.6 $ 694.8 Ceded losses and LAE incurred $ 9.5 $ (0.5 ) $ 0.1 Ceded losses and LAE incurred includes the amortization of the Deferred Gain, LPT Reserve Adjustments, and LPT Contingent Commission Adjustments. Excess of Loss Reinsurance The Company has consistently maintained excess of loss reinsurance coverage to protect it against the impact of large and/or catastrophic losses in its workers' compensation business. The Company currently maintains reinsurance for losses from a single occurrence or catastrophic event in excess of $10.0 million and up to $200.0 million , subject to certain exclusions. This current reinsurance program is effective July 1, 2018 through June 30, 2019 . The coverage under the Company's annual reinsurance programs that ended July 1, 2018 and 2017 was $190.0 million , in excess of its $10.0 million retention on a per occurrence basis. The reinsurance coverage includes coverage for acts of terrorism, excluding nuclear, biological, chemical, and radiological events. Any liability outside the coverage limits of the reinsurance program is retained by the Company. LPT Agreement Recoverables from reinsurers on unpaid losses and LAE amounted to $504.4 million and $537.0 million at December 31, 2018 and 2017 , respectively. At each of December 31, 2018 and 2017 , $408.2 million and $438.9 million , respectively, of those recoverables was related to the LPT Agreement that was entered into in 1999 by the Fund and assumed by EICN. Under the LPT Agreement, substantially all of the Fund's losses and LAE on claims incurred prior to July 1, 1995 have been ceded to three unaffiliated reinsurers on a 100% quota share basis. Investments totaling $311.6 million and $380.8 million at December 31, 2018 and 2017 , respectively, have been placed in trust by the three reinsurers as security for payment of the reinsured claims. Under the LPT Agreement, initially $1.5 billion in liabilities for the incurred but unpaid losses and LAE related to claims incurred prior to July 1, 1995, were reinsured for consideration of $775.0 million . The LPT Agreement provides coverage up to $2.0 billion . Through December 31, 2018 , the Company has paid losses and LAE claims totaling $773.7 million related to the LPT Agreement. The Company amortized $11.9 million , $11.3 million , and $11.7 million of the Deferred Gain for the years ended December 31, 2018 , 2017 , and 2016 , respectively. Additionally, the Deferred Gain was reduced by $2.2 million and $3.1 million for the years ended December 31, 2018 and 2016 , respectively, due to favorable LPT Reserve Adjustments and by $0.5 million , $0.3 million , and $1.8 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively, due to favorable LPT Contingent Commission Adjustments (Note 2 ).

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2018
Notes Payable [Abstract]
Notes Payable	Notes Payable and Other Financing Arrangements Notes payable is comprised of the following: December 31, 2018 2017 (in millions) Dekania Surplus Note, due April 29, 2034 $ 10.0 $ 10.0 Alesco Surplus Note, due December 15, 2034 10.0 10.0 Total $ 20.0 $ 20.0 EPIC has a $10.0 million surplus note to Dekania CDO II, Ltd. issued as part of a pooled transaction. The note matures in 2034 and became callable by the Company in 2009 . The terms of the note provide for quarterly interest payments at a rate 425 basis points in excess of the 90-day LIBOR. Both the payment of interest and repayment of the principal under this note and the surplus notes described in the succeeding two paragraphs are subject to the prior approval of the Florida Department of Financial Services. Interest paid during each of the years ended December 31, 2018 , 2017 , and 2016 was $0.7 million , $0.6 million , and $0.5 million . Interest accrued as of December 31, 2018 and 2017 was $0.1 million . EPIC has a $10.0 million surplus note to Alesco Preferred Funding V, LTD issued as part of a pooled transaction. The note matures in 2034 and became callable by the Company in 2009 . The terms of the note provide for quarterly interest payments at a rate 405 basis points in excess of the 90-day LIBOR. Interest paid during each of the years ended December 31, 2018 , 2017 , and 2016 was $0.6 million , $0.5 million , and $0.5 million , respectively. Interest accrued as of December 31, 2018 and 2017 was less than $0.1 million . EPIC had a $12.0 million surplus note to ICONS, Inc. issued as part of a pooled transaction. This note was purchased by EHI in 2017 for $9.9 million , resulting in a $2.1 million gain. As a result of EHI's purchase of the note, it was no longer considered outstanding on a consolidated basis at December 31, 2017 . The note was formally redeemed and retired by EPIC in May 2018. Interest paid to third parties during each of the years ended December 31, 2017 and 2016 was $0.3 million and $0.6 million , respectively. Principal payment obligations on notes payable outstanding at December 31, 2018 , were as follows: Year Principal Due (in millions) 2019 - 2023 $ — Thereafter 20.0 Total $ 20.0 Other financing arrangements is comprised of the following: Each of the Company's insurance subsidiaries is a member of the FHLB. Membership allows the insurance subsidiaries access to collateralized advances, which may be used to support and enhance liquidity management. The amount of advances that may be taken is dependent on statutory admitted assets on a per company basis. Currently, none of the Company's insurance subsidiaries has advances outstanding under the FHLB facility. FHLB membership also allows the Company's insurance subsidiaries access to standby letters of credit. On March 9, 2018, ECIC, EPIC, and EAC entered into standby Letter of Credit Reimbursement Agreements (Letter of Credit Agreements) with the FHLB. The Letter of Credit Agreements are between the FHLB and each of EAC, in the amount of $40.0 million , ECIC, in the amount of $50.0 million , and EPIC, in the amount of $50.0 million . The Letter of Credit Agreements became effective March 9, 2018 and expire March 31, 2019 ; however, the Letter of Credit Agreements will remain evergreen with automatic one-year extensions unless the FHLB notifies the beneficiary at least 60 days prior to the then applicable expiration date of its election not to renew. The Letter of Credit Agreements may only be used to satisfy, in whole or in part, insurance deposit requirements with the State of California and are fully secured with eligible collateral at all times. The Letter of Credit Agreements are subject to annual maintenance charges and a fee of 15 basis points on issued amounts. As of December 31, 2018 letters of credit totaling $140.0 million were issued in lieu of securities on deposit with the State of California under these Letter of Credit Agreements. As of December 31, 2018 , investment securities having a fair value of $244.1 million were pledged to the FHLB by the Company's insurance subsidiaries in support of the collateralized advance facility and the Letter of Credit Agreements.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies [Abstract]
Commitments and Contingencies Disclosure	Commitments and Contingencies Leases The Company leases office facilities and certain equipment under operating and capital leases. Most leases have renewal options, typically with increased rental rates during the option period. Certain of these leases contain options to purchase the property at amounts that approximate fair market value; other leases contain options to purchase at a bargain purchase price. At December 31, 2018 , the remaining lease terms expire over the next nine years . The future lease payments for the next five years on these non-cancellable operating and capital leases at December 31, 2018 , were as follows: Year Operating Leases Capital Leases (in millions) 2019 $ 5.3 $ 0.3 2020 4.4 0.3 2021 2.9 0.2 2022 1.9 0.1 2023 1.8 — Thereafter 6.2 — Total $ 22.5 $ 0.9 Included in the future minimum capital lease payments are future interest charges of $0.2 million . Facilities rent expense was $5.0 million , $4.8 million , and $4.9 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. Property held under capital leases is included in property and equipment as follows: Asset Class 2018 2017 (in millions) Automobiles 1.1 1.1 Accumulated amortization (0.4 ) (0.3 ) Total $ 0.7 $ 0.8 Contingencies Surrounding Insurance Assessments All of the states where the Company's insurance subsidiaries are licensed to transact business require property and casualty insurers doing business within the respective state to pay various insurance assessments. The Company accrues a liability for estimated insurance assessments as direct premiums are written, losses are recorded, or as other events occur in accordance with various states' laws and regulations, and defers these costs and recognizes them as an expense as the related premiums are earned. The Company had an accrued liability for guaranty fund assessments, second injury funds assessments, and other insurance assessments totaling $18.6 million and $12.4 million as of December 31, 2018 and 2017 , respectively. These liabilities are generally expected to be paid over one to eighty year periods based on individual state's regulations. The Company also recorded an asset of $14.9 million and $14.1 million , as of December 31, 2018 and 2017 , respectively, for prepaid policy charges still to be collected in the future from policyholders, or assessments that may be recovered through a reduction in future premium taxes in certain states. These assets are expected to be realized over one to ten year periods in accordance with their type and each individual state's regulations.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity Attributable to Parent [Abstract]
Treasury Stock	Stockholders' Equity Stock Repurchase Programs On February 21, 2018, the Board of Directors authorized a share repurchase program for up to $50.0 million of the Company's common stock from February 26, 2018 through February 26, 2020 (the 2018 Program). The Company expects that its common stock may be purchased at prevailing market prices through a variety of methods, including open market or private transactions, in accordance with applicable laws and regulations and as determined by management. The timing and actual number of shares repurchased will depend on a variety of factors, including the share price, corporate and regulatory requirements, and other market and economic conditions. Repurchases under the 2018 Program may be commenced, modified, or suspended from time-to-time without prior notice, and the 2018 Program may be suspended or discontinued at any time. Through December 31, 2018 , the Company has repurchased a total of 112,528 shares of common stock at an average price of $40.95 per share, including commissions, for a total of $4.6 million under the 2018 Program. Since the Company's initial public offering in January 2007 through December 31, 2018 , the Company has repurchased a total of 24,209,883 shares of common stock at an average cost per share of $16.04 through various stock repurchase programs, which is reported as treasury stock, at cost, on its Consolidated Balance Sheets.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Stock-Based Compensation [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Employers Holdings, Inc. Amended and Restated Equity and Incentive Plan (the Plan) is administered by the Compensation Committee of the Board of Directors, which is authorized to grant, at its discretion, awards to officers, employees, non-employee directors, consultants, and independent contractors. The maximum number of common shares reserved for grants of awards under the Plan was 5,500,000 shares, prior to reductions for grants made. The Plan provides for the grant of stock options (both incentive stock options and nonqualified stock options), stock appreciation rights, shares of restricted stock, restricted stock units (RSUs), performance stock units (PSUs), and other stock-based awards. Commencing in 2017, employees who were awarded RSUs and PSUs are entitled to receive dividend equivalents for eligible awards, payable in cash, when the underlying award vests and becomes payable. If the underlying award does not vest or is forfeited, dividend equivalents with respect to the underlying award will also fail to become payable and will be forfeited. These awards are not considered participating securities for the purposes of determining earnings per share. As of December 31, 2018 , the only incentive awards outstanding under the Plan were nonqualified stock options, RSUs, and PSUs. Compensation costs are recognized based on expected performance, if applicable, net of any estimated forfeitures on a straight-line basis over the requisite employee service periods. Forfeiture rates are based on historical experience and are adjusted in subsequent periods for differences in actual forfeitures from those estimated. Net stock-based compensation expense recognized in the Company's Consolidated Statements of Comprehensive Income was as follows: Years Ended December 31, 2018 2017 2016 Stock-based compensation expense related to: (in millions) Stock options $ 0.3 $ 0.5 $ 0.7 RSUs 2.5 2.0 1.9 PSUs 6.5 4.3 3.2 Total 9.3 6.8 5.8 Less: related tax benefit 2.0 2.4 2.0 Net stock-based compensation expense $ 7.3 $ 4.4 $ 3.8 Stock Options The fair value of the stock options granted is estimated using a Black-Scholes option pricing model that uses the assumptions noted in the following table. During the year ended December 31, 2016 , the expected stock price volatility used to value the stock options granted in 2016 was based on the volatility of the Company's historical stock price since February 2007. No stock options were granted in 2018 or 2017 . The expected term of the stock options granted in 2016 was calculated using the 'plain-vanilla' calculation provided in the guidance of the SEC's SAB No. 107. The dividend yield was calculated using amounts authorized by the Board of Directors. The risk-free interest rate is the yield on the grant date of the stock options of U.S. Treasury zero coupon securities with a maturity comparable to the expected term of the stock options. The Company anticipates issuing new shares of common stock upon the exercise of its outstanding stock options. The fair value of the stock options granted during the year ended December 31, 2016 was calculated using the following weighted average assumptions: 2016 Expected volatility 38.0 % Expected life (in years) 4.8 Dividend yield 1.3 % Risk-free interest rate 1.4 % Weighted average grant date fair values of stock options granted $8.46 Changes in outstanding stock options for the year ended December 31, 2018 were as follows: Number of Stock Options Weighted-Average Price Weighted Average Remaining Contractual Life Stock options outstanding at December 31, 2015 1,121,545 $ 18.31 2.8 years Granted 67,431 27.72 6.2 years Exercised (586,132 ) 16.39 Expired (6,075 ) 22.48 Forfeited (32,673 ) 24.35 Stock options outstanding at December 31, 2016 564,096 21.04 3.3 years Exercised (307,076 ) 19.44 Forfeited (9,673 ) 24.45 Stock options outstanding at December 31, 2017 247,347 22.90 3.4 years Exercised (57,091 ) 20.17 Forfeited — — Stock options outstanding at December 31, 2018 190,256 23.71 2.7 years Exercisable at December 31, 2018 149,327 22.95 2.4 years At December 31, 2018 , the Company had yet to recognize $0.2 million of unamortized expense related to stock option grants and expects to recognize these costs on a straight-line basis over the next 15 months . The fair value of stock options vested and the intrinsic value of outstanding and exercisable stock options as of December 31, were as follows: 2018 2017 2016 (in millions) Fair value of stock options vested $ 0.4 $ 0.6 $ 0.8 Intrinsic value of outstanding stock options 3.4 5.3 10.6 Intrinsic value of exercisable stock options 2.8 3.6 7.6 The intrinsic value of stock options exercised was $1.4 million , $7.6 million , and $7.6 million for the years ended December 31, 2018 , 2017 , and 2016 . RSUs The Company has awarded RSUs to non-employee members of the Board of Directors and certain employees of the Company. The RSUs awarded to non-employee members of the Board of Directors generally vest on the first anniversary of the award date. RSU grants allow each non-employee Director to decide whether to defer settlement of the RSUs until six months after termination of Board service or settle the RSUs at vesting. Dividend equivalents are granted to Directors who elected to defer settlement of the RSUs after the grants vested. RSUs awarded to employees of the Company have a service vesting period of approximately four years from the date awarded and vest 25% on or after each of the subsequent four anniversaries of such date . These RSUs are subject to accelerated vesting in certain limited circumstances, such as: retirement, death or disability of the holder, or in connection with a change of control of the Company. Changes in outstanding RSUs for the year ended December 31, 2018 were as follows: Number of RSUs Weighted Average Grant Date Fair Value RSUs outstanding at December 31, 2015 319,033 $ 20.71 Granted 100,218 28.20 Forfeited (21,872 ) 24.87 Vested (72,995 ) 21.56 RSUs outstanding at December 31, 2016 324,384 22.55 Granted 87,276 37.94 Forfeited (13,711 ) 29.28 Vested (102,785 ) 22.89 RSUs outstanding at December 31, 2017 295,164 26.67 Granted 87,857 40.26 Forfeited (3,370 ) 33.51 Vested (129,351 ) 24.53 RSUs outstanding at December 31, 2018 250,300 32.45 Vested but unsettled RSUs at December 31, 2018 67,620 23.35 At December 31, 2018 , the Company had yet to recognize $4.7 million of unamortized expense related to outstanding RSUs and expects to recognize these costs on a straight-line basis over the next 39 months . The grant date fair value of RSUs vested and the intrinsic value of vested RSUs for the years ended December 31, were as follows: 2018 2017 2016 (in millions) Grant date fair value of RSUs vested $ 3.2 $ 2.4 $ 1.6 Intrinsic value of RSUs vested 5.5 4.3 2.1 The intrinsic value of outstanding RSUs was $10.5 million , $13.1 million , and $12.8 million at December 31, 2018 , 2017 , and 2016 . PSUs The Company has awarded PSUs to certain employees of the Company as follows: Date of Grant Target Number Awarded Fair Value on Date of Grant Aggregate Fair Value on Date of Grant (in millions) March 2016 (1) 97,236 $ 27.72 $ 2.7 March 2017 (1) 97,440 37.60 3.7 March 2018 (1) 96,940 40.30 3.9 (1) The PSUs awarded in March 2016, 2017, and 2018 were awarded to certain employees 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 values shown in the table represent the aggregate number of PSUs awarded at the target level. At December 31, 2018 , the Company had yet to recognize $5.5 million of unamortized expense related to PSU grants and expects to recognize these costs on a straight-line basis over the next 24 months . This is based on the expectation of the Company achieving a 200% of target rate for the 2016 PSUs, a 200% of target rate for the 2017 PSUs, and a 125% of target rate for the 2018 PSUs.

Statutory Matters

Statutory Matters	12 Months Ended
	Dec. 31, 2018
Stautory Matters [Abstract]
Statutory Financial Data Disclosure	Statutory Matters Statutory Financial Data The combined capital stock, surplus, and net income of the Company's insurance subsidiaries (EICN, ECIC, EPIC, and EAC), prepared in accordance with the statutory accounting practices (SAP) of the National Association of Insurance Commissioners (NAIC) as well as SAP permitted by the states of California, Florida, and Nevada, were as follows: December 31, 2018 2017 (in millions) Capital stock and unassigned surplus $ 558.5 $ 510.6 Paid in capital 349.4 349.8 Surplus notes 20.0 32.0 Total statutory surplus $ 927.9 $ 892.4 Net income for the Company's insurance subsidiaries prepared in accordance with SAP for the years ended December 31, 2018 , 2017 and 2016 was $159.3 million , $116.8 million , and $101.4 million , respectively. Treatment of the LPT Agreement, deferred policy acquisition costs, fair value of financial instruments, and the surplus notes (see Notes 5 , 10 , and 11 ) are the primary differences in the SAP-basis capital stock and total surplus of the insurance subsidiaries of $927.9 million and $892.4 million , and the GAAP-basis equity of the Company of $1,018.2 million and $947.7 million as of December 31, 2018 and 2017 , respectively. Under SAP accounting, the retroactive reinsurance gain resulting from the LPT Agreement is recorded as a special component of surplus (special surplus funds) in the initial year of the contract, and not reported as unassigned surplus until the Company has recovered amounts in excess of the original consideration paid. The special surplus funds are also reduced by the amount of extraordinary dividends as approved by the Nevada Division of Insurance. Under SAP, the surplus notes are recorded as a separate component of surplus. Under SAP, changes to the estimated contingent profit commission under the LPT Agreement are reflected in commission expense in the period that the estimate is revised. Insurance Company Dividends and Regulatory Requirements and Restrictions The ability of EHI to pay dividends on the Company's common stock and to pay other expenses will be dependent to a significant extent upon the ability of the Nevada domiciled insurance company, EICN, the California domiciled insurance company, ECIC, and the Florida domiciled insurance companies, EPIC and EAC, to pay dividends to their immediate holding company, Employers Group, Inc. (EGI) and, in turn, the ability of EGI to pay dividends to EHI. The amount of dividends each of the Company's subsidiaries may pay to their immediate parent is limited by the laws of its respective state of domicile. Nevada law limits the payment of cash dividends by EICN to its parent by providing that payments cannot be made except from available and accumulated surplus, otherwise unrestricted (unassigned), and derived from realized net operating profits and realized and unrealized capital gains. A stock dividend may be paid out of any available surplus. A cash or stock dividend prohibited by these restrictions may only be declared and distributed as an extraordinary dividend upon the prior approval of the Nevada Commissioner of Insurance (Nevada Commissioner). EICN may not pay such an extraordinary dividend or make an extraordinary distribution until the Nevada Commissioner either approves or does not disapprove the payment within 30 days after receiving notice of its declaration. An extraordinary dividend or distribution is defined by statute to include any dividend or distribution of cash or property whose fair market value, together with that of other dividends or distributions made within the preceding 12 months, exceeds the lesser of: (a) 10% of EICN's statutory surplus as regards to policyholders at the next preceding December 31; or (b) EICN's statutory net income, not including realized capital gains, for the 12-month period ending at the next preceding December 31. As of December 31, 2018 , EICN had positive unassigned surplus of $195.3 million . During 2018 , EICN paid an ordinary dividend in the amount of $17.7 million to its parent company, EGI. As a result of that payment, EICN can pay $2.1 million of dividends through January 25, 2019 and $19.8 million thereafter without regulatory approval, provided that no dividends are paid prior to January 25, 2019. Under Florida law, without regulatory approval, EPIC and EAC may pay dividends if they do not exceed the greater of: the lesser of 10% of surplus or net income, not including realized capital gains, plus a 2-year carry forward; 10% of surplus, with dividends payable limited to unassigned funds minus 25% of unrealized capital gains; or, the lesser of 10% of surplus or net investment income plus a 3-year carry forward with dividends payable limited to unassigned funds minus 25% of unrealized capital gains. During 2018 , EAC paid an ordinary dividend in the amount of $18.9 million to its parent company, EGI. As a result of that payment, EAC can pay $0.9 million of dividends through May 18, 2019 and $19.8 million thereafter without regulatory approval from the Florida Office of Insurance Regulation (FOIR), provided that no dividends are paid prior to May 18, 2019. During 2018 , EPIC did not pay any dividends. The maximum dividends that may be paid in 2019 by EPIC without prior regulatory approval from the FOIR is $19.0 million . ECIC is subject to regulation by the California Department of Insurance (California DOI). The ability of ECIC to pay dividends was further limited by restrictions imposed by the California DOI in its approval of the Company's October 1, 2008 reinsurance pooling agreement. Under that approval: (a) ECIC must initiate discussions of its business plan with the California DOI if its net written premium to policyholder surplus ratio exceeds 1.5 to 1 ; (b) ECIC will not exceed a ratio of net written premium to policyholder surplus of 2 to 1 without approval of the California DOI; (c) if at any time ECIC's policyholder surplus decreases to 80% or less than the September 30, 2008 balance, ECIC shall cease issuing new policies in California, but may continue to renew existing policies until it has (i) received a capital infusion to bring its surplus position to the same level as that as of September 30, 2008 and (ii) submitted a new business plan to the California DOI; (d) ECIC will maintain a risk based capital (RBC) level of at least 350% of the authorized control level; (e) should ECIC fail to comply with any commitments listed herein, ECIC will consent to any request by the California DOI to cease issuing new policies in California, but may continue to renew existing policies until such time that as ECIC is able to achieve full compliance with each commitment; and (f) the obligations listed shall only terminate with the written consent of the California DOI. During the years ended December 31, 2018 , 2017 , and 2016 , ECIC was in compliance with these requirements. Additionally, the California Insurance Holding Company System Regulatory Act limits the ability of ECIC to pay dividends to its parent. California law provides that, absent prior approval of the California Insurance Commissioner, dividends may only be declared from earned surplus. For purpose of this statute, earned surplus excludes amounts (1) derived from net appreciation in the value of assets not yet realized, or (2) derived from an exchange of assets, unless the assets received are currently realizable in cash. In addition, California law provides that the appropriate insurance regulatory authorities in the state of California must approve (or, within a 30-day notice period, not disapprove) any dividend that, together with all other such dividends paid during the preceding 12 months, exceeds the greater of: (a) 10% of the paying company's statutory surplus as regards to policyholders at the preceding December 31; or (b) 100% of net income for the preceding year. During 2018 , ECIC paid an ordinary dividend in the amount of $48.4 million to its parent company, EGI. As a result of that payment, ECIC can pay $8.8 million of dividends through September 5, 2019 and $57.2 million thereafter without prior regulatory approval, provided that no dividends are paid prior to September 5, 2019. EPIC and EAC are subject to regulation by the Florida Department of Financial Services (FDFS). Florida statute Section 624.408 requires EPIC and EAC to maintain minimum capital and surplus of the greater of $4.0 million or 10% of total liabilities. Florida statute Section 624.4095 requires EPIC and EAC to maintain a ratio of written premiums, defined as 1.25 times written premiums, to surplus of no greater than 10-to-1 for gross written premiums and 4-to-1 for net written premiums. During the years ended December 31, 2018 , 2017 , and 2016 , EPIC and EAC were in compliance with these statutes. Additionally, EICN, ECIC, EPIC, and EAC are required to comply with RBC requirements. RBC is a method of measuring the amount of capital appropriate for an insurance company to support its overall business operations in light of its size and risk profile. NAIC RBC standards are used by regulators to determine appropriate regulatory actions relating to insurers that show signs of weak or deteriorating conditions. As of December 31, 2018 , 2017 , and 2016 , EICN, ECIC, EPIC, and EAC each had total adjusted capital above all regulatory action levels.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income, Net	12 Months Ended
	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income, Net	Accumulated Other Comprehensive (Loss) Income Accumulated other comprehensive (loss) income is comprised of unrealized (losses) gains on investments classified as available-for-sale, net of deferred tax expense. Beginning in 2018, with the adoption of ASU No. 2016-01, the Company's investments in equity securities at fair value are no longer considered to be AFS and are reported at fair value with unrealized gains and losses included in Net realized and unrealized (losses) gains on investments on the Company's Consolidated Statements of Comprehensive Income. Prior to 2018, investments in equity securities at fair value were classified as AFS and changes in fair value were excluded from earnings and reported in accumulated other comprehensive (loss) income. The following table summarizes the components of Accumulated other comprehensive (loss) income: Years Ended December 31, 2018 2017 (in millions) Net unrealized (losses) gains on investments, before taxes $ (17.3 ) $ 136.0 Deferred tax benefit (expense) on net unrealized (losses) gains 3.6 (28.6 ) Total accumulated other comprehensive (loss) income $ (13.7 ) $ 107.4

Employee Benefit and Retirement

Employee Benefit and Retirement Plans	12 Months Ended
	Dec. 31, 2018
Employee Benefit and Retirement Plans [Abstract]
Compensation and Employee Benefit Plans	Employee Benefit and Retirement Plans The Company maintains a 401(k) defined contribution plan covering all eligible Company employees (the Employers 401(k) Plan). Under the Employers 401(k) Plan, the Company's safe harbor matching consists of 100% matching contribution on salary deferrals up to 3% of compensation and then 50% matching contribution on salary deferrals from 3% to 5% of compensation. The Company's matching contribution to the Employers 401(k) Plan was $2.0 million , $1.9 million , and $1.9 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Common Share Basic earnings per share, which includes no dilution from outstanding stock-based awards, is computed by dividing net income by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflect the potential dilutive impact of all outstanding stock-based awards on earnings per share. Diluted earnings per share includes common shares assumed issued under the “treasury stock method,” which reflects the potential dilution that would occur if outstanding RSUs and PSUs vested, and stock options were to be exercised. Commencing in 2017, certain stock-based compensation awards are eligible to receive dividend equivalents on awards that fully vest or become payable. These awards are not considered participating securities for the purposes of determining earnings per share. The following table presents the net income and the weighted average shares outstanding used in the earnings per share common share calculations. Years Ended December 31, 2018 2017 2016 (in millions, except share data) Net income $ 141.3 $ 101.2 $ 106.7 Weighted average number of shares outstanding–basic 32,884,828 32,501,576 32,434,580 Effect of dilutive securities: Stock options 97,810 208,602 246,562 PSUs 268,030 271,738 222,594 RSUs 60,669 78,844 73,099 Dilutive potential shares 426,509 559,184 542,255 Weighted average number of shares outstanding–diluted 33,311,337 33,060,760 32,976,835 Diluted earnings per share excludes those outstanding stock options and any other common stock equivalents in periods where the inclusion of such stock options and common stock equivalents would be anti-dilutive. The following table presents the number of stock options, PSUs and RSUs that were excluded from the Company's calculation of diluted earnings per share. Years Ended December 31, 2018 2017 2016 Stock options excluded as the exercise price was greater than the average market price — — — Stock options excluded under the treasury method, as the potential proceeds on settlement or exercise was greater than the value of shares acquired — — 89,221

Selected Quarterly Financial Da

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2018
Selecled Quarterly Financial Data (Unaudited) [Abstract]
Quarterly Financial Information	Selected Quarterly Financial Data (Unaudited) Quarterly results for the years ended December 31, 2018 and 2017 were as follows: 2018 Quarters Ended March 31 June 30 September 30 December 31 (in millions, except per share data) Net premiums earned $ 176.6 $ 178.0 $ 192.9 $ 183.6 Net realized and unrealized (losses) gains on investments (8.0 ) 5.7 15.6 (26.4 ) Losses and loss adjustment expenses 95.4 87.8 106.6 86.9 Commission expense 23.7 24.5 24.8 21.2 Underwriting and other operating expenses 39.2 40.1 38.8 40.4 Income tax expense 3.8 8.8 10.7 4.9 Net income 25.6 42.5 47.6 25.6 Earnings per common share: Basic 0.78 1.29 1.45 0.78 Diluted 0.77 1.28 1.43 0.77 2017 Quarters Ended March 31 June 30 September 30 December 31 (in millions, except per share data) Net premiums earned $ 175.3 $ 171.7 $ 187.9 $ 181.6 Net realized gains on investments 2.2 1.1 4.1 — Losses and loss adjustment expenses 109.0 106.1 116.9 85.2 Commission expense 21.5 21.5 23.7 24.7 Underwriting and other operating expenses 35.9 32.6 33.6 37.8 Other expenses — — 7.5 — Income tax expense 6.3 7.8 7.0 21.7 Net income 23.2 24.8 21.9 31.3 Earnings per common share: Basic 0.72 0.76 0.67 0.96 Diluted 0.70 0.75 0.66 0.94 Significant Quarterly Adjustments Changes in Net unrealized (losses) gains on investments in 2018 were due to volatility in equity markets. Beginning in 2018, equity securities at fair value are no longer classified as AFS and changes in fair value are included in Net realized and unrealized (losses) gains on investments on the Company's Consolidated Statements of Comprehensive Income. Additionally, Income tax expense was impacted by the volatility in Net unrealized (losses) gains on investments, affecting net income for each quarter of 2018. The first quarter of 2018 was impacted by: (1) favorable prior accident year loss development of $12.4 million , which decreased losses and LAE by the same amount; (2) the inclusion of $12.9 million in net unrealized losses on equity securities during the period. The second quarter of 2018 was impacted by: (1) favorable prior accident year loss development of $16.5 million , which decreased losses and LAE by the same amount; (2) favorable development in the estimated reserves ceded under the LPT Agreement that resulted in a $2.2 million LPT Reserve Adjustment and a $0.5 million LPT Contingent Commission Adjustment, which decreased losses and LAE by the same amount; and (3) the inclusion of $3.5 million in net unrealized gains on equity securities. The third quarter of 2018 was impacted by: (1) favorable prior accident year loss development of $11.9 million , which decreased losses and LAE by the same amount; and (2) the inclusion of $11.2 million in net unrealized gains on equity securities during the period. The fourth quarter of 2018 was impacted by: (1) favorable prior accident year loss development of $25.4 million , which decreased losses and LAE by the same amount; and (2) the inclusion of $27.4 million in net unrealized losses on equity securities during the period. The second quarter of 2017 was favorably impacted by a $2.1 million gain from EHI's purchase of a $12.0 million note payable. The third quarter of 2017 was negatively impacted by a write-off of $7.5 million of previously capitalized costs relating to the development of information technology capabilities that had not yet been placed in service. The fourth quarter of 2017 was impacted by: (1) favorable prior accident year loss development of $18.0 million ; (2) a reduction in our current accident year loss provision rate that reduced Losses and LAE by $10.6 million ; and (3) $7.0 million in additional income tax expense from a revaluation of the Company's net deferred tax asset resulting from Enactment.

Schedule II. Condensed Financia

Schedule II. Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2018
Notes to Condensed Financial Statments [Abstract]
Schedule II. Condensed Financial Information of Registrant	Employers Holdings, Inc. Condensed Balance Sheets December 31, 2018 2017 Assets (in millions, except share data) Investments: Investment in subsidiaries $ 873.8 $ 849.6 Fixed maturity securities at fair value (amortized cost $24.2 at December 31, 2018 and $40.2 at December 31, 2017) 24.6 41.4 Equity securities at fair value (cost $40.0 at December 31, 2018) 38.7 — Short-term investments at fair value (amortized cost $25.0 at December 31, 2018 and $3.7 at December 31, 2017) 25.0 3.7 Total investments 962.1 894.7 Cash and cash equivalents 41.3 39.6 Accrued investment income 0.3 0.3 Intercompany receivable 0.3 — Federal income taxes receivable 22.7 4.2 Deferred income taxes, net — 14.5 Other assets 0.9 0.8 Total assets $ 1,027.6 $ 954.1 Liabilities and stockholders' equity Accounts payable and accrued expenses $ 5.0 $ 4.5 Intercompany payable — 1.9 Deferred income taxes, net 0.4 — Other liabilities 4.0 — Total liabilities 9.4 6.4 Stockholders' equity : Common stock, $0.01 par value; 150,000,000 shares authorized; 56,975,675 and 56,695,174 shares issued and 32,765,792 and 32,597,819 shares outstanding at December 31, 2018 and 2017, respectively 0.6 0.6 Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued — — Additional paid-in capital 388.8 381.2 Retained earnings 1,030.7 842.2 Accumulated other comprehensive (loss) income, net of tax (13.7 ) 107.4 Treasury stock, at cost (24,209,883 shares at December 31, 2018 and 24,097,355 shares at December 31, 2017) (388.2 ) (383.7 ) Total stockholders' equity 1,018.2 947.7 Total liabilities and stockholders' equity $ 1,027.6 $ 954.1 Employers Holdings, Inc. Condensed Statements of Income Years Ended December 31, 2018 2017 2016 (in millions, except per share data) Revenues Net investment income $ 2.5 $ 1.3 $ 1.9 Net realized and unrealized gains on investments 0.8 — 8.0 Total revenues 3.3 1.3 9.9 Expenses Other operating expenses 17.5 15.2 13.8 Total expenses 17.5 15.2 13.8 Loss before income taxes and equity in earnings of subsidiaries (14.2 ) (13.9 ) (3.9 ) Income tax benefit (4.3 ) (5.8 ) (3.5 ) Net loss before equity in earnings of subsidiaries (9.9 ) (8.1 ) (0.4 ) Equity in earnings of subsidiaries 151.2 109.3 107.1 Net income $ 141.3 $ 101.2 $ 106.7 Earnings per common share: Basic $ 4.30 $ 3.11 $ 3.29 Diluted $ 4.24 $ 3.06 $ 3.24 Cash dividends declared per common share $ 0.80 $ 0.60 $ 0.36 Employers Holdings, Inc. Condensed Statement of Cash Flows Years Ended December 31, 2018 2017 2016 (in millions) Operating activities Net income $ 141.3 $ 101.2 $ 106.7 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Equity in undistributed earnings of subsidiaries (66.7 ) (71.5 ) (107.1 ) Net realized and unrealized gains on investments (0.8 ) — (8.0 ) Stock-based compensation 9.4 6.8 5.8 Amortization of premium on investments, net 0.2 0.1 0.4 Deferred income tax expense 14.7 5.3 2.9 Change in operating assets and liabilities: Accounts payable and accrued expenses 0.2 (0.3 ) (0.7 ) Federal income taxes (18.5 ) 5.4 (7.9 ) Other assets (0.1 ) (0.1 ) 0.8 Intercompany payables and receivables (2.2 ) 1.8 0.3 Other — — (0.4 ) Net cash provided by (used in) operating activities 77.5 48.7 (7.2 ) Investing activities Purchases of fixed maturity securities (14.4 ) (30.6 ) (31.0 ) Purchases of equity securities (40.0 ) — (3.6 ) Purchases of short-term securities (59.6 ) (7.9 ) — Proceeds from sale of fixed maturity securities 12.0 5.0 — Proceeds from maturities and redemptions of investments 59.2 4.5 24.9 Proceeds from sale of equity securities — — 88.5 Net change in unsettled purchases and sales 3.9 — — Capital contributions to subsidiaries (4.2 ) (5.6 ) (8.0 ) Net cash (used in) provided by investing activities (43.1 ) (34.6 ) 70.8 Financing activities Acquisition of common stock (4.2 ) — (21.1 ) Cash transactions related to stock-based compensation (1.8 ) 3.8 9.0 Dividends paid to stockholders (26.7 ) (19.7 ) (11.5 ) Net cash used in financing activities (32.7 ) (15.9 ) (23.6 ) Net increase (decrease) in cash and cash equivalents 1.7 (1.8 ) 40.0 Cash and cash equivalents at the beginning of the period 39.6 41.4 1.4 Cash and cash equivalents at the end of the period $ 41.3 $ 39.6 $ 41.4

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Cash and Cash Equivalents, Policy	Cash and Cash Equivalents The Company considers all liquid investments with maturities of less than three months, as measured from the date of purchase, to be cash equivalents.
Restricted Cash and Cash Equivalents, Policy	Restricted Cash and Cash Equivalents Restricted cash and cash equivalents represent cash and cash equivalents held in trust in order to secure certain of the Company's obligations and, accordingly, are restricted as to withdrawal or usage. As of December 31, 2018 and 2017 the Company held $23.2 million and $24.5 million , respectively, in cash and investments in trust for reinsurance obligations, of which $0.6 million and $1.0 million , respectively, represented restricted cash and cash equivalents.
Investments, Policy	Short-Term Investments The Company considers all liquid investments with maturities of between three and twelve months, as measured from the date of purchase, to be short-term investments. Investment Securities The Company's investments in fixed maturity securities, equity securities at fair value (prior to 2018), and short-term investments are classified as available-for-sale (AFS) and are reported at fair value with unrealized gains and losses excluded from earnings and reported as a separate component of stockholders' equity, net of deferred taxes, in Accumulated other comprehensive (loss) income on the Company’s Consolidated Balance Sheets. Beginning in 2018, with the adoption of ASU Number 2016-01, Financial Instruments - Overall (Subtopic 825-10) , the Company's investments in equity securities at fair value are no longer classified as AFS and changes in fair value are included in Net realized and unrealized (losses) gains on investments on the Company's Consolidated Statements of Comprehensive Income. Effective January 1, 2018, the Company's investment in FHLB stock is presented within Equity securities at cost on the Company's Consolidated Balance Sheets. As of December 31, 2017, the Company's investment in FHLB stock was presented within Equity securities at fair value on the Company's Consolidated Balance Sheet. The adoption of ASU 2016-01 also removed the impairment assessment for equity securities at fair value beginning in 2018 and changes in fair value are included in Net realized and unrealized (losses) gains on investments on the Company's Consolidated Statements of Comprehensive Income. Prior to adoption of this standard, when, in the opinion of management, a decline in the fair value of an equity security below its cost was considered to be “other-than-temporary,” the equity security's cost was written down to its fair value at the time the other-than-temporary decline is identified. The determination of an other-than-temporary decline for fixed maturity securities includes, in addition to other relevant factors, a presumption that if the market value is below cost by a significant amount for a period of time, a bifurcation of the write-down may be necessary based on the portion of the loss that is deemed to be a “credit loss”, which is considered a realized loss, and the portion that is deemed to be an “other than credit loss”, which is considered to be an unrealized loss. If management has the intent to sell the fixed maturity security or more likely than not will be required to sell the fixed maturity security before its anticipated recovery, the investment is written down to its fair value and the entire impairment is recorded as a realized loss in the Company's Consolidated Statements of Comprehensive Income. If management does not have the intent to sell or will not be required to sell the fixed maturity security but does not expect to recover the amortized cost basis of the fixed maturity security, the amount of the other-than-temporary impairment is bifurcated (see Note 6 ). Investment income consists primarily of interest and dividends generated by investment securities. Interest is recorded as earned on an accrual basis and dividends are recorded as earned at the ex-dividend date. Interest income on mortgage-backed and asset-backed securities is determined using the effective-yield method based on estimated principal repayments. Mortgage-backed securities are adjusted for the effects of changes in prepayment assumptions on the related accretion of discount or amortization of premium of such securities using the retrospective method. Realized gains and losses on investments are determined on a specific-identification basis.
Revenue Recognition, Policy	Revenue Recognition Premiums written are recognized as revenues, net of any applicable underlying reinsurance coverage, and are earned over the term of the related policy. At the end of the policy term, payroll-based premium audits are performed on substantially all policyholder accounts to determine the actual amount of net premiums earned for that policy year. Earned but unbilled premiums include estimated future audit premiums based on the Company's historical experience. These estimates are subject to changes in policyholders' payrolls, economic conditions, and seasonality, and are continually reviewed and adjusted as experience develops or new information becomes known. Any such adjustments are included in current operations; however, they are partially offset by the resulting changes in losses and LAE, commission expenses, and premium taxes. The Company's premiums receivable on its Consolidated Balance Sheets included $63.7 million and $64.2 million of additional premiums expected to be received from policyholders for final audits at December 31, 2018 and 2017 , respectively. The Company establishes a bad debt allowance on its premiums receivable through a charge included in underwriting and other operating expenses in its Consolidated Statements of Comprehensive Income. This bad debt allowance is determined based on estimates and assumptions to project future experience. After all collection efforts have been exhausted, the Company reduces the bad debt allowance for write-offs of premiums receivable that have been deemed uncollectible. The Company's bad debt allowance was $6.7 million and $10.0 million at December 31, 2018 and 2017 , respectively. The Company had write offs, net of recoveries of amounts previously written off, of $8.2 million , $3.2 million , and $6.0 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively.
Deferred Policy Acquisition Costs, Policy	Deferred Policy Acquisition Costs Policy acquisition costs, those costs that relate directly to the successful acquisition of new or renewal insurance contracts, including underwriting, policy issuance and processing, medical and inspection, and sales force contract selling are deferred and amortized as the related premiums are earned. Amortization of deferred policy acquisition costs for the years ended December 31, 2018 , 2017 , and 2016 , was $112.0 million , $108.2 million , and $104.5 million , respectively. If the sum of a policy’s expected losses and LAE and deferred policy acquisition costs exceeds the related unearned premiums and projected investment income, a premium deficiency is determined to exist. In this event, deferred policy acquisition costs are immediately expensed to the extent necessary to eliminate the premium deficiency. If the premium deficiency exceeds deferred acquisition costs, a liability is accrued for the excess deficiency. There were no premium deficiency adjustments recognized during the years ended December 31, 2018 , 2017 , and 2016 .
Unpaid Loss and LAE Reserves, Policy	Unpaid Loss and LAE Reserves Unpaid loss and LAE reserves represent management's best estimate of the ultimate net cost of all reported and unreported losses incurred for the applicable periods, less payments made. The estimated reserves for losses and LAE include the accumulation of estimates for all claims reported prior to the balance sheet date, estimates of claims incurred but not reported, and estimates of expenses for investigating and adjusting all incurred and unadjusted claims (based on projections of relevant historical data). Amounts reported are subject to the impact of future changes in economic, regulatory and social conditions. Management believes that, subject to the inherent variability in any such estimate, the reserves are within a reasonable and acceptable range of adequacy. Estimates for claims prior to the balance sheet date are continually monitored and reviewed, and as settlements are made or reserves adjusted, the differences are reported in current operations. Salvage and subrogation recoveries are estimated based on a review of the level of historical salvage and subrogation recoveries.
Reinsurance, Policy	Reinsurance In the ordinary course of business, the Company purchases excess of loss reinsurance in order to protect it against the impact of large and/or catastrophic losses. Additionally, the Company is a party to the LPT Agreement (see Note 10 ). These reinsurance arrangements reduce the Company's exposure to such losses since its reinsurers are liable to the Company to the extent of the reinsurance protection provided. However, the Company remains liable for all losses it incurs to the extent that any reinsurer is unable or unwilling to make timely payments under its reinsurance agreements. Balances due from reinsurers on unpaid losses, including an estimate of such recoverables related to reserves for incurred but not reported losses, are reported as reinsurance recoverables on the Company’s Consolidated Balance Sheets. Reinsurance recoverables on paid losses represents amounts currently due from reinsurers. Reinsurance recoverables on unpaid losses represents amounts that will be collectible from reinsurers once the losses are paid. Reinsurance recoverables on unpaid losses and LAE amounted to $504.4 million and $537.0 million at December 31, 2018 and 2017 , respectively. Ceded reinsurance premiums are accounted for on a basis consistent with those used in accounting for the underlying premiums, and are reported as reductions to arrive at net premiums written and earned. Ceded losses and LAE are also accounted for on a basis consistent with those used in accounting for the original policies issued and the terms of the relevant reinsurance agreement, and are recorded as reductions to losses and LAE incurred. Pursuant to the LPT Agreement, LAE is deemed to be 7% of total losses paid and is payable to the Company as compensation for management of the claims under the LPT Agreement. The Deferred Gain is amortized using the recovery method, whereby the amortization is determined by the proportion of actual reinsurance recoveries to total estimated recoveries through the life of the LPT Agreement, and is recorded in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income. Any adjustment to the estimated loss and LAE reserves ceded under the LPT Agreement results in a cumulative adjustment to the Deferred Gain, which is also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, such that the Deferred Gain reflects the balance that would have existed had the revised reserves been recognized at the inception of the LPT Agreement. Additionally, the Company is entitled to receive a contingent profit commission under the LPT Agreement. The contingent profit commission is equal to 30% of the favorable difference between actual paid losses and LAE and expected paid losses and LAE as established in the LPT Agreement based on losses paid through June 30, 2024. The contingent profit commission is paid every five years beginning June 30, 2004 for the first 25 years of the agreement. The Company could be required to return any previously received contingent profit commission, plus interest, in the event of unfavorable differences through June 30, 2024. The Company records an estimate of contingent profit commission in its Consolidated Balance Sheets as Contingent commission receivable–LPT Agreement and a corresponding liability is recorded as Deferred reinsurance gain–LPT Agreement. The Contingent commission receivable–LPT Agreement is reduced as amounts are received from participating reinsurers. The Deferred reinsurance gain–LPT Agreement is amortized using the recovery method. The amortization of the contingent profit commission is determined by the proportion of actual reinsurance recoveries to total estimated recoveries over the life of the contingent profit commission (through June 30, 2024), and is recorded in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income. Any adjustment to the contingent profit commission under the LPT Agreement results in a cumulative adjustment to the Deferred Gain, which is also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, such that the Deferred Gain reflects the balance that would have existed had the revised contingent profit commission been recognized at the inception of the LPT Agreement.
Property, and Equipment, Policy	Property and Equipment Property and equipment are stated at cost less accumulated depreciation (see Note 7 ). Expenditures for maintenance and repairs are charged against operations as incurred. Electronic data processing equipment, software, furniture and equipment, and automobiles are depreciated using the straight-line method over three to seven years . Leasehold improvements are carried at cost less accumulated amortization. The Company amortizes leasehold improvements using the straight-line method over the lesser of the useful life of the asset or the remaining original lease term, excluding options or renewal periods. Leasehold improvements are generally amortized over three to eight years .
Cloud Computing Arrangements, Policy	Cloud Computing Arrangements The Company capitalizes software license fees and implementation costs associated with hosting arrangements that are service contracts. These amounts are included in Cloud computing arrangements on the Company's Consolidated Balance Sheets. Amortization of the software license fees is calculated using the straight-line method over the term of the service contract or based on the expected utilization of the asset. Amortization of the implementation costs are calculated using the straight-line method based on the term of the service contract and commence once the module or component is ready for its intended use, regardless of whether the hosted software has been placed into service, and will be recognized over the remaining life of the service contract.
Lessee, Leases [Policy Text Block]	Obligations Held Under Capital Leases Leased property and equipment meeting capital lease criteria are capitalized at the lower of the present value of the related lease payments or the fair value of the leased asset at the inception of the lease. Amortization is calculated using the straight-line method based on the term of the lease and is included in the depreciation expense of property and equipment. See Note 12 for additional disclosures related to capital leases.
Income Taxes, Policy	Income Taxes The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the Company's financial statements. Under this method, the Company determines deferred tax assets and liabilities on the basis of the differences between the financial statement and tax bases of assets and liabilities by using enacted tax rates in effect for the year in which the differences are expected to reverse. As of December 22, 2017, the date that the Tax Cuts and Jobs Act was enacted (Enactment), the effect of the change in tax rates on the Company's deferred tax assets and liabilities was recognized in income and created stranded tax effects within accumulated other comprehensive income that did not reflect the newly enacted tax rate. The Company reclassified the net tax effects from Accumulated other comprehensive income, net of tax, to Retained earnings as of the date of Enactment. The Company records uncertain tax positions in accordance with ASC 740, Income Taxes , on the basis of a two-step process. Recognition (Step 1) occurs when the Company concludes that a tax position, based solely on its technical merits, is more likely than not to be sustained upon examination. Measurement (Step 2) is addressed only if Step 1 has been satisfied. Under Step 2, the tax benefit is measured as the largest amount of benefit, determined on a cumulative probability basis, that is more likely than not to be realized upon ultimate settlement. The Company recognizes deferred tax assets when it determines that such assets are more likely than not to be realized in future periods. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, tax-planning strategies, projected future taxable income, projected future tax rates, and results of recent operations. If the Company determines that it is not more likely than not that it could realize its deferred tax assets in future periods, it would establish a deferred tax asset valuation allowance that would increase the Company's provision for income taxes. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of its net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.
Credit Risk, Policy	Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash and cash equivalents (including restricted cash equivalents), short-term investments, investment securities, premiums receivable, and reinsurance recoverable balances. The Company’s cash equivalents and short-term investments include investments in money market securities and securities backed by the U.S. government. The Company's investment securities are diversified throughout many industries and geographic regions and include investments in U.S. government and U.S. government-sponsored enterprises. The Company believes that it has no significant concentrations of credit risk from a single issue or issuer within its cash equivalents, short-term investments and investment securities other than concentrations in U.S. government and U.S. government-sponsored enterprises. The Company's premiums receivable are generally diversified due to the large number of entities composing the Company's policyholder base and their dispersion across many different industries. The Company monitors the financial condition of its reinsurers to minimize its exposure to significant losses from reinsurer insolvencies. The Company also obtains collateral from its reinsurers in order to mitigate the risks related to insolvencies. At December 31, 2018 , $2.0 million of the Company's reinsurance recoverables were collateralized by cash or letters of credit and an additional $311.6 million was in trust accounts for reinsurance recoverables specifically related to the LPT Agreement.
Fair Value of Financial Instruments, Policy	Fair Value of Financial Instruments The fair values of the Company's financial instruments have been determined using available market information and other appropriate valuation methodologies. Judgment is required in developing fair value estimates where quoted market prices are not available. Accordingly, these estimates are not necessarily indicative of the amounts that could be realized in a current market exchange. The use of different market assumptions or estimating methodologies may have an effect on the estimated fair value amounts. The following methods and assumptions were used by the Company in estimating the fair value of its financial instruments: Cash and cash equivalents, short-term investments, premiums receivable, accounts payable and accrued expenses, and other liabilities. The carrying amounts for each of these financial instruments as reported in the Company's Consolidated Balance Sheets approximate their fair values. Investment securities. The Company’s investment securities are predominantly valued on the basis of actual market transactions or observable inputs. A small portion of the Company’s investment securities are valued on the basis of pricing models with significant unobservable inputs or nonbinding broker quotes. See Note 5 .
Goodwill and Other Intangible Assets, Policy	Goodwill and Other Intangible Assets The Company tests for impairment of goodwill and non-amortizable intangible assets in the fourth quarter of each year. At the end of each quarter, management considers the results of the previous analysis as well as any recent developments that may constitute triggering events requiring the impairment analysis of goodwill and other intangible assets to be updated. The Company has assessed the effects of current economic conditions on the Company's financial condition and results of operations and changes in the Company's stock price and determined that there were no impairments of these assets as of December 31, 2018 and 2017 . Intangible assets related to state licenses are not subject to amortization. Intangibles related to insurance relationships were amortized in proportion to the expected period of benefit and were fully amortized as of December 31, 2018 . The gross carrying value, accumulated amortization, and net carrying value for the Company's intangible assets, by major class, as of December 31, were as follows: 2018 2017 Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value (in millions) State licenses $ 7.7 $ — $ 7.7 $ 7.7 $ — $ 7.7 Insurance relationships 9.4 $ (9.4 ) — 9.4 $ (9.2 ) 0.2 Total $ 17.1 $ (9.4 ) $ 7.7 $ 17.1 $ (9.2 ) $ 7.9 During the years ended December 31, 2018 , 2017 , and 2016 , the Company recognized $0.2 million , $0.3 million , and $0.3 million in amortization expense associated with its intangible assets, respectively. These amortization expenses are included in the Company's Consolidated Statements of Comprehensive Income in underwriting and other operating expenses.
Stock-based Compensation, Policy	Stock-Based Compensation The Company provides stock-based compensation to its directors and certain of its employees, which is recognized in its Consolidated Statements of Comprehensive Income based on estimated fair values over the relevant service period (see Note 14 ).

Changes in Estimates (Tables)

Changes in Estimates (Tables)	12 Months Ended
	Dec. 31, 2018
Changes in Estimates [Abstract]
Change to Contingent Profit Commission [Table Text Block]	The Company increased its estimate of Contingent commission receivable – LPT Agreement (LPT Contingent Commission Adjustments) in each of 2018 , 2017 , and 2016 as a result of the determination that adjustments were necessary to reflect observed favorable paid loss trends in each of those years. The following table shows the impact to the Consolidated Statements of Comprehensive Income related to these changes in estimates. 2018 2017 2016 (in millions, except per share data) LPT Contingent Commission Adjustments $ 0.5 $ 0.3 $ 1.9 Net income impact from this change in estimate 0.5 0.3 1.8 Earnings per common share impact from this change in estimate: Basic 0.02 0.01 0.06 Diluted 0.02 0.01 0.05
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Table Text Block]	The Company reduced its estimated loss and LAE reserves ceded under the LPT Agreement (LPT Reserve Adjustments) in each of the years 2018 and 2016 as a result of the determination that adjustments were necessary to reflect observed favorable paid loss trends in each of these years. There were no LPT Reserve Adjustments in 2017. The following table shows the financial statement impact related to the LPT Reserve Adjustments. 2018 2016 (in millions, except per share data) LPT Reserve Adjustments $ (6.3 ) $ (5.0 ) Cumulative adjustment to the Deferred Gain (1) (2.2 ) (3.1 ) Net income impact from this change in estimate 2.2 3.1 Earnings per common share impact from this change in estimate: Basic 0.07 0.10 Diluted 0.07 0.09 (1) The cumulative adjustments to the Deferred Gain were also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised loss and LAE reserves been recognized at the inception of the LPT Agreement.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Schedule of intangible assets table	The gross carrying value, accumulated amortization, and net carrying value for the Company's intangible assets, by major class, as of December 31, were as follows: 2018 2017 Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value (in millions) State licenses $ 7.7 $ — $ 7.7 $ 7.7 $ — $ 7.7 Insurance relationships 9.4 $ (9.4 ) — 9.4 $ (9.2 ) 0.2 Total $ 17.1 $ (9.4 ) $ 7.7 $ 17.1 $ (9.2 ) $ 7.9

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
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 at fair value were as follows as of December 31 : 2018 2017 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value Financial assets (in millions) Investments at fair value (Note 6) $ 2,721.3 $ 2,721.3 $ 2,677.7 $ 2,677.7 Cash and cash equivalents 101.4 101.4 73.3 73.3 Restricted cash and cash equivalents 0.6 0.6 1.0 1.0 Financial liabilities Notes payable (Note 11) $ 20.0 $ 23.5 $ 20.0 $ 23.6
Fair value, assets and liabilities measured on recurring basis table	The following table presents the Company's investments at fair value and the corresponding fair value measurements. December 31, 2018 December 31, 2017 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities U.S. Treasuries $ — $ 106.4 $ — $ — $ 137.0 $ — U.S. Agencies — 11.4 — — 11.8 — States and municipalities — 528.0 — — 642.5 — Corporate securities — 1,090.4 — — 1,118.0 — Residential mortgage-backed securities — 451.5 — — 389.3 — Commercial mortgage-backed securities — 94.3 — — 106.0 — Asset-backed securities — 64.5 — — 58.8 — Other securities — 149.9 — — — — Total fixed maturity securities $ — $ 2,496.4 $ — $ — $ 2,463.4 $ — Equity securities at fair value Industrial and miscellaneous $ 174.8 $ — $ — $ 181.7 $ — $ — Non-redeemable preferred (FHLB stock) — — — — — 4.7 Other 25.1 — — 23.9 — — Total equity securities at fair value $ 199.9 $ — $ — $ 205.6 $ — $ 4.7 Short-term investments $ — $ 25.0 $ — $ — $ 4.0 $ — Total investments at fair value $ 199.9 $ 2,521.4 $ — $ 205.6 $ 2,467.4 $ 4.7
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table presents cash equivalents at NAV and total cash and cash equivalents carried at fair value on the Company's Consolidated Balance Sheets. December 31, 2018 December 31, 2017 Cash and cash equivalents at fair value $ 43.9 $ 34.3 Cash equivalents measured at NAV, which approximates fair value 57.5 39.0 Total cash and cash equivalents $ 101.4 $ 73.3
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 years ended December 31, 2018 and 2017 . Level 3 Securities 2018 2017 (in millions) Beginning balance, January 1 $ 4.7 $ 11.9 Transfers out of Level 3 (1) (4.7 ) (7.0 ) Purchases and sales, net — (0.2 ) Ending balance, December 31 $ — $ 4.7

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2018
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 AFS investments were as follows: Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value At December 31, 2018 (in millions) Fixed maturity securities U.S. Treasuries $ 106.7 $ 0.9 $ (1.2 ) $ 106.4 U.S. Agencies 11.3 0.1 — 11.4 States and municipalities 513.4 15.3 (0.7 ) 528.0 Corporate securities 1,106.2 5.8 (21.6 ) 1,090.4 Residential mortgage-backed securities 459.1 2.2 (9.8 ) 451.5 Commercial mortgage-backed securities 96.7 0.1 (2.5 ) 94.3 Asset-backed securities 64.7 0.2 (0.4 ) 64.5 Other securities (1) 155.6 — (5.7 ) 149.9 Total fixed maturity securities 2,513.7 24.6 (41.9 ) 2,496.4 Short-term investments 25.0 — — 25.0 Total AFS investments $ 2,538.7 $ 24.6 $ (41.9 ) $ 2,521.4 At December 31, 2017 Fixed maturity securities U.S. Treasuries $ 135.8 $ 2.0 $ (0.8 ) $ 137.0 U.S. Agencies 11.3 0.5 — 11.8 States and municipalities 617.0 25.5 — 642.5 Corporate securities 1,103.4 18.0 (3.4 ) 1,118.0 Residential mortgage-backed securities 388.3 3.6 (2.6 ) 389.3 Commercial mortgage-backed securities 106.5 0.4 (0.9 ) 106.0 Asset-backed securities 58.7 0.3 (0.2 ) 58.8 Total fixed maturity securities 2,421.0 50.3 (7.9 ) 2,463.4 Equity securities at fair value Industrial and miscellaneous 100.8 81.5 (0.6 ) 181.7 Non-redeemable preferred (FHLB stock) 4.7 — — 4.7 Other 11.2 12.7 — 23.9 Total equity securities at fair value 116.7 94.2 (0.6 ) 210.3 Short-term investments 4.0 — — 4.0 Total AFS investments $ 2,541.7 $ 144.5 $ (8.5 ) $ 2,677.7 (1) Other securities within fixed maturity securities consist of bank loans, which are classified as AFS and reported at fair value.
Equity securities table	The cost and estimated fair value of the Company's equity securities recorded at fair value at December 31, 2018 were as follows: Cost Estimated Fair Value (in millions) At December 31, 2018 Equity securities at fair value Industrial and miscellaneous $ 114.6 $ 174.8 Other 17.3 25.1 Total equity securities at fair value $ 131.9 $ 199.9
Investments classified by contractual maturity date table	The amortized cost and estimated fair value of the Company's fixed maturity securities at December 31, 2018 , 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 $ 141.8 $ 142.1 Due after one year through five years 856.9 856.3 Due after five years through ten years 794.3 784.3 Due after ten years 100.2 103.4 Mortgage and asset-backed securities 620.5 610.3 Total $ 2,513.7 $ 2,496.4
Unrealized loss on investments table	The following is a summary of AFS 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 December 31, 2018 and 2017 . December 31, 2018 December 31, 2017 Estimated Fair Value Gross Unrealized Losses Number of Issues Estimated Fair Value Gross Unrealized Losses Number of Issues Less than 12 months: (dollars in millions) Fixed maturity securities U.S. Treasuries $ 12.2 $ (0.1 ) 7 $ 86.0 $ (0.5 ) 28 States and municipalities 70.1 (0.7 ) 21 — — — Corporate securities 624.4 (13.4 ) 205 307.6 (2.3 ) 113 Residential mortgage-backed securities 156.9 (2.5 ) 59 165.0 (0.8 ) 45 Commercial mortgage-backed securities 30.9 (0.5 ) 13 41.8 (0.2 ) 19 Asset-backed securities 25.1 (0.2 ) 18 29.3 (0.2 ) 25 Other securities 137.1 (5.7 ) 215 — — — Total less than 12 months $ 1,056.7 $ (23.1 ) 538 $ 629.7 $ (4.0 ) 230 12 months or greater: Fixed maturity securities U.S. Treasuries $ 72.7 $ (1.1 ) 25 $ 23.4 $ (0.3 ) 10 Corporate securities 193.7 (8.2 ) 69 53.2 (1.1 ) 17 Residential mortgage-backed securities 199.8 (7.3 ) 72 77.1 (1.8 ) 32 Commercial mortgage-backed securities 55.0 (2.0 ) 22 25.1 (0.7 ) 8 Asset-backed securities 16.5 (0.2 ) 17 — — — Total 12 months or greater $ 537.7 $ (18.8 ) 205 $ 178.8 $ (3.9 ) 67
Unrealized gain (loss) on investments table	Net realized gains on investments and the change in unrealized gains (losses) on the Company's investments recorded at fair value are determined on a specific-identification basis and were as follows: Gross Realized Gains Gross Realized Losses Change in Net Unrealized Gains (Losses) Changes in Fair Value Reflected in Earnings Changes in Fair Value Reflected in AOCI, before tax (in millions) Year Ended December 31, 2018 Fixed maturity securities $ 2.2 $ (4.0 ) $ (59.7 ) $ (1.8 ) $ (59.7 ) Equity securities 15.9 (1.6 ) (25.6 ) (11.3 ) — Total investments $ 18.1 $ (5.6 ) $ (85.3 ) $ (13.1 ) $ (59.7 ) Year Ended December 31, 2017 Fixed maturity securities $ 4.7 $ (2.2 ) $ 3.9 $ 2.5 $ 3.9 Equity securities 9.3 (4.4 ) 17.5 4.9 17.5 Total investments $ 14.0 $ (6.6 ) $ 21.4 $ 7.4 $ 21.4 Year Ended December 31, 2016 Fixed maturity securities $ 1.9 $ (0.7 ) $ (28.9 ) $ 1.2 $ (28.9 ) Equity securities 16.6 (6.6 ) 14.9 10.0 14.9 Total investments $ 18.5 $ (7.3 ) $ (14.0 ) $ 11.2 $ (14.0 )
Investment income table	Net investment income was as follows: Years Ended December 31, 2018 2017 2016 (in millions) Fixed maturity securities $ 76.0 $ 70.4 $ 68.5 Equity securities 6.5 6.9 7.4 Short-term investments 0.3 0.1 — Cash equivalents and restricted cash 2.0 0.6 0.4 Gross investment income 84.8 78.0 76.3 Investment expenses (3.6 ) (3.4 ) (3.1 ) Net investment income $ 81.2 $ 74.6 $ 73.2

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property and Equipment [Abstract]
Property, plant and equipment table	Property and equipment consists of the following: As of December 31, 2018 2017 (in millions) Furniture and equipment $ 3.3 $ 1.7 Leasehold improvements 3.2 2.9 Computers and software 61.9 54.2 Automobiles 1.1 1.1 Property and equipment, gross 69.5 59.9 Accumulated depreciation (51.3 ) (46.0 ) Property and equipment, net $ 18.2 $ 13.9

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Taxes [Abstract]
Summary of income tax contingencies table	The Company's provision for income taxes consisted of the following: Years Ended December 31, 2018 2017 2016 Current tax expense: (in millions) Federal $ 13.2 $ 17.9 $ 20.3 State 0.6 0.7 0.3 Total current tax expense 13.8 18.6 20.6 Deferred federal tax expense: Impact of tax Enactment (0.4 ) 7.0 — Other 14.8 17.2 13.4 Total deferred federal tax expense 14.4 24.2 13.4 Income tax expense $ 28.2 $ 42.8 $ 34.0
Reconciliation of federal staturoty income tax rates to the effective tax rates table	The differences between the statutory federal tax rate of 21% for 2018 and 35% for 2017 and 2016 and the Company's effective tax rate on net income before income taxes as reflected in the Consolidated Statements of Comprehensive Income were as follows: Years Ended December 31, 2018 2017 2016 (in millions) Expense computed at statutory rate $ 35.6 $ 50.4 $ 49.3 Tax-advantaged investment income (2.9 ) (7.6 ) (8.5 ) LPT deferred gain amortization (2.6 ) (4.0 ) (4.7 ) Stock based compensation (1.4 ) (3.4 ) (1.6 ) LPT Reserve Adjustment (0.5 ) — (1.1 ) Impact of tax Enactment (0.4 ) 7.0 — Other 0.4 0.4 0.6 Income tax expense $ 28.2 $ 42.8 $ 34.0
Deferred tax assets and liabilities	The significant components of deferred income taxes, net, were as follows as of December 31: 2018 2017 Deferred Tax Deferred Tax Assets Liabilities Assets Liabilities (in millions) Unrealized capital gains, net $ — $ 10.6 $ — $ 28.5 Deferred policy acquisition costs — 10.3 — 9.7 Intangible assets — 1.6 — 1.7 Loss reserve discounting for tax reporting 31.1 — 29.0 — Unearned premiums 13.3 — 12.8 — Allowance for bad debt 1.4 — 2.1 — Stock-based compensation 2.9 — 2.5 — Accrued liabilities 4.9 — 4.2 — Minimum tax credit — — 20.0 — Other 2.6 6.8 2.8 4.8 Total $ 56.2 $ 29.3 $ 73.4 $ 44.7 Deferred income taxes, net $ 26.9 $ 28.7

Liability for Unpaid Losses a_2

Liability for Unpaid Losses and Loss Adjustment Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
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. Years Ended December 31, 2018 2017 2016 (in millions) Unpaid losses and LAE at beginning of period $ 2,266.1 $ 2,301.0 $ 2,347.5 Less reinsurance recoverable on unpaid losses and LAE 537.0 580.0 628.2 Net unpaid losses and LAE at beginning of period 1,729.1 1,721.0 1,719.3 Losses and LAE, net of reinsurance, incurred during the period related to: Current year 457.5 447.3 452.9 Prior years (1) (66.2 ) (18.5 ) (18.4 ) Total net losses and LAE incurred during the period (1) 391.3 428.8 434.5 Paid losses and LAE, net of reinsurance, related to: Current year 93.0 76.9 78.7 Prior years (2) 323.9 343.8 354.1 Total net paid losses and LAE during the period (2) 416.9 420.7 432.8 Ending unpaid losses and LAE, net of reinsurance 1,703.5 1,729.1 1,721.0 Reinsurance recoverable on unpaid losses and LAE 504.4 537.0 580.0 Unpaid losses and LAE at end of period $ 2,207.9 $ 2,266.1 $ 2,301.0 (1) Losses and LAE, net of reinsurance, incurred during the period related to prior years and Total net losses and LAE incurred during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10 ). Including these amounts, Losses and LAE, net of reinsurance, incurred during the period related to prior years was $(80.8) million , $(30.1) million , and $(35.0) million and Total net losses and LAE incurred during the period was $376.7 million , $417.2 million , and $417.9 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively. (2) Paid losses and LAE, net of reinsurance, related to prior years and Total net paid losses and LAE during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10 ). Including these amounts, Paid losses and LAE, net of reinsurance, related to prior years was $309.3 million , $332.2 million , and $337.5 million and Total net paid losses and LAE during the period was $402.4 million , $409.1 million , and $416.2 million for the years ended December 31, 2018 , 2017 , and 2016 , respectively.
Short-duration Insurance Contracts, Claims Development [Table Text Block]	The Company analyzed the usefulness of disaggregation of its results and determined the characteristics associated with the policies and the related unpaid loss reserves, incurred losses, and payment patterns are similar in nature. As such, the following tables show the Company's historical incurred and cumulative paid losses and LAE development, net of reinsurance, as well as IBNR loss reserves and the number of reported claims on an aggregated basis as of December 31, 2018 for each of the previous 10 accident years. Incurred Losses and LAE, Net of Reinsurance Years Ended December 31, As of December 31, 2018 Accident Year 2009 (1) 2010 (1) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 IBNR Cumulative number of reported claims (in millions, except claims counts) 2009 $ 255.4 $ 266.9 $ 279.0 $ 280.1 $ 283.6 $ 283.7 $ 291.2 $ 290.5 $ 290.5 $ 287.9 $ 11.0 22,681 2010 204.9 224.4 228.1 246.1 250.2 262.0 259.9 258.8 255.2 16.7 18,540 2011 253.7 267.3 272.0 277.4 296.3 292.6 288.8 287.8 24.0 19,578 2012 348.8 359.9 360.9 386.4 388.2 382.8 379.8 41.1 25,989 2013 452.6 460.6 478.6 472.6 468.9 464.6 61.2 28,869 2014 463.4 445.8 432.9 434.6 430.5 72.2 28,524 2015 422.2 425.8 423.9 419.6 78.7 27,135 2016 419.0 414.6 395.4 94.4 25,621 2017 412.4 391.3 145.1 24,746 2018 422.5 220.0 23,617 Total $ 3,734.7 Cumulative Paid Losses and LAE, Net of Reinsurance Years Ended December 31, Accident Year 2009 (1) 2010 (1) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 (in millions) 2009 $ 59.0 $ 130.6 $ 174.1 $ 202.0 $ 219.3 $ 232.1 $ 242.3 $ 249.5 $ 255.1 $ 258.7 2010 47.1 105.6 143.8 171.7 190.7 206.2 215.4 221.3 226.5 2011 47.4 115.1 162.6 193.8 217.5 230.1 238.2 243.8 2012 58.6 148.3 214.2 261.4 289.9 305.0 316.9 2013 68.5 184.4 263.8 317.4 346.1 365.9 2014 65.3 172.7 248.9 297.2 323.4 2015 65.5 174.5 246.9 290.5 2016 65.6 166.8 227.7 2017 63.5 160.2 2018 77.9 Total $ 2,491.6 All outstanding liabilities for unpaid losses and LAE prior to 2009, net of reinsurance 371.5 Total outstanding liabilities for unpaid losses and LAE, net of reinsurance $ 1,614.6 (1) Data presented for these calendar years is required supplementary information, which is unaudited
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Table Text Block]	The following table represents a reconciliation of claims development to the aggregate carrying amount of the liability for unpaid losses and LAE: December 31, 2018 (in millions) Liabilities for unpaid losses and LAE, net of reinsurance $ 1,614.6 Reinsurance recoverable on unpaid losses 504.4 Unallocated LAE (adjusting and other) 88.9 Total liability for unpaid losses and LAE $ 2,207.9
Short-duration Insurance Contracts, Schedule of Historical Claims Duration [Table Text Block]	The following table presents the average annual percentage payout of incurred claims by age, net of reinsurance, as of December 31, 2018 and is presented as required supplementary information, which is unaudited: Average Annual Percentage Payout of Claims by Age, Net of Reinsurance Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 16.8 % 24.6 % 16.4 % 11.0 % 6.9 % 4.6 % 3.3 % 2.3 % 2.0 % 1.3 %

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2018
Reinsurance [Abstract]
Supplemental schedule of reinsurance premiums for insurance companies table	The effects of reinsurance on the Company's written and earned premiums and on its losses and LAE incurred were as follows: Years Ended December 31, 2018 2017 2016 Written Earned Written Earned Written Earned (in millions) Direct premiums $ 739.0 $ 727.2 $ 719.5 $ 712.5 $ 691.0 $ 691.0 Assumed premiums 9.9 10.0 10.2 10.0 10.4 10.6 Gross premiums 748.9 737.2 729.7 722.5 701.4 701.6 Ceded premiums (6.1 ) (6.1 ) (6.0 ) (6.0 ) (6.8 ) (6.8 ) Net premiums $ 742.8 $ 731.1 $ 723.7 $ 716.5 $ 694.6 $ 694.8 Ceded losses and LAE incurred $ 9.5 $ (0.5 ) $ 0.1 Ceded losses and LAE incurred includes the amortization of the Deferred Gain, LPT Reserve Adjustments, and LPT Contingent Commission Adjustments.

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2018
Notes Payable [Abstract]
Schedule of long-term debt instruments table	Notes payable is comprised of the following: December 31, 2018 2017 (in millions) Dekania Surplus Note, due April 29, 2034 $ 10.0 $ 10.0 Alesco Surplus Note, due December 15, 2034 10.0 10.0 Total $ 20.0 $ 20.0
Schedule of maturities of long-term debt table	Principal payment obligations on notes payable outstanding at December 31, 2018 , were as follows: Year Principal Due (in millions) 2019 - 2023 $ — Thereafter 20.0 Total $ 20.0

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies [Abstract]
Operating and capital leases schedule of future minimum lease payments table	The future lease payments for the next five years on these non-cancellable operating and capital leases at December 31, 2018 , were as follows: Year Operating Leases Capital Leases (in millions) 2019 $ 5.3 $ 0.3 2020 4.4 0.3 2021 2.9 0.2 2022 1.9 0.1 2023 1.8 — Thereafter 6.2 — Total $ 22.5 $ 0.9
Schedule of capital leased asssets table	Property held under capital leases is included in property and equipment as follows: Asset Class 2018 2017 (in millions) Automobiles 1.1 1.1 Accumulated amortization (0.4 ) (0.3 ) Total $ 0.7 $ 0.8

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Stock-Based Compensation [Abstract]
Schedule of compensation cost for share-based payment arrangements, allocation of share-based compensation costs by plan table	Net stock-based compensation expense recognized in the Company's Consolidated Statements of Comprehensive Income was as follows: Years Ended December 31, 2018 2017 2016 Stock-based compensation expense related to: (in millions) Stock options $ 0.3 $ 0.5 $ 0.7 RSUs 2.5 2.0 1.9 PSUs 6.5 4.3 3.2 Total 9.3 6.8 5.8 Less: related tax benefit 2.0 2.4 2.0 Net stock-based compensation expense $ 7.3 $ 4.4 $ 3.8
Schedule of share-based payment award, stock options, valuation assumptions table	The fair value of the stock options granted during the year ended December 31, 2016 was calculated using the following weighted average assumptions: 2016 Expected volatility 38.0 % Expected life (in years) 4.8 Dividend yield 1.3 % Risk-free interest rate 1.4 % Weighted average grant date fair values of stock options granted $8.46
Schedule of share-based compensation arrangement by share-based payment award, options, vested and expected to vest, outstanding table	Changes in outstanding stock options for the year ended December 31, 2018 were as follows: Number of Stock Options Weighted-Average Price Weighted Average Remaining Contractual Life Stock options outstanding at December 31, 2015 1,121,545 $ 18.31 2.8 years Granted 67,431 27.72 6.2 years Exercised (586,132 ) 16.39 Expired (6,075 ) 22.48 Forfeited (32,673 ) 24.35 Stock options outstanding at December 31, 2016 564,096 21.04 3.3 years Exercised (307,076 ) 19.44 Forfeited (9,673 ) 24.45 Stock options outstanding at December 31, 2017 247,347 22.90 3.4 years Exercised (57,091 ) 20.17 Forfeited — — Stock options outstanding at December 31, 2018 190,256 23.71 2.7 years Exercisable at December 31, 2018 149,327 22.95 2.4 years
Schedule of fair value of options vested and instrinsic value of outstanding and exercisable options table	he fair value of stock options vested and the intrinsic value of outstanding and exercisable stock options as of December 31, were as follows: 2018 2017 2016 (in millions) Fair value of stock options vested $ 0.4 $ 0.6 $ 0.8 Intrinsic value of outstanding stock options 3.4 5.3 10.6 Intrinsic value of exercisable stock options 2.8 3.6 7.6
Schedule of share-based compensation, restricted stock and restricted stock units activity	Changes in outstanding RSUs for the year ended December 31, 2018 were as follows: Number of RSUs Weighted Average Grant Date Fair Value RSUs outstanding at December 31, 2015 319,033 $ 20.71 Granted 100,218 28.20 Forfeited (21,872 ) 24.87 Vested (72,995 ) 21.56 RSUs outstanding at December 31, 2016 324,384 22.55 Granted 87,276 37.94 Forfeited (13,711 ) 29.28 Vested (102,785 ) 22.89 RSUs outstanding at December 31, 2017 295,164 26.67 Granted 87,857 40.26 Forfeited (3,370 ) 33.51 Vested (129,351 ) 24.53 RSUs outstanding at December 31, 2018 250,300 32.45 Vested but unsettled RSUs at December 31, 2018 67,620 23.35
Schedule of fair value of RSUs vested and instrinsic value of outstanding and vested RSUs table	The grant date fair value of RSUs vested and the intrinsic value of vested RSUs for the years ended December 31, were as follows: 2018 2017 2016 (in millions) Grant date fair value of RSUs vested $ 3.2 $ 2.4 $ 1.6 Intrinsic value of RSUs vested 5.5 4.3 2.1
PSUs awarded to certain officers table	The Company has awarded PSUs to certain employees of the Company as follows: Date of Grant Target Number Awarded Fair Value on Date of Grant Aggregate Fair Value on Date of Grant (in millions) March 2016 (1) 97,236 $ 27.72 $ 2.7 March 2017 (1) 97,440 37.60 3.7 March 2018 (1) 96,940 40.30 3.9 (1) The PSUs awarded in March 2016, 2017, and 2018 were awarded to certain employees 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 values shown in the table represent the aggregate number of PSUs awarded at the target level.

Statutory Matters (Tables)

Statutory Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Stautory Matters [Abstract]
Statutory accounting practices disclosure table	The combined capital stock, surplus, and net income of the Company's insurance subsidiaries (EICN, ECIC, EPIC, and EAC), prepared in accordance with the statutory accounting practices (SAP) of the National Association of Insurance Commissioners (NAIC) as well as SAP permitted by the states of California, Florida, and Nevada, were as follows: December 31, 2018 2017 (in millions) Capital stock and unassigned surplus $ 558.5 $ 510.6 Paid in capital 349.4 349.8 Surplus notes 20.0 32.0 Total statutory surplus $ 927.9 $ 892.4

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of accumulated other comprehensive income (loss) table	The following table summarizes the components of Accumulated other comprehensive (loss) income: Years Ended December 31, 2018 2017 (in millions) Net unrealized (losses) gains on investments, before taxes $ (17.3 ) $ 136.0 Deferred tax benefit (expense) on net unrealized (losses) gains 3.6 (28.6 ) Total accumulated other comprehensive (loss) income $ (13.7 ) $ 107.4

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
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 shares outstanding used in the earnings per share common share calculations. Years Ended December 31, 2018 2017 2016 (in millions, except share data) Net income $ 141.3 $ 101.2 $ 106.7 Weighted average number of shares outstanding–basic 32,884,828 32,501,576 32,434,580 Effect of dilutive securities: Stock options 97,810 208,602 246,562 PSUs 268,030 271,738 222,594 RSUs 60,669 78,844 73,099 Dilutive potential shares 426,509 559,184 542,255 Weighted average number of shares outstanding–diluted 33,311,337 33,060,760 32,976,835
Antidilutive securities excluded from computation of earnings per share table	The following table presents the number of stock options, PSUs and RSUs that were excluded from the Company's calculation of diluted earnings per share. Years Ended December 31, 2018 2017 2016 Stock options excluded as the exercise price was greater than the average market price — — — Stock options excluded under the treasury method, as the potential proceeds on settlement or exercise was greater than the value of shares acquired — — 89,221

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2018
Selecled Quarterly Financial Data (Unaudited) [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	Quarterly results for the years ended December 31, 2018 and 2017 were as follows: 2018 Quarters Ended March 31 June 30 September 30 December 31 (in millions, except per share data) Net premiums earned $ 176.6 $ 178.0 $ 192.9 $ 183.6 Net realized and unrealized (losses) gains on investments (8.0 ) 5.7 15.6 (26.4 ) Losses and loss adjustment expenses 95.4 87.8 106.6 86.9 Commission expense 23.7 24.5 24.8 21.2 Underwriting and other operating expenses 39.2 40.1 38.8 40.4 Income tax expense 3.8 8.8 10.7 4.9 Net income 25.6 42.5 47.6 25.6 Earnings per common share: Basic 0.78 1.29 1.45 0.78 Diluted 0.77 1.28 1.43 0.77 2017 Quarters Ended March 31 June 30 September 30 December 31 (in millions, except per share data) Net premiums earned $ 175.3 $ 171.7 $ 187.9 $ 181.6 Net realized gains on investments 2.2 1.1 4.1 — Losses and loss adjustment expenses 109.0 106.1 116.9 85.2 Commission expense 21.5 21.5 23.7 24.7 Underwriting and other operating expenses 35.9 32.6 33.6 37.8 Other expenses — — 7.5 — Income tax expense 6.3 7.8 7.0 21.7 Net income 23.2 24.8 21.9 31.3 Earnings per common share: Basic 0.72 0.76 0.67 0.96 Diluted 0.70 0.75 0.66 0.94

Basis of Presentation Pending P

Basis of Presentation Pending Purchase of PRUS (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Estimated statutory capital and surplus of pending acquisition	$ 40
Net cash payment to acquire business	$ 5.8

Schedule II - Balance Sheet Par

Schedule II - Balance Sheet Parenthetical (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018		Dec. 31, 2017
Debt securities, available-for-sale, amortized cost	$ 2,513.7		$ 0
Equity Securities, FV-NI, Cost	131.9		0
Amortized cost	$ 0		$ 2,541.7
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)	56,975,675		56,695,174
Common stock, shares outstanding (in shares)	32,765,792		32,597,819
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)	24,209,883		24,097,355
Parent Company [Member]
Debt securities, available-for-sale, amortized cost	$ 24.2
Equity Securities, FV-NI, Cost	$ 40		$ 0
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)	56,975,675		56,695,174
Common stock, shares outstanding (in shares)	32,765,792		32,597,819
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)	24,209,883		24,097,355
Debt Securities [Member]
Amortized cost	$ 0		$ 2,421
Debt Securities [Member] | Parent Company [Member]
Amortized cost			40.2
Equity Securities [Member]
Amortized cost	0		116.7
Short-term Investments [Member]
Total AFS, amortized cost	25	[1]	0
Amortized cost	0		4
Short-term Investments [Member] | Parent Company [Member]
Total AFS, amortized cost	25		0
Amortized cost	$ 0		$ 3.7
[1]	Other securities within fixed maturity securities consist of bank loans, which are classified as AFS and reported at fair value.

Changes in Estimates (Details)

Changes in Estimates (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016		Dec. 31, 2015
Change in Accounting Estimate [Line Items]
Unpaid losses and loss adjustment expenses	$ 2,207,900				$ 2,266,100				$ 2,207,900		$ 2,266,100	$ 2,301,000		$ 2,347,500
Amortization of deferred gain									(11,900)		(11,300)	(11,700)
Net income	$ 25,600	$ 47,600	$ 42,500	$ 25,600	$ 31,300	$ 21,900	$ 24,800	$ 23,200	$ 141,300		$ 101,200	$ 106,700
Basic	$ 0.78	$ 1.45	$ 1.29	$ 0.78	$ 0.96	$ 0.67	$ 0.76	$ 0.72	$ 4.30		$ 3.11	$ 3.29
Diluted	$ 0.77	$ 1.43	$ 1.28	$ 0.77	$ 0.94	$ 0.66	$ 0.75	$ 0.70	$ 4.24		$ 3.06	$ 3.24
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Member]
Change in Accounting Estimate [Line Items]
Unpaid losses and loss adjustment expenses	$ (6,300)				$ 0				$ (6,300)		$ 0	$ (5,000)
Amortization of deferred gain				$ (2,200)					(2,200)	[1]		(3,100)	[1]
Net income									$ 2,200		0	$ 3,100
Basic									$ 0.07			$ 0.10
Diluted									$ 0.07			$ 0.09
Change to Contingent Profit Commission [Member]
Change in Accounting Estimate [Line Items]
Amortization of deferred gain									$ (500)		(300)	$ (1,800)
Change in estimate of contingent commission receivable									500		300	1,900
Net income									$ 500		$ 300	$ 1,800
Basic									$ 0.02		$ 0.01	$ 0.06
Diluted									$ 0.02		$ 0.01	$ 0.05
[1]	The cumulative adjustments to the Deferred Gain were also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised loss and LAE reserves been recognized at the inception of the LPT Agreement.

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Funds held under reinsurance agreements, asset	$ 23,200,000	$ 24,500,000
Restricted cash and cash equivalents	600,000	1,000,000
Premiums receivable from policyholders for final audit	63,700,000	64,200,000
Premiums receivable, bad debt allowance	6,700,000	10,000,000
Write-offs, net of recoveries of amounts previously written off	8,200,000	3,200,000	$ 6,000,000
Deferred policy acquisition cost, amortization expense	112,000,000	108,200,000	104,500,000
Premium Deficiency	0	0	0
Unpaid losses	$ 504,400,000	537,000,000
LPT - loss expense as a percentange of losses paid, for management of LPT claims	7.00%
LPT favorable/ unfavorable difference, percentage	30.00%
LPT actual amounts paid versus expected amounts, period	every five years
LPT actual amounts paid versus expected amounts, expiration period	25
Collateralized by cash or letter of credit	$ 2,000,000
LPT collateral held in trust account	311,600,000	380,800,000
Goodwill and other intangible asset impairment	0	0
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible assets, gross carrying amount	17,100,000	17,100,000
Intangible assets, accumulated amortization	(9,400,000)	(9,200,000)
Intangible assets, net	7,700,000	7,900,000
Amortization of intangible assets	200,000	300,000	$ 300,000
Funds Held in Trust, Reinsurance Agreement [Domain]
Restricted cash and cash equivalents	600,000	1,000,000
Licensing Agreements [Member]
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible assets, gross carrying amount	7,700,000	7,700,000
Intangible assets, accumulated amortization	0	0
Intangible assets, net	7,700,000	7,700,000
Service Agreements [Member]
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Intangible assets, gross carrying amount	9,400,000	9,400,000
Intangible assets, accumulated amortization	(9,400,000)	(9,200,000)
Intangible assets, net	$ 0	$ 200,000
Electronic Data Processing Equipment, Software, Furniture and Equipment and Automobiles [Member]
Finite-Lived intangible assets, amortization method	straight-line method over three to seven years
Leasehold improvements
Finite-Lived intangible assets, amortization method	amortized over three to eight years

New Accounting Standards Recent

New Accounting Standards Recently issued ASUs (Details) - Accounting Standards Update 2016-02 [Member] $ in Millions	Dec. 31, 2018USD ($)
Right-of-use asset	$ 18.4
Lease liabilities	$ 20.2

New Accounting Standards Rece_2

New Accounting Standards Recently Adopted Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cloud computing arrangements	$ 0	$ 26	$ 0
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 7	(0.4)	7	$ 0
Net impact of tax enactment on net unrealized gains on investments			0
Cumulative Effect of New Accounting Principle in Period of Adoption		0
Retained Earnings
Net impact of tax enactment on net unrealized gains on investments			(17.8)
Cumulative Effect of New Accounting Principle in Period of Adoption		74
Accumulated Other Comprehensive Income, Net
Net impact of tax enactment on net unrealized gains on investments			17.8
Cumulative Effect of New Accounting Principle in Period of Adoption		(74)
Accounting Standards Update 2018-15 [Member]
Cloud computing arrangements		4.8
Accounting Standards Update 2018-05 [Member]
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		(0.4)
Accounting Standards Update 2018-02 [Member] | Retained Earnings
Net impact of tax enactment on net unrealized gains on investments			(17.8)
Accounting Standards Update 2018-02 [Member] | Accumulated Other Comprehensive Income, Net
Net impact of tax enactment on net unrealized gains on investments			$ 17.8
Accounting Standards Update 2016-01 [Member] | Retained Earnings
Cumulative Effect of New Accounting Principle in Period of Adoption		74
Accounting Standards Update 2016-01 [Member] | Accumulated Other Comprehensive Income, Net
Cumulative Effect of New Accounting Principle in Period of Adoption		$ (74)

Fair Value of Financial Instr_3

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	$ 2,721,300	$ 2,677,700
Total investments at fair value, estimated fair value	2,721,300	2,677,700
Cash and cash equivalents	101,400	73,300
Cash and cash equivalents, estimated fair value	101,400	73,300
Restricted cash and cash equivalents	600	1,000
Notes payable	20,000	20,000
Notes payable, estimated fair value	23,500	23,600
Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash and cash equivalents	$ 600	$ 1,000

Fair Value of Financial Instr_4

Fair Value of Financial Instruments, Fair Value Inputs (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			$ 2,677,700
Fixed maturity securities, fair value		$ 2,496,400	2,463,400
Equity Securities, FV-NI		199,900	0
Short-term Investments		25,000	4,000
Investments		2,727,700	2,677,700
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			205,600
Investments		199,900
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			2,467,400
Investments		2,521,400
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments		0	4,700	$ 11,900
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			4,700
Investments		0
Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			2,463,400
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
Fixed maturity securities, fair value		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			2,463,400
Fixed maturity securities, fair value		2,496,400
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
Fixed maturity securities, fair value		0
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			137,000
Fixed maturity securities, fair value		106,400
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
Fixed maturity securities, fair value		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			137,000
Fixed maturity securities, fair value		106,400
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
Fixed maturity securities, fair value		0
US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			11,800
Fixed maturity securities, fair value		11,400
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
Fixed maturity securities, fair value		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			11,800
Fixed maturity securities, fair value		11,400
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
Fixed maturity securities, fair value		0
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			642,500
Fixed maturity securities, fair value		528,000
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
Fixed maturity securities, fair value		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			642,500
Fixed maturity securities, fair value		528,000
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
Fixed maturity securities, fair value		0
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			1,118,000
Fixed maturity securities, fair value		1,090,400
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
Fixed maturity securities, fair value		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			1,118,000
Fixed maturity securities, fair value		1,090,400
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
Fixed maturity securities, fair value		0
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			389,300
Fixed maturity securities, fair value		451,500
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
Fixed maturity securities, fair value		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			389,300
Fixed maturity securities, fair value		451,500
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
Fixed maturity securities, fair value		0
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			106,000
Fixed maturity securities, fair value		94,300
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
Fixed maturity securities, fair value		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			106,000
Fixed maturity securities, fair value		94,300
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
Fixed maturity securities, fair value		0
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			58,800
Fixed maturity securities, fair value		64,500
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
Fixed maturity securities, fair value		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			58,800
Fixed maturity securities, fair value		64,500
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
Fixed maturity securities, fair value		0
Other Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	[1]	149,900
Other Debt Obligations [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
Fixed maturity securities, fair value		0
Other Debt Obligations [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
Fixed maturity securities, fair value		149,900
Other Debt Obligations [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
Fixed maturity securities, fair value		0
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			210,300
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			205,600
Equity Securities, FV-NI		199,900
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
Equity Securities, FV-NI		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			4,700
Equity Securities, FV-NI		0
Industrial and miscellaneous
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			181,700
Equity Securities, FV-NI		174,800	0
Industrial and miscellaneous | 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			181,700
Equity Securities, FV-NI		174,800
Industrial and miscellaneous | 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
Equity Securities, FV-NI		0
Industrial and miscellaneous | 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
Equity Securities, FV-NI		0
Federal home loan bank stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			4,700
Federal home loan bank stock | 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
Equity Securities, FV-NI		0
Federal home loan bank stock | 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
Equity Securities, FV-NI		0
Federal home loan bank stock | 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			4,700
Equity Securities, FV-NI		0
Other equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			23,900
Equity Securities, FV-NI		25,100	0
Other equities | 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			23,900
Equity Securities, FV-NI		25,100
Other equities | 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
Equity Securities, FV-NI		0
Other equities | 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
Equity Securities, FV-NI		0
Short-term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments			4,000
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
Short-term Investments		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			4,000
Short-term Investments		25,000
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
Short-term Investments		$ 0
[1]	Other securities within fixed maturity securities consist of bank loans, which are classified as AFS and reported at fair value.

Fair Value of Financial Instr_5

Fair Value of Financial Instruments Cash Equivalents at NAV and Total Cash and Cash Equivalents Carried at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents at fair value	$ 43.9	$ 34.3
Cash equivalents measured at NAV, which approximates fair value	57.5	39
Total cash and cash equivalents	$ 101.4	$ 73.3

Fair Value of Financial Instr_6

Fair Value of Financial Instruments Fair Value of Financial Instruments, Reconciliation of Level 3 Securities (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance, January 1		$ 2,677,700
Ending balance, December 31		2,727,700	$ 2,677,700
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance, January 1		4,700	11,900
Transfers out of Level 3(1)	[1]	(4,700)	(7,000)
Purchases and sales, net		0	(200)
Ending balance, December 31		$ 0	$ 4,700
[1]	(1)The transfer during the year ended December 31, 2018 was the result of adoption of ASU 2016-01, which specified that FHLB stock shall be carried at cost and is no longer measured at fair value. Transfers during the year ended December 31, 2017 were from Level 3 to Level 2 because observable market data became available for the securities.

Investments (Details)

Investments (Details) - USD ($) $ in Millions		Dec. 31, 2018		Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		$ 2,513.7		$ 0
Debt securities, available-for-sale, gross unrealized gain		24.6
Debt securities, available-for-sale, gross unrealized loss		(41.9)
Fixed maturity securities, fair value		2,496.4		2,463.4
Amortized cost		0		2,541.7
Gross unrealized gains				144.5
Gross unrealized loss				(8.5)
Investments				2,677.7
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized cost		0		2,421
Gross unrealized gains				50.3
Gross unrealized loss				(7.9)
Investments				2,463.4
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		106.7
Debt securities, available-for-sale, gross unrealized gain		0.9
Debt securities, available-for-sale, gross unrealized loss		(1.2)
Fixed maturity securities, fair value		106.4
Amortized cost				135.8
Gross unrealized gains				2
Gross unrealized loss				(0.8)
Investments				137
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		11.3
Debt securities, available-for-sale, gross unrealized gain		0.1
Debt securities, available-for-sale, gross unrealized loss		0
Fixed maturity securities, fair value		11.4
Amortized cost				11.3
Gross unrealized gains				0.5
Gross unrealized loss				0
Investments				11.8
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		513.4
Debt securities, available-for-sale, gross unrealized gain		15.3
Debt securities, available-for-sale, gross unrealized loss		(0.7)
Fixed maturity securities, fair value		528
Amortized cost				617
Gross unrealized gains				25.5
Gross unrealized loss				0
Investments				642.5
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		1,106.2
Debt securities, available-for-sale, gross unrealized gain		5.8
Debt securities, available-for-sale, gross unrealized loss		(21.6)
Fixed maturity securities, fair value		1,090.4
Amortized cost				1,103.4
Gross unrealized gains				18
Gross unrealized loss				(3.4)
Investments				1,118
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		459.1
Debt securities, available-for-sale, gross unrealized gain		2.2
Debt securities, available-for-sale, gross unrealized loss		(9.8)
Fixed maturity securities, fair value		451.5
Amortized cost				388.3
Gross unrealized gains				3.6
Gross unrealized loss				(2.6)
Investments				389.3
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		96.7
Debt securities, available-for-sale, gross unrealized gain		0.1
Debt securities, available-for-sale, gross unrealized loss		(2.5)
Fixed maturity securities, fair value		94.3
Amortized cost				106.5
Gross unrealized gains				0.4
Gross unrealized loss				(0.9)
Investments				106
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost		64.7
Debt securities, available-for-sale, gross unrealized gain		0.2
Debt securities, available-for-sale, gross unrealized loss		(0.4)
Fixed maturity securities, fair value		64.5
Amortized cost				58.7
Gross unrealized gains				0.3
Gross unrealized loss				(0.2)
Investments				58.8
Other Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	[1]	155.6
Debt securities, available-for-sale, gross unrealized gain	[1]	0
Debt securities, available-for-sale, gross unrealized loss	[1]	(5.7)
Fixed maturity securities, fair value	[1]	149.9
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized cost				116.7
Gross unrealized gains				94.2
Gross unrealized loss				(0.6)
Investments				210.3
Other equities
Debt Securities, Available-for-sale [Line Items]
Amortized cost				11.2
Gross unrealized gains				12.7
Gross unrealized loss				0
Investments				23.9
Federal home loan bank stock
Debt Securities, Available-for-sale [Line Items]
Amortized cost				4.7
Gross unrealized gains				0
Gross unrealized loss				0
Investments				4.7
Industrial and miscellaneous
Debt Securities, Available-for-sale [Line Items]
Amortized cost				100.8
Gross unrealized gains				81.5
Gross unrealized loss				(0.6)
Investments				181.7
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Total AFS, amortized cost		25	[1]	0
Total AFS, gross unrealized gain	[1]	0
Total AFS investments, gross unrealized loss	[1]	0
Total AFS investments	[1]	25
Amortized cost		0		4
Gross unrealized gains				0
Gross unrealized loss				0
Investments				$ 4
Total AFS Investments [Domain]
Debt Securities, Available-for-sale [Line Items]
Total AFS, amortized cost		2,538.7
Total AFS, gross unrealized gain		24.6
Total AFS investments, gross unrealized loss		41.9
Total AFS investments		$ 2,521.4
[1]	Other securities within fixed maturity securities consist of bank loans, which are classified as AFS and reported at fair value.

Investments Equity Securities (

Investments Equity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Equity Securities [Line Items]
Equity Securities, FV-NI, Cost	$ 131,900	$ 0
Equity Securities, FV-NI	199,900	0
Industrial and miscellaneous
Equity Securities [Line Items]
Equity Securities, FV-NI, Cost	114,600	0
Equity Securities, FV-NI	174,800	0
Other equities
Equity Securities [Line Items]
Equity Securities, FV-NI, Cost	17,300	0
Equity Securities, FV-NI	$ 25,100	$ 0

Investments, Amortized Cost and

Investments, Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost
Due in one year or less, amortized cost	$ 141.8
Due after one year through five years, amortized cost	856.9
Due after five years through ten years, amortized cost	794.3
Due after ten years, amortized cost	100.2
Mortgage and asset-backed securities, amortized cost	620.5
Fixed maturity securities, amortized cost	2,513.7	$ 0
Estimated Fair Value
Due in one year or less, fair value	142.1
Due after one year through five years, fair value	856.3
Due after five years through ten years, fair value	784.3
Due after ten years, fair value	103.4
Mortgage and asset-backed securities, fair value	610.3
Fixed maturity securities, fair value	$ 2,496.4	$ 2,463.4

Investments, Continuous Loss Po

Investments, Continuous Loss Position (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,056.7	$ 629.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	537.7	178.8
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	23.1	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 18.8	$ 3.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	538	230
Debt Securities, number of issues in loss position, 12 months or longer | shares	205	67
Debt Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Total impairments, value	$ 3.3	$ 0.5
Total impairments, number of securitites | shares	66	9	0
US Treasury Securities [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 12.2	$ 86
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	72.7	23.4
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.1	0.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 1.1	$ 0.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	7	28
Debt Securities, number of issues in loss position, 12 months or longer | shares	25	10
US States and Political Subdivisions Debt Securities [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 70.1	$ 0
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 0.7	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	21	0
Corporate Debt Securities [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 624.4	$ 307.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	193.7	53.2
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	13.4	2.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 8.2	$ 1.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	205	113
Debt Securities, number of issues in loss position, 12 months or longer | shares	69	17
Residential Mortgage Backed Securities [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 156.9	$ 165
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	199.8	77.1
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2.5	0.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 7.3	$ 1.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	59	45
Debt Securities, number of issues in loss position, 12 months or longer | shares	72	32
Commercial Mortgage Backed Securities [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 30.9	$ 41.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	55	25.1
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.5	0.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 2	$ 0.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	13	19
Debt Securities, number of issues in loss position, 12 months or longer | shares	22	8
Asset-backed Securities [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 25.1	$ 29.3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	16.5	0
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0.2	0.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0.2	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	18	25
Debt Securities, number of issues in loss position, 12 months or longer | shares	17	0
Other Debt Obligations [Member]
Estimated Fair Value
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 137.1	$ 0
Gross Unrealized Losses
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (5.7)	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Debt Securities, number of issues in loss position, less than 12 months | shares	215	0
Equity Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Available-for-sale Securities, unrealized losses, less than 12 months		$ 0.6
Available-for-sale, number of issues in loss position, less than one year | shares		24
Total impairments, value		$ 0.9	$ 5.8
Total impairments, number of securitites | shares		7	37

Investments, Net Realized Gains

Investments, Net Realized Gains (Losses) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in unrealized gains (losses)
AFS, change in unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI									$ (59.7)	$ 21.4	$ (14)
Equity securities, FV-NI, unrealized gain (loss)									(25.6)	0	0
Total change in net unrealized gains (losses)									(85.3)	21.4	(14)
AFS, net realized gains (losses)
Total gross realized gains									18.1	14	18.5
Total gross realized losses									(5.6)	(6.6)	(7.3)
Net realized and unrealized (losses) gains on investments	$ (26.4)	$ 15.6	$ 5.7	$ (8)	$ 0	$ 4.1	$ 1.1	$ 2.2	(13.1)	7.4	11.2
Debt Securities [Member]
Change in unrealized gains (losses)
AFS, change in unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI									(59.7)	3.9	(28.9)
AFS, net realized gains (losses)
AFS, gross gains from sales									2.2	4.7	1.9
AFS, gross losses from sales									(4)	(2.2)	(0.7)
Net realized and unrealized (losses) gains on investments									(1.8)	2.5	1.2
Equity Securities [Member]
Change in unrealized gains (losses)
AFS, change in unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI									0	17.5	14.9
Equity securities, FV-NI, unrealized gain (loss)									(25.6)
Equity securities:
Equity securities, FV-NI, realized gain									15.9	9.3	16.6
Equity securities, FV-NI, realized loss									(1.6)	(4.4)	(6.6)
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments									$ (11.3)	$ 4.9	$ 10

Net Investment Income (Details)

Net Investment Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 84.8	$ 78	$ 76.3
Investment expenses	(3.6)	(3.4)	(3.1)
Net investment income	81.2	74.6	73.2
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	76	70.4	68.5
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income related to equity securities	6.5	6.9	7.4
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	0.3	0.1	0
Cash and Cash Equivalents [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	$ 2	$ 0.6	$ 0.4

Investments Investments, held i

Investments Investments, held in Trust or on Deposit (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Deposit Assets [Abstract]
Investments	$ 2,727.7	$ 2,677.7
Assets Held-in-trust [Abstract]
Funds held under reinsurance agreements, asset	23.2	24.5
Federal Home Loan Bank [Member]
Deposit Assets [Abstract]
Investments	140
Required by various state laws and regulations to hold securities or letters of credit in depository account [Member]
Deposit Assets [Abstract]
Investments	$ 867.7	$ 1,009.7

Property and Equipment Property

Property and Equipment Property and Equipment breakout (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property and Equipment [Line Items]
Property and equipment, gross		$ 69.5	$ 59.9
Accumulated depreciation, depletion and amortization, property and equipment		51.3	46
Property and equipment, net		18.2	13.9
Utilities operating expense, depreciation and amortization		6.1	7.9	$ 8.2
Payments to develop software		2.9	2.1
Asset impairment charges	$ 7.5		7.5
Cloud computing arrangements		26	0
Capitalized Computer Software, Amortization		0.8
Furniture and equipment
Property and Equipment [Line Items]
Property and equipment, gross		3.3	1.7
Leasehold improvements
Property and Equipment [Line Items]
Property and equipment, gross		3.2	2.9
Computer and software
Property and Equipment [Line Items]
Property and equipment, gross		61.9	54.2
Automobiles
Property and Equipment [Line Items]
Property and equipment, gross		$ 1.1	$ 1.1

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statutory federal tax rate									21.00%	35.00%	35.00%
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current federal tax expense (benefit)									$ 13,200,000	$ 17,900,000	$ 20,300,000
Current state and local tax expense (benefit)									600,000	700,000	300,000
Current income tax expense (benefit)									13,800,000	18,600,000	20,600,000
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Revaluation of deferred tax asset					$ 7,000,000				(400,000)	7,000,000	0
Routine/other									14,800,000	17,200,000	13,400,000
Deferred income tax expense (benefit)									14,400,000	24,200,000	13,400,000
Income tax expense	$ 4,900,000	$ 10,700,000	$ 8,800,000	$ 3,800,000	21,700,000	$ 7,000,000	$ 7,800,000	$ 6,300,000	28,200,000	42,800,000	34,000,000
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Expense computed at statutory rate									35,600,000	50,400,000	49,300,000
Dividends received deduction and tax-exempt interest									(2,900,000)	(7,600,000)	(8,500,000)
LPT deferred gain amortization									(2,600,000)	(4,000,000)	(4,700,000)
Stock based compensation									(1,400,000)	(3,400,000)	(1,600,000)
LPT reserve adjustment									(500,000)	0	(1,100,000)
Revaluation of deferred tax asset					7,000,000				(400,000)	7,000,000	0
Income tax reconciliation, other									400,000	400,000	600,000
Net income	25,600,000	$ 47,600,000	$ 42,500,000	$ 25,600,000	31,300,000	$ 21,900,000	$ 24,800,000	$ 23,200,000	141,300,000	101,200,000	106,700,000
Unrecognized tax benefits	0				0				0	0	0
Income Taxes Paid, Net									4,200,000	21,300,000	13,700,000
Deferred Tax Liabilities [Abstract]
Unrealized capital gains, net	10,600,000				28,500,000				10,600,000	28,500,000
Deferred policy acquisition cost	10,300,000				9,700,000				10,300,000	9,700,000
Intangible assets	1,600,000				1,700,000				1,600,000	1,700,000
Other deferred tax liabilities	6,800,000				4,800,000				6,800,000	4,800,000
Total deferred tax liabilities	29,300,000				44,700,000				29,300,000	44,700,000
Deferred Tax Assets [Abstract]
Loss reserves discounting for tax reporting	31,100,000				29,000,000				31,100,000	29,000,000
Unearned premiums	13,300,000				12,800,000				13,300,000	12,800,000
Allowance for bad debt	1,400,000				2,100,000				1,400,000	2,100,000
Stock based compensation	2,900,000				2,500,000				2,900,000	2,500,000
Accrued liabilities	4,900,000				4,200,000				4,900,000	4,200,000
Minimum tax credit	0				20,000,000				0	20,000,000
Other deferred tax assets	2,600,000				2,800,000				2,600,000	2,800,000
Total deferred tax assets	56,200,000				73,400,000				56,200,000	73,400,000
Deferred income taxes, net	26,900,000				$ 28,700,000				26,900,000	28,700,000
Impact to the company's minimum tax credit due to tax enactment	$ 0								0
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Member]
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Net income									2,200,000	0	3,100,000
Change to Contingent Profit Commission [Member]
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Net income									$ 500,000	$ 300,000	$ 1,800,000

Liability for Unpaid Losses a_3

Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Prior year claims and claims adjustment expense Including LPT amortization and adj										$ (80.8)		$ (30.1)		$ (35)
Losses and loss adjustment expenses		$ 86.9	$ 106.6	$ 87.8	$ 95.4	$ 85.2	$ 116.9	$ 106.1	$ 109	376.7		417.2		417.9
Paid losses and LAE, including LPT amortization and adj related to prior periods										309.3		332.2		337.5
Payments for losses and loss adjustment expense including LPT amortization and adj										402.4		409.1		416.2
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Unpaid losses and LAE, gross of reinsurance, at beginning of period					2,266.1				2,301	2,266.1		2,301		2,347.5
Loss reinsurance recoverable, excluding bad debt, on unpaid losses					537				580	537		580		628.2
Net unpaid losses and LAE at beginning of period					1,729.1				$ 1,721	1,729.1		1,721		1,719.3
Losses and LAE, net of reinsurance, incurred in:
Current year										457.5		447.3		452.9
Prior years		25.4	$ 11.9	$ 16.5	$ 12.4	(18)				(66.2)	[1]	(18.5)	[1]	(18.4)	[1]
Total net losses and LAE incurred during the period	[1]									391.3		428.8		434.5
Deduct payments for losses and LAE, net of reinsurance, related to:
Current year										93		76.9		78.7
Prior years	[2]									323.9		343.8		354.1
Total net payments for losses and LAE during the period	[2]									416.9		420.7		432.8
Ending unpaid losses and LAE, net of reinsurance		1,703.5				1,729.1				1,703.5		1,729.1		1,721
Loss reinsurance recoverable, excluding bad debt, on unpaid losses		504.4				537				504.4		537		580
Unpaid losses and LAE, gross of reinsurance, at end of period		2,207.9				2,266.1				2,207.9		2,266.1		2,301
Salvage and subrogation recoveries, value		$ 34.4				$ 35				34.4		35
Voluntary risk business
Losses and LAE, net of reinsurance, incurred in:
Prior years										(65.5)		(17.4)		(17)
Involuntary assigned risk business
Losses and LAE, net of reinsurance, incurred in:
Prior years										$ (0.7)		$ (1.1)		$ (1.4)
[1]	Losses and LAE, net of reinsurance, incurred during the period related to prior years and Total net losses and LAE incurred during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10). Including these amounts, Losses and LAE, net of reinsurance, incurred during the period related to prior years was $(80.8) million, $(30.1) million, and $(35.0) million and Total net losses and LAE incurred during the period was $376.7 million, $417.2 million, and $417.9 million for the years ended December 31, 2018, 2017, and 2016, respectively.
[2]	Paid losses and LAE, net of reinsurance, related to prior years and Total net paid losses and LAE during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10). Including these amounts, Paid losses and LAE, net of reinsurance, related to prior years was $309.3 million, $332.2 million, and $337.5 million and Total net paid losses and LAE during the period was $402.4 million, $409.1 million, and $416.2 million for the years ended December 31, 2018, 2017, and 2016, respectively.

Liability for Unpaid Losses a_4

Liability for Unpaid Losses and Loss Adjustment Expenses Historical Incurred Losses and LAE (Details) $ in Millions	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	[1]	Dec. 31, 2016USD ($)	[1]	Dec. 31, 2015USD ($)	[1]	Dec. 31, 2014USD ($)	[1]	Dec. 31, 2013USD ($)	[1]	Dec. 31, 2012USD ($)	[1]	Dec. 31, 2011USD ($)	[1]	Dec. 31, 2010USD ($)	[1]	Dec. 31, 2009USD ($)	[1]
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	$ 3,734.7
Cumulative paid losses and LAE, net of reinsurance	2,491.6
Liabilities for unpaid losses and LAE, net of reinsurance	1,614.6
Accident years prior to 2009
Claims Development [Line Items]
Cumulative paid losses and LAE, net of reinsurance	371.5
Accident year 2009
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	287.9	$ 290.5		$ 290.5		$ 291.2		$ 283.7		$ 283.6		$ 280.1		$ 279		$ 266.9		$ 255.4
IBNR	$ 11
Cumulative number of reported claims	22,681
Cumulative paid losses and LAE, net of reinsurance	$ 258.7	255.1		249.5		242.3		232.1		219.3		202		174.1		130.6		$ 59
Accident year 2010
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	255.2	258.8		259.9		262		250.2		246.1		228.1		224.4		204.9
IBNR	$ 16.7
Cumulative number of reported claims	18,540
Cumulative paid losses and LAE, net of reinsurance	$ 226.5	221.3		215.4		206.2		190.7		171.7		143.8		105.6		$ 47.1
Accident year 2011
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	287.8	288.8		292.6		296.3		277.4		272		267.3		253.7
IBNR	$ 24
Cumulative number of reported claims	19,578
Cumulative paid losses and LAE, net of reinsurance	$ 243.8	238.2		230.1		217.5		193.8		162.6		115.1		$ 47.4
Accident year 2012
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	379.8	382.8		388.2		386.4		360.9		359.9		348.8
IBNR	$ 41.1
Cumulative number of reported claims	25,989
Cumulative paid losses and LAE, net of reinsurance	$ 316.9	305		289.9		261.4		214.2		148.3		$ 58.6
Accident year 2013
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	464.6	468.9		472.6		478.6		460.6		452.6
IBNR	$ 61.2
Cumulative number of reported claims	28,869
Cumulative paid losses and LAE, net of reinsurance	$ 365.9	346.1		317.4		263.8		184.4		$ 68.5
Accident Year 2014
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	430.5	434.6		432.9		445.8		463.4
IBNR	$ 72.2
Cumulative number of reported claims	28,524
Cumulative paid losses and LAE, net of reinsurance	$ 323.4	297.2		248.9		172.7		$ 65.3
Accident Year 2015
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	419.6	423.9		425.8		422.2
IBNR	$ 78.7
Cumulative number of reported claims	27,135
Cumulative paid losses and LAE, net of reinsurance	$ 290.5	246.9		174.5		$ 65.5
Accident year 2016
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	395.4	414.6		419
IBNR	$ 94.4
Cumulative number of reported claims	25,621
Cumulative paid losses and LAE, net of reinsurance	$ 227.7	166.8		$ 65.6
Accident year 2017
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	391.3	412.4
IBNR	$ 145.1
Cumulative number of reported claims	24,746
Cumulative paid losses and LAE, net of reinsurance	$ 160.2	$ 63.5
Accident Year 2018
Claims Development [Line Items]
Incurred losses and LAE, net of reinsurance	422.5
IBNR	$ 220
Cumulative number of reported claims	23,617
Cumulative paid losses and LAE, net of reinsurance	$ 77.9
[1]	Data presented for these calendar years is required supplementary information, which is unaudite

Liability for Unpaid Losses a_5

Liability for Unpaid Losses and Loss Adjustment Expenses Reconciliation of Claims Development to Aggregate Carrying Amount of the Liability for Unpaid Losses and LAE (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liabilities for unpaid losses and LAE, net of reinsurance	$ 1,614.6
Reinsurance recoverable on unpaid losses	504.4	$ 537	$ 580	$ 628.2
Unallocated LAE	88.9
Unpaid losses and loss adjustment expenses	$ 2,207.9	$ 2,266.1	$ 2,301	$ 2,347.5

Liability for Unpaid Losses a_6

Liability for Unpaid Losses and Loss Adjustment Expenses Short Duration Insurance Contracts, Historcial Claims Duration (Details)	Dec. 31, 2018
Average annual percentage payout of incurred claims by age, net of reinsurance
Year one	16.80%
Year two	24.60%
Year three	16.40%
Year four	11.00%
Year five	6.90%
Year six	4.60%
Year seven	3.30%
Year eight	2.30%
Year nine	2.00%
Year ten	1.30%

Reinsurance Reinsurance Premium

Reinsurance Reinsurance Premium Note (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Premiums Written, Net
Direct premiums, written	$ 739	$ 719.5	$ 691
Assumed premiums written	9.9	10.2	10.4
Gross premiums written	748.9	729.7	701.4
Ceded premiums written	(6.1)	(6)	(6.8)
Premiums written, net	742.8	723.7	694.6
Premiums Earned, Net
Direct premiums earned	727.2	712.5	691
Assumed premiums earned	10	10	10.6
Gross premiums, earned	737.2	722.5	701.6
Ceded premiums earned	(6.1)	(6)	(6.8)
Premiums earned, net	731.1	716.5	694.8
Ceded losses and LAE incurred	$ 9.5	$ (0.5)	$ 0.1

Reinsurance Excess of Loss (Det

Reinsurance Excess of Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Effects of Reinsurance [Line Items]
Retention amount on a per occurrence basis		$ 10
Excess of retention amount on a per occurrence basis		$ 190
Scenario, Forecast [Member]
Effects of Reinsurance [Line Items]
Retention amount on a per occurrence basis	$ 10
Maximum reinsurance for losses from single occurence or event	$ 200

Reinsurance LPT Agreement (Deta

Reinsurance LPT Agreement (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Reinsurance Agreement [Line Items]
Available-for-sale Securities				$ 2,677,700
Unpaid losses		$ 504,400		537,000
Recoverables was related to the LPT agreement		$ 408,200		438,900
Reinsurance quota share, percentage		100.00%
LPT collateral held in trust account		$ 311,600		380,800
Ceded premiums written		6,100		6,000	$ 6,800
Coverage provided under LPT agreement		2,000,000
Paid losses and LAE claims related to LPT		773,700
Amortization of deferred gain		11,900		11,300	11,700
LPT Agreement [Member]
Reinsurance Agreement [Line Items]
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
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Member]
Reinsurance Agreement [Line Items]
Amortization of deferred gain	$ 2,200	2,200	[1]		3,100	[1]
Change to Contingent Profit Commission [Member]
Reinsurance Agreement [Line Items]
Amortization of deferred gain		$ 500		$ 300	$ 1,800
[1]	The cumulative adjustments to the Deferred Gain were also recognized in losses and LAE incurred in the Company's Consolidated Statements of Comprehensive Income, so that the Deferred Gain reflects the balance that would have existed had the revised loss and LAE reserves been recognized at the inception of the LPT Agreement.

Notes Payable Outstanding (Deta

Notes Payable Outstanding (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Notes payable		$ 20,000	$ 20,000
Redemption of notes payable		0	9,900	$ 0
Gain on redemption of notes payable	$ 2,100	0	2,100	0
Dekania Surplus Note [Member]
Debt Instrument [Line Items]
Notes payable		$ 10,000	10,000
Notes payable, maturity date		Apr. 30, 2034
Notes payable, callable		2,009
Interest rate, basis points in excess of the 90-day LIBOR		425
Cash paid for interest		$ 700	600	500
Accrued interest		100	100
Alesco Surplus Note [Member]
Debt Instrument [Line Items]
Notes payable		$ 10,000	10,000
Notes payable, maturity date		Dec. 15, 2034
Notes payable, callable		2,009
Interest rate, basis points in excess of the 90-day LIBOR		405
Cash paid for interest		$ 600	500	500
Accrued interest		$ 100	100
ICONS Surpuls Note [Member]
Debt Instrument [Line Items]
Notes payable	$ 12,000		12,000
Cash paid for interest			300	$ 600
Redemption of notes payable			9,900
Gain on redemption of notes payable			$ 2,100

Notes Payable Principal payment

Notes Payable Principal payment obligations on notes payable outstanding (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Capitalization, Long-term Debt [Line Items]
Repayments of principal in next twelve months	$ 0
Repayments of principal in year two	0
Repayments of principal in year three	0
Repayments of principal in year four	0
Repayments of principal in year five	0
Repayments of principal after year five	20
Notes payable	$ 20	$ 20

Notes Payable Letters of Credit

Notes Payable Letters of Credit (Details) - Federal Home Loan Bank [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)
Letters of Credit [Line Items]
Letter of credit, effective date	Mar. 9, 2018
Letter of credit, expiration date	Mar. 31, 2019
Letter of credit, unused capacity, commitment fee percentage	0.15%
Letter of credit, maximum borrowing capacity	$ 140
Letter of credit collateral amount	244.1
EAC
Letters of Credit [Line Items]
Letter of credit, maximum borrowing capacity	40
ECIC
Letters of Credit [Line Items]
Letter of credit, maximum borrowing capacity	50
EPIC
Letters of Credit [Line Items]
Letter of credit, maximum borrowing capacity	$ 50

Commitments and Contingencies F

Commitments and Contingencies Future Lease Payments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies [Abstract]
Remaining lease terms expire over the next	9 years
Future lease payments for non-cancelable operating and capital leases, in years	5 years
Operating Leases, Future Minimum Payments Due [Abstract]
Operating leases, future minimum payments due, current	$ 5.3
Operating leases, future minimum payments, due in two years	4.4
Operating leases, future minimum payments, due in three years	2.9
Operating leases, future minimum payments, due in four years	1.9
Operating leases, future minimum payments, due in five years	1.8
Operating leases, future minimum payments, due thereafter	6.2
Operating leases, future minimum payments due	22.5
Capital Leases, Future Minimum Payments Due [Abstract]
Capital leases, future minimum payments due, current	0.3
Capital leases, future minimum payments due in two years	0.3
Capital leases, future minimum payments due in three years	0.2
Capital leases, future minimum payments due in four years	0.1
Capital leases, future minimum payments due in five years	0
Capital leases, Future minimum payments due thereafter	0
Capital leases, future minimum payments due	0.9
Future interest charges included in capital lease payments	0.2
Facilities rent expense	$ 5	$ 4.8	$ 4.9

Commitments and Contingencies P

Commitments and Contingencies Property held under capital leases is included in property and equipment (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Property held under capital leases
Accumulated depreciation, depletion and amortization, property and equipment	$ (51.3)	$ (46)
Automobiles
Property held under capital leases
Property held under captial leases	1.1	1.1
Assets Held under Capital Leases [Member]
Property held under capital leases
Accumulated depreciation, depletion and amortization, property and equipment	(0.4)	(0.3)
Total property held under capital leases	$ 0.7	$ 0.8

Commitments and Contingencies C

Commitments and Contingencies Contingencies Surrounding Insurance Assessments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Amount of Insurance-related assessment liability	$ 18.6	$ 12.4
Payment period for assessment liability based on individual states regulations	one to eighty year periods
Other assets, prepaid policy surcharges	$ 14.9	$ 14.1
Expected realization period for assets related to policy surcharges	one to ten year periods

Commitments and Contingencies_2

Commitments and Contingencies Capital Commitment (Details) $ in Millions	Dec. 31, 2018USD ($)
Capital Commitment [Abstract]
Unfunded commitment, private investment fund	$ 50

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Millions	12 Months Ended	144 Months Ended
	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Accelerated Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount	$ 50	$ 50
Stock repurchased during period, shares | shares	112,528	24,209,883
Accelerated share repurchases, final price paid per share | $ / shares	$ 40.95	$ 16.04
Stock Repurchased During Period, Value	$ 4.6

Stock-Based Compensation Expens

Stock-Based Compensation Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares reserved for grants	5,500,000
Stock-based compensation expense [Abstract]
Stock-based compensation expense	$ 9.3	$ 6.8	$ 5.8
Less: related tax benefit	2	2.4	2
Net stock-based compensation expense	7.3	4.4	3.8
Stock Option [Member]
Stock-based compensation expense [Abstract]
Stock-based compensation expense	0.3	0.5	0.7
Restricted stock units (RSUs)
Stock-based compensation expense [Abstract]
Stock-based compensation expense	2.5	2	1.9
Performance shares units [Member]
Stock-based compensation expense [Abstract]
Stock-based compensation expense	$ 6.5	$ 4.3	$ 3.2

Stock-Based Compensation Fair M

Stock-Based Compensation Fair Market Value of Stock Options Granted, Calculated (Details) - Stock Options [Member]	12 Months Ended
	Dec. 31, 2016$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	38.00%
Expected life (in years)	4 years 274 days
Dividend yield	1.30%
Risk free interest rate	1.40%
Weighted average grant date fair value	$ 8.46

Stock-Based Compensation Change

Stock-Based Compensation Changes in Outstanding Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	190,256	247,347	564,096	1,121,545
Number of options or share units, granted	0	0	67,431
Stock-options exercised, shares	(57,091)	(307,076)	(586,132)
Number of options or share units, expired			(6,075)
Number of options or share units, forfeited	0	(9,673)	(32,673)
Number of exercisable options or share units	149,327
Weighted average exercise price, outstanding	$ 23.71	$ 22.90	$ 21.04	$ 18.31
Weighted average exercise price, grants			27.72
Weighted average exercise price, exercises	20.17	19.44	16.39
Weighted average exercise price, expirations			22.48
Weighted average exercise price, forfeitures	0	$ 24.45	24.35
Weighted average exercisable price	$ 22.95
Weighted average grant date fair value			$ 8.46
Weighted average remaining contractual life	2 years 270 days	3 years 150 days	3 years 125 days	2 years 300 days
Share-based compensation expense, deferred	$ 0.2
Options exercised, intrinsic value	1.4	$ 7.6	$ 7.6
Options vested, fair value	0.4	0.6	0.8
Options exercisable, intrinsic value	2.8	3.6	7.6
Options outstanding, intrinsic value	$ 3.4	$ 5.3	$ 10.6
Stock Options Granted [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual life			6 years 73 days
Stock Options Exercisable [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual life	2 years 150 days
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	250,300	295,164	324,384	319,033
Number of options or share units, granted	87,857	87,276	100,218
Number of options or share units, forfeited	(3,370)	(13,711)	(21,872)
Weighted average exercise price, grants	$ 40.26	$ 37.94	$ 28.20
Number of vested options or share units	(129,351)	(102,785)	(72,995)
Weighted average exercise price, forfeitures	$ 33.51	$ 29.28	$ 24.87
Weighted average grant date fair value	32.45	26.67	22.55	$ 20.71
Weighted average exercise price, vested	$ 24.53	$ 22.89	$ 21.56
Share-based compensation expense, deferred	$ 4.7
Share-based compensation expense, Period for Recognition	39 months
Service vesting period for options awarded	4 years
Vesting rights for options awarded	vest 25% on or after each of the subsequent four anniversaries of such date
Options vested, fair value	$ 3.2	$ 2.4	$ 1.6
Options exercisable, intrinsic value	5.5	4.3	2.1
Options outstanding, intrinsic value	$ 10.5	$ 13.1	$ 12.8
Restricted Stock Units Vested but Unsettled [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	67,620
Weighted average grant date fair value	$ 23.35

Stock-Based Compensation Perfor

Stock-Based Compensation Performance Share Awards (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards, minimum payout		0.00%
Performane share awards, maximum payout		200.00%
Performance share awards, expected target		125.00%	200.00%
Performance share awards, ultimate payout				200.00%
Performance shares units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	[1]	96,940	97,440	97,236
Share-based compensation options, exercise price on grant date	[1]	$ 40.30	$ 37.60	$ 27.72
Fair value of awards awarded on grant date	[1]	$ 3.9	$ 3.7	$ 2.7
Share-based compensation expense, deferred		$ 5.5
Share-based compensation expense, Period for Recognition		24 months
[1]	The PSUs awarded in March 2016, 2017, and 2018 were awarded to certain employees 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 values shown in the table represent the aggregate number of PSUs awarded at the target level.

Statutory Matters Statutory Mat

Statutory Matters Statutory Matters (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2019	Sep. 06, 2019	Sep. 05, 2019	May 19, 2019	May 18, 2019	Jan. 26, 2019	Jan. 25, 2019
Statutory Accounting Practices [Line Items]
Capital stock and unassigned surplus	$ 558.5	$ 510.6
Paid in capital	349.4	349.8
Surplus notes	20	32
Total statutory surplus	927.9	892.4
SAP, net income amount	159.3	116.8	$ 101.4
Total stockholders’ equity	$ 1,018.2	$ 947.7
Will maintain a risk based capital (RBC) level of at least	350.00%
EICN
Statutory Accounting Practices [Line Items]
Capital stock and unassigned surplus	$ 195.3
Extraordinary dividends, approves or does not disapprove the payment within	30 days
Percentage of surplus of EICN's statutory surplus as regards to policyholders	10.00%
Dividends paid, without approval of regulatory agency	$ 17.7
EICN | Scenario, Forecast [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments with Regulatory Approval									$ 19.8	$ 2.1
EPIC
Statutory Accounting Practices [Line Items]
Percentage of surplus used to calculate the lesser of 10% of surplus or net income, not including realized capital gains, plus a 2-year carry forward.	10.00%
Percentage of surplus used to calculate 10% of surplus, with dividends payable limited to unassigned funds minus 25% of unrealized capital gains	10.00%
Percentage of surplus used to calculate the lesser of 10% of surplus or net investment income plus a 3-year carry forward with dividends payable limited to unassigned funds minus 25% of unrealized capital gains	10.00%
Percentage of unassigned gains used to calculate 10% of surplus, with dividends payable limited to unassigned funds minus 25% of unrealized capital gains	25.00%
Percentage of unassigned gains used to calculate the lesser of 10% of surplus or net investment income plus a 3-year carry forward with dividends payable limited to unassigned funds minus 25% of unrealized capital gains	25.00%
EPIC | Scenario, Forecast [Member]
Statutory Accounting Practices [Line Items]
Maximum dividends that may be paid without prior approval				$ 19
EAC
Statutory Accounting Practices [Line Items]
Dividends paid, without approval of regulatory agency	$ 18.9
EAC | Scenario, Forecast [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments with Regulatory Approval							$ 19.8	$ 0.9
ECIC
Statutory Accounting Practices [Line Items]
ECIC must initiate discussions of its business plan with the California DOI if its premium to policyholder surplus ratio exceeds	1.5 to 1
ECIC will not exceed a ratio of premium to policyholder surplus of	2 to 1
If at any time ECIC's policyholder surplus decreases to	80.00%
Dividends paid, without approval of regulatory agency	$ 48.4
ECIC | Scenario, Forecast [Member]
Statutory Accounting Practices [Line Items]
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments with Regulatory Approval					$ 57.2	$ 8.8
EAC and EPIC
Statutory Accounting Practices [Line Items]
Total statutory surplus	$ 4
Florida statute section 624.408 requires EPIC and EAC to maintain minimum capital and surplus of the greater of $4.0 million or 10% of total liabilities.	10.00%
Used to calculate ratio of written premium to surplus	1.25
Net gross premiums to surplus ratio. Florida statute section 624.4095 requires net gross premiums times 1.25 not exceed this ratio.	10-to-1
Net written premiums to surplus ratio. Florida statute section 624.4095 requires net written premiums times 1.25 not exceed this ratio.	4-to-1

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized gain on investments, before taxes	$ (17,300)	$ 136,000
Deferred tax expense	3,600	(28,600)
Total accumulated other comprehensive income, net	$ (13,700)	$ 107,400

Employee Benefit and Retireme_2

Employee Benefit and Retirement Plans Employee Benefit and Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Benefit and Retirement Plans [Abstract]
Safe habor matching, 100%	100.00%
Employee contributions, 100% match, percentage	3.00%
Safe harbor matching 50%	50.00%
Employee contributions 50% match, percentage	3.00%
Employee contributions, maximum match, percentage	5.00%
Company's contributions to Employers 401(k)	$ 2	$ 1.9	$ 1.9

Earnings Per Share Earnings Per

Earnings Per Share Earnings Per Share (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income	$ 25.6	$ 47.6	$ 42.5	$ 25.6	$ 31.3	$ 21.9	$ 24.8	$ 23.2	$ 141.3	$ 101.2	$ 106.7
Weighted average number of shares outstanding - basic									32,884,828	32,501,576	32,434,580
Effect of diluted securities:									426,509	559,184	542,255
Weighted average number of shares outstanding - diluted									33,311,337	33,060,760	32,976,835
Employee Stock Option [Member]
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Effect of diluted securities:									97,810	208,602	246,562
Performance shares units [Member]
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Effect of diluted securities:									268,030	271,738	222,594
Restricted stock units (RSUs)
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Effect of diluted securities:									60,669	78,844	73,099

Earnings Per Share Antidilutive

Earnings Per Share Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of EPS	0	0	89,221
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of EPS	0	0	0

Selected Quarterly Financial _3

Selected Quarterly Financial Data Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Net premiums earned	$ 183.6	$ 192.9	$ 178	$ 176.6	$ 181.6	$ 187.9	$ 171.7	$ 175.3	$ 731.1	$ 716.5	$ 694.8
Net realized and unrealized (losses) gains on investments	(26.4)	15.6	5.7	(8)	0	4.1	1.1	2.2	(13.1)	7.4	11.2
Losses and loss adjustment expenses	86.9	106.6	87.8	95.4	85.2	116.9	106.1	109	376.7	417.2	417.9
Commission expense	21.2	24.8	24.5	23.7	24.7	23.7	21.5	21.5	94.2	91.4	83.5
Underwriting and other operating expenses	40.4	38.8	40.1	39.2	37.8	33.6	32.6	35.9	158.5	139.9	136.1
Other expenses					0	7.5	0	0	0	7.5	0
Income tax expense	4.9	10.7	8.8	3.8	21.7	7	7.8	6.3	28.2	42.8	34
Net income	$ 25.6	$ 47.6	$ 42.5	$ 25.6	$ 31.3	$ 21.9	$ 24.8	$ 23.2	$ 141.3	$ 101.2	$ 106.7
Earnings per common share (Note 18):
Basic	$ 0.78	$ 1.45	$ 1.29	$ 0.78	$ 0.96	$ 0.67	$ 0.76	$ 0.72	$ 4.30	$ 3.11	$ 3.29
Diluted	$ 0.77	$ 1.43	$ 1.28	$ 0.77	$ 0.94	$ 0.66	$ 0.75	$ 0.70	$ 4.24	$ 3.06	$ 3.24

Selected Quarterly Financial _4

Selected Quarterly Financial Data Significant Quarterly Adjustments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Prior years	$ 25,400	$ 11,900	$ 16,500	$ 12,400	$ (18,000)				$ (66,200)	[1]	$ (18,500)	[1]	$ (18,400)	[1]
Equity securities, change in unrealized gains (losses)	27,400	11,200	3,500	12,900
Net income for the period	25,600	$ 47,600	$ 42,500	$ 25,600	31,300	$ 21,900	$ 24,800	$ 23,200	141,300		101,200		106,700
Gain on redemption of notes payable							2,100		0		2,100		0
Notes payable	$ 20,000				20,000				20,000		20,000
Asset impairment charges						$ 7,500					7,500
Reduction in Current Accident Year Losses and LAE Due Provision Rate					10,600
Revaluation of deferred tax asset					7,000				(400)		7,000		0
ICONS Surpuls Note [Member]
Gain on redemption of notes payable											2,100
Notes payable					$ 12,000		$ 12,000				12,000
Voluntary risk business
Prior years									(65,500)		(17,400)		(17,000)
Involuntary assigned risk business
Prior years									(700)		(1,100)		(1,400)
Change Due to Estimated Reserves Ceded Under the LPT Agreement [Member]
Net income for the period									2,200		0		3,100
Change to Contingent Profit Commission [Member]
Net income for the period									$ 500		$ 300		$ 1,800
[1]	Losses and LAE, net of reinsurance, incurred during the period related to prior years and Total net losses and LAE incurred during the period included in the above table excludes the impact of the amortization of the Deferred Gain and LPT Reserve Adjustments (Note 10). Including these amounts, Losses and LAE, net of reinsurance, incurred during the period related to prior years was $(80.8) million, $(30.1) million, and $(35.0) million and Total net losses and LAE incurred during the period was $376.7 million, $417.2 million, and $417.9 million for the years ended December 31, 2018, 2017, and 2016, respectively.

Schedule II. Condensed Financ_2

Schedule II. Condensed Financial Information of Registrant (Condensed Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments
Fixed maturity securities at fair value (amortized cost $24.2 at December 31, 2018 and $40.2 at December 31, 2017)	$ 2,496,400	$ 2,463,400
Equity securities at fair value (cost $40.0 at December 31, 2018)	199,900	0
Short-term investments at fair value (amortized cost $25.0 at December 31, 2018 and $3.7 at December 31, 2017)	25,000	4,000
Total investments	2,727,700	2,677,700
Cash and cash equivalents	101,400	73,300
Accrued investment income	18,000	19,600
Deferred income taxes, net	26,900	28,700
Other assets	32,100	33,700
Total assets	3,919,200	3,840,100
Liabilities and stockholders’ equity
Accounts payable and accrued expenses	37,100	23,700
Other liabilities	74,000	42,700
Total liabilities	2,901,000	2,892,400
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 56,975,675 and 56,695,174 shares issued and 32,765,792 and 32,597,819 shares outstanding at December 31, 2018 and 2017, respectively	600	600
Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued	0	0
Additional paid-in capital	388,800	381,200
Retained earnings	1,030,700	842,200
Accumulated other comprehensive (loss) income, net of tax	(13,700)	107,400
Treasury stock, at cost (24,209,883 shares at December 31, 2018 and 24,097,355 shares at December 31, 2017)	(388,200)	(383,700)
Total stockholders’ equity	1,018,200	947,700
Total liabilities and stockholders’ equity	3,919,200	3,840,100
Parent Company [Member]
Investments
Investment in subsidiaries	873,800	849,600
Fixed maturity securities at fair value (amortized cost $24.2 at December 31, 2018 and $40.2 at December 31, 2017)	24,600	41,400
Equity securities at fair value (cost $40.0 at December 31, 2018)	38,700	0
Short-term investments at fair value (amortized cost $25.0 at December 31, 2018 and $3.7 at December 31, 2017)	25,000	3,700
Total investments	962,100	894,700
Cash and cash equivalents	41,300	39,600	$ 41,400	$ 1,400
Accrued investment income	300	300
Accounts Receivable, Related Parties, Current	300	0
Federal income taxes recoverable	22,700	4,200
Deferred income taxes, net	0	14,500
Other assets	900	800
Total assets	1,027,600	954,100
Liabilities and stockholders’ equity
Accounts payable and accrued expenses	5,000	4,500
Intercompany payable	0	1,900
Deferred tax liabilities	400	0
Other liabilities	4,000	0
Total liabilities	9,400	6,400
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 56,975,675 and 56,695,174 shares issued and 32,765,792 and 32,597,819 shares outstanding at December 31, 2018 and 2017, respectively	600	600
Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued	0	0
Additional paid-in capital	388,800	381,200
Retained earnings	1,030,700	842,200
Accumulated other comprehensive (loss) income, net of tax	(13,700)	107,400
Treasury stock, at cost (24,209,883 shares at December 31, 2018 and 24,097,355 shares at December 31, 2017)	(388,200)	(383,700)
Total stockholders’ equity	1,018,200	947,700
Total liabilities and stockholders’ equity	$ 1,027,600	$ 954,100

Schedule II. Condensed Financ_3

Schedule II. Condensed Financial Information of Registrant (Condensed Statements of Income) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues
Net investment income									$ 81.2	$ 74.6	$ 73.2
Net realized and unrealized gains on investments	$ (26.4)	$ 15.6	$ 5.7	$ (8)	$ 0	$ 4.1	$ 1.1	$ 2.2	(13.1)	7.4	11.2
Total revenues									800.4	801.4	779.8
Expenses
Other operating expenses					0	7.5	0	0	0	7.5	0
Total expenses									630.9	657.4	639.1
Income tax expense	4.9	10.7	8.8	3.8	21.7	7	7.8	6.3	28.2	42.8	34
Net income	$ 25.6	$ 47.6	$ 42.5	$ 25.6	$ 31.3	$ 21.9	$ 24.8	$ 23.2	$ 141.3	$ 101.2	$ 106.7
Earnings per common share for the stated periods (Note 18):
Basic	$ 0.78	$ 1.45	$ 1.29	$ 0.78	$ 0.96	$ 0.67	$ 0.76	$ 0.72	$ 4.30	$ 3.11	$ 3.29
Diluted	$ 0.77	$ 1.43	$ 1.28	$ 0.77	$ 0.94	$ 0.66	$ 0.75	$ 0.70	4.24	3.06	3.24
Cash dividends declared per common share and eligible RSUs and PSUs									$ 0.80	$ 0.60	$ 0.36
Parent Company [Member]
Revenues
Net investment income									$ 2.5	$ 1.3	$ 1.9
Net realized and unrealized gains on investments									0.8	0	8
Total revenues									3.3	1.3	9.9
Expenses
Other operating expenses									17.5	15.2	13.8
Total expenses									17.5	15.2	13.8
Income (loss) before income taxes and equity in earnings of subsidiaries									(14.2)	(13.9)	(3.9)
Income tax expense									(4.3)	(5.8)	(3.5)
Net income (loss) before equity in earnings of subsidiaries									(9.9)	(8.1)	(0.4)
Equity in earnings of subsidiary									151.2	109.3	107.1
Net income									$ 141.3	$ 101.2	$ 106.7
Earnings per common share for the stated periods (Note 18):
Basic									$ 4.30	$ 3.11	$ 3.29
Diluted									$ 4.24	$ 3.06	$ 3.24

Schedule II. Condensed Financ_4

Schedule II. Condensed Financial Information of Registrant (Condensed Balance Sheets Parenthetical) (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Fixed maturity securities, amortized cost	$ 0	$ 2,541.7
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)	56,975,675	56,695,174
Common stock, shares outstanding (in shares)	32,765,792	32,597,819
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)	24,209,883	24,097,355
Parent Company [Member]
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)	56,975,675	56,695,174
Common stock, shares outstanding (in shares)	32,765,792	32,597,819
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)	24,209,883	24,097,355
Debt Securities [Member]
Fixed maturity securities, amortized cost	$ 0	$ 2,421
Debt Securities [Member] | Parent Company [Member]
Fixed maturity securities, amortized cost		40.2
Equity Securities [Member]
Fixed maturity securities, amortized cost		$ 116.7

Schedule II. Condensed Financ_5

Schedule II. Condensed Financial Information of Registrant (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 25,600	$ 47,600	$ 42,500	$ 25,600	$ 31,300	$ 21,900	$ 24,800	$ 23,200	$ 141,300	$ 101,200	$ 106,700
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Realized gains on investments									13,100	(7,400)	(11,200)
Stock-based compensation									9,400	6,800	5,800
Amortization of premium on investments, net									8,400	14,300	14,600
Deferred income tax expense									14,400	24,200	13,400
Change in operating assets and liabilities:
Accounts payable, accrued expenses and other liabilities									19,100	(7,000)	(4,200)
Federal income taxes									8,600	(2,700)	7,700
Other									(3,000)	12,300	(2,400)
Net cash provided by (used in) operating activities									180,200	142,300	122,800
Investing activities
Purchases of fixed maturity securities									(636,700)	(592,300)	(466,800)
Purchase of equity securities									(79,300)	(36,800)	(49,100)
Purchases of short-term investments									(59,700)	(8,200)	(10,000)
Proceeds from sale of fixed maturity securities									204,800	249,800	132,400
Proceeds from maturities and redemptions of fixed maturity securities									329,400	215,700	230,600
Proceeds from sale of equity securities									70,700	41,200	80,400
Net change in unsettled purchases and sales									22,400	5,800	0
Net cash (used in) provided by investing activities									(119,600)	(112,800)	(87,500)
Financing activities
Acquisition of common stock									(4,200)	0	(21,100)
Cash transactions related to stock-based compensation									(1,800)	3,800	9,000
Dividends paid to stockholders									(26,700)	(19,700)	(11,500)
Net cash used in financing activities									(32,900)	(26,000)	(23,600)
Cash and cash equivalents at the beginning of the period				73,300					73,300
Cash and cash equivalents at the end of the period	101,400				73,300				101,400	73,300
Parent Company [Member]
Operating activities
Net income									141,300	101,200	106,700
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in net income of subsidiaries									66,700	71,500	107,100
Realized gains on investments									(800)	0	(8,000)
Stock-based compensation									9,400	6,800	5,800
Amortization of premium on investments, net									200	100	400
Deferred income tax expense									14,700	5,300	2,900
Change in operating assets and liabilities:
Accounts payable, accrued expenses and other liabilities									200	(300)	(700)
Federal income taxes									(18,500)	5,400	(7,900)
Other assets									100	100	(800)
Intercompany payable/receivable									(2,200)	1,800	300
Other									0	0	(400)
Net cash provided by (used in) operating activities									77,500	48,700	(7,200)
Investing activities
Purchases of fixed maturity securities									(14,400)	(30,600)	(31,000)
Purchase of equity securities									(40,000)	0	(3,600)
Purchases of short-term investments									(59,600)	(7,900)	0
Proceeds from sale of fixed maturity securities									12,000	5,000	0
Proceeds from maturities and redemptions of fixed maturity securities									59,200	4,500	24,900
Proceeds from sale of equity securities									0	0	88,500
Net change in unsettled purchases and sales									3,900	0	0
Capital Contributions to subsidiary									(4,200)	(5,600)	(8,000)
Net cash (used in) provided by investing activities									(43,100)	(34,600)	70,800
Financing activities
Acquisition of common stock									(4,200)	0	(21,100)
Cash transactions related to stock-based compensation									(1,800)	3,800	9,000
Dividends paid to stockholders									(26,700)	(19,700)	(11,500)
Net cash used in financing activities									(32,700)	(15,900)	(23,600)
Net increase (decrease) in cash and cash equivalents									1,700	(1,800)	40,000
Cash and cash equivalents at the beginning of the period				$ 39,600				$ 41,400	39,600	41,400	1,400
Cash and cash equivalents at the end of the period	$ 41,300				$ 39,600				$ 41,300	$ 39,600	$ 41,400