Employers (EIG) 10-Q 26 Apr 21 2021 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2021	Apr. 15, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-33245
Entity Registrant Name	EMPLOYERS HOLDINGS, INC.
Entity Incorporation, State or Country Code	NV
Entity Tax Identification Number	04-3850065
Entity Address, Address Line One	10375 Professional Circle
Entity Address, City or Town	Reno,
Entity Address, State or Province	NV
Entity Address, Postal Zip Code	89521
City Area Code	888
Local Phone Number	682-6671
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	EIG
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		28,522,190
Entity Central Index Key	0001379041
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments:
Fixed maturity securities at fair value (amortized cost $2,385.4 at March 31, 2021 and $2,333.6 at December 31, 2020, net of CECL allowance of $0.2 at March 31, 2021 and $0.7 at December 31, 2020)	$ 2,485.4	$ 2,479.2
Equity securities at fair value (cost $124.8 at March 31, 2021 and $112.4 at December 31, 2020)	229.7	208.5
Equity securities at cost	6.7	6.7
Other invested assets (cost $42.3 at March 31, 2021 and $36.8 at December 31, 2020)	42.4	36.2
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)	1	26.6
Total investments	2,765.2	2,757.2
Cash and cash equivalents	85.4	160.4
Restricted cash and cash equivalents	0.2	0.2
Accrued investment income	17.2	15.3
Premiums receivable (less CECL allowance of $12.2 at March 31, 2021 and $10.8 at December 31, 2020)	243.7	232.1
Reinsurance recoverable for:
Paid losses	7.2	7.6
Unpaid losses (less CECL allowance of $0.4 at March 31, 2021 and $0.4 at December 31, 2020)	491.9	496.6
Deferred policy acquisition costs	44.1	43.2
Property and equipment, net	18.1	19.1
Operating lease right-of-use assets	16.4	17.4
Intangible assets, net	13.6	13.6
Goodwill	36.2	36.2
Contingent commission receivable—LPT Agreement	13.4	13.4
Cloud computing arrangements	49.7	50.2
Other assets	61.7	60.1
Total assets	3,864	3,922.6
Liabilities and stockholders’ equity
Unpaid losses and loss adjustment expenses	2,034.1	2,069.4
Unearned premiums	313.8	299.1
Commissions and premium taxes payable	38.3	43
Accounts payable and accrued expenses	23.3	22.9
Deferred reinsurance gain—LPT Agreement	123.3	125.4
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	15	20
Deferred Tax Liabilities, Tax Deferred Income	7.4	15.5
Operating lease liability	19.1	19.9
Non-cancellable obligations	24.2	24.1
Other liabilities	78.9	70.5
Total liabilities	2,677.4	2,709.8
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 57,625,808 and 57,413,806 shares issued and 28,478,254 and 28,564,798 shares outstanding at March 31, 2021 and December 31, 2020, respectively	0.6	0.6
Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued	0	0
Additional paid-in capital	407.9	404.3
Retained earnings	1,263.8	1,247.9
Accumulated other comprehensive income, net of tax	79	115.1
Treasury stock, at cost (29,147,554 shares at March 31, 2021 and 28,849,008 shares at December 31, 2020)	(564.7)	(555.1)
Total stockholders’ equity	1,186.6	1,212.8
Total liabilities and stockholders’ equity	$ 3,864	$ 3,922.6

Consolidated Balance Sheets Con

Consolidated Balance Sheets Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Available for sale:
Debt securities, available-for-sale, amortized cost	$ 2,385.4	$ 2,333.6
Equity Securities, FV-NI, Cost	124.8	112.4
Other Investments and Securities, at Cost	42.3	36.8
Available for sale, short-term investments, at amortized cost	1	26.5
Debt Securities, Available-for-sale, Allowance for Credit Loss	0.2	0.7
Accounts Receivable, Allowance for Credit Loss, Current	12.2	10.8
Reinsurance recoverables on unpaid losses, allowance	$ 0.4	$ 0.4
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)	57,625,808	57,413,806
Common stock, shares outstanding (in shares)	28,478,254	28,564,798
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)	29,147,554	28,849,008

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues
Net premiums earned	$ 133.9	$ 167.9
Net investment income	18.4	19.9
Net realized and unrealized (losses) gains on investments	10.9	(61.1)
Other income	0.4	0.3
Total revenues	163.6	127
Expenses
Losses and loss adjustment expenses	69.6	104.3
Commission expense	16.8	21.3
Underwriting and general and administrative expenses	46.6	46.7
Interest and financing expenses	0.1	0
Other Expenses	2.9	0
Total expenses	136	172.3
Net income (loss) before income taxes	27.6	(45.3)
Income tax expense (benefit)	4.5	(10.4)
Net income (loss)	23.1	(34.9)
Comprehensive income (loss)
Unrealized AFS investment losses arising during the period (net of tax benefit of $9.4 and $7.6 for the three months ended March 31, 2021 and 2020, respectively)	(35.5)	(29.2)
Reclassification adjustment for realized AFS investment (gains) losses in net income (net of tax (expense) benefit of $0.2 and $(1.4) for the three months ended March 31, 2021 and 2020, respectively)	(0.6)	5.5
Other comprehensive loss, net of tax	(36.1)	(23.7)
Total comprehensive loss	(13)	(58.6)
Net realized and unrealized gains (losses) on investments
Net realized and unrealized gains (losses) on investments before impairments	10.9	(61.1)
Net realized and unrealized (losses) gains on investments	$ 10.9	$ (61.1)
Earnings (loss) per common share (Note 13):
Basic	$ 0.81	$ (1.14)
Diluted	0.80	(1.14)
Cash dividends declared per common share, RSUs and PSUs	$ 0.25	$ 0.25

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement Parenthetical [Abstract]
Other comprehensive income (loss), unrealized holding gain (loss) on securities arising during period, tax	$ 9.4	$ 7.6
Other comprehensive income (loss), reclassification adjustment for sale of securities included in net income, tax	$ 0.2	$ (1.4)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders Equity Statement - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income, Net	Treasury Stock [Member]
Stockholders' equity, shares at Dec. 31, 2019		57,184,370
Stockholders' equity, value at Dec. 31, 2019	$ 1,165.8	$ 0.6	$ 396.4	$ 1,158.8	$ 65.3	$ (455.3)
Stock-based obligations, shares		0
Stock-based obligations, value	$ 2.5	$ 0	2.5	0	0	0
Stock-options exercised, shares	36,500	36,500
Stock-options exercised, value	$ 0.8	$ 0	0.8	0	0	0
Vesting of RSUs and PSUs, net of shares withheld to satisfy minimum tax withholding, shares		154,715
Vesting of RSUs and PSUs, net of shares withheld to satisfy minimum tax withholding, value	(2.7)	$ 0	(2.7)	0	0	0
Acquisition of common stock, shares		0
Acquisition of common stock, value	(42.5)	$ 0	0		0	(42.5)
Dividends declared, shares		0
Dividends declared, value	(8)	$ 0	0	(8)	0	0
Net income	(34.9)	0	0	(34.9)	0	0
Change in net unrealized gains in investments, net of tax	(23.7)	$ 0	0	0	(23.7)	0
Stockholders' equity, shares at Mar. 31, 2020		57,375,585
Stockholders' equity, value at Mar. 31, 2020	1,057.3	$ 0.6	397	1,115.9	41.6	(497.8)
Stockholders' equity, shares at Dec. 31, 2019		57,184,370
Stockholders' equity, value at Dec. 31, 2019	$ 1,165.8	$ 0.6	396.4	1,158.8	65.3	(455.3)
Stock-options exercised, shares	40,800
Stockholders' equity, shares at Dec. 31, 2020	57,413,806	57,413,806
Stockholders' equity, value at Dec. 31, 2020	$ 1,212.8	$ 0.6	404.3	1,247.9	115.1	(555.1)
Stock-based obligations, shares		0
Stock-based obligations, value	$ 5.2	$ 0	5.2	0	0	0
Stock-options exercised, shares	41,851	41,851
Stock-options exercised, value	$ 0.9	$ 0	0.9	0	0	0
Vesting of RSUs and PSUs, net of shares withheld to satisfy minimum tax withholding, shares		170,151
Vesting of RSUs and PSUs, net of shares withheld to satisfy minimum tax withholding, value	(2.5)	$ 0	(2.5)	0	0	0
Acquisition of common stock, shares		0
Acquisition of common stock, value	(9.6)	$ 0	0		0	(9.6)
Dividends declared, shares		0
Dividends declared, value	(7.1)	$ 0	0	(7.1)	0	0
Net income	23.1	0	0	23.1	0	0
Change in net unrealized gains in investments, net of tax	$ (36.1)	$ 0	0	0	(36.1)	0
Stockholders' equity, shares at Mar. 31, 2021	57,625,808	57,625,808
Stockholders' equity, value at Mar. 31, 2021	$ 1,186.6	$ 0.6	$ 407.9	$ 1,263.8	$ 79	$ (564.7)

Consolidated Statements of St_2

Consolidated Statements of Stockholders Equity (Parentheticals) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Stockholders' Equity [Abstract]
Change in net unrealized (losses) gains on investments, net of tax	$ 9.6	$ 6.2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Mar. 31, 2021	Dec. 31, 2020
Operating activities
Net income	$ 23.1	$ (34.9)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	1.9	2.1
Stock-based compensation	5.2	2.4
Amortization of cloud computing arrangements	3.1	1.6	$ 9
Amortization of premium on investments, net	1.5	3.2
Allowance for expected credit losses	1.4	(0.3)
Deferred income tax expense	9.5	(13.6)
Net realized and unrealized (gains) losses on investments	(10.9)	61.1
Change in operating assets and liabilities:
Premiums receivable	(13)	(5.8)
Reinsurance recoverable on paid and unpaid losses	5.1	5.2
Cloud computing arrangements	(2.6)	(4.5)
Operating lease right-of-use-assets	1	1
Current federal income taxes	(5.3)	3
Unpaid losses and loss adjustment expenses	35.3	1.1
Unearned premiums	14.7	16.7
Accounts payable, accrued expenses and other liabilities	3.1	(1.9)
Deferred reinsurance gain—LPT Agreement	(2.1)	(2.4)
Operating lease liabilities	(0.8)	(1)
Non-cancellable obligations	0.1	(1.7)
Other	(11.1)	(13.6)
Net cash (used by) provided by operating activities	(11.4)	15.5
Investing activities
Purchases of fixed maturity securities	(243.6)	(228.3)
Purchases of equity securities	(19.3)	(89.3)
Purchases of short-term investments	0	(76.2)
Purchases of other invested assets	(5.6)	(2.7)
Proceeds from sale of fixed maturity securities	74	220.2
Proceeds from sale of equity securities	8	86.5
Proceeds from maturities and redemptions of fixed maturity securities	116.7	86.6
Proceeds from maturities of short-term investments	25.5	66.9
Net change in unsettled investment purchases and sales	5.6	(5.6)
Capital expenditures and other	(1.1)	(1.9)
Net cash (used by) provided by investing activities	(39.8)	56.2
Financing activities
Acquisition of common stock	(10)	(42.5)
Cash transactions related to stock-based compensation	(1.7)	(1.9)
Dividends paid to stockholders	(7.1)	(8)
Repayments of FHLBank Advance, Investing Activities	5	0	15
Proceeds from Lines of Credit	12	0
Repayments on LOC	12	0
Payments on capital leases	0	0.1
Net cash used in financing activities	(23.8)	(52.5)
Net (decrease) increase in cash, cash equivalents and restricted cash	(75)	19.2
Cash, cash equivalents, restricted cash and restricted cash equivalents at the beginning of the period	160.6	155.2	155.2
Cash, cash equivalents, restricted cash and restricted cash equivalents at the end of the period	85.6	174.4	160.6
Cash and cash equivalents				$ 85.4	$ 160.4
Restricted cash and cash equivalents				0.2	0.2
Total cash, cash equivalents, restricted cash	$ 85.6	$ 174.4	$ 155.2	$ 85.6	$ 160.6

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Description and Basis of Presentation	Basis of Presentation and Summary of Operations Employers Holdings, Inc. (EHI) is a Nevada holding company. Through its wholly owned insurance subsidiaries, Employers Insurance Company of Nevada (EICN), Employers Compensation Insurance Company (ECIC), Employers Preferred Insurance Company (EPIC), Employers Assurance Company (EAC), and Cerity Insurance Company (CIC), 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: (i) all claims under the covered policies have closed; (ii) the LPT Agreement is commuted or terminated, upon the mutual agreement of the parties; or (iii) 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 Note 9). 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. The accompanying consolidated financial statements have been prepared in accordance with United States (U.S.) generally accepted accounting principles (GAAP) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X of the Securities Exchange Act of 1934, as amended. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal, recurring adjustments) necessary for a fair presentation of the Company’s consolidated financial position and results of operations for the periods presented have been included. The results of operations for an interim period are not necessarily indicative of the results for an entire year. These financial statements have been prepared consistent with the accounting policies described in the Company’s Form 10-K for the year ended December 31, 2020 (Annual Report). The Company operates through two reportable segments: Employers and Cerity . Each of the segments represents a separate and distinct underwriting platform through which the Company conducts insurance business. This presentation allows the reader, as well as the Company's chief operating decision makers, to objectively analyze the business originated through each of the Company's underwriting platforms. Detailed financial information about the Company's operating segments is presented in Note 14. 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.

New Accounting Standards

New Accounting Standards	3 Months Ended
	Mar. 31, 2021
New Accounting Standards [Abstract]
New Accounting Standards	New Accounting Standards Recently Issued Accounting Standards In March 2020, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2020-04, Reference Rate Reform (Topic 848) . This update provides optional transition guidance to ease the potential accounting burden associated with transitioning away from the London Interbank Offered Rate (LIBOR), with optional expedients and exceptions related to the application of US GAAP to contracts, hedging relationships and other transactions affected by reference rate reform. Companies can apply this ASU immediately, but early adoption is only available through December 31, 2022 when this ASU becomes effective. The Company is evaluating the impact of LIBOR on its existing contracts and investments, but does not expect that this update will have a material impact on its consolidated financial condition or results of operations. Recently Adopted Accounting Standards In October 2020, the FASB issued ASU 2020-10, Codification Improvements . This update ensures all disclosure guidance that requires or provides an option for an entity to provide notes to the financial statements is included in the Disclosure Section (Section 50) of the Codification. This update also provides codification where the original guidance was unclear. The Company adopted this standard and there was no impact to its consolidated financial condition or results of operations. In October 2020, the FASB issued ASU 2020-08 , Codification Improvements to Subtopic 310-20, Receivable-Nonrefundable Fees and Other Costs . The amendments in this update shortened the amortization period for certain purchased callable debt securities held at a premium by requiring that entities amortize the premium associated with those callable debt securities within the scope of paragraph 310-20-25-33 to the earliest call date. The amendments affect the guidance in ASU 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities . The Company adopted this standard and there was no impact to its consolidated financial condition or results of operations. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740). This update simplifies the accounting for income taxes within Accounting Standards Codification (ASC) topic 740 by removing certain exceptions and clarifies existing guidance. The Company adopted this standard and there was no impact to its consolidated financial condition or results of operations.

Valuation of Financial Instrume

Valuation of Financial Instruments	3 Months Ended
	Mar. 31, 2021
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	Valuation of Financial Instruments Financial Instruments Carried at Fair Value The carrying value and the estimated fair value of the Company’s financial instruments at fair value were as follows: March 31, 2021 December 31, 2020 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) Financial assets Total investments at fair value $ 2,716.1 $ 2,716.1 $ 2,714.3 $ 2,714.3 Cash and cash equivalents 85.4 85.4 160.4 160.4 Restricted cash and cash equivalents 0.2 0.2 0.2 0.2 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 non-binding 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 prices, when available, as they represent 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 speed assumptions. There were no material adjustments to the valuation methodology utilized by third party pricing services as of March 31, 2021 and December 31, 2020. These methods of valuation 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 following table presents the Company’s investments at fair value and the corresponding fair value measurements. March 31, 2021 December 31, 2020 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities: U.S. Treasuries $ — $ 78.3 $ — $ — $ 78.3 $ — U.S. Agencies — 3.0 — — 3.1 — States and municipalities — 442.3 — — 482.7 — Corporate securities — 1,107.3 — — 1,046.4 — Residential mortgage-backed securities — 431.9 — — 461.0 — Commercial mortgage-backed securities — 98.0 — — 102.4 — Asset-backed securities — 50.7 — — 42.6 — Collateralized loan obligations — 84.3 — — 83.6 — Foreign government securities — 12.3 — — 8.2 — Other securities — 177.3 — — 170.9 — Total fixed maturity securities $ — $ 2,485.4 $ — $ — $ 2,479.2 $ — Equity securities at fair value: Industrial and miscellaneous $ 199.6 $ — $ — $ 179.1 $ — $ — Other 30.1 — — 29.4 — — Total equity securities at fair value $ 229.7 $ — $ — $ 208.5 $ — $ — Short-term investments $ — $ 1.0 $ — $ 4.0 $ 22.6 $ — Total investments at fair value $ 229.7 $ 2,486.4 $ — $ 212.5 $ 2,501.8 $ — Financial Instruments Carried at Cost EICN, ECIC, EPIC, and EAC are members 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 Company also has investments in convertible preferred shares of real estate investment trusts which are carried at cost and approximate fair value. Financial Instruments Carried at Net Asset Value (NAV) The Company has investments in private equity limited partnership interests that are included in Other invested assets on the Company’s Consolidated Balance Sheets. These investments do not have readily determinable fair values and are carried at NAV and therefore are excluded from the fair value hierarchy. The Company initially estimates the value of these investments using the transaction price. In subsequent periods, the Company measures these investments using NAV per share provided quarterly by the general partner, based on financial statements that are audited annually. These investments are generally not redeemable by the investees and cannot be sold without approval of the general partner. These investments have a fund term of 10 to 12 years, subject to two or three one year extensions at the general partner’s discretion. The Company will receive distributions of proceeds from dividends and interest from fund investments, as well as from the disposition of a fund investment, or portion thereof. The Company expects these distributions from time-to-time during the full course of the fund term. As of March 31, 2021, the Company had unfunded commitments to these private equity limited partnerships totaling $57.9 million. Additionally, certain cash equivalents, principally money market securities, are measured using NAV, which approximates fair value. The following table presents cash and investments carried at NAV on the Company’s Consolidated Balance Sheets. March 31, 2021 December 31, 2020 (in millions) Cash equivalents carried at NAV $ 45.7 $ 58.7 Other invested assets carried at NAV 22.4 16.2

Investments

Investments	3 Months Ended
	Mar. 31, 2021
Investments [Abstract]
Investments	Investments The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the Company’s available-for-sale (AFS) investments were as follows: Amortized Gross Gross Estimated (in millions) At March 31, 2021 Fixed maturity securities U.S. Treasuries $ 75.7 $ 2.6 $ — $ 78.3 U.S. Agencies 2.8 0.2 — 3.0 States and municipalities 415.3 27.2 (0.2) 442.3 Corporate securities 1,052.7 58.4 (3.8) 1,107.3 Residential mortgage-backed securities 422.6 12.6 (3.3) 431.9 Commercial mortgage-backed securities 93.1 5.1 (0.2) 98.0 Asset-backed securities 50.3 0.9 (0.5) 50.7 Collateralized loan obligations 84.5 — (0.2) 84.3 Foreign government securities 12.7 — (0.4) 12.3 Other securities 175.7 1.9 (0.3) 177.3 Total fixed maturity securities $ 2,385.4 $ 108.9 $ (8.9) $ 2,485.4 Short-term investments 1.0 — — 1.0 Total AFS investments $ 2,386.4 $ 108.9 $ (8.9) $ 2,486.4 At December 31, 2020 Fixed maturity securities U.S. Treasuries $ 74.3 $ 4.0 $ — $ 78.3 U.S. Agencies 2.8 0.3 — 3.1 States and municipalities 449.4 33.3 — 482.7 Corporate securities 963.5 83.2 (0.3) 1,046.4 Residential mortgage-backed securities 444.6 16.7 (0.3) 461.0 Commercial mortgage-backed securities 94.7 7.8 (0.1) 102.4 Asset-backed securities 42.0 0.9 (0.3) 42.6 Collateralized loan obligations 84.4 — (0.8) 83.6 Foreign government securities 8.0 0.2 — 8.2 Other securities 169.9 1.5 (0.5) 170.9 Total fixed maturity securities $ 2,333.6 $ 147.9 $ (2.3) $ 2,479.2 Short-term investments 26.5 0.1 — 26.6 Total AFS investments $ 2,360.1 $ 148.0 $ (2.3) $ 2,505.8 The cost and estimated fair value of the Company’s equity securities recorded at fair value at March 31, 2021 and December 31, 2020 were as follows: Cost Estimated Fair Value (in millions) At March 31, 2021 Equity securities at fair value Industrial and miscellaneous $ 109.0 $ 199.6 Other 15.8 30.1 Total equity securities at fair value $ 124.8 $ 229.7 At December 31, 2020 Equity securities at fair value Industrial and miscellaneous $ 94.1 $ 179.1 Other 18.3 29.4 Total equity securities at fair value $ 112.4 $ 208.5 The Company had Other invested assets totaling $42.4 million and $36.2 million at March 31, 2021 and December 31, 2020, respectively. These investments consisted of: (i) private equity limited partnerships that totaled $22.4 million and $16.2 million (initial cost of $22.3 million and $16.8 million) at March 31, 2021 and December 31, 2020, respectively, which are carried at NAV based on information provided by the general partner; and (ii) convertible preferred shares of real estate investment trusts that totaled $20.0 million at each of March 31, 2021 and December 31, 2020, which are carried at cost and approximate fair value. These investments are non-redeemable until conversion and are periodically evaluated by the Company for impairment based on the ultimate recovery of the investment. Changes in the value of these investments are recorded through net realized and unrealized gains and losses on the Company’s Consolidated Statements of Comprehensive Income. The amortized cost and estimated fair value of the Company’s fixed maturity securities at March 31, 2021, 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 $ 129.9 $ 131.7 Due after one year through five years 682.2 719.9 Due after five years through ten years 814.6 858.3 Due after ten years 108.2 110.6 Mortgage and asset-backed securities 650.5 664.9 Total $ 2,385.4 $ 2,485.4 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 March 31, 2021 and December 31, 2020. March 31, 2021 December 31, 2020 Estimated Fair Value Gross Number of Issues Estimated Fair Value Gross Number of Issues (dollars in millions) Less than 12 months: Fixed maturity securities States and municipalities $ 12.9 $ (0.2) 9 $ — $ — — Corporate securities 165.8 (3.8) 111 9.7 (0.3) 10 Residential mortgage-backed securities 144.6 (3.3) 34 47.4 (0.3) 13 Commercial mortgage-backed securities 5.0 (0.2) 5 5.5 (0.1) 6 Asset-backed securities 21.4 (0.5) 9 7.8 (0.3) 6 Collateralized loan obligations 18.4 (0.1) 6 74.6 (0.8) 18 Foreign government securities 12.3 (0.4) 2 — — — Other securities 37.9 (0.2) 125 60.4 (0.5) 146 Total fixed maturity securities 418.3 (8.7) 301 205.4 (2.3) 199 Total less than 12 months $ 418.3 $ (8.7) 301 $ 205.4 $ (2.3) 199 12 months or greater: Fixed maturity securities Collateralized loan obligations $ 38.6 $ (0.1) 7 $ — $ — — Other securities 7.9 (0.1) 31 — — — Total fixed maturity securities 46.5 (0.2) 38 — — — Total 12 months or greater $ 46.5 $ (0.2) 38 $ — $ — — As of March 31, 2021 and December 31, 2020, the Company had an allowance for current expected credit losses (CECL) on AFS debt securities of $0.2 million and $0.7 million, respectively (See Note 5). Those fixed maturity securities whose total fair value was less than amortized cost at March 31, 2021 and December 31, 2020, were those in which the Company had no intent, need or requirement to sell at an amount less than their amortized 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 or for changes in the expected credit loss allowance. Net realized gains and losses on investments and the change in unrealized gains and 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 Net Change in CECL Allowance Change in Net Unrealized Gains Changes in Fair Value Reflected in Earnings Changes in Fair Value Reflected in AOCI, before tax (in millions) Three Months Ended March 31, 2021 Fixed maturity securities $ 0.7 $ (0.4) $ 0.5 $ (45.6) $ 0.8 $ (45.6) Equity securities 0.9 (0.3) — 8.8 9.4 — Other invested assets — — — 0.7 0.7 — Short-term investments — — — (0.1) — (0.1) Total investments $ 1.6 $ (0.7) $ 0.5 $ (36.2) $ 10.9 $ (45.7) Three Months Ended March 31, 2020 Fixed maturity securities $ 4.1 $ (0.3) $ (10.7) $ (29.9) $ (6.9) $ (29.9) Equity securities 22.7 (7.3) — (69.2) (53.8) — Other invested assets — — — (0.4) (0.4) — Total investments $ 26.8 $ (7.6) $ (10.7) $ (99.5) $ (61.1) $ (29.9) Proceeds from the sales of fixed maturity securities were $74.0 million for the three months ended March 31, 2021, compared to $220.2 million for the three months ended March 31, 2020. Net investment income was as follows: Three Months Ended March 31, 2021 2020 (in millions) Fixed maturity securities $ 18.2 $ 19.3 Equity securities 0.9 1.3 Other invested assets 0.2 0.6 Short-term investments 0.2 0.1 Cash equivalents and restricted cash — 0.2 Gross investment income 19.5 21.5 Investment expenses (1.1) (1.6) Net investment income $ 18.4 $ 19.9 The Company is required by various state laws and regulations to support, through securities on deposit or otherwise, its outstanding loss reserves in 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 March 31, 2021 and December 31, 2020, securities having a fair value of $925.6 million and $768.7 million, respectively, were on deposit. Additionally, standby letters of credit from the FHLB were in place in lieu of $130.0 million and $275.0 million of securities on deposit as of March 31, 2021 and December 31, 2020, respectively (See Note 10).

Current Expected Credit Losses

Current Expected Credit Losses	3 Months Ended
	Mar. 31, 2021
Credit Loss [Abstract]
Credit Losses	Current Expected Credit Losses Premiums Receivable Premiums receivable balances are all due within one year or less. The Company currently determines the allowance for premiums receivable based on an internal aging schedule using collectability and historical payment patterns, as well as current and expected future market conditions to determine the appropriateness of the allowance. Historical payment patterns provide the basis for the estimation along with similar risk characteristics and the Company's business strategy, which have not changed significantly over time. However, current and future market conditions have deteriorated as compared with the economic conditions included in the historical information. Specifically, as a result of the COVID-19 pandemic, unemployment and the temporary and permanent closures of small businesses have increased as of March 31, 2021, and the Company expects this trend to continue until such time that businesses can operate at a more normalized rate. Based on our past experience with generally similar conditions, the Company will continually assess the historical payment patterns and aging schedule to reflect the differences in our current conditions and future forecasted changes. Changes in the allowance for credit losses are recorded through underwriting and general and administrative expenses. The table below shows the changes in the allowance for expected credit losses on premiums receivable. Three Months Ended March 31, 2021 2020 (in millions) Beginning balance of the allowance for expected credit losses on premiums receivable $ 10.8 $ 4.6 Current period provision for expected credit losses 3.3 4.1 Write-offs charged against the allowance (0.1) (4.8) Recoveries collected (1.8) — Ending balance of the allowance for expected credit losses on premiums receivable $ 12.2 $ 3.9 Reinsurance Recoverable In assessing an allowance for reinsurance assets, which includes reinsurance recoverables and contingent commission receivables, the Company considers historical information, financial strength of reinsurers, collateralization amounts and ratings to determine the appropriateness of the allowance. Historically, the Company has not experienced a credit loss from reinsurance transactions. In assessing future default, the Company evaluated the CECL allowance under the ratings-based method using the A.M. Best Average Cumulative Net Impairment Rates. Reinsurer ratings are also assessed through this process. Changes in the allowance for credit losses are recorded through underwriting and general and administrative expenses. The table below shows the changes in the allowance for expected credit losses on reinsurance recoverables. Three Months Ended March 31, 2021 2020 (in millions) Beginning balance of the allowance for expected credit losses on reinsurance recoverables $ 0.4 $ — Current period provision for expected credit losses — 0.4 Ending balance of the allowance for expected credit losses on reinsurance recoverables $ 0.4 $ 0.4 Investments The Company assesses all AFS debt securities in an unrealized loss position for expected credit losses. The Company first assesses whether it intends to sell, or it is more likely than not that it will be required to sell, the security before recovery of its amortized cost basis. If either of the criteria is met, the security's amortized cost basis is written down to its fair value. For AFS debt securities that do not meet either criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, management considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. Any impairment that has not been recorded through an allowance for credit losses is recognized in Accumulated other comprehensive income on the Company's Consolidated Balance Sheets. Changes in the allowance for credit losses are recorded through realized capital losses. As of March 31, 2021, the Company established an aggregate allowance for credit losses in the amount of $0.2 million. For the Company’s investments in fixed-income debt securities, the allowance for credit losses was determined by: (i) observing the credit characteristics of those debt securities that may have demonstrated a credit loss as of that date and by comparing the present value of cash flows expected to be collected to its amortized cost basis; and (ii) observing the credit characteristics of those debt securities that are expected to demonstrate a credit loss in the future by comparing the present value of cash flows expected to be collected to its amortized cost basis. The expected present value of cash flows are calculated using scenario based credit loss models derived from the discounted cash flows under the Comprehensive Capital Analysis Review (CCAR) framework, which is adopted by the Federal Reserve. As of March 31, 2021, the Company did not intend to sell any of its AFS debt securities in which its amortized cost exceeded its fair value. Accrued interest receivable on AFS debt securities totaled $17.2 million at March 31, 2021 and is excluded from the estimate of credit losses based on historically timely payments. The table below shows the changes in the allowance for expected credit losses on available-for-sale securities. Three Months Ended March 31, 2021 2020 (in millions) Beginning balance of the allowance for expected credit losses on AFS securities $ 0.7 $ — Current period provision for expected credit losses — 10.7 Reductions in allowance from disposals (0.2) — Recoveries of amounts previously written off (0.3) — Ending balance of the allowance for expected credit losses on AFS securities $ 0.2 $ 10.7

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	Property and Equipment Property and equipment consists of the following: As of March 31 As of December 31, 2021 2020 (in millions) Furniture and equipment $ 3.4 $ 3.4 Leasehold improvements 5.5 5.5 Computers and software 50.9 53.3 Automobiles 0.9 0.8 Property and equipment, gross 60.7 63.0 Accumulated depreciation (42.6) (43.9) Property and equipment, net $ 18.1 $ 19.1 Depreciation expenses related to property and equipment for the three months ended March 31, 2021 were $1.9 million, and $8.2 million for the year ended December 31, 2020. Internally developed software costs of $0.5 million were capitalized during the three months ended March 31, 2021, and $3.2 million in internally developed software costs were capitalized during the year ended December 31, 2020. Cloud Computing Arrangements The Company’s capitalized costs associated with cloud computing arrangements totaled $49.7 million and $50.2 million, which were comprised of service contract fees and implementation costs associated with hosting arrangements on the Company’s Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020, respectively. Total amortization for hosting arrangements was $3.1 million for the three months ended March 31, 2021, and $9.0 million for the year ended December 31, 2020. Leases The Company determines if an arrangement is a lease at the inception of the transaction. Operating leases for offices are presented as a right-of-use asset (ROU asset) and lease liability on the Company’s Consolidated Balance Sheets. Financing leases for automobiles are included in property and equipment and other liabilities on the Company’s Consolidated Balance Sheets. ROU assets represent the right to use an underlying asset for the lease term and the lease liability represents the obligation to make lease payments arising from the lease transaction. Operating lease ROU assets and liabilities are recognized at the commencement date based on the present value of the lease payments over the lease term. The Company uses collateralized incremental borrowing rates to determine the present value of lease payments. The ROU assets also include lease payments less any lease incentives within a lease agreement. The Company’s lease terms may include options to extend or terminate a lease. Lease expense for lease payments is recognized on a straight-line basis over the lease term. As of March 31, 2021, the Company’s operating leases have remaining terms of 1 year to 8 years, with options to extend up to 9 years with no termination provision. The Company’s finance leases have an option to terminate after 1 year. Components of lease expense were as follows: Three Months Ended March 31, 2021 2020 (in millions) Operating lease expense $ 1.1 $ 1.3 Finance lease expense — 0.1 Total lease expense $ 1.1 $ 1.4 As of March 31, 2021 , the weighted average remaining lease term for operating leases was 5.9 years and for finance leases was 3.6 years. The weighted average discount rate was 2.2% and 3.7% for operating and finance leases, respectively . Maturities of lease liabilities were as follows: As of March 31, 2021 Operating Leases Finance Leases (in millions) 2021 $ 3.1 $ 0.1 2022 3.2 0.1 2023 3.2 0.2 2024 3.2 0.1 2025 3.0 0.1 Thereafter 4.7 — Total lease payments 20.4 0.6 Less: imputed interest (1.3) — Total $ 19.1 $ 0.6 Supplemental balance sheet information related to leases was as follows: As of March 31, As of December 31, 2021 2020 (in millions) Operating leases: Operating lease right-of-use asset $ 16.4 $ 17.4 Operating lease liability 19.1 19.9 Finance leases: Property and equipment, gross 0.9 0.8 Accumulated depreciation (0.3) (0.4) Property and equipment, net 0.6 0.4 Other liabilities $ 0.6 $ 0.4 Supplemental cash flow information related to leases was as follows: Three Months Ended March 31, 2021 2020 (in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 1.1 $ 1.3 Financing cash flows used for finance leases — 0.1

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2021
Income Taxes [Abstract]
Income Taxes	Income TaxesThe Company’s effective tax rate was 16.3% for the three months ended March 31, 2021, compared to 23.0% for the corresponding period of 2020. The effective rates during each of the periods presented included income tax benefits associated with tax-advantaged investment income, LPT adjustments, and deferred gain amortization.

Liability for Unpaid Losses and

Liability for Unpaid Losses and Loss Adjustment Expenses	3 Months Ended
	Mar. 31, 2021
Liability for Unpaid Losses and Loss Adjustment Expenses [Abstract]
Liability for Unpaid Losses and Loss Adjustment Expenses	Liability for Unpaid Losses and Loss Adjustment Expenses The following table represents a reconciliation of changes in the liability for unpaid losses and LAE. Three Months Ended March 31, 2021 2020 (in millions) Unpaid losses and LAE at beginning of period $ 2,069.4 $ 2,192.8 Less reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 497.0 532.5 Net unpaid losses and LAE at beginning of period 1,572.4 1,660.3 Losses and LAE, net of reinsurance, incurred during the period related to: Current period 85.6 110.2 Prior periods (13.9) (3.5) Total net losses and LAE incurred during the period 71.7 106.7 Paid losses and LAE, net of reinsurance, related to: Current period 4.7 6.9 Prior periods 97.6 95.4 Total net paid losses and LAE during the period 102.3 102.3 Ending unpaid losses and LAE, net of reinsurance 1,541.8 1,664.7 Reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 492.3 527.0 Unpaid losses and LAE at end of period $ 2,034.1 $ 2,191.7 Total net losses and LAE included in the above table exclude amortization of the deferred reinsurance gain—LPT Agreement, which totaled $2.1 million and $2.4 million for the three months ended March 31, 2021 and 2020, respectively (See Note 9).

LPT Agreement

LPT Agreement	3 Months Ended
	Mar. 31, 2021
LPT Agreement [Abstract]
LPT Agreement	LPT AgreementThe Company is party to the LPT Agreement under which $1.5 billion in liabilities for losses and LAE related to claims incurred by the Fund prior to July 1, 1995 were reinsured for consideration of $775.0 million. The LPT Agreement provides coverage up to $2.0 billion. The Company records its estimate of contingent profit commission in the accompanying Consolidated Balance Sheets as Contingent commission receivable–LPT Agreement and a corresponding liability is recorded in the accompanying Consolidated Balance Sheets in Deferred reinsurance gain–LPT Agreement. The Deferred Gain is being amortized using the recovery method. Amortization is determined by the proportion of actual reinsurance recoveries to total estimated recoveries over the life of the LPT Agreement, except for the contingent profit commission, which is amortized through June 30, 2024, the date through which the Company is entitled to receive a contingent profit commission under the LPT Agreement. The amortization is recorded in losses and LAE incurred in the accompanying consolidated statements of comprehensive income. Any adjustments to the Deferred Gain are recorded in losses and LAE incurred in the accompanying consolidated statements of comprehensive income. The Company amortized $2.1 million and $2.4 million of the Deferred Gain for the three months ended March 31, 2021 and 2020, respectively. The remaining Deferred Gain was $123.3 million and $125.4 million as of March 31, 2021 and December 31, 2020, respectively. The estimated remaining liabilities subject to the LPT Agreement were $348.5 million and $353.5 million as of March 31, 2021 and December 31, 2020, respectively. Losses and LAE paid with respect to the LPT Agreement totaled $823.9 million and $818.9 million from inception through March 31, 2021 and December 31, 2020, respectively.

Notes Payable

Notes Payable	3 Months Ended
	Mar. 31, 2021
Notes Payable [Abstract]
Debt Disclosure [Text Block]	FHLB Advances, Notes Payable and Other Financing Arrangements On December 15, 2020, the Company entered into a Credit Agreement (the Credit Agreement) with a syndicate of financial institutions. The Credit Agreement provides for a $75.0 million three-year revolving credit facility and is guaranteed by certain of the Company’s wholly owned subsidiaries (Employers Group, Inc. and Cerity Group, Inc.). Borrowings under the Credit Agreement may be used for working capital and general corporate purposes of the Company and its subsidiaries. Pursuant to the Credit Agreement, the Company also has an option to request an increase of the credit available under the facility up to a maximum facility amount of $125.0 million, subject to the consent of lenders and the satisfaction of certain conditions. The interest rates applicable to loans under the Credit Agreement are generally based on a base rate plus a specified margin, ranging from 0.25% to 1.25%, or the Eurodollar rate (which will convert to an alternative reference rate once LIBOR is discontinued), plus a specified margin, ranging from 1.25% to 2.25%. In addition, the Company will pay a fee on each lender’s commitment, ranging from 0.20% to 0.50%, irrespective of usage. The applicable margin and the amount of such commitment fee vary based upon the financial strength rating of the Company’s insurance subsidiaries as most recently announced by A.M. Best or the Company’s debt to total capitalization ratio if such financial strength rating is not available. Interest paid during the three months ended March 31, 2021 totaled less than $0.1 million. The Credit Agreement contains covenants that require the Company and its consolidated subsidiaries to maintain: (i) a minimum consolidated net worth of no less than 70% of the Company’s stockholders’ equity as of September 30, 2020, plus 50% of the Company’s aggregate net income thereafter; and (ii) a debt to total capitalization ratio of no more than 35%, in each case as determined in accordance with the Credit Agreement. At March 31, 2021, the Company was in compliance with all debt covenants. The Company incurred $0.7 million in debt issuance costs, which are being amortized over the three-year life of the facility in Interest and Financing expenses. The annual commitment and administrative fee on the unused portion of the facility is 0.30%, for a maximum of $225,000, and an annual agency fee of $25,000. Advances can be repaid at any time without prepayment penalties or additional fees. The Company borrowed and subsequently repaid $12.0 million under the credit facility during the three months ended March 31, 2021. As of March 31, 2021, the Company had no outstanding borrowings on the credit facility. Other financing arrangements are comprised of the following: EICN, ECIC, EPIC, and EAC are members 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. During the second quarter of 2020, the FHLB announced its Zero Interest Recovery Advance program (the FHLB Advance Program). The FHLB Advance Program is a zero percent interest, six-month or one-year credit product that members can use to provide immediate relief to property owners, businesses, and other customers from the effects of the COVID-19 pandemic. Each member was allocated up to $10.0 million in advances under the FHLB Advance Program. On May 11, 2020, the Company's insurance subsidiaries received a total of $35.0 million of advances under the Advance Program. The advances were secured by collateral previously pledged to the FHLB by the Company’s insurance subsidiaries in support of their existing collateralized advance facility, which has been reduced by the amount of these outstanding advances. The Company repaid $15.0 million on November 4, 2020 and $5.0 million on March 31, 2021. The remaining advances of $15.0 million are required to be repaid to the FHLB by May 11, 2021. FHLB membership also allows the Company’s insurance subsidiaries access to standby letters of credit (Letter of Credit Agreements). On January 26, 2021, the Company chose to amend its existing Letter of Credit Agreements among the FHLB, ECIC and EAC to decrease their respective letter of credit amounts. The current Letter of Credit Agreements, as amended, are in the amounts of $50.0 million for EAC, $70.0 million for ECIC, and $10.0 million for EPIC. The amended Letter of Credit Agreements will expire on March 31, 2022, and 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 March 31, 2021 and December 31, 2020, letters of credit totaling $130.0 million and $275.0 million, respectively, were issued in lieu of securities on deposit with the State of California under these Letter of Credit Agreements. As of March 31, 2021 and December 31, 2020, investment securities having a fair value of $355.8 million and $385.6 million, respectively, were pledged to the FHLB by the Company’s insurance subsidiaries in support of the collateralized advance facility and the Letter of Credit Agreements.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2021
Accumulated Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income, Net	Accumulated Other Comprehensive Income Accumulated other comprehensive income is comprised of unrealized gains on investments classified as AFS, net of deferred tax expense. The following table summarizes the components of accumulated other comprehensive income: March 31, 2021 December 31, 2020 (in millions) Net unrealized gains on investments, before taxes $ 100.0 $ 145.7 Deferred tax expense on net unrealized gains (21.0) (30.6) Total accumulated other comprehensive income $ 79.0 $ 115.1

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2021
Stock-Based Compensation [Abstract]
Stock-Based compensation	Stock-Based Compensation The Company awarded restricted stock units (RSUs) and performance share units (PSUs) to certain employees and non-employee Directors of the Company as follows: Number Awarded Weighted Average Fair Value on Date of Grant Aggregate Fair Value on Date of Grant (in millions) March 2021 RSUs (1) 66,560 $ 37.54 $ 2.5 PSUs (2) 77,320 37.54 2.9 (1) The RSUs awarded in March 2021 were awarded to certain employees of the Company and vest 25% on March 15, 2022, and each of the subsequent three anniversaries of that date. The RSUs are subject to accelerated vesting in certain circumstances, including but not limited to: death, disability, retirement, or in connection with a change of control of the Company. (2) The PSUs awarded in March 2021 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 value shown in the table represents the aggregate number of PSUs awarded at the target level. 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. Stock options exercised totaled 41,851 for the three months ended March 31, 2021, 36,500 for the three months ended March 31, 2020, and 40,800 for the year ended December 31, 2020. As of March 31, 2021, the Company had 71,365 options, 230,267 RSUs, and 244,951 PSUs (based on target number awarded) outstanding.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Common Share Basic earnings per share is computed by dividing net income by the weighted average number of common shares outstanding for the period. Diluted earnings per share reflects the potential dilutive impact of all common stock equivalents 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. RSUs and PSUs are entitled to receive dividend equivalents on awards that fully vest or become payable. The dividend equivalents are reflected in the Company’s net income; therefore, 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 number of shares outstanding used in the earnings per common share calculations. Three Months Ended March 31, 2021 2020 (in millions, except share data) Net income (loss) $ 23.1 $ (34.9) Weighted average number of shares outstanding—basic 28,516,731 30,697,496 Effect of dilutive securities: PSUs 344,615 331,806 Stock options 34,530 64,539 RSUs 72,463 62,308 Dilutive potential shares 451,608 458,653 Weighted average number of shares outstanding—diluted 28,968,339 31,156,149

Segment Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2021
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	Segment Reporting In 2019, the Company made changes to its corporate structure, mainly involving the launch and further development of a new digital insurance platform offered under the Cerity brand name (Cerity). The Company has determined that it has two reportable segments: Employers and Cerity. Each of these segments represents a separate and distinct underwriting platform through which the Company conducts insurance business. The nature and composition of each reportable segment and its Corporate and Other activities are as follows: The Employers segment represents the traditional business offered through the EMPLOYERS brand name (Employers) through its agents, including business originated from the Company's strategic partnerships and alliances. The Cerity segment represents the business offered under the Cerity brand name, which includes the Company's direct-to-customer business. Corporate and Other activities consist of those holding company expenses that are not considered to be underwriting in nature, the financial impact of the LPT agreement, and legacy business assumed and ceded by CIC. These expenses are not considered to be part of a reportable segment and are not otherwise allocated to a reportable segment. The Company has determined that it is not practicable to report identifiable assets by segment since certain assets are used interchangeably among the segments. The following table summarizes the Company's written premium and components of net income before income taxes by reportable segment. Employers Cerity Corporate and Other Total (in millions) Three Months Ended March 31, 2021 Gross premiums written $ 148.0 $ 0.3 $ — $ 148.3 Net premiums written 146.6 0.3 — 146.9 Net premiums earned 133.9 — — 133.9 Net investment income 17.6 0.7 0.1 18.4 Net realized and unrealized gains on investments 10.8 0.1 — 10.9 Other income 0.4 — — 0.4 Total revenues 162.7 0.8 0.1 163.6 Losses and loss adjustment expenses 71.7 — (2.1) 69.6 Commission expense 16.8 — — 16.8 Underwriting and general and administrative expenses 37.3 3.7 5.6 46.6 Interest and financing expenses — — 0.1 0.1 Other expenses 2.9 — — 2.9 Total expenses 128.7 3.7 3.6 136.0 Net income (loss) before income taxes $ 34.0 $ (2.9) $ (3.5) $ 27.6 Three Months Ended March 31, 2020 Gross premiums written $ 184.7 $ — $ — $ 184.7 Net premiums written 183.4 — — 183.4 Net premiums earned 167.9 — — 167.9 Net investment income 18.6 0.8 0.5 19.9 Net realized and unrealized losses on investments (57.3) (1.7) (2.1) (61.1) Other income 0.3 — — 0.3 Total revenues 129.5 (0.9) (1.6) 127.0 Losses and loss adjustment expenses 106.7 — (2.4) 104.3 Commission expense 21.3 — — 21.3 Underwriting and general and administrative expenses 39.2 3.8 3.7 46.7 Total expenses 167.2 3.8 1.3 172.3 Net loss before income taxes $ (37.7) $ (4.7) $ (2.9) $ (45.3) Entity-Wide Disclosures The Company operates solely within the U.S. and does not have revenue from transactions with a single policyholder accounting for 10% or more of its revenues. The following table shows the Company's in-force premiums and number of policies in-force for each state with approximately five percent or more of our in-force premiums and all other states combined for the periods presented: March 31, 2021 December 31, 2020 March 31, 2020 December 31, 2019 State In-force Premiums Policies In-force Premiums Policies In-force Policies In-force Policies (dollars in millions) California $ 251.4 39,264 $ 262.0 39,610 $ 309.5 42,794 $ 329.8 43,079 Florida 38.6 7,303 37.9 6,898 37.3 6,110 36.3 5,822 New York 25.6 6,724 26.7 6,657 31.3 6,302 31.7 5,679 Other (43 states and D.C.) 237.7 51,481 251.3 50,341 264.5 46,223 266.8 44,104 Total $ 553.3 104,772 $ 577.9 103,506 $ 642.6 101,429 $ 664.6 98,684

Valuation of Financial Instru_2

Valuation of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2021
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: March 31, 2021 December 31, 2020 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) Financial assets Total investments at fair value $ 2,716.1 $ 2,716.1 $ 2,714.3 $ 2,714.3 Cash and cash equivalents 85.4 85.4 160.4 160.4 Restricted cash and cash equivalents 0.2 0.2 0.2 0.2
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. March 31, 2021 December 31, 2020 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities: U.S. Treasuries $ — $ 78.3 $ — $ — $ 78.3 $ — U.S. Agencies — 3.0 — — 3.1 — States and municipalities — 442.3 — — 482.7 — Corporate securities — 1,107.3 — — 1,046.4 — Residential mortgage-backed securities — 431.9 — — 461.0 — Commercial mortgage-backed securities — 98.0 — — 102.4 — Asset-backed securities — 50.7 — — 42.6 — Collateralized loan obligations — 84.3 — — 83.6 — Foreign government securities — 12.3 — — 8.2 — Other securities — 177.3 — — 170.9 — Total fixed maturity securities $ — $ 2,485.4 $ — $ — $ 2,479.2 $ — Equity securities at fair value: Industrial and miscellaneous $ 199.6 $ — $ — $ 179.1 $ — $ — Other 30.1 — — 29.4 — — Total equity securities at fair value $ 229.7 $ — $ — $ 208.5 $ — $ — Short-term investments $ — $ 1.0 $ — $ 4.0 $ 22.6 $ — Total investments at fair value $ 229.7 $ 2,486.4 $ — $ 212.5 $ 2,501.8 $ —
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Table Text Block]	Financial Instruments Carried at Net Asset Value (NAV) The Company has investments in private equity limited partnership interests that are included in Other invested assets on the Company’s Consolidated Balance Sheets. These investments do not have readily determinable fair values and are carried at NAV and therefore are excluded from the fair value hierarchy. The Company initially estimates the value of these investments using the transaction price. In subsequent periods, the Company measures these investments using NAV per share provided quarterly by the general partner, based on financial statements that are audited annually. These investments are generally not redeemable by the investees and cannot be sold without approval of the general partner. These investments have a fund term of 10 to 12 years, subject to two or three one year extensions at the general partner’s discretion. The Company will receive distributions of proceeds from dividends and interest from fund investments, as well as from the disposition of a fund investment, or portion thereof. The Company expects these distributions from time-to-time during the full course of the fund term. As of March 31, 2021, the Company had unfunded commitments to these private equity limited partnerships totaling $57.9 million. Additionally, certain cash equivalents, principally money market securities, are measured using NAV, which approximates fair value. The following table presents cash and investments carried at NAV on the Company’s Consolidated Balance Sheets. March 31, 2021 December 31, 2020 (in millions) Cash equivalents carried at NAV $ 45.7 $ 58.7 Other invested assets carried at NAV 22.4 16.2

Investments (Tables)

Investments (Tables)	3 Months Ended
	Mar. 31, 2021
Investments [Abstract]
Available-for-sale securities table	The amortized cost, gross unrealized gains, gross unrealized losses, and estimated fair value of the Company’s available-for-sale (AFS) investments were as follows: Amortized Gross Gross Estimated (in millions) At March 31, 2021 Fixed maturity securities U.S. Treasuries $ 75.7 $ 2.6 $ — $ 78.3 U.S. Agencies 2.8 0.2 — 3.0 States and municipalities 415.3 27.2 (0.2) 442.3 Corporate securities 1,052.7 58.4 (3.8) 1,107.3 Residential mortgage-backed securities 422.6 12.6 (3.3) 431.9 Commercial mortgage-backed securities 93.1 5.1 (0.2) 98.0 Asset-backed securities 50.3 0.9 (0.5) 50.7 Collateralized loan obligations 84.5 — (0.2) 84.3 Foreign government securities 12.7 — (0.4) 12.3 Other securities 175.7 1.9 (0.3) 177.3 Total fixed maturity securities $ 2,385.4 $ 108.9 $ (8.9) $ 2,485.4 Short-term investments 1.0 — — 1.0 Total AFS investments $ 2,386.4 $ 108.9 $ (8.9) $ 2,486.4 At December 31, 2020 Fixed maturity securities U.S. Treasuries $ 74.3 $ 4.0 $ — $ 78.3 U.S. Agencies 2.8 0.3 — 3.1 States and municipalities 449.4 33.3 — 482.7 Corporate securities 963.5 83.2 (0.3) 1,046.4 Residential mortgage-backed securities 444.6 16.7 (0.3) 461.0 Commercial mortgage-backed securities 94.7 7.8 (0.1) 102.4 Asset-backed securities 42.0 0.9 (0.3) 42.6 Collateralized loan obligations 84.4 — (0.8) 83.6 Foreign government securities 8.0 0.2 — 8.2 Other securities 169.9 1.5 (0.5) 170.9 Total fixed maturity securities $ 2,333.6 $ 147.9 $ (2.3) $ 2,479.2 Short-term investments 26.5 0.1 — 26.6 Total AFS investments $ 2,360.1 $ 148.0 $ (2.3) $ 2,505.8
Equity securities table	The cost and estimated fair value of the Company’s equity securities recorded at fair value at March 31, 2021 and December 31, 2020 were as follows: Cost Estimated Fair Value (in millions) At March 31, 2021 Equity securities at fair value Industrial and miscellaneous $ 109.0 $ 199.6 Other 15.8 30.1 Total equity securities at fair value $ 124.8 $ 229.7 At December 31, 2020 Equity securities at fair value Industrial and miscellaneous $ 94.1 $ 179.1 Other 18.3 29.4 Total equity securities at fair value $ 112.4 $ 208.5
Other invested assets	The Company had Other invested assets totaling $42.4 million and $36.2 million at March 31, 2021 and December 31, 2020, respectively. These investments consisted of: (i) private equity limited partnerships that totaled $22.4 million and $16.2 million (initial cost of $22.3 million and $16.8 million) at March 31, 2021 and December 31, 2020, respectively, which are carried at NAV based on information provided by the general partner; and (ii) convertible preferred shares of real estate investment trusts that totaled $20.0 million at each of March 31, 2021 and December 31, 2020, which are carried at cost and approximate fair value. These investments are non-redeemable until conversion and are periodically evaluated by the Company for impairment based on the ultimate recovery of the investment. Changes in the value of these investments are recorded through net realized and unrealized gains and losses on the Company’s Consolidated Statements of Comprehensive Income.
Investments classified by contractual maturity date table	The amortized cost and estimated fair value of the Company’s fixed maturity securities at March 31, 2021, 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 $ 129.9 $ 131.7 Due after one year through five years 682.2 719.9 Due after five years through ten years 814.6 858.3 Due after ten years 108.2 110.6 Mortgage and asset-backed securities 650.5 664.9 Total $ 2,385.4 $ 2,485.4
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 March 31, 2021 and December 31, 2020. March 31, 2021 December 31, 2020 Estimated Fair Value Gross Number of Issues Estimated Fair Value Gross Number of Issues (dollars in millions) Less than 12 months: Fixed maturity securities States and municipalities $ 12.9 $ (0.2) 9 $ — $ — — Corporate securities 165.8 (3.8) 111 9.7 (0.3) 10 Residential mortgage-backed securities 144.6 (3.3) 34 47.4 (0.3) 13 Commercial mortgage-backed securities 5.0 (0.2) 5 5.5 (0.1) 6 Asset-backed securities 21.4 (0.5) 9 7.8 (0.3) 6 Collateralized loan obligations 18.4 (0.1) 6 74.6 (0.8) 18 Foreign government securities 12.3 (0.4) 2 — — — Other securities 37.9 (0.2) 125 60.4 (0.5) 146 Total fixed maturity securities 418.3 (8.7) 301 205.4 (2.3) 199 Total less than 12 months $ 418.3 $ (8.7) 301 $ 205.4 $ (2.3) 199 12 months or greater: Fixed maturity securities Collateralized loan obligations $ 38.6 $ (0.1) 7 $ — $ — — Other securities 7.9 (0.1) 31 — — — Total fixed maturity securities 46.5 (0.2) 38 — — — Total 12 months or greater $ 46.5 $ (0.2) 38 $ — $ — —
Unrealized gain (loss) on investments	Net realized gains and losses on investments and the change in unrealized gains and 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 Net Change in CECL Allowance Change in Net Unrealized Gains Changes in Fair Value Reflected in Earnings Changes in Fair Value Reflected in AOCI, before tax (in millions) Three Months Ended March 31, 2021 Fixed maturity securities $ 0.7 $ (0.4) $ 0.5 $ (45.6) $ 0.8 $ (45.6) Equity securities 0.9 (0.3) — 8.8 9.4 — Other invested assets — — — 0.7 0.7 — Short-term investments — — — (0.1) — (0.1) Total investments $ 1.6 $ (0.7) $ 0.5 $ (36.2) $ 10.9 $ (45.7) Three Months Ended March 31, 2020 Fixed maturity securities $ 4.1 $ (0.3) $ (10.7) $ (29.9) $ (6.9) $ (29.9) Equity securities 22.7 (7.3) — (69.2) (53.8) — Other invested assets — — — (0.4) (0.4) — Total investments $ 26.8 $ (7.6) $ (10.7) $ (99.5) $ (61.1) $ (29.9)
Investment income table	Net investment income was as follows: Three Months Ended March 31, 2021 2020 (in millions) Fixed maturity securities $ 18.2 $ 19.3 Equity securities 0.9 1.3 Other invested assets 0.2 0.6 Short-term investments 0.2 0.1 Cash equivalents and restricted cash — 0.2 Gross investment income 19.5 21.5 Investment expenses (1.1) (1.6) Net investment income $ 18.4 $ 19.9

Current Expected Credit Losses

Current Expected Credit Losses (Tables)	3 Months Ended
	Mar. 31, 2021
Credit Loss [Abstract]
Premium Receivable, Allowance for Credit Loss [Table Text Block]	The table below shows the changes in the allowance for expected credit losses on premiums receivable. Three Months Ended March 31, 2021 2020 (in millions) Beginning balance of the allowance for expected credit losses on premiums receivable $ 10.8 $ 4.6 Current period provision for expected credit losses 3.3 4.1 Write-offs charged against the allowance (0.1) (4.8) Recoveries collected (1.8) — Ending balance of the allowance for expected credit losses on premiums receivable $ 12.2 $ 3.9
Reinsurance Recoverable, Allowance for Credit Loss [Table Text Block]	The table below shows the changes in the allowance for expected credit losses on reinsurance recoverables. Three Months Ended March 31, 2021 2020 (in millions) Beginning balance of the allowance for expected credit losses on reinsurance recoverables $ 0.4 $ — Current period provision for expected credit losses — 0.4 Ending balance of the allowance for expected credit losses on reinsurance recoverables $ 0.4 $ 0.4
Debt Securities, Available-for-sale, Allowance for Credit Loss [Table Text Block]	The table below shows the changes in the allowance for expected credit losses on available-for-sale securities. Three Months Ended March 31, 2021 2020 (in millions) Beginning balance of the allowance for expected credit losses on AFS securities $ 0.7 $ — Current period provision for expected credit losses — 10.7 Reductions in allowance from disposals (0.2) — Recoveries of amounts previously written off (0.3) — Ending balance of the allowance for expected credit losses on AFS securities $ 0.2 $ 10.7

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2021
Property, Plant and Equipment [Abstract]
Property and Equipment [Table Text Block]	Property and equipment consists of the following: As of March 31 As of December 31, 2021 2020 (in millions) Furniture and equipment $ 3.4 $ 3.4 Leasehold improvements 5.5 5.5 Computers and software 50.9 53.3 Automobiles 0.9 0.8 Property and equipment, gross 60.7 63.0 Accumulated depreciation (42.6) (43.9) Property and equipment, net $ 18.1 $ 19.1
Lease, Cost [Table Text Block]	Components of lease expense were as follows: Three Months Ended March 31, 2021 2020 (in millions) Operating lease expense $ 1.1 $ 1.3 Finance lease expense — 0.1 Total lease expense $ 1.1 $ 1.4
Lessee, Operating and Finance Lease Liability Maturity [Table Text Block]	Maturities of lease liabilities were as follows: As of March 31, 2021 Operating Leases Finance Leases (in millions) 2021 $ 3.1 $ 0.1 2022 3.2 0.1 2023 3.2 0.2 2024 3.2 0.1 2025 3.0 0.1 Thereafter 4.7 — Total lease payments 20.4 0.6 Less: imputed interest (1.3) — Total $ 19.1 $ 0.6
Supplemental Balance Sheet Information related to Leases [Table Text Block]	Supplemental balance sheet information related to leases was as follows: As of March 31, As of December 31, 2021 2020 (in millions) Operating leases: Operating lease right-of-use asset $ 16.4 $ 17.4 Operating lease liability 19.1 19.9 Finance leases: Property and equipment, gross 0.9 0.8 Accumulated depreciation (0.3) (0.4) Property and equipment, net 0.6 0.4 Other liabilities $ 0.6 $ 0.4
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Supplemental cash flow information related to leases was as follows: Three Months Ended March 31, 2021 2020 (in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 1.1 $ 1.3 Financing cash flows used for finance leases — 0.1

Liability for Unpaid Losses a_2

Liability for Unpaid Losses and Loss Adjustment Expenses (Tables)	3 Months Ended
	Mar. 31, 2021
Liability for Unpaid Losses and Loss Adjustment Expenses [Abstract]
Changes in the liability for unpaid losses and LAE table	The following table represents a reconciliation of changes in the liability for unpaid losses and LAE. Three Months Ended March 31, 2021 2020 (in millions) Unpaid losses and LAE at beginning of period $ 2,069.4 $ 2,192.8 Less reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 497.0 532.5 Net unpaid losses and LAE at beginning of period 1,572.4 1,660.3 Losses and LAE, net of reinsurance, incurred during the period related to: Current period 85.6 110.2 Prior periods (13.9) (3.5) Total net losses and LAE incurred during the period 71.7 106.7 Paid losses and LAE, net of reinsurance, related to: Current period 4.7 6.9 Prior periods 97.6 95.4 Total net paid losses and LAE during the period 102.3 102.3 Ending unpaid losses and LAE, net of reinsurance 1,541.8 1,664.7 Reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 492.3 527.0 Unpaid losses and LAE at end of period $ 2,034.1 $ 2,191.7

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2021
Accumulated Other Comprehensive Income [Abstract]
Schedule of accumulated other comprehensive income (loss) table	The following table summarizes the components of accumulated other comprehensive income: March 31, 2021 December 31, 2020 (in millions) Net unrealized gains on investments, before taxes $ 100.0 $ 145.7 Deferred tax expense on net unrealized gains (21.0) (30.6) Total accumulated other comprehensive income $ 79.0 $ 115.1

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Stock-Based Compensation [Abstract]
Share-based compensation arrangements by share-based payment award table	The Company awarded restricted stock units (RSUs) and performance share units (PSUs) to certain employees and non-employee Directors of the Company as follows: Number Awarded Weighted Average Fair Value on Date of Grant Aggregate Fair Value on Date of Grant (in millions) March 2021 RSUs (1) 66,560 $ 37.54 $ 2.5 PSUs (2) 77,320 37.54 2.9 (1) The RSUs awarded in March 2021 were awarded to certain employees of the Company and vest 25% on March 15, 2022, and each of the subsequent three anniversaries of that date. The RSUs are subject to accelerated vesting in certain circumstances, including but not limited to: death, disability, retirement, or in connection with a change of control of the Company. (2) The PSUs awarded in March 2021 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 value shown in the table represents the aggregate number of PSUs awarded at the target level.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2021
Earnings Per Share [Abstract]
Net income and weighted average common shares outstanding used in earnings per share calculations table	The following table presents the net income and the weighted average number of shares outstanding used in the earnings per common share calculations. Three Months Ended March 31, 2021 2020 (in millions, except share data) Net income (loss) $ 23.1 $ (34.9) Weighted average number of shares outstanding—basic 28,516,731 30,697,496 Effect of dilutive securities: PSUs 344,615 331,806 Stock options 34,530 64,539 RSUs 72,463 62,308 Dilutive potential shares 451,608 458,653 Weighted average number of shares outstanding—diluted 28,968,339 31,156,149

Segment Reporting (Tables)

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2021
Net Income before income taxes by segment [Abstract]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Employers Cerity Corporate and Other Total (in millions) Three Months Ended March 31, 2021 Gross premiums written $ 148.0 $ 0.3 $ — $ 148.3 Net premiums written 146.6 0.3 — 146.9 Net premiums earned 133.9 — — 133.9 Net investment income 17.6 0.7 0.1 18.4 Net realized and unrealized gains on investments 10.8 0.1 — 10.9 Other income 0.4 — — 0.4 Total revenues 162.7 0.8 0.1 163.6 Losses and loss adjustment expenses 71.7 — (2.1) 69.6 Commission expense 16.8 — — 16.8 Underwriting and general and administrative expenses 37.3 3.7 5.6 46.6 Interest and financing expenses — — 0.1 0.1 Other expenses 2.9 — — 2.9 Total expenses 128.7 3.7 3.6 136.0 Net income (loss) before income taxes $ 34.0 $ (2.9) $ (3.5) $ 27.6 Three Months Ended March 31, 2020 Gross premiums written $ 184.7 $ — $ — $ 184.7 Net premiums written 183.4 — — 183.4 Net premiums earned 167.9 — — 167.9 Net investment income 18.6 0.8 0.5 19.9 Net realized and unrealized losses on investments (57.3) (1.7) (2.1) (61.1) Other income 0.3 — — 0.3 Total revenues 129.5 (0.9) (1.6) 127.0 Losses and loss adjustment expenses 106.7 — (2.4) 104.3 Commission expense 21.3 — — 21.3 Underwriting and general and administrative expenses 39.2 3.8 3.7 46.7 Total expenses 167.2 3.8 1.3 172.3 Net loss before income taxes $ (37.7) $ (4.7) $ (2.9) $ (45.3)
Revenue from External Customers by Geographic Areas [Table Text Block]	March 31, 2021 December 31, 2020 March 31, 2020 December 31, 2019 State In-force Premiums Policies In-force Premiums Policies In-force Policies In-force Policies (dollars in millions) California $ 251.4 39,264 $ 262.0 39,610 $ 309.5 42,794 $ 329.8 43,079 Florida 38.6 7,303 37.9 6,898 37.3 6,110 36.3 5,822 New York 25.6 6,724 26.7 6,657 31.3 6,302 31.7 5,679 Other (43 states and D.C.) 237.7 51,481 251.3 50,341 264.5 46,223 266.8 44,104 Total $ 553.3 104,772 $ 577.9 103,506 $ 642.6 101,429 $ 664.6 98,684

Basis of Presentation (Details)

Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Reportable Segments	2

Fair Value of Financial Instrum

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	$ 2,716.1	$ 2,714.3
Total Investments at fair value, estimated fair value	2,716.1	2,714.3
Cash and cash equivalents	85.4	160.4
Cash and cash equivalents, estimated fair value	85.4	160.4
Restricted cash and cash equivalents	0.2	0.2
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash and cash equivalents	$ 0.2	$ 0.2

Fair Value of Financial Instr_2

Fair Value of Financial Instruments, Fair Value Inputs (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	$ 2,485.4	$ 2,479.2
Equity Securities, FV-NI	229.7	208.5
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)	1	26.6
Investments	2,765.2	2,757.2
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	229.7	208.5
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)	0	4
Investments	229.7	212.5
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	0	0
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)	1	22.6
Investments	2,486.4	2,501.8
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	0	0
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)	0	0
Investments	0	0
Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	2,485.4	2,479.2
Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	78.3	78.3
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	78.3	78.3
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
US Government Agencies Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	3	3.1
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	3	3.1
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	442.3	482.7
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	442.3	482.7
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	1,107.3	1,046.4
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	1,107.3	1,046.4
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	431.9	461
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	431.9	461
Residential Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	98	102.4
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	98	102.4
Commercial Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	50.7	42.6
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	50.7	42.6
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Foreign Government Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	12.3	8.2
Foreign Government Debt | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Foreign Government Debt | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	12.3	8.2
Foreign Government Debt | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	84.3	83.6
Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	84.3	83.6
Collateralized Loan Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Other Debt Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	177.3	170.9
Other Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Other Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	177.3	170.9
Other Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	0	0
Industrial and Miscellaneous [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	199.6	179.1
Industrial and Miscellaneous [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	199.6	179.1
Industrial and Miscellaneous [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	0	0
Industrial and Miscellaneous [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	0	0
Other [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	30.1	29.4
Other [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	30.1	29.4
Other [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	0	0
Other [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI	$ 0	$ 0

Valuation of Financial Instru_3

Valuation of Financial Instruments Investments at NAV (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Investments at NAV [Abstract]
Fair value investments entities that calculate net asset value per share liquidating investment original expected lives increments	1 year
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 57.9
Cash Equivalents Measured at Net Asset Value	45.7	$ 58.7
Other invested assets at NAV	$ 22.4	$ 16.2
Maximum [Member]
Investments at NAV [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	12 years
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	12 years
Minimum [Member]
Investments at NAV [Abstract]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	10 years
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Liquidating Investment, Remaining Period	10 years

Investments Available for Sale

Investments Available for Sale Securities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	$ 2,385.4	$ 2,333.6
Debt securities, available-for-sale, gross unrealized gain	108.9	147.9
Debt securities, available-for-sale, gross unrealized loss	(8.9)	(2.3)
Fixed maturity securities, fair value	2,485.4	2,479.2
Total AFS, amortized cost	2,386.4	2,360.1
Total AFS, gross unrealized gain	108.9	148
Total AFS, gross unrealized loss	8.9	2.3
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)	1	26.6
Total AFS investments	2,486.4	2,505.8
Other invested assets (cost $42.3 at March 31, 2021 and $36.8 at December 31, 2020)	42.4	36.2
Other invested assets at NAV	22.4	16.2
Investment Owned, at Cost	22.3	16.8
Real Estate Investments, Unconsolidated Real Estate and Other Joint Ventures	20	20
Debt Securities, Available-for-sale, Allowance for Credit Loss	0.2	0.7	$ 10.7	$ 0
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	75.7	74.3
Debt securities, available-for-sale, gross unrealized gain	2.6	4
Debt securities, available-for-sale, gross unrealized loss	0	0
Fixed maturity securities, fair value	78.3	78.3
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	2.8	2.8
Debt securities, available-for-sale, gross unrealized gain	0.2	0.3
Debt securities, available-for-sale, gross unrealized loss	0	0
Fixed maturity securities, fair value	3	3.1
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	415.3	449.4
Debt securities, available-for-sale, gross unrealized gain	27.2	33.3
Debt securities, available-for-sale, gross unrealized loss	(0.2)	0
Fixed maturity securities, fair value	442.3	482.7
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	1,052.7	963.5
Debt securities, available-for-sale, gross unrealized gain	58.4	83.2
Debt securities, available-for-sale, gross unrealized loss	(3.8)	(0.3)
Fixed maturity securities, fair value	1,107.3	1,046.4
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	422.6	444.6
Debt securities, available-for-sale, gross unrealized gain	12.6	16.7
Debt securities, available-for-sale, gross unrealized loss	(3.3)	(0.3)
Fixed maturity securities, fair value	431.9	461
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	93.1	94.7
Debt securities, available-for-sale, gross unrealized gain	5.1	7.8
Debt securities, available-for-sale, gross unrealized loss	(0.2)	(0.1)
Fixed maturity securities, fair value	98	102.4
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	50.3	42
Debt securities, available-for-sale, gross unrealized gain	0.9	0.9
Debt securities, available-for-sale, gross unrealized loss	(0.5)	(0.3)
Fixed maturity securities, fair value	50.7	42.6
Foreign Government Debt
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	12.7	8
Debt securities, available-for-sale, gross unrealized gain	0	0.2
Debt securities, available-for-sale, gross unrealized loss	(0.4)	0
Fixed maturity securities, fair value	12.3	8.2
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	84.5	84.4
Debt securities, available-for-sale, gross unrealized gain	0	0
Debt securities, available-for-sale, gross unrealized loss	(0.2)	(0.8)
Fixed maturity securities, fair value	84.3	83.6
Other Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	175.7	169.9
Debt securities, available-for-sale, gross unrealized gain	1.9	1.5
Debt securities, available-for-sale, gross unrealized loss	(0.3)	(0.5)
Fixed maturity securities, fair value	177.3	170.9
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Total AFS, amortized cost	1	26.5
Total AFS, gross unrealized gain	0	0.1
Total AFS, gross unrealized loss	$ 0	$ 0

Investments Equity Securities (

Investments Equity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Schedule of Equity Securities and Other [Line Items]
Equity Securities, FV-NI, Cost	$ 124.8	$ 112.4
Equity Securities, FV-NI	229.7	208.5
Industrial and Miscellaneous [Member]
Schedule of Equity Securities and Other [Line Items]
Equity Securities, FV-NI, Cost	109	94.1
Equity Securities, FV-NI	199.6	179.1
Other [Member]
Schedule of Equity Securities and Other [Line Items]
Equity Securities, FV-NI, Cost	15.8	18.3
Equity Securities, FV-NI	$ 30.1	$ 29.4

Investments Other Invested Asse

Investments Other Invested Assets (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Other Invest Assets [Abstract]
Other invested assets at NAV	$ 22.4	$ 16.2
Investment Owned, at Cost	22.3	16.8
Total other invested assets	42.4	36.2
Real Estate Investments, Unconsolidated Real Estate and Other Joint Ventures	$ 20	$ 20

Investments, Amortized Cost and

Investments, Amortized Cost and Estimated Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less, amortized cost	$ 129.9
Due after one year through five years, amortized cost	682.2
Due after five years through ten years, amortized cost	814.6
Due after ten years, amortized cost	108.2
Mortgage and asset-backed securities, amortized cost	650.5
Total, amortized cost	2,385.4	$ 2,333.6
Estimated Fair Value
Due in one year or less, fair value	131.7
Due after one year through five years, fair value	719.9
Due after five years through ten years, fair value	858.3
Due after ten years, fair value	110.6
Mortgage and asset-backed securities, fair value	664.9
Total, fair value	$ 2,485.4	$ 2,479.2

Investments, Continuous Loss Po

Investments, Continuous Loss Position (Details) $ in Millions	Mar. 31, 2021USD ($)sharesshares	Dec. 31, 2020USD ($)shares
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 418.3	$ 205.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	46.5	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8.7)	(2.3)
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	301	199
Debt Securities, number of issues in loss position, 12 months or greater	38	0
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 418.3	$ 205.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	46.5	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(8.7)	(2.3)
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	301	199
Debt Securities, number of issues in loss position, 12 months or greater | shares	38	0
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 12.9	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, 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	9	0
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 165.8	$ 9.7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (3.8)	$ (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	111	10
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 144.6	$ 47.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (3.3)	$ (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	34	13
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 5	$ 5.5
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (0.2)	$ (0.1)
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	5	6
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 21.4	$ 7.8
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (0.5)	$ (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	9	6
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 18.4	$ 74.6
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	38.6	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.1)	(0.8)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (0.1)	$ 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	6	18
Debt Securities, number of issues in loss position, 12 months or greater | shares	7	0
Other Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 37.9	$ 60.4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7.9	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.2)	(0.5)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ (0.1)	$ 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	125	146
Debt Securities, number of issues in loss position, 12 months or greater | shares	31	0
Foreign Government Debt
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 12.3	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (0.4)	$ 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	2	0

Investments Investments, Net Re

Investments Investments, Net Realized Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Equity securities:
Equity Securities, FV-NI, Realized Gain	$ 0.9	$ 22.7
Equity Securities, FV-NI, Realized Loss	0.3	7.3
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	(45.7)	(29.9)
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	10.9	(61.1)
Total gross realized gains	1.6	26.8
Investments, Gross Realized Losses	(0.7)	(7.6)
Total change in net unrealized gains (losses)	(36.2)	(99.5)
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Unrealized Gain (Loss)	8.8	(69.2)
Proceeds from sale of fixed maturity securities	74	220.2
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0.5	(10.7)
Debt Securities [Member]
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	(45.6)	(29.9)
AFS, net realized gains (losses)
AFS, Gross gains from sales	0.7	4.1
AFS, Gross losses from sales	(0.4)	(0.3)
Net realized and unrealized (losses) gains on investments	0.8	(6.9)
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0.5	(10.7)
Equity Securities [Member]
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	0	0
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	9.4	(53.8)
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0	0
Other Investments [Member]
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	0	0
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	0.7	(0.4)
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Trading Securities, Realized Gain	0	0
Trading Securities, Realized Loss	0	0
Trading Securities, Change in Unrealized Holding Gain (Loss)	0.7	(0.4)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0	$ 0
Short-term investments at fair value (amortized cost $1.0 at March 31, 2021 and $26.5 at December 31, 2020)
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	(0.1)
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	0
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Trading Securities, Realized Gain	0
Trading Securities, Realized Loss	0
Trading Securities, Change in Unrealized Holding Gain (Loss)	(0.1)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	$ 0

Net Investment Income (Details)

Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 19.5	$ 21.5
Investment expenses	1.1	1.6
Net investment income	18.4	19.9
Debt Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	18.2	19.3
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	0.9	1.3
Other Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	0.2	0.6
Short-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	0.2	0.1
Cash and Cash Equivalents [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	$ 0	$ 0.2

Investments Investments, Held i

Investments Investments, Held in Trust or on Deposit (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Other invested assets (cost $42.3 at March 31, 2021 and $36.8 at December 31, 2020)	$ 42.4	$ 36.2
Deposit Assets [Abstract]
Investments	2,765.2	2,757.2
Assets Held-in-trust [Abstract]
Funds Held under Reinsurance Agreements, Asset	3.1	3.2
Federal Home Loan Bank [Member]
Deposit Assets [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	130	275
Required by various state laws and regulations to hold securities or letters of credit in depository account [Member]
Deposit Assets [Abstract]
Investments	$ 925.6	$ 768.7

Current Expected Credit Losse_2

Current Expected Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Current Expected Credit Losses [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 12.2		$ 10.8
Premium Receivable, Allowance for Credit Loss, Period Increase (Decrease)	3.3	$ 4.1
Premium Receivable, Allowance for Credit Loss, Writeoff	0.1	4.8
Premium Receivable, Allowance for Credit Loss, Recovery	1.8	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	0.2	10.7	0.7	$ 0
Reinsurance recoverables on unpaid losses, allowance	0.4	0.4	0.4	0
Reinsurance Recoverable, Allowance for Credit Loss, Period Increase (Decrease)	0	0.4
Accrued investment income	17.2		15.3
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(0.2)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Recovery	(0.3)	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Writeoff	0	10.7
Premium Receivable, Allowance for Credit Loss	$ 12.2	$ 3.9	$ 10.8	$ 4.6

Property and Equipment Property

Property and Equipment Property and Equipment (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Property and Equipment [Line Items]
Property and equipment, gross	$ 60.7		$ 63
Accumulated depreciation, depletion and amortization, property and equipment	(42.6)		(43.9)
Property and equipment, net	18.1		19.1
Utilities operating expense, depreciation and amortization	1.9		8.2
Payments to develop software	0.5		3.2
Cloud computing arrangements	49.7		50.2
Amortization of cloud computing arrangements	3.1	$ 1.6	9
Furniture and equipment
Property and Equipment [Line Items]
Property and equipment, gross	3.4		3.4
Leasehold improvements
Property and Equipment [Line Items]
Property and equipment, gross	5.5		5.5
Computer and software
Property and Equipment [Line Items]
Property and equipment, gross	50.9		53.3
Automobiles
Property and Equipment [Line Items]
Property and equipment, gross	$ 0.9		$ 0.8

Property and Equipment Leases (

Property and Equipment Leases (Details)	Mar. 31, 2021
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	1 year
Lessee, Finance Lease, Term of Contract	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, operating lease, remaining lease term	8 years
Lessee, operating lease, renewal term	9 years

Property and Equipment Leases,

Property and Equipment Leases, Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Components of Lease Expense [Abstract]
Operating lease expense	$ 1.1	$ 1.3
Finance lease expense	0	0.1
Total lease expense	$ 1.1	$ 1.4

Property and Equipment Leases_2

Property and Equipment Leases, Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Lessee, operating lease liabilities due
Operating lease liabilities due next twelve months	$ 3.1
Operating lease liabilities due year two	3.2
Operating lease liabilities due year three	3.2
Operating lease liabilities due year four	3.2
Operating lease liabilities due year five	3
Operating lease liabilities due after year five	4.7
Operating lease liabilities due	20.4
Less: inputed interest, Operating lease liability	(1.3)
Operating lease liability	$ 19.1	$ 19.9
Operating lease, weighted average remaining lease term	5 years 10 months 24 days
Operating lease, weighted average discount rate, percent	2.20%
Lessee, finance lease liabilities due
Finance lease liabilities due next twelve months	$ 0.1
Finance lease liabilities due year two	0.1
Finance lease liabilities due year three	0.2
Finance lease liabilities due year four	0.1
Finance lease liabilities due year five	0.1
Finance lease liabilities due after year five	0
Finance lease liabilities due	0.6
Less: inputed interest, finance lease	0
Finance lease, liability	$ 0.6	$ 0.4
Finance lease, weighted average remaining lease term	3 years 7 months 6 days
Finance lease, weighted average discount rate, percent	3.70%

Property and Equipment Leases_3

Property and Equipment Leases, Supplement Balance Sheet Information (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 16.4	$ 17.4
Operating lease liability	19.1	19.9
Property and equipment, gross	60.7	63
Accumulated depreciation, depletion and amortization, property and equipment	(42.6)	(43.9)
Property and equipment, net	18.1	19.1
Other liabilities	78.9	70.5
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization	0.9	0.8
Finance Lease, Right-of-Use Asset, Accumulated Amortization	0.3	0.4
Finance Lease, Right-of-Use Asset, after Accumulated Amortization	0.6	0.4
Finance lease, liability	$ 0.6	$ 0.4

Property and Equipment Leases_4

Property and Equipment Leases, Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Leases, Supplement Balance Sheet Information [Abstract]
Operating cash flows from operating leases	$ 1.1	$ 1.3
Financing cash flows from finance leases	$ 0	$ 0.1

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Effective tax rate	16.30%	23.00%

Liability for Unpaid Losses a_3

Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Unpaid losses and LAE at beginning of period	$ 2,069.4	$ 2,192.8
Less reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE	497	532.5
Net unpaid losses and LAE at beginning of period	1,572.4	1,660.3
Losses and LAE, net of reinsurance, incurred during the period related to:
Current period	85.6	110.2
Prior periods	(13.9)	(3.5)
Total net losses and LAE incurred during the period	71.7	106.7
Deduct payments for losses and LAE, net of reinsurance, related to:
Current period	4.7	6.9
Prior periods	97.6	95.4
Total net paid losses and LAE during the period	102.3	102.3
Ending unpaid losses and LAE, net of reinsurance	1,541.8	1,664.7
Reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE	492.3	527
Unpaid losses and LAE at end of period	2,034.1	2,191.7
Impact of the LPT Agreement	2.1	2.4
Involuntary Assigned Risk Business [Member]
Losses and LAE, net of reinsurance, incurred during the period related to:
Prior periods	(0.5)	(0.5)
Voluntary Risk Business [Member]
Losses and LAE, net of reinsurance, incurred during the period related to:
Prior periods	$ (13.4)	$ (3)

LPT Agreement (Details)

LPT Agreement (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Reinsurance Agreement [Line Items]
Liabilities for the incurred but unpaid losses and LAE related to claims prior to July 1, 1995	$ 1,500
Ceded premiums written	775
Amortization of deferred gain	2.1	$ 2.4
Net income	23.1	(34.9)
Deferred reinsurance gain—LPT Agreement	123.3		$ 125.4
Estimated remaining liabilities - LPT Agreement	348.5		353.5
Paid losses and LAE claims related to LPT	823.9		$ 818.9
Impact of the LPT Agreement	2.1	$ 2.4
Indemnification Agreement [Member]
Reinsurance Agreement [Line Items]
Coverage provided under LPT Agreement	$ 2,000

Notes Payable Letters of Credit

Notes Payable Letters of Credit (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Letters of Credit Facilities [Line Items]
Letters of credit, unused capacity, commitment fee percentage	15.00%
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	$ 15,000		$ 20,000
Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available	10,000
Line of Credit Facility, Current Borrowing Capacity	$ 75,000
Line of Credit Facility, Commitment Fee Percentage	0.30%
Repayments on LOC	$ 12,000	$ 0
Interest and financing expenses	100	0
Line of Credit Facility, Commitment Fee Amount	25
Debt Issuance Costs, Gross	$ 700
Debt Instrument, Covenant Description	a minimum consolidated net worth of no less than 70% of the Company’s stockholders’ equity as of September 30, 2020, plus 50% of the Company’s aggregate net income thereafter
Line of Credit Facility, Covenant Terms	a debt to total capitalization ratio of no more than 35%, in each case as determined in accordance with the Credit Agreement
Proceeds from FHLBank Advance, Investing Activities			35,000
Repayments of FHLBank Advance, Investing Activities	$ 5,000	$ 0	15,000
Line of Credit Facility, Fair Value of Amount Outstanding	0
Maximum [Member]
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 125,000
Line of Credit Facility, Interest Rate at Period End	1.25%
Debt Instrument, Interest Rate, Stated Percentage	2.25%
Line of Credit Facility, Commitment Fee Percentage	0.50%
Line of Credit Facility, Commitment Fee Amount	$ 225
Minimum [Member]
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Interest Rate at Period End	0.25%
Debt Instrument, Interest Rate, Stated Percentage	1.25%
Line of Credit Facility, Commitment Fee Percentage	0.20%
Federal Home Loan Bank [Member]
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 130,000		275,000
Letters of credit collateral amount	355,800		$ 385,600
Federal Home Loan Bank [Member] | EAC
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	50,000
Federal Home Loan Bank [Member] | ECIC
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	70,000
Federal Home Loan Bank [Member] | EPIC
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 10,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income [Abstract]
Net unrealized gains on investments, before taxes	$ 100	$ 145.7
Deferred tax expense on net unrealized gains	(21)	(30.6)
Total accumulated other comprehensive income	$ 79	$ 115.1

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended		12 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-options exercised		41,851	36,500	40,800
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units		71,365
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units		230,267
Restricted Stock Units (RSUs) [Member] | Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation award, shares issued	[1]	66,560
Share-based compensation options, exercise price on grant date	[1]	$ 37.54
Fair value of awards awarded on grant date	[1]	$ 2.5
Vesting rights for RSUs awarded		vest 25% on March 15, 2022, and each of the subsequent three anniversaries of that date
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units		244,951
Performance Shares [Member] | Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation award, shares issued	[2]	77,320
Share-based compensation options, exercise price on grant date	[2]	$ 37.54
Fair value of awards awarded on grant date	[2]	$ 2.9
Performance share awards performance period		two years
Share-based compensation arrangement by share-based payment award, award vesting period		1 year
Performance share awards, minimum payout		0.00%
Performance share awards, maximum payout		200.00%
[1]	The RSUs awarded in March 2021 were awarded to certain employees of the Company and vest 25% on March 15, 2022, and each of the subsequent three anniversaries of that date. The RSUs are subject to accelerated vesting in certain circumstances, including but not limited to: death, disability, retirement, or in connection with a change of control of the Company.
[2]	The PSUs awarded in March 2021 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 value shown in the table represents the aggregate number of PSUs awarded at the target level.

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income available to stockholders - basic and diluted	$ 23.1	$ (34.9)
Weighted average number of shares outstanding - basic	28,516,731	30,697,496
Effect of dilutive securities:
Dilutive securities	451,608	458,653
Weighted average number of shares outstanding - diluted	28,968,339	31,156,149
Performance Shares [Member]
Effect of dilutive securities:
Dilutive securities	344,615	331,806
Stock Option [Member]
Effect of dilutive securities:
Dilutive securities	34,530	64,539
Restricted Stock Units (RSUs) [Member]
Effect of dilutive securities:
Dilutive securities	72,463	62,308

Segment Reporting Segment Net I

Segment Reporting Segment Net Income Before Taxes (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021USD ($)	Mar. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments	2
Premiums Written, Gross	$ 148.3	$ 184.7
Premiums Written, Net	146.9	183.4
Net premiums earned	133.9	167.9
Net investment income	18.4	19.9
Net realized and unrealized (losses) gains on investments	10.9	(61.1)
Other income	0.4	0.3
Revenues	163.6	127
Losses and loss adjustment expenses	69.6	104.3
Commission expense	16.8	21.3
Underwriting and general and administrative expenses	46.6	46.7
Interest and financing expenses	0.1	0
Other Expenses	2.9	0
Operating Expenses	136	172.3
Net (loss) income before income taxes	27.6	(45.3)
Employers Segment [Member]
Segment Reporting Information [Line Items]
Premiums Written, Gross	148	184.7
Premiums Written, Net	146.6	183.4
Net premiums earned	133.9	167.9
Net investment income	17.6	18.6
Net realized and unrealized (losses) gains on investments	10.8	(57.3)
Other income	0.4	0.3
Revenues	162.7	129.5
Losses and loss adjustment expenses	71.7	106.7
Commission expense	16.8	21.3
Underwriting and general and administrative expenses	37.3	39.2
Interest and financing expenses	0
Other Expenses	2.9
Operating Expenses	128.7	167.2
Net (loss) income before income taxes	34	(37.7)
Cerity Segment [Member]
Segment Reporting Information [Line Items]
Premiums Written, Gross	0.3	0
Premiums Written, Net	0.3	0
Net premiums earned	0	0
Net investment income	0.7	0.8
Net realized and unrealized (losses) gains on investments	0.1	(1.7)
Other income	0	0
Revenues	0.8	(0.9)
Losses and loss adjustment expenses	0	0
Commission expense	0	0
Underwriting and general and administrative expenses	3.7	3.8
Interest and financing expenses	0
Other Expenses	0
Operating Expenses	3.7	3.8
Net (loss) income before income taxes	(2.9)	(4.7)
Corporate Segment
Segment Reporting Information [Line Items]
Premiums Written, Gross	0	0
Premiums Written, Net	0	0
Net premiums earned	0	0
Net investment income	0.1	0.5
Net realized and unrealized (losses) gains on investments	0	(2.1)
Other income	0	0
Revenues	0.1	(1.6)
Losses and loss adjustment expenses	(2.1)	(2.4)
Commission expense	0	0
Underwriting and general and administrative expenses	5.6	3.7
Interest and financing expenses	0.1
Other Expenses	0
Operating Expenses	3.6	1.3
Net (loss) income before income taxes	$ (3.5)	$ (2.9)

Segment Reporting Geographic In

Segment Reporting Geographic Information (Details) $ in Millions	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)
CALIFORNIA
Revenue, Major Customer [Line Items]
Premiums In Force	$ 251.4	$ 262	$ 309.5	$ 329.8
Policies In force	39,264	39,610	42,794	43,079
FLORIDA
Revenue, Major Customer [Line Items]
Premiums In Force	$ 38.6	$ 37.9	$ 37.3	$ 36.3
Policies In force	7,303	6,898	6,110	5,822
NEW YORK
Revenue, Major Customer [Line Items]
Premiums In Force	$ 25.6	$ 26.7	$ 31.3	$ 31.7
Policies In force	6,724	6,657	6,302	5,679
AllOtherStates [Member]
Revenue, Major Customer [Line Items]
Premiums In Force	$ 237.7	$ 251.3	$ 264.5	$ 266.8
Policies In force	51,481	50,341	46,223	44,104
UNITED STATES
Revenue, Major Customer [Line Items]
Premiums In Force	$ 553.3	$ 577.9	$ 642.6	$ 664.6
Policies In force	104,772	103,506	101,429	98,684