Employers (EIG) 10-Q27 Oct 202020 Q3 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	9 Months Ended
Cover Page - shares	Sep. 30, 2020	Oct. 15, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
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		29,021,111
Entity Central Index Key	0001379041
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Investments:
Fixed maturity securities at fair value (amortized cost $2,301.6 at September 30, 2020 and $2,403.3 at December 31, 2019, net of CECL allowance of $1.2 at September 30, 2020)	$ 2,442.6	$ 2,485.9
Equity securities at fair value (cost $110.8 at September 30, 2020 and $155.6 at December 31, 2019)	188.7	256.7
Equity securities at cost	6.7	6.7
Other invested assets (cost $33.0 at September 30, 2020 and $28.4 at December 31, 2019)	32.8	29.1
Short-term investments at fair value (amortized cost $45.4 at September 30, 2020)	45.8	0
Total investments	2,716.6	2,778.4
Cash and cash equivalents	237.3	154.9
Restricted cash and cash equivalents	0.3	0.3
Accrued investment income	17.2	16.4
Premiums receivable (less CECL allowance of $10.4 at September 30, 2020 and less bad debt allowance of $4.6 at December 31, 2019)	251.6	285.7
Reinsurance recoverable for:
Paid losses	7.7	7.2
Unpaid losses (less CECL allowance of $0.4 at September 30, 2020)	513.3	532.5
Deferred policy acquisition costs	46.6	47.9
Property and equipment, net	20.2	21.9
Operating lease right-of-use assets	18.6	15.9
Intangible assets, net	13.6	13.6
Goodwill	36.2	36.2
Contingent commission receivable—LPT Agreement	13.2	13.2
Cloud computing arrangements	43	33.6
Other assets	49.7	46.4
Total assets	3,985.1	4,004.1
Liabilities and stockholders’ equity
Unpaid losses and loss adjustment expenses	2,141.4	2,192.8
Unearned premiums	325.6	337.1
Commissions and premium taxes payable	45.5	48.6
Accounts payable and accrued expenses	23.2	29.8
Deferred reinsurance gain—LPT Agreement	129.7	137.1
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	35	0
Operating lease liability	20.9	17.8
Non-cancellable obligations	22.9	23
Other liabilities	73.5	52.1
Total liabilities	2,817.7	2,838.3
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value; 150,000,000 shares authorized; 57,389,615 and 57,184,370 shares issued and 29,069,753 and 31,355,378 shares outstanding at September 30, 2020 and December 31, 2019, respectively	0.6	0.6
Preferred stock, $0.01 par value; 25,000,000 shares authorized; none issued	0	0
Additional paid-in capital	401.6	396.4
Retained earnings	1,191.4	1,158.8
Accumulated other comprehensive income, net of tax	111.7	65.3
Treasury stock, at cost (28,319,862 shares at September 30, 2020 and 25,828,992 shares at December 31, 2019)	(537.9)	(455.3)
Total stockholders’ equity	1,167.4	1,165.8
Total liabilities and stockholders’ equity	$ 3,985.1	$ 4,004.1

Consolidated Balance Sheets Con

Consolidated Balance Sheets Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Available for sale:
Debt securities, available-for-sale, amortized cost	$ 2,301.6	$ 2,403.3
Equity Securities, FV-NI, Cost	110.8	155.6
Other Investments and Securities, at Cost	33	28.4
Available for sale, short-term investments, at amortized cost	45.4	0
Debt Securities, Available-for-sale, Allowance for Credit Loss	1.2	0
Accounts Receivable, Allowance for Credit Loss, Current	10.4	4.6
Reinsurance recoverables on unpaid losses, allowance	$ 0.4	$ 0
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	57,389,615	57,184,370
Common stock, shares outstanding (in shares)	29,069,753	31,355,378
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)	28,319,862	25,828,992

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Consolidated Statements of Income - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues
Net premiums earned	$ 144.4	$ 175.8	$ 463.8	$ 526.1
Net investment income	18.5	22.3	58.3	65.5
Net realized and unrealized (losses) gains on investments	19.1	2.6	(2.3)	33.3
Other income (loss)	(0.1)	0.3	0.5	0.6
Total revenues	181.9	201	520.3	625.5
Expenses
Losses and loss adjustment expenses	77.1	92.9	254.5	268.2
Commission expense	19.4	21.9	59.9	67.7
Underwriting and general and administrative expenses	46.4	45.3	137.9	136.6
Interest and financing expenses	0	0	0	0.6
Other Expenses	0.7	0	0.7	0
Total expenses	143.6	160.1	453	473.1
Net income before income taxes	38.3	40.9	67.3	152.4
Income tax expense	7.2	8.1	11.5	27
Net income	31.1	32.8	55.8	125.4
Comprehensive income
Unrealized AFS investment gains arising during the period (net of tax expense of $(2.2) and $(4.3) for the three months ended September 30, 2020 and 2019, respectively, and $(12.9) and $(22.3) for the nine months ended September 30, 2020 and 2019, respectively)	8	16.4	48.2	84.1
Reclassification adjustment for realized AFS investment gains in net income (net of tax expense of $0.4 and $0.4 for the three months ended September 30, 2020 and 2019, respectively, and $0.5 and $0.6 for the nine months ended September 30, 2020 and 2019, respectively)	(1.3)	(1.6)	(1.8)	(2.3)
Other comprehensive income, net of tax	6.7	14.8	46.4	81.8
Total comprehensive income	37.8	47.6	102.2	207.2
Net realized and unrealized gains (losses) on investments
Net realized and unrealized gains (losses) on investments before impairments	19.1	2.6	(2.3)	33.3
Net realized and unrealized (losses) gains on investments	$ 19.1	$ 2.6	$ (2.3)	$ 33.3
Earnings per common share (Note 13):
Basic	$ 1.06	$ 1.03	$ 1.85	$ 3.90
Diluted	1.05	1.01	1.83	3.85
Cash dividends declared per common share, RSUs and PSUs	$ 0.25	$ 0.22	$ 0.75	$ 0.66

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement Parenthetical [Abstract]
Other comprehensive income (loss), unrealized holding gain (loss) on securities arising during period, tax	$ (2.2)	$ (4.3)	$ (12.9)	$ (22.3)
Other comprehensive income (loss), reclassification adjustment for sale of securities included in net income, tax	$ 0.4	$ 0.4	$ 0.5	$ 0.6

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, 2018		56,975,675
Stockholders' equity, value at Dec. 31, 2018	$ 1,018.2	$ 0.6	$ 388.8	$ 1,030.7	$ (13.7)	$ (388.2)
Stock-based obligations, shares		0
Stock-based obligations, value	$ 6.8	$ 0	6.8	0	0	0
Stock-options exercised, shares	25,580	25,580
Stock-options exercised, value	$ 0.6	$ 0	0.6	0	0	0
Vesting of RSUs and PSUs, net of shares withheld to satisfy minimum tax withholding, shares		177,065
Vesting of RSUs and PSUs, net of shares withheld to satisfy minimum tax withholding, value	(3.2)	$ 0	(3.2)	0	0	0
Acquisition of common stock, shares		0
Acquisition of common stock, value	(47.4)	$ 0	0	0	0	(47.4)
Dividends declared, shares		0
Dividends declared, value	(21.8)	$ 0	0	(21.8)	0	0
Net income	125.4	0	0	125.4	0	0
Change in net unrealized gains in investments, net of tax	81.8	$ 0	0	0	81.8	0
Stockholders' equity, shares at Sep. 30, 2019		57,178,320
Stockholders' equity, value at Sep. 30, 2019	1,160.4	$ 0.6	393	1,134.3	68.1	(435.6)
Stockholders' equity, shares at Dec. 31, 2018		56,975,675
Stockholders' equity, value at Dec. 31, 2018	$ 1,018.2	$ 0.6	388.8	1,030.7	(13.7)	(388.2)
Stock-options exercised, shares	31,630
Stockholders' equity, shares at Dec. 31, 2019	57,184,370	57,184,370
Stockholders' equity, value at Dec. 31, 2019	$ 1,165.8	$ 0.6	396.4	1,158.8	65.3	(455.3)
Stockholders' equity, shares at Jun. 30, 2019		57,157,926
Stockholders' equity, value at Jun. 30, 2019	1,121.5	$ 0.6	389.8	1,108.7	53.3	(430.9)
Stock-based obligations, shares		0
Stock-based obligations, value	2.7	$ 0	2.7	0	0	0
Stock-options exercised, shares		20,394
Stock-options exercised, value	0.5	$ 0	0.5	0	0	0
Acquisition of common stock, shares		0
Acquisition of common stock, value	(4.7)	$ 0	0	0	0	(4.7)
Dividends declared, shares		0
Dividends declared, value	(7.2)	$ 0	0	(7.2)	0	0
Net income	32.8	0	0	32.8	0	0
Change in net unrealized gains in investments, net of tax	14.8	$ 0	0	0	14.8	0
Stockholders' equity, shares at Sep. 30, 2019		57,178,320
Stockholders' equity, value at Sep. 30, 2019	$ 1,160.4	$ 0.6	393	1,134.3	68.1	(435.6)
Stockholders' equity, shares at Dec. 31, 2019	57,184,370	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	$ 7	$ 0	7	0	0	0
Stock-options exercised, shares	39,600	39,600
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		165,645
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	(82.6)	$ 0	0		0	(82.6)
Dividends declared, shares		0
Dividends declared, value	(23.3)	$ 0	0	(23.3)	0	0
Net income	55.8	0	0	55.8	0	0
Change in net unrealized gains in investments, net of tax	$ 46.4	$ 0	0	0	46.4	0
Stockholders' equity, shares at Sep. 30, 2020	57,389,615	57,389,615
Stockholders' equity, value at Sep. 30, 2020	$ 1,167.4	$ 0.6	401.6	1,191.4	111.7	(537.9)
Stockholders' equity, shares at Jun. 30, 2020		57,388,515
Stockholders' equity, value at Jun. 30, 2020	1,144	$ 0.6	399.2	1,167.8	105	(528.6)
Stock-based obligations, shares		0
Stock-based obligations, value	2.4	$ 0	2.4	0	0	0
Stock-options exercised, shares		1,100
Stock-options exercised, value	0	$ 0	0	0	0	0
Acquisition of common stock, shares		0
Acquisition of common stock, value	(9.3)	$ 0	0	0	0	(9.3)
Dividends declared, shares		0
Dividends declared, value	(7.5)	$ 0	0	(7.5)	0	0
Net income	31.1	0	0	31.1	0	0
Change in net unrealized gains in investments, net of tax	$ 6.7	$ 0	0	0	6.7	0
Stockholders' equity, shares at Sep. 30, 2020	57,389,615	57,389,615
Stockholders' equity, value at Sep. 30, 2020	$ 1,167.4	$ 0.6	$ 401.6	$ 1,191.4	$ 111.7	$ (537.9)

Consolidated Statements of St_2

Consolidated Statements of Stockholders Equity (Parentheticals) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Stockholders' Equity [Abstract]
Change in net unrealized (losses) gains on investments, net of tax	$ (1.8)	$ (3.9)	$ (12.4)	$ (21.7)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Sep. 30, 2020	Dec. 31, 2019
Operating activities
Net income	$ 31.1	$ 32.8	$ 55.8	$ 125.4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization			6.3	6.5
Stock-based compensation			6.9	6.8
Amortization of cloud computing arrangements	2.4		5.8	3.8	$ 5.3
Amortization of premium on investments, net			7.7	7.1
Allowance for expected credit losses			6.2	(1)
Deferred income tax expense			(12.4)	5.1
Net realized and unrealized losses (gains) on investments			2.3	(33.3)
Operating Lease, Impairment Loss	0.7		0.7	0
Change in operating assets and liabilities:
Premiums receivable			28.3	19.4
Reinsurance recoverable on paid and unpaid losses			18.2	25.9
Cloud computing arrangements			(15.2)	(8.2)
Operating lease right-of-use-assets			(3.4)	(15)
Current federal income taxes			9.9	(5.8)
Unpaid losses and loss adjustment expenses			51.4	58.9
Unearned premiums			(11.5)	24
Accounts payable, accrued expenses and other liabilities			0.6	(12)
Deferred reinsurance gain—LPT Agreement			(7.4)	(10.2)
Contingent commission receivable—LPT Agreement			0	18.8
Operating lease liabilities			3.1	17.1
Non-cancellable obligations			(0.1)	1.6
Other			(2.8)	(4.5)
Net cash provided by operating activities			47.6	112.6
Investing activities
Purchases of fixed maturity securities			(462.7)	(250.1)
Purchases of equity securities			(177.5)	(219.7)
Purchases of short-term investments			(135.6)	0
Purchases of other invested assets			(4.6)	(24.9)
Proceeds from sale of fixed maturity securities	64.9	52.9	314.7	147.3
Proceeds from sale of equity securities			241.7	166.8
Proceeds from maturities and redemptions of fixed maturity securities			243.3	226.6
Proceeds from maturities of short-term investments			91.2	25
Net change in unsettled investment purchases and sales			1	(24.3)
Capital expenditures and other			(4.5)	(12.4)
Payments to Acquire Businesses, Net of Cash Acquired			0	15.9
Net cash provided by investing activities			107	18.4
Financing activities
Acquisition of common stock			(81.9)	(47.8)
Cash transactions related to stock-based compensation			(1.8)	(2.6)
Dividends paid to stockholders			(23.3)	(21.8)
Proceeds from FHLBank Advance, Investing Activities			35	0
Redemption of notes payable			0	20
Payments on capital leases			0.2	0.2
Net cash used in financing activities			(72.2)	(92.4)
Net increase in cash, cash equivalents and restricted cash			82.4	38.6
Cash, cash equivalents, restricted cash and restricted cash equivalents at the beginning of the period			155.2	102	102
Cash, cash equivalents, restricted cash and restricted cash equivalents at the end of the period	237.6	140.6	237.6	140.6	155.2
Cash and cash equivalents						$ 237.3	$ 154.9
Restricted cash and cash equivalents						0.3	0.3
Total cash, cash equivalents, restricted cash	$ 237.6	$ 140.6	$ 155.2	$ 140.6	$ 155.2	$ 237.6	$ 155.2

Basis of Presentation

Basis of Presentation	9 Months Ended
Basis of Presentation	Sep. 30, 2020
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 all claims under the covered policies have closed, the LPT Agreement is commuted or terminated, upon the mutual agreement of the parties, or the reinsurers’ aggregate maximum limit of liability is exhausted, whichever occurs first. The LPT Agreement does not provide for any additional termination terms. On January 1, 2000, EICN assumed all of the assets, liabilities and operations of the Fund, including the Fund’s rights and obligations associated with the LPT Agreement (See 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, 2019 (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. Prior to December 31, 2019, the Company operated under a single reportable segment. All periods prior to December 31, 2019 have been conformed to the current presentation. 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	9 Months Ended
New Accounting Standards	Sep. 30, 2020
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 the 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. 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 clarifying existing guidance. This update becomes effective for fiscal years, and interim periods within those fiscal years beginning after December 15, 2020. The Company has determined that the impact of this new standard will not be material to its consolidated financial condition and results of operations. Recently Adopted Accounting Standards In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments . The amendments in this update represent changes to clarify, correct errors in, or improve the codification within various ASC topics. The Company adopted the updates related to Topic 815 when it adopted ASU 2016-13 . The Company determined that the impact of these improvements was not material to its consolidated financial condition and results of operations. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This update removes the disclosure requirements for the amounts of and the reasons for transfers between Level 1 and Level 2 and disclosure of the policy for timing of transfers between levels. This update also removes disclosure requirements for the valuation processes for Level 3 fair value measurements. Additionally, this update adds disclosure requirements for the changes in unrealized gains and losses for recurring Level 3 fair value measurements and quantitative information for certain unobservable inputs in Level 3 fair value measurements. Additionally, in March 2020, the FASB issued ASU 2020-03, Codification Improvements to Financial Instruments. This update provided clarification and eliminated inconsistencies on a variety of topics within the codification. The Company adopted the applicable standards and there was no impact on its consolidated financial condition and results of operations. In January 2017, the FASB issued ASU 2017-04, Intangibles-Goodwill and Other (Topic 350) . This update simplifies the measurement of goodwill by eliminating the performance of Step 2 in the goodwill impairment testing. This update allows the testing to be performed by comparing the fair value of a reporting unit with its carrying amount and recognizing an impairment charge when the carrying amount exceeds fair value. Additionally, this update eliminates the requirements of any reporting unit with a zero or negative carrying value to perform Step 2, but requires disclosure of the amount of goodwill allocated to a reporting unit with zero or negative carrying amount of net assets. The Company adopted this standard and there was no impact on its consolidated financial condition and results of operations. In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) . This update replaces the incurred loss impairment methodology for recognizing credit losses on financial instruments with a methodology that reflects an entity's current estimate of all expected credit losses. This update requires financial assets (including receivables and reinsurance recoverables) measured at amortized cost to be presented net of an allowance for credit losses. Additionally, this update requires credit losses on available-for-sale fixed maturity securities to be presented as an allowance rather than as a write-down, allowing an entity to also record reversals of credit losses in current period net income. This update is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Additionally, in December 2018, the FASB issued ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses. This update provides clarification on the effective and transition dates and the exclusion of operating lease receivables from Topic 326. In May 2019, the FASB issued ASU 2019-05, Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief . This update adds optional transition relief for entities to elect the fair value option for certain financial assets previously measured at amortized cost basis to increase comparability of similar financial assets. In December 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments - Credit Losses which provides clarification on certain aspects of the guidance in ASC 326 including purchased credit-deteriorated financial assets, transition relief for troubled debt restructurings, disclosure relief for accrued interest receivables and allows a practical expedient for financial assets secured by collateral maintenance provisions. The Company adopted these standards on January 1, 2020 and did not make any opening balance sheet adjustments due to the immaterial amounts. See Note 5 regarding the impact of this adoption on the Company's consolidated financial condition and results of operations.

Valuation of Financial Instrume

Valuation of Financial Instruments	9 Months Ended
Valuation of Financial Instruments	Sep. 30, 2020
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: September 30, 2020 December 31, 2019 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) Financial assets Total investments at fair value $ 2,677.1 $ 2,677.1 $ 2,742.6 $ 2,742.6 Cash and cash equivalents 237.3 237.3 154.9 154.9 Restricted cash and cash equivalents 0.3 0.3 0.3 0.3 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 it 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 made to the prices obtained from third party pricing services as of September 30, 2020 and December 31, 2019. These methods of valuation only produce an estimate of fair value if there is objectively verifiable information to produce a valuation. When objectively verifiable information is not available, the Company produces 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. September 30, 2020 December 31, 2019 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities: U.S. Treasuries $ — $ 82.9 $ — $ — $ 85.6 $ — U.S. Agencies — 3.1 — — 2.9 — States and municipalities — 478.7 — — 484.5 — Corporate securities — 1,029.9 — — 1,079.0 — Residential mortgage-backed securities — 462.8 — — 480.4 — Commercial mortgage-backed securities — 107.2 — — 110.6 — Asset-backed securities — 33.0 — — 61.2 — Collateralized loan obligations — 82.9 — — — — Other securities — 162.1 — — 181.7 — Total fixed maturity securities $ — $ 2,442.6 $ — $ — $ 2,485.9 $ — Equity securities at fair value: Industrial and miscellaneous $ 163.7 $ — $ — $ 216.4 $ — $ — Other 25.0 — — 40.3 — — Total equity securities at fair value $ 188.7 $ — $ — $ 256.7 $ — $ — Short-term investments $ 4.0 $ 41.8 $ — $ — $ — $ — Total investments at fair value $ 192.7 $ 2,484.4 $ — $ 256.7 $ 2,485.9 $ — 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 September 30, 2020, the Company had unfunded commitments to these private equity limited partnerships totaling $67.4 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. September 30, 2020 December 31, 2019 (in millions) Cash equivalents carried at NAV $ 58.5 $ 14.4 Other invested assets carried at NAV 12.8 9.1

Investments

Investments	9 Months Ended
Investments	Sep. 30, 2020
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 September 30, 2020 Fixed maturity securities U.S. Treasuries $ 78.2 $ 4.7 $ — $ 82.9 U.S. Agencies 2.8 0.3 — 3.1 States and municipalities 445.2 33.5 — 478.7 Corporate securities 949.6 81.8 (1.5) 1,029.9 Residential mortgage-backed securities 445.5 17.6 (0.3) 462.8 Commercial mortgage-backed securities 99.3 8.1 (0.2) 107.2 Asset-backed securities 32.9 0.7 (0.6) 33.0 Collateralized loan obligations 84.4 — (1.5) 82.9 Other securities 163.7 0.7 (2.3) 162.1 Total fixed maturity securities $ 2,301.6 147.4 (6.4) $ 2,442.6 Short-term investments 45.4 0.4 — 45.8 Total AFS investments $ 2,347.0 $ 147.8 $ (6.4) $ 2,488.4 At December 31, 2019 Fixed maturity securities U.S. Treasuries $ 83.7 $ 1.9 $ — $ 85.6 U.S. Agencies 2.8 0.1 — 2.9 States and municipalities 458.2 26.3 — 484.5 Corporate securities 1,038.6 40.4 — 1,079.0 Residential mortgage-backed securities 471.7 9.4 (0.7) 480.4 Commercial mortgage-backed securities 107.4 3.2 — 110.6 Asset-backed securities 60.4 0.9 (0.1) 61.2 Other securities 180.5 1.6 (0.4) 181.7 Total AFS investments $ 2,403.3 83.8 (1.2) $ 2,485.9 The cost and estimated fair value of the Company’s equity securities recorded at fair value at September 30, 2020 and December 31, 2019 were as follows: Cost Estimated Fair Value (in millions) At September 30, 2020 Equity securities at fair value Industrial and miscellaneous $ 92.3 $ 163.7 Other 18.5 25.0 Total equity securities at fair value $ 110.8 $ 188.7 At December 31, 2019 Equity securities at fair value Industrial and miscellaneous $ 129.1 $ 216.4 Other 26.5 40.3 Total equity securities at fair value $ 155.6 $ 256.7 The Company had Other invested assets totaling $32.8 million and $29.1 million at September 30, 2020 and December 31, 2019, respectively. These investments consisted of: (i) private equity limited partnerships that totaled $12.8 million and $9.1 million (initial cost of $13.0 million and $8.4 million) at September 30, 2020 and December 31, 2019, 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 September 30, 2020 and December 31, 2019, 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 September 30, 2020, 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 $ 120.7 $ 122.8 Due after one year through five years 692.9 735.6 Due after five years through ten years 737.8 804.7 Due after ten years 88.1 93.6 Mortgage and asset-backed securities 662.1 685.9 Total $ 2,301.6 $ 2,442.6 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 September 30, 2020 and December 31, 2019. September 30, 2020 December 31, 2019 Estimated Fair Value Gross Number of Issues Estimated Fair Value Gross Number of Issues (in millions, except number of issues data) Less than 12 months: Fixed maturity securities Corporate securities $ 41.2 $ (1.5) 33 $ — $ — — Residential mortgage-backed securities 57.4 (0.3) 12 56.9 (0.2) 29 Commercial mortgage-backed securities 5.7 (0.2) 8 — — — Asset-backed securities 7.3 (0.6) 7 10.1 (0.1) 6 Collateralized loan obligations 82.9 (1.5) 20 — — — Other securities 113.4 (2.3) 233 15.2 (0.3) 64 Total less than 12 months $ 307.9 $ (6.4) 313 $ 82.2 $ (0.6) 99 12 months or greater: Fixed maturity securities Residential mortgage-backed securities $ — $ — — $ 40.0 $ (0.5) 19 Other securities — — — 5.9 (0.1) 19 Total 12 months or greater $ — $ — — $ 45.9 $ (0.6) 38 The Company recorded an allowance for expected credit losses on available-for-sale debt securities of $1.2 million during the nine months ended September 30, 2020 (See Note 5). There were no other-than-temporary impairments on fixed maturity securities recognized during the nine months ended September 30, 2019. Those fixed maturity securities whose total fair value was less than amortized cost at September 30, 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 (losses) on investments and the change in unrealized gains 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 (Losses) Changes in Fair Value Reflected in Earnings Changes in Fair Value Reflected in AOCI, before tax (in millions) Three Months Ended September 30, 2020 Fixed maturity securities $ 2.4 $ (0.7) $ — $ 8.5 $ 1.7 $ 8.5 Equity securities 16.9 (3.0) — 3.7 17.6 — Other invested assets — — — (0.2) (0.2) — Short-term investments — — — — — — Total investments $ 19.3 $ (3.7) $ — $ 12.0 $ 19.1 $ 8.5 Nine Months Ended September 30, 2020 Fixed maturity securities $ 7.1 $ (3.6) $ (1.2) $ 58.4 $ 2.3 $ 58.4 Equity securities 41.3 (21.8) — (23.2) (3.7) — Other invested assets — — — (0.9) (0.9) — Short-term investments — — — 0.4 — 0.4 Total investments $ 48.4 $ (25.4) $ (1.2) $ 34.7 $ (2.3) $ 58.8 Three Months Ended September 30, 2019 Fixed maturity securities $ 2.3 $ (0.3) $ — $ 18.7 $ 2.0 $ 18.7 Equity securities 14.0 (3.0) — (10.3) 0.7 — Other invested assets — — — (0.2) (0.2) — Cash equivalents 0.1 — — — 0.1 — Total investments $ 16.4 $ (3.3) $ — $ 8.2 $ 2.6 $ 18.7 Nine Months Ended September 30, 2019 Fixed maturity securities $ 3.9 $ (1.0) $ — $ 103.5 $ 2.9 $ 103.5 Equity securities 16.7 (3.9) — 17.7 30.5 — Other invested assets — — — (0.2) (0.2) — Cash equivalents 0.1 — — — 0.1 — Total investments $ 20.7 $ (4.9) $ — $ 121.0 $ 33.3 $ 103.5 Proceeds from the sales of fixed maturity securities were $64.9 million and $314.7 million for the three and nine months ended September 30, 2020, respectively, compared to $52.9 million and $147.3 million for the three and nine months ended September 30, 2019, respectively. Net investment income was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions) Fixed maturity securities $ 17.6 $ 20.2 $ 55.6 $ 60.8 Equity securities 1.1 2.4 3.5 6.1 Other invested assets 0.7 0.4 2.0 0.5 Short-term investments 0.6 — 1.0 — Cash equivalents and restricted cash 0.1 0.5 0.5 1.5 Gross investment income 20.1 23.5 62.6 68.9 Investment expenses (1.6) (1.2) (4.3) (3.4) Net investment income $ 18.5 $ 22.3 $ 58.3 $ 65.5

Current Expected Credit Losses

Current Expected Credit Losses	9 Months Ended
Current Expected Credit Losses	Sep. 30, 2020
Credit Loss [Abstract]
Credit Losses	Current Expected Credit Losses The Company adopted AS U 2016-13, Financial Instruments - Credit Losses (Topic 326) in the first quarter of 2020 , which replaced the incurred loss methodology with an expected loss methodology known as the current expected loss methodology (CECL). The measurement of CECL is applicable to financial assets measured at amortized cost, which includes held-to-maturity securities, trade receivables, lease receivables, reinsurance recoverables, financial guarantee contracts, loan commitments, and financial assets with evidence of credit deterioration. Additionally, Topic 326 made changes to the accounting for AFS debt securities. This change requires credit losses to be presented as an allowance rather than as a write-down on AFS debt securities that the Company does not intend to sell or believes that it is more likely than not that it will be required to sell. 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, unemployment and the temporary closures of small businesses have increased rapidly as of September 30, 2020, and the Company expects this trend to continue. Based on our past experience with generally similar conditions, the Company adjusted 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 general and administrative expenses. The table below shows the changes in the allowance for expected credit losses on premiums receivable. Three Months Ended Nine Months Ended September 30, September 30, 2020 2020 (in millions) Beginning balance of the allowance for expected credit losses on premiums receivable $ 8.1 $ 4.6 Current period provision for expected credit losses 3.9 12.2 Write-offs charged against the allowance (1.6) (6.4) Ending balance of the allowance for expected credit losses on premiums receivable $ 10.4 $ 10.4 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 general and administrative expenses. The table below shows the changes in the allowance for expected credit losses on reinsurance recoverables. Three Months Ended Nine Months Ended September 30, September 30, 2020 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 September 30, 2020, the Company established an aggregate allowance for credit losses in the amount of $1.2 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 September 30, 2020, 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 September 30, 2020 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 Nine Months Ended September 30, September 30, 2020 2020 (in millions) Beginning balance of the allowance for expected credit losses on AFS securities $ 1.2 $ — Current period provision for expected credit losses 0.3 3.6 Reductions in allowance from disposals (0.3) (2.4) Ending balance of the allowance for expected credit losses on AFS securities $ 1.2 $ 1.2

Property and Equipment

Property and Equipment	9 Months Ended
Property and Equipment	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	Property and Equipment Property and equipment consists of the following: As of September 30, As of December 31, 2020 2019 (in millions) Furniture and equipment $ 3.1 $ 2.5 Leasehold improvements 5.3 6.0 Computers and software 58.1 60.3 Automobiles 1.1 1.1 Property and equipment, gross 67.6 69.9 Accumulated depreciation (47.4) (48.0) Property and equipment, net $ 20.2 $ 21.9 Depreciation expenses related to property and equipment for the three and nine months ended September 30, 2020 were $1.9 million and $6.3 million, respectively, and $9.0 million for the year ended December 31, 2019. Internally developed software costs of $0.7 million and $2.3 million were capitalized during the three and nine months ended September 30, 2020, respectively, and $3.2 million in internally developed software costs were capitalized during the year ended December 31, 2019. Cloud Computing Arrangements The Company’s capitalized costs associated with cloud computing arrangements totaled $43.0 million and $33.6 million, which were comprised of service contract fees and implementation costs associated with hosting arrangements on the Company’s Consolidated Balance Sheets as of September 30, 2020 and December 31, 2019, respectively. Total amortization for hosting arrangements was $2.4 million and $5.8 million for the three and nine months ended September 30, 2020, respectively, and $5.3 million for the year ended December 31, 2019, respectively. 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. The Company’s operating leases have remaining terms of 1 year to 8 years, with options to extend up to 10 years with no termination provision. The Company’s finance leases have an option to terminate after 1 year. Due to the evolving nature of the Company's business impacted by the COVID-19 pandemic and the continuation of work-from-home status, the Company made the decision to reduce its real estate footprint in order to achieve operating efficiencies. As a result, during the third quarter of 2020, the Company recorded charges of $0.7 million related to the abandonment of operating leases, which is recognized in Other expenses in the Company's Consolidated Statements of Comprehensive Income. Components of lease expense were as follows: Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions) Operating lease expense $ 1.4 $ 1.3 $ 3.8 $ 3.8 Finance lease expense 0.1 0.1 0.2 0.2 Total lease expense $ 1.5 $ 1.4 $ 4.0 $ 4.0 As of September 30, 2020 , the weighted average remaining lease term for operating leases was 6.2 years and for finance leases was 3.1 years. The weighted average discount rate was 2.8% and 3.7% for operating and finance leases, respectively . Maturities of lease liabilities were as follows: As of September 30, 2020 Operating Leases Finance Leases (in millions) 2020 $ 1.1 $ 0.1 2021 4.2 0.2 2022 3.3 0.2 2023 3.2 — 2024 3.2 — Thereafter 7.4 — Total lease payments 22.4 0.5 Less: imputed interest (1.5) — Total $ 20.9 $ 0.5 Supplemental balance sheet information related to leases was as follows: As of September 30, As of December 31, 2020 2019 (in millions) Operating leases: Operating lease right-of-use asset $ 18.6 $ 15.9 Operating lease liability 20.9 17.8 Finance leases: Property and equipment, gross 1.1 1.1 Accumulated depreciation (0.7) (0.5) Property and equipment, net 0.4 0.6 Other liabilities $ 0.5 $ 0.6 Supplemental cash flow information related to leases was as follows: Nine Months Ended September 30, 2020 2019 (in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 3.8 $ 3.8 Financing cash flows used for finance leases 0.2 0.2

Income Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2020
Income Taxes [Abstract]
Income Taxes	Income TaxesThe Company’s effective tax rates were 18.8% and 17.1% for the three and nine months ended September 30, 2020, respectively, compared to 19.8% and 17.7% for the corresponding periods of 2019. The lower effective tax rates for the three and nine month periods ended September 30, 2020, versus those of the corresponding 2019 periods, were primarily due to having a higher proportion of tax-advantaged income to total pre-tax income in the current periods.

Liability for Unpaid Losses and

Liability for Unpaid Losses and Loss Adjustment Expenses	9 Months Ended
Liability for Unpaid Losses and Loss Adjustment Expenses	Sep. 30, 2020
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 Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions) Unpaid losses and LAE at beginning of period $ 2,170.7 $ 2,161.8 $ 2,192.8 $ 2,207.9 Less reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 523.6 484.2 532.5 504.4 Net unpaid losses and LAE at beginning of period 1,647.1 1,677.6 1,660.3 1,703.5 Losses and LAE, net of reinsurance, incurred during the period related to: Current period 94.4 115.4 303.8 344.8 Prior periods (14.8) (20.2) (41.9) (66.1) Total net losses and LAE incurred during the period 79.6 95.2 261.9 278.7 Paid losses and LAE, net of reinsurance, related to: Current period 26.7 32.9 50.7 63.5 Prior periods 72.3 69.7 243.8 248.5 Total net paid losses and LAE during the period 99.0 102.6 294.5 312.0 Ending unpaid losses and LAE, net of reinsurance 1,627.7 1,670.2 1,627.7 1,670.2 Reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 513.7 527.1 513.7 527.1 Unpaid losses and LAE at end of period $ 2,141.4 $ 2,197.3 $ 2,141.4 $ 2,197.3 Total net losses and LAE included in the above table exclude amortization of the deferred reinsurance gain—LPT Agreement, LPT Reserve Adjustments, and LPT Contingent Commission Adjustments, which totaled $2.5 million and $2.3 million for the three months ended September 30, 2020 and 2019, respectively, and $7.4 million and $10.5 million for the nine months ended September 30, 2020 and 2019, respectively (See Note 9). The change in incurred losses and LAE attributable to prior periods for the three and nine months ended September 30, 2020 included $15.0 million and $41.5 million of favorable development on the Company’s voluntary risk business, respectively, and $0.2 million of unfavorable development and $0.4 million of favorable development on the Company’s assigned risk business for the same periods. The change in incurred losses and LAE attributable to prior periods for the three and nine months ended September 30, 2019 included $20.0 million and $66.0 million of favorable development on the Company’s voluntary risk business, respectively, and $0.2 million and $0.1 million of favorable development on the Company’s assigned risk business for the same periods. The favorable prior accident year loss development on voluntary business during the three and nine months ended September 30, 2020 was the result of observed favorable loss cost trends across most accident years; however, the Company believes that the current economic conditions resulting from the COVID-19 pandemic have introduced significant risk of a prolonged recession, which could impact future development trends, including the increased risk of cumulative trauma claims and latent claim reporting, particularly for the more recent prior accident years. The favorable prior accident year loss development on voluntary business during the three and nine months ended September 30, 2019 was the result of observed favorable loss cost trends, which have been impacted by the Company's internal initiatives to reduce loss costs, including the accelerated claims settlement activity that began in 2014 and continued into 2019.

LPT Agreement

LPT Agreement	9 Months Ended
LPT Agreement	Sep. 30, 2020
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 $2.5 million and $2.3 million of the Deferred Gain for the three months ended September 30, 2020 and 2019, respectively, and $7.4 million and $8.5 million for the nine months ended September 30, 2020 and 2019, respectively. Additionally, the Company recognized favorable development in the estimated reserves ceded under the LPT Agreement of $5.3 million, that reduced the Deferred Gain by $1.8 million for the nine months ended September 30, 2019 due to favorable LPT Reserve Adjustments, and by $0.2 million for the three and nine months ended September 30, 2019 due to favorable LPT Contingent Commission Adjustments. The remaining Deferred Gain was $129.7 million and $137.1 million as of September 30, 2020 and December 31, 2019, respectively. The estimated remaining liabilities subject to the LPT Agreement were $362.7 million and $380.4 million as of September 30, 2020 and December 31, 2019, respectively. Losses and LAE paid with respect to the LPT Agreement totaled $813.9 million and $796.2 million from inception through September 30, 2020 and December 31, 2019, respectively.

Notes Payable

Notes Payable	9 Months Ended
Notes Payable	Sep. 30, 2020
Notes Payable [Abstract]
Debt Disclosure [Text Block]	Financing Arrangements 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 struggling with the financial impacts of the COVID-19 pandemic. Each member was allocated up to $10 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 advances are required to be repaid to the FHLB on November 12, 2020 in the amount of $15.0 million and on May 11, 2021 in the amount of $20.0 million. FHLB membership also allows the Company’s insurance subsidiaries access to standby letters of credit. On March 9, 2018, ECIC, EPIC, and EAC entered into standby Letter of Credit Reimbursement Agreements (Letter of Credit Agreements) with the FHLB. On March 1, 2019, the FHLB and ECIC amended its Letter of Credit Agreement to increase its credit amount and on March 2, 2020, the FHLB and EAC and EPIC each amended their Letter of Credit Agreements to increase their respective credit amounts. The Letter of Credit Agreements are between the FHLB and each of EAC, in the amount of $80.0 million, and EPIC, in the amount of $125.0 million. On April 20, 2020, the FHLB and ECIC, amended its Letter of Credit Agreement to decrease its credit amount to $70.0 million. The amended Letter of Credit Agreements will expire March 31, 2021, 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 September 30, 2020 and December 31, 2019, letters of credit totaling $275.0 million and $260.0 million, respectively, were issued in lieu of securities on deposit with the State of California under these Letter of Credit Agreements. As of September 30, 2020 and December 31, 2019, investment securities having a fair value of $398.0 million and $326.8 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	9 Months Ended
Accumulated Other Comprehensive Income	Sep. 30, 2020
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: September 30, 2020 December 31, 2019 (in millions) Net unrealized gains on investments, before taxes $ 141.4 $ 82.6 Deferred tax expense on net unrealized gains (29.7) (17.3) Total accumulated other comprehensive income $ 111.7 $ 65.3

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2020
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 2020 RSUs (1) 77,560 $ 37.81 $ 2.9 PSUs (2) 105,180 37.81 4.0 May 2020 RSUs (3) 20,592 $ 29.59 $ 0.6 (1) The RSUs awarded in March 2020 were awarded to certain employees of the Company and vest 25% on March 15, 2021, 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 2020 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. (3) The RSUs awarded in May 2020 were awarded to non-employee Directors of the Company and vest in full on May 28, 2021. Employees who were awarded RSUs and PSUs are entitled to receive dividend equivalents, payable in cash, when the underlying award vests and becomes payable. If the underlying award does not vest or is forfeited, any dividend equivalents with respect to the underlying award will also fail to become payable and will be forfeited. Stock options exercised totaled 39,600 for the nine months ended September 30, 2020, 25,580 for the nine months ended September 30, 2019, and 31,630 for the year ended December 31, 2019. As of September 30, 2020, the Company had 114,416 options, 266,740 RSUs, and 275,961 PSUs (based on target number awarded) outstanding.

Earnings Per Share

Earnings Per Share	9 Months Ended
Earnings Per Share	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share is computed by dividing net income by the weighted average number of 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 shares that are assumed to be issued under the “treasury stock method,” which reflects the potential dilution that would occur if outstanding RSUs and PSUs had vested and options were to be exercised. 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 Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions, except share data) Net income—basic and diluted $ 31.1 $ 32.8 $ 55.8 $ 125.4 Weighted average number of shares outstanding—basic 29,337,426 31,946,851 30,241,148 32,168,826 Effect of dilutive securities: PSUs 195,860 255,663 224,126 278,641 Stock options 27,490 80,889 39,184 79,954 RSUs 7,630 34,614 28,452 60,034 Dilutive potential shares 230,980 371,166 291,762 418,629 Weighted average number of shares outstanding—diluted 29,568,406 32,318,017 30,532,910 32,587,455 Diluted earnings per share excludes outstanding options and other common stock equivalents in periods where the inclusion of such options and common stock equivalents would be anti-dilutive. The following table presents options, PSUs, and RSUs that were excluded from diluted earnings per share. Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Options, PSUs, and RSUs excluded under the treasury method, as the potential proceeds on settlement or exercise was greater than the value of shares acquired 153,620 — 107,337 —

Segment Reporting

Segment Reporting	9 Months Ended
Segment Reporting	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	Segment Reporting The Company has recently 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). As of December 31, 2019, 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 is defined as 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 is defined as 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. Prior to December 31, 2019, the Company operated under a single reportable segment. All periods prior to December 31, 2019 presented herein have been conformed to the current presentation. 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 September 30, 2020 Gross premiums written $ 131.2 $ 0.1 $ — $ 131.3 Net premiums written 129.5 0.1 — 129.6 Net premiums earned 144.4 — — 144.4 Net investment income 17.5 0.8 0.2 18.5 Net realized and unrealized gains (losses) on investments 19.2 (0.1) — 19.1 Other income (loss) (0.1) — — (0.1) Total revenues 181.0 0.7 0.2 181.9 Losses and loss adjustment expenses 79.5 0.1 (2.5) 77.1 Commission expense 19.4 — — 19.4 Underwriting and general and administrative expenses 38.6 3.8 4.0 46.4 Other expenses 0.7 — — 0.7 Total expenses 138.2 3.9 1.5 143.6 Net income (loss) before income taxes $ 42.8 $ (3.2) $ (1.3) $ 38.3 Three Months Ended September 30, 2019 Gross premiums written $ 166.4 $ 0.1 $ — $ 166.5 Net premiums written 165.1 0.1 — 165.2 Net premiums earned 175.8 — — 175.8 Net investment income 21.4 0.2 0.7 22.3 Net realized and unrealized gains (losses) on investments 2.6 0.1 (0.1) 2.6 Other income 0.3 — — 0.3 Total revenues 200.1 0.3 0.6 201.0 Losses and loss adjustment expenses 95.2 — (2.3) 92.9 Commission expense 21.9 — — 21.9 Underwriting and general and administrative expenses 36.2 4.1 5.0 45.3 Total expenses 153.3 4.1 2.7 160.1 Net income (loss) before income taxes $ 46.8 $ (3.8) $ (2.1) $ 40.9 Employers Cerity Corporate and Other Total (in millions) Nine Months Ended September 30, 2020 Gross premiums written $ 456.1 $ 0.1 $ — $ 456.2 Net premiums written 451.9 0.1 — 452.0 Net premiums earned 463.7 0.1 — 463.8 Net investment income 54.9 2.5 0.9 58.3 Net realized and unrealized gains (losses) on investments 0.1 (0.5) (1.9) (2.3) Other income 0.5 — — 0.5 Total revenues 519.2 2.1 (1.0) 520.3 Losses and loss adjustment expenses 261.8 0.1 (7.4) 254.5 Commission expense 59.9 — — 59.9 Underwriting and general and administrative expenses 116.2 11.9 9.8 137.9 Other expenses 0.7 — — 0.7 Total expenses 438.6 12.0 2.4 453.0 Net income (loss) before income taxes $ 80.6 $ (9.9) $ (3.4) $ 67.3 Nine Months Ended September 30, 2019 Gross premiums written $ 553.0 $ 0.1 $ — $ 553.1 Net premiums written 549.0 0.1 — 549.1 Net premiums earned 526.1 — — 526.1 Net investment income 62.3 0.2 3.0 65.5 Net realized and unrealized gains on investments 30.3 0.1 2.9 33.3 Other income 0.6 — — 0.6 Total revenues 619.3 0.3 5.9 625.5 Losses and loss adjustment expenses 278.7 — (10.5) 268.2 Commission expense 67.7 — — 67.7 Underwriting and general and administrative expenses 111.4 11.7 13.5 136.6 Interest and financing expenses 0.6 — — 0.6 Total expenses 458.4 11.7 3.0 473.1 Net income (loss) before income taxes $ 160.9 $ (11.4) $ 2.9 $ 152.4 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: September 30, 2020 December 31, 2019 September 30, 2019 December 31, 2018 State In-force Premiums Policies In-force Premiums Policies In-force Policies In-force Policies (dollars in millions) California $ 273.6 40,567 $ 329.8 43,079 $ 338.3 43,465 $ 357.1 41,988 Florida 37.0 6,680 36.3 5,822 37.0 5,688 41.0 5,833 New York 27.8 6,625 31.7 5,679 31.4 5,120 23.9 3,663 Other (43 states and D.C.) 254.5 49,478 266.8 44,104 257.8 42,627 244.2 40,014 Total $ 592.9 103,350 $ 664.6 98,684 $ 664.5 96,900 $ 666.2 91,498

Valuation of Financial Instru_2

Valuation of Financial Instruments (Tables)	9 Months Ended
Valuation of Financial Instruments (Tables)	Sep. 30, 2020
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: September 30, 2020 December 31, 2019 Carrying Value Estimated Fair Value Carrying Value Estimated Fair Value (in millions) Financial assets Total investments at fair value $ 2,677.1 $ 2,677.1 $ 2,742.6 $ 2,742.6 Cash and cash equivalents 237.3 237.3 154.9 154.9 Restricted cash and cash equivalents 0.3 0.3 0.3 0.3
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. September 30, 2020 December 31, 2019 Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 (in millions) Fixed maturity securities: U.S. Treasuries $ — $ 82.9 $ — $ — $ 85.6 $ — U.S. Agencies — 3.1 — — 2.9 — States and municipalities — 478.7 — — 484.5 — Corporate securities — 1,029.9 — — 1,079.0 — Residential mortgage-backed securities — 462.8 — — 480.4 — Commercial mortgage-backed securities — 107.2 — — 110.6 — Asset-backed securities — 33.0 — — 61.2 — Collateralized loan obligations — 82.9 — — — — Other securities — 162.1 — — 181.7 — Total fixed maturity securities $ — $ 2,442.6 $ — $ — $ 2,485.9 $ — Equity securities at fair value: Industrial and miscellaneous $ 163.7 $ — $ — $ 216.4 $ — $ — Other 25.0 — — 40.3 — — Total equity securities at fair value $ 188.7 $ — $ — $ 256.7 $ — $ — Short-term investments $ 4.0 $ 41.8 $ — $ — $ — $ — Total investments at fair value $ 192.7 $ 2,484.4 $ — $ 256.7 $ 2,485.9 $ —
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 September 30, 2020, the Company had unfunded commitments to these private equity limited partnerships totaling $67.4 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. September 30, 2020 December 31, 2019 (in millions) Cash equivalents carried at NAV $ 58.5 $ 14.4 Other invested assets carried at NAV 12.8 9.1

Investments (Tables)

Investments (Tables)	9 Months Ended
Investments (Tables)	Sep. 30, 2020
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 September 30, 2020 Fixed maturity securities U.S. Treasuries $ 78.2 $ 4.7 $ — $ 82.9 U.S. Agencies 2.8 0.3 — 3.1 States and municipalities 445.2 33.5 — 478.7 Corporate securities 949.6 81.8 (1.5) 1,029.9 Residential mortgage-backed securities 445.5 17.6 (0.3) 462.8 Commercial mortgage-backed securities 99.3 8.1 (0.2) 107.2 Asset-backed securities 32.9 0.7 (0.6) 33.0 Collateralized loan obligations 84.4 — (1.5) 82.9 Other securities 163.7 0.7 (2.3) 162.1 Total fixed maturity securities $ 2,301.6 147.4 (6.4) $ 2,442.6 Short-term investments 45.4 0.4 — 45.8 Total AFS investments $ 2,347.0 $ 147.8 $ (6.4) $ 2,488.4 At December 31, 2019 Fixed maturity securities U.S. Treasuries $ 83.7 $ 1.9 $ — $ 85.6 U.S. Agencies 2.8 0.1 — 2.9 States and municipalities 458.2 26.3 — 484.5 Corporate securities 1,038.6 40.4 — 1,079.0 Residential mortgage-backed securities 471.7 9.4 (0.7) 480.4 Commercial mortgage-backed securities 107.4 3.2 — 110.6 Asset-backed securities 60.4 0.9 (0.1) 61.2 Other securities 180.5 1.6 (0.4) 181.7 Total AFS investments $ 2,403.3 83.8 (1.2) $ 2,485.9
Equity securities table	The cost and estimated fair value of the Company’s equity securities recorded at fair value at September 30, 2020 and December 31, 2019 were as follows: Cost Estimated Fair Value (in millions) At September 30, 2020 Equity securities at fair value Industrial and miscellaneous $ 92.3 $ 163.7 Other 18.5 25.0 Total equity securities at fair value $ 110.8 $ 188.7 At December 31, 2019 Equity securities at fair value Industrial and miscellaneous $ 129.1 $ 216.4 Other 26.5 40.3 Total equity securities at fair value $ 155.6 $ 256.7
Other invested assets	The Company had Other invested assets totaling $32.8 million and $29.1 million at September 30, 2020 and December 31, 2019, respectively. These investments consisted of: (i) private equity limited partnerships that totaled $12.8 million and $9.1 million (initial cost of $13.0 million and $8.4 million) at September 30, 2020 and December 31, 2019, 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 September 30, 2020 and December 31, 2019, 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 September 30, 2020, 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 $ 120.7 $ 122.8 Due after one year through five years 692.9 735.6 Due after five years through ten years 737.8 804.7 Due after ten years 88.1 93.6 Mortgage and asset-backed securities 662.1 685.9 Total $ 2,301.6 $ 2,442.6
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 September 30, 2020 and December 31, 2019. September 30, 2020 December 31, 2019 Estimated Fair Value Gross Number of Issues Estimated Fair Value Gross Number of Issues (in millions, except number of issues data) Less than 12 months: Fixed maturity securities Corporate securities $ 41.2 $ (1.5) 33 $ — $ — — Residential mortgage-backed securities 57.4 (0.3) 12 56.9 (0.2) 29 Commercial mortgage-backed securities 5.7 (0.2) 8 — — — Asset-backed securities 7.3 (0.6) 7 10.1 (0.1) 6 Collateralized loan obligations 82.9 (1.5) 20 — — — Other securities 113.4 (2.3) 233 15.2 (0.3) 64 Total less than 12 months $ 307.9 $ (6.4) 313 $ 82.2 $ (0.6) 99 12 months or greater: Fixed maturity securities Residential mortgage-backed securities $ — $ — — $ 40.0 $ (0.5) 19 Other securities — — — 5.9 (0.1) 19 Total 12 months or greater $ — $ — — $ 45.9 $ (0.6) 38
Unrealized gain (loss) on investments	Net realized gains (losses) on investments and the change in unrealized gains 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 (Losses) Changes in Fair Value Reflected in Earnings Changes in Fair Value Reflected in AOCI, before tax (in millions) Three Months Ended September 30, 2020 Fixed maturity securities $ 2.4 $ (0.7) $ — $ 8.5 $ 1.7 $ 8.5 Equity securities 16.9 (3.0) — 3.7 17.6 — Other invested assets — — — (0.2) (0.2) — Short-term investments — — — — — — Total investments $ 19.3 $ (3.7) $ — $ 12.0 $ 19.1 $ 8.5 Nine Months Ended September 30, 2020 Fixed maturity securities $ 7.1 $ (3.6) $ (1.2) $ 58.4 $ 2.3 $ 58.4 Equity securities 41.3 (21.8) — (23.2) (3.7) — Other invested assets — — — (0.9) (0.9) — Short-term investments — — — 0.4 — 0.4 Total investments $ 48.4 $ (25.4) $ (1.2) $ 34.7 $ (2.3) $ 58.8 Three Months Ended September 30, 2019 Fixed maturity securities $ 2.3 $ (0.3) $ — $ 18.7 $ 2.0 $ 18.7 Equity securities 14.0 (3.0) — (10.3) 0.7 — Other invested assets — — — (0.2) (0.2) — Cash equivalents 0.1 — — — 0.1 — Total investments $ 16.4 $ (3.3) $ — $ 8.2 $ 2.6 $ 18.7 Nine Months Ended September 30, 2019 Fixed maturity securities $ 3.9 $ (1.0) $ — $ 103.5 $ 2.9 $ 103.5 Equity securities 16.7 (3.9) — 17.7 30.5 — Other invested assets — — — (0.2) (0.2) — Cash equivalents 0.1 — — — 0.1 — Total investments $ 20.7 $ (4.9) $ — $ 121.0 $ 33.3 $ 103.5
Investment income table	Net investment income was as follows: Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions) Fixed maturity securities $ 17.6 $ 20.2 $ 55.6 $ 60.8 Equity securities 1.1 2.4 3.5 6.1 Other invested assets 0.7 0.4 2.0 0.5 Short-term investments 0.6 — 1.0 — Cash equivalents and restricted cash 0.1 0.5 0.5 1.5 Gross investment income 20.1 23.5 62.6 68.9 Investment expenses (1.6) (1.2) (4.3) (3.4) Net investment income $ 18.5 $ 22.3 $ 58.3 $ 65.5

Current Expected Credit Losses

Current Expected Credit Losses (Tables)	9 Months Ended
Current Expected Credit Losses (Tables)	Sep. 30, 2020
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 Nine Months Ended September 30, September 30, 2020 2020 (in millions) Beginning balance of the allowance for expected credit losses on premiums receivable $ 8.1 $ 4.6 Current period provision for expected credit losses 3.9 12.2 Write-offs charged against the allowance (1.6) (6.4) Ending balance of the allowance for expected credit losses on premiums receivable $ 10.4 $ 10.4
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 Nine Months Ended September 30, September 30, 2020 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 Nine Months Ended September 30, September 30, 2020 2020 (in millions) Beginning balance of the allowance for expected credit losses on AFS securities $ 1.2 $ — Current period provision for expected credit losses 0.3 3.6 Reductions in allowance from disposals (0.3) (2.4) Ending balance of the allowance for expected credit losses on AFS securities $ 1.2 $ 1.2

Property and Equipment (Tables)

Property and Equipment (Tables)	9 Months Ended
Property and Equipment (Tables)	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Property and Equipment [Table Text Block]	Property and equipment consists of the following: As of September 30, As of December 31, 2020 2019 (in millions) Furniture and equipment $ 3.1 $ 2.5 Leasehold improvements 5.3 6.0 Computers and software 58.1 60.3 Automobiles 1.1 1.1 Property and equipment, gross 67.6 69.9 Accumulated depreciation (47.4) (48.0) Property and equipment, net $ 20.2 $ 21.9
Lease, Cost [Table Text Block]	Components of lease expense were as follows: Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions) Operating lease expense $ 1.4 $ 1.3 $ 3.8 $ 3.8 Finance lease expense 0.1 0.1 0.2 0.2 Total lease expense $ 1.5 $ 1.4 $ 4.0 $ 4.0
Lessee, Operating and Finance Lease Liability Maturity [Table Text Block]	Maturities of lease liabilities were as follows: As of September 30, 2020 Operating Leases Finance Leases (in millions) 2020 $ 1.1 $ 0.1 2021 4.2 0.2 2022 3.3 0.2 2023 3.2 — 2024 3.2 — Thereafter 7.4 — Total lease payments 22.4 0.5 Less: imputed interest (1.5) — Total $ 20.9 $ 0.5
Supplemental Balance Sheet Information related to Leases [Table Text Block]	Supplemental balance sheet information related to leases was as follows: As of September 30, As of December 31, 2020 2019 (in millions) Operating leases: Operating lease right-of-use asset $ 18.6 $ 15.9 Operating lease liability 20.9 17.8 Finance leases: Property and equipment, gross 1.1 1.1 Accumulated depreciation (0.7) (0.5) Property and equipment, net 0.4 0.6 Other liabilities $ 0.5 $ 0.6
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Supplemental cash flow information related to leases was as follows: Nine Months Ended September 30, 2020 2019 (in millions) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 3.8 $ 3.8 Financing cash flows used for finance leases 0.2 0.2

Liability for Unpaid Losses a_2

Liability for Unpaid Losses and Loss Adjustment Expenses (Tables)	9 Months Ended
	Sep. 30, 2020
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 Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions) Unpaid losses and LAE at beginning of period $ 2,170.7 $ 2,161.8 $ 2,192.8 $ 2,207.9 Less reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 523.6 484.2 532.5 504.4 Net unpaid losses and LAE at beginning of period 1,647.1 1,677.6 1,660.3 1,703.5 Losses and LAE, net of reinsurance, incurred during the period related to: Current period 94.4 115.4 303.8 344.8 Prior periods (14.8) (20.2) (41.9) (66.1) Total net losses and LAE incurred during the period 79.6 95.2 261.9 278.7 Paid losses and LAE, net of reinsurance, related to: Current period 26.7 32.9 50.7 63.5 Prior periods 72.3 69.7 243.8 248.5 Total net paid losses and LAE during the period 99.0 102.6 294.5 312.0 Ending unpaid losses and LAE, net of reinsurance 1,627.7 1,670.2 1,627.7 1,670.2 Reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE 513.7 527.1 513.7 527.1 Unpaid losses and LAE at end of period $ 2,141.4 $ 2,197.3 $ 2,141.4 $ 2,197.3

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
Accumulated Other Comprehensive Income (Tables)	Sep. 30, 2020
Accumulated Other Comprehensive Income [Abstract]
Schedule of accumulated other comprehensive income (loss) table	The following table summarizes the components of accumulated other comprehensive income: September 30, 2020 December 31, 2019 (in millions) Net unrealized gains on investments, before taxes $ 141.4 $ 82.6 Deferred tax expense on net unrealized gains (29.7) (17.3) Total accumulated other comprehensive income $ 111.7 $ 65.3

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
Stock-Based Compensation (Tables)	Sep. 30, 2020
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 2020 RSUs (1) 77,560 $ 37.81 $ 2.9 PSUs (2) 105,180 37.81 4.0 May 2020 RSUs (3) 20,592 $ 29.59 $ 0.6 (1) The RSUs awarded in March 2020 were awarded to certain employees of the Company and vest 25% on March 15, 2021, 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 2020 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. (3) The RSUs awarded in May 2020 were awarded to non-employee Directors of the Company and vest in full on May 28, 2021.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
Earnings Per Share (Tables)	Sep. 30, 2020
Earnings Per Share [Abstract]
Net income and weighted average common shares outstanding used in earnings per share calculations table	The following table presents the net income and the weighted average number of shares outstanding used in the earnings per common share calculations. Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 (in millions, except share data) Net income—basic and diluted $ 31.1 $ 32.8 $ 55.8 $ 125.4 Weighted average number of shares outstanding—basic 29,337,426 31,946,851 30,241,148 32,168,826 Effect of dilutive securities: PSUs 195,860 255,663 224,126 278,641 Stock options 27,490 80,889 39,184 79,954 RSUs 7,630 34,614 28,452 60,034 Dilutive potential shares 230,980 371,166 291,762 418,629 Weighted average number of shares outstanding—diluted 29,568,406 32,318,017 30,532,910 32,587,455
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	Diluted earnings per share excludes outstanding options and other common stock equivalents in periods where the inclusion of such options and common stock equivalents would be anti-dilutive. The following table presents options, PSUs, and RSUs that were excluded from diluted earnings per share. Three Months Ended Nine Months Ended September 30, September 30, 2020 2019 2020 2019 Options, PSUs, and RSUs excluded under the treasury method, as the potential proceeds on settlement or exercise was greater than the value of shares acquired 153,620 — 107,337 —

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
Segment Reporting (Tables)	Sep. 30, 2020
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 September 30, 2020 Gross premiums written $ 131.2 $ 0.1 $ — $ 131.3 Net premiums written 129.5 0.1 — 129.6 Net premiums earned 144.4 — — 144.4 Net investment income 17.5 0.8 0.2 18.5 Net realized and unrealized gains (losses) on investments 19.2 (0.1) — 19.1 Other income (loss) (0.1) — — (0.1) Total revenues 181.0 0.7 0.2 181.9 Losses and loss adjustment expenses 79.5 0.1 (2.5) 77.1 Commission expense 19.4 — — 19.4 Underwriting and general and administrative expenses 38.6 3.8 4.0 46.4 Other expenses 0.7 — — 0.7 Total expenses 138.2 3.9 1.5 143.6 Net income (loss) before income taxes $ 42.8 $ (3.2) $ (1.3) $ 38.3 Three Months Ended September 30, 2019 Gross premiums written $ 166.4 $ 0.1 $ — $ 166.5 Net premiums written 165.1 0.1 — 165.2 Net premiums earned 175.8 — — 175.8 Net investment income 21.4 0.2 0.7 22.3 Net realized and unrealized gains (losses) on investments 2.6 0.1 (0.1) 2.6 Other income 0.3 — — 0.3 Total revenues 200.1 0.3 0.6 201.0 Losses and loss adjustment expenses 95.2 — (2.3) 92.9 Commission expense 21.9 — — 21.9 Underwriting and general and administrative expenses 36.2 4.1 5.0 45.3 Total expenses 153.3 4.1 2.7 160.1 Net income (loss) before income taxes $ 46.8 $ (3.8) $ (2.1) $ 40.9 Employers Cerity Corporate and Other Total (in millions) Nine Months Ended September 30, 2020 Gross premiums written $ 456.1 $ 0.1 $ — $ 456.2 Net premiums written 451.9 0.1 — 452.0 Net premiums earned 463.7 0.1 — 463.8 Net investment income 54.9 2.5 0.9 58.3 Net realized and unrealized gains (losses) on investments 0.1 (0.5) (1.9) (2.3) Other income 0.5 — — 0.5 Total revenues 519.2 2.1 (1.0) 520.3 Losses and loss adjustment expenses 261.8 0.1 (7.4) 254.5 Commission expense 59.9 — — 59.9 Underwriting and general and administrative expenses 116.2 11.9 9.8 137.9 Other expenses 0.7 — — 0.7 Total expenses 438.6 12.0 2.4 453.0 Net income (loss) before income taxes $ 80.6 $ (9.9) $ (3.4) $ 67.3 Nine Months Ended September 30, 2019 Gross premiums written $ 553.0 $ 0.1 $ — $ 553.1 Net premiums written 549.0 0.1 — 549.1 Net premiums earned 526.1 — — 526.1 Net investment income 62.3 0.2 3.0 65.5 Net realized and unrealized gains on investments 30.3 0.1 2.9 33.3 Other income 0.6 — — 0.6 Total revenues 619.3 0.3 5.9 625.5 Losses and loss adjustment expenses 278.7 — (10.5) 268.2 Commission expense 67.7 — — 67.7 Underwriting and general and administrative expenses 111.4 11.7 13.5 136.6 Interest and financing expenses 0.6 — — 0.6 Total expenses 458.4 11.7 3.0 473.1 Net income (loss) before income taxes $ 160.9 $ (11.4) $ 2.9 $ 152.4
Revenue from External Customers by Geographic Areas [Table Text Block]	September 30, 2020 December 31, 2019 September 30, 2019 December 31, 2018 State In-force Premiums Policies In-force Premiums Policies In-force Policies In-force Policies (dollars in millions) California $ 273.6 40,567 $ 329.8 43,079 $ 338.3 43,465 $ 357.1 41,988 Florida 37.0 6,680 36.3 5,822 37.0 5,688 41.0 5,833 New York 27.8 6,625 31.7 5,679 31.4 5,120 23.9 3,663 Other (43 states and D.C.) 254.5 49,478 266.8 44,104 257.8 42,627 244.2 40,014 Total $ 592.9 103,350 $ 664.6 98,684 $ 664.5 96,900 $ 666.2 91,498

Basis of Presentation (Details)

Basis of Presentation (Details)	9 Months Ended
Basis of Presentation (Details)	Sep. 30, 2020
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	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	$ 2,677.1	$ 2,742.6
Total Investments at fair value, estimated fair value	2,677.1	2,742.6
Cash and cash equivalents	237.3	154.9
Cash and cash equivalents, estimated fair value	237.3	154.9
Restricted cash and cash equivalents	0.3	0.3
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restricted cash and cash equivalents	$ 0.3	$ 0.3

Fair Value of Financial Instr_2

Fair Value of Financial Instruments, Fair Value Inputs (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	$ 2,442.6	$ 2,485.9
Equity Securities, FV-NI	188.7	256.7
Short-term investments at fair value (amortized cost $45.4 at September 30, 2020)	45.8	0
Investments	2,716.6	2,778.4
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	188.7	256.7
Short-term investments at fair value (amortized cost $45.4 at September 30, 2020)	4	0
Investments	192.7	256.7
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 $45.4 at September 30, 2020)	41.8	0
Investments	2,484.4	2,485.9
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 $45.4 at September 30, 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	2,442.6	2,485.9
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	82.9	85.6
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	82.9	85.6
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	3.1	2.9
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	3.1	2.9
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	478.7	484.5
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	478.7	484.5
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	1,029.9	1,079
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	1,029.9	1,079
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	462.8	480.4
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	462.8	480.4
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	107.2	110.6
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	107.2	110.6
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	33	61.2
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	33	61.2
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
Collateralized Loan Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturity securities, fair value	82.9
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	82.9	0
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	162.1	181.7
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	162.1	181.7
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	163.7	216.4
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	163.7	216.4
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	25	40.3
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	25	40.3
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	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
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	$ 67.4
Cash Equivalents Measured at Net Asset Value	58.5	$ 14.4
Other invested assets at NAV	$ 12.8	$ 9.1
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	9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	$ 2,301.6		$ 2,403.3
Debt securities, available-for-sale, gross unrealized gain	147.4		83.8
Debt securities, available-for-sale, gross unrealized loss	(6.4)		(1.2)
Fixed maturity securities, fair value	2,442.6		2,485.9
Total AFS, amortized cost	2,347
Total AFS, gross unrealized gain	147.8
Total AFS, gross unrealized loss	6.4
Short-term investments at fair value (amortized cost $45.4 at September 30, 2020)	45.8		0
Total AFS investments	2,488.4
Other invested assets (cost $33.0 at September 30, 2020 and $28.4 at December 31, 2019)	32.8		29.1
Other invested assets at NAV	12.8		9.1
Investment Owned, at Cost	13		8.4
Real Estate Investments, Unconsolidated Real Estate and Other Joint Ventures	20		20
Debt Securities, Available-for-sale, Allowance for Credit Loss	1.2	$ 1.2	0
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Other than temporary impairment, credit losses recognized in earnings	0
US Treasury Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	78.2		83.7
Debt securities, available-for-sale, gross unrealized gain	4.7		1.9
Debt securities, available-for-sale, gross unrealized loss	0		0
Fixed maturity securities, fair value	82.9		85.6
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	0.3		0.1
Debt securities, available-for-sale, gross unrealized loss	0		0
Fixed maturity securities, fair value	3.1		2.9
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	445.2		458.2
Debt securities, available-for-sale, gross unrealized gain	33.5		26.3
Debt securities, available-for-sale, gross unrealized loss	0		0
Fixed maturity securities, fair value	478.7		484.5
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	949.6		1,038.6
Debt securities, available-for-sale, gross unrealized gain	81.8		40.4
Debt securities, available-for-sale, gross unrealized loss	(1.5)		0
Fixed maturity securities, fair value	1,029.9		1,079
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	445.5		471.7
Debt securities, available-for-sale, gross unrealized gain	17.6		9.4
Debt securities, available-for-sale, gross unrealized loss	(0.3)		(0.7)
Fixed maturity securities, fair value	462.8		480.4
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	99.3		107.4
Debt securities, available-for-sale, gross unrealized gain	8.1		3.2
Debt securities, available-for-sale, gross unrealized loss	(0.2)		0
Fixed maturity securities, fair value	107.2		110.6
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	32.9		60.4
Debt securities, available-for-sale, gross unrealized gain	0.7		0.9
Debt securities, available-for-sale, gross unrealized loss	(0.6)		(0.1)
Fixed maturity securities, fair value	33		61.2
Collateralized Loan Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	84.4
Debt securities, available-for-sale, gross unrealized gain	0
Debt securities, available-for-sale, gross unrealized loss	(1.5)
Fixed maturity securities, fair value	82.9
Other Debt Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, amortized cost	163.7		180.5
Debt securities, available-for-sale, gross unrealized gain	0.7		1.6
Debt securities, available-for-sale, gross unrealized loss	(2.3)		(0.4)
Fixed maturity securities, fair value	162.1		$ 181.7
Short-term Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Total AFS, amortized cost	45.4
Total AFS, gross unrealized gain	0.4
Total AFS, gross unrealized loss	$ 0

Investments Equity Securities (

Investments Equity Securities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Schedule of Equity Securities and Other [Line Items]
Equity Securities, FV-NI, Cost	$ 110.8	$ 155.6
Equity Securities, FV-NI	188.7	256.7
Industrial and Miscellaneous [Member]
Schedule of Equity Securities and Other [Line Items]
Equity Securities, FV-NI, Cost	92.3	129.1
Equity Securities, FV-NI	163.7	216.4
Other [Member]
Schedule of Equity Securities and Other [Line Items]
Equity Securities, FV-NI, Cost	18.5	26.5
Equity Securities, FV-NI	$ 25	$ 40.3

Investments Other Invested Asse

Investments Other Invested Assets (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Other Invest Assets [Abstract]
Other invested assets at NAV	$ 12.8	$ 9.1
Investment Owned, at Cost	13	8.4
Total other invested assets	32.8	29.1
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	Sep. 30, 2020	Dec. 31, 2019
Amortized Cost
Due in one year or less, amortized cost	$ 120.7
Due after one year through five years, amortized cost	692.9
Due after five years through ten years, amortized cost	737.8
Due after ten years, amortized cost	88.1
Mortgage and asset-backed securities, amortized cost	662.1
Total, amortized cost	2,301.6	$ 2,403.3
Estimated Fair Value
Due in one year or less, fair value	122.8
Due after one year through five years, fair value	735.6
Due after five years through ten years, fair value	804.7
Due after ten years, fair value	93.6
Mortgage and asset-backed securities, fair value	685.9
Total, fair value	$ 2,442.6	$ 2,485.9

Investments, Continuous Loss Po

Investments, Continuous Loss Position (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)sharesshares	Dec. 31, 2019USD ($)shares
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 307.9	$ 82.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	45.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(6.4)	(0.6)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0	$ (0.6)
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	313	99
Debt Securities, number of issues in loss position, 12 months or greater	0	38
Debt Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Number of Positions [Abstract]
Other than temporary impairment, credit losses recognized in earnings	$ 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	41.2	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (1.5)	$ 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	33	0
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	$ 57.4	$ 56.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	40
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(0.3)	(0.2)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0	$ (0.5)
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	12	29
Debt Securities, number of issues in loss position, 12 months or greater	0	19
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	$ 5.7	$ 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	8	0
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 7.3	$ 10.1
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (0.6)	$ (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	7	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	$ 82.9	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ (1.5)	$ 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	20	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	$ 113.4	$ 15.2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	5.9
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(2.3)	(0.3)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 0	$ (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	233	64
Debt Securities, number of issues in loss position, 12 months or greater \| shares	0	19

Investments Investments, Net Re

Investments Investments, Net Realized Gains and Losses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Equity securities:
Equity Securities, FV-NI, Realized Gain	$ 16.9	$ 14	$ 41.3	$ 16.7
Equity Securities, FV-NI, Realized Loss	3	3	21.8	3.9
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	8.5	18.7	58.8	103.5
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	19.1	2.6	(2.3)	33.3
Total gross realized gains	19.3	16.4	48.4	20.7
Investments, Gross Realized Losses	(3.7)	(3.3)	(25.4)	(4.9)
Total change in net unrealized gains (losses)	12	8.2	34.7	121
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Equity Securities, FV-NI, Unrealized Gain (Loss)	3.7	(10.3)	(23.2)	17.7
Proceeds from sale of fixed maturity securities	64.9	52.9	314.7	147.3
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0	0	(1.2)	0
Debt Securities [Member]
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	8.5	18.7	58.4	103.5
AFS, net realized gains (losses)
AFS, Gross gains from sales	2.4	2.3	7.1	3.9
AFS, Gross losses from sales	(0.7)	(0.3)	(3.6)	(1)
Net realized and unrealized (losses) gains on investments	1.7	2	2.3	2.9
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0	0	(1.2)	0
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	0	0
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	17.6	0.7	(3.7)	30.5
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0	0	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	0	0
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	(0.2)	(0.2)	(0.9)	(0.2)
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Trading Securities, Realized Gain	0	0	0	0
Trading Securities, Realized Loss	0	0	0	0
Trading Securities, Change in Unrealized Holding Gain (Loss)	(0.2)	(0.2)	(0.9)	(0.2)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	0	0	0	0
Short-term investments at fair value (amortized cost $45.4 at September 30, 2020)
AFS, change in unrealized gains (losses)
AFS, change unrealized gains (losses) on fixed maturity and equity securities reflected in AOCI	0	0	0.4	0
AFS, net realized gains (losses)
Net realized and unrealized (losses) gains on investments	0	0.1	0	0.1
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Abstract]
Trading Securities, Realized Gain	0	0.1	0	0.1
Trading Securities, Realized Loss	0	0	0	0
Trading Securities, Change in Unrealized Holding Gain (Loss)	0	0	0.4	0
Debt Securities, Available-for-sale, Allowance for Credit Loss, Period Increase (Decrease)	$ 0	$ 0	$ 0	$ 0

Net Investment Income (Details)

Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Net Investment Income (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Gross investment income	$ 20.1	$ 23.5	$ 62.6	$ 68.9
Investment expenses	1.6	1.2	4.3	3.4
Net investment income	18.5	22.3	58.3	65.5
Debt Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	17.6	20.2	55.6	60.8
Equity Securities [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	1.1	2.4	3.5	6.1
Other Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	0.7	0.4	2	0.5
Short-term Investments [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	0.6	0	1	0
Cash and Cash Equivalents [Member]
Schedule of Investment Income, Reported Amounts, by Category [Line Items]
Investment income	$ 0.1	$ 0.5	$ 0.5	$ 1.5

Investments Investments, Held i

Investments Investments, Held in Trust or on Deposit (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Other invested assets (cost $33.0 at September 30, 2020 and $28.4 at December 31, 2019)	$ 32.8	$ 29.1
Deposit Assets [Abstract]
Investments	2,716.6	2,778.4
Assets Held-in-trust [Abstract]
Funds Held under Reinsurance Agreements, Asset	3.3	2.9
Federal Home Loan Bank [Member]
Deposit Assets [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	275	260
Required by various state laws and regulations to hold securities or letters of credit in depository account [Member]
Deposit Assets [Abstract]
Investments	$ 772.9	$ 844.9

Current Expected Credit Losse_2

Current Expected Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Current Expected Credit Losses [Abstract]
Accounts Receivable, Allowance for Credit Loss, Current	$ 10.4	$ 10.4	$ 8.1	$ 4.6
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	3.9	12.2
Accounts Receivable, Allowance for Credit Loss, Writeoff	(1.6)	(6.4)
Debt Securities, Available-for-sale, Allowance for Credit Loss	1.2	1.2	1.2	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	17.2		$ 16.4
Debt Securities, Available-for-sale, Allowance for Credit Loss, Securities Sold	(0.3)	(2.4)
Debt Securities, Available-for-sale, Allowance for Credit Loss, Recovery	$ 0.3
Debt Securities, Available-for-sale, Allowance for Credit Loss, Writeoff		$ 3.6

Property and Equipment Property

Property and Equipment Property and Equipment (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Property and Equipment [Line Items]
Property and equipment, gross	$ 67.6	$ 67.6		$ 69.9
Accumulated depreciation, depletion and amortization, property and equipment	(47.4)	(47.4)		(48)
Property and equipment, net	20.2	20.2		21.9
Utilities operating expense, depreciation and amortization	1.9	6.3		9
Payments to develop software	0.7	2.3		3.2
Cloud computing arrangements	43	43		33.6
Amortization of cloud computing arrangements	2.4	5.8	$ 3.8	5.3
Furniture and equipment
Property and Equipment [Line Items]
Property and equipment, gross	3.1	3.1		2.5
Leasehold improvements
Property and Equipment [Line Items]
Property and equipment, gross	5.3	5.3		6
Computer and software
Property and Equipment [Line Items]
Property and equipment, gross	58.1	58.1		60.3
Automobiles
Property and Equipment [Line Items]
Property and equipment, gross	$ 1.1	$ 1.1		$ 1.1

Property and Equipment Leases (

Property and Equipment Leases (Details)	Sep. 30, 2020
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	10 years

Property and Equipment Leases,

Property and Equipment Leases, Components of Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Components of Lease Expense [Abstract]
Operating lease expense	$ 1.4	$ 1.3	$ 3.8	$ 3.8
Finance lease expense	0.1	0.1	0.2	0.2
Total lease expense	1.5	$ 1.4	4	4
Operating Lease, Impairment Loss	$ 0.7		$ 0.7	$ 0

Property and Equipment Leases_2

Property and Equipment Leases, Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Lessee, operating lease liabilities due
Operating lease liabilities due next twelve months	$ 1.1
Operating lease liabilities due year two	4.2
Operating lease liabilities due year three	3.3
Operating lease liabilities due year four	3.2
Operating lease liabilities due year five	3.2
Operating lease liabilities due after year five	7.4
Operating lease liabilities due	22.4
Less: inputed interest, Operating lease liability	(1.5)
Operating lease liability	$ 20.9	$ 17.8
Operating lease, weighted average remaining lease term	6 years 2 months 12 days
Operating lease, weighted average discount rate, percent	2.80%
Lessee, finance lease liabilities due
Finance lease liabilities due next twelve months	$ 0.1
Finance lease liabilities due year two	0.2
Finance lease liabilities due year three	0.2
Finance lease liabilities due year four	0
Finance lease liabilities due year five	0
Finance lease liabilities due after year five	0
Finance lease liabilities due	0.5
Less: inputed interest, finance lease	0
Finance lease, liability	$ 0.5	$ 0.6
Finance lease, weighted average remaining lease term	3 years 1 month 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	Sep. 30, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 18.6	$ 15.9
Operating lease liability	20.9	17.8
Property and equipment, gross	67.6	69.9
Accumulated depreciation, depletion and amortization, property and equipment	(47.4)	(48)
Property and equipment, net	20.2	21.9
Other liabilities	73.5	52.1
Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, before Accumulated Depreciation and Amortization	1.1	1.1
Finance Lease, Right-of-Use Asset, Accumulated Amortization	0.7	0.5
Finance Lease, Right-of-Use Asset, after Accumulated Amortization	0.4	0.6
Finance lease, liability	$ 0.5	$ 0.6

Property and Equipment Leases_4

Property and Equipment Leases, Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Leases, Supplement Balance Sheet Information [Abstract]
Operating cash flows from operating leases	$ 3.8	$ 3.8
Financing cash flows from finance leases	$ 0.2	$ 0.2

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended		9 Months Ended
Income Taxes (Details)	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Effective tax rate	18.80%	19.80%	17.10%	17.70%

Liability for Unpaid Losses a_3

Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Unpaid losses and LAE at beginning of period	$ 2,170.7	$ 2,161.8	$ 2,192.8	$ 2,207.9
Less reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE	523.6	484.2	532.5	504.4
Net unpaid losses and LAE at beginning of period	1,647.1	1,677.6	1,660.3	1,703.5
Losses and LAE, net of reinsurance, incurred during the period related to:
Current period	94.4	115.4	303.8	344.8
Prior periods	(14.8)	(20.2)	(41.9)	(66.1)
Total net losses and LAE incurred during the period	79.6	95.2	261.9	278.7
Deduct payments for losses and LAE, net of reinsurance, related to:
Current period	26.7	32.9	50.7	63.5
Prior periods	72.3	69.7	243.8	248.5
Total net paid losses and LAE during the period	99	102.6	294.5	312
Ending unpaid losses and LAE, net of reinsurance	1,627.7	1,670.2	1,627.7	1,670.2
Reinsurance recoverable, excluding CECL allowance, on unpaid losses and LAE	513.7	527.1	513.7	527.1
Unpaid losses and LAE at end of period	2,141.4	2,197.3	2,141.4	2,197.3
Impact of the LPT Agreement	2.5	2.3	7.4	10.5
Involuntary Assigned Risk Business [Member]
Losses and LAE, net of reinsurance, incurred during the period related to:
Prior periods	0.2	(0.2)	(0.4)	(0.1)
Voluntary Risk Business [Member]
Losses and LAE, net of reinsurance, incurred during the period related to:
Prior periods	$ (15)	$ (20)	$ (41.5)	$ (66)

LPT Agreement (Details)

LPT Agreement (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
LPT Agreement (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Reinsurance Agreement [Line Items]
Liabilities for the incurred but unpaid losses and LAE related to claims prior to July 1, 1995	$ 1,500		$ 1,500
Ceded premiums written			775
Amortization of deferred gain	2.5	$ 2.3	7.4	$ 8.5
Cumulative adjustment to the Deferred Gain				(1.8)
Net income	31.1	32.8	55.8	125.4
Change in estimate of contingent commission receivable				(0.2)
Deferred reinsurance gain—LPT Agreement	129.7		129.7		$ 137.1
Estimated remaining liabilities - LPT Agreement	362.7		362.7		380.4
Paid losses and LAE claims related to LPT	813.9		813.9		$ 796.2
Impact of the LPT Agreement	2.5	$ 2.3	7.4	10.5
Change in estimate of estimated LPT reserves				$ 5.3
Indemnification Agreement [Member]
Reinsurance Agreement [Line Items]
Coverage provided under LPT Agreement	$ 2,000		$ 2,000

Notes Payable Letters of Credit

Notes Payable Letters of Credit (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	May 11, 2021	Nov. 12, 2020	Dec. 31, 2019
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	$ 35			$ 0
Federal Home Loan Bank, Advances, General Debt Obligations, Maximum Amount Available	10
Debt Instrument, Redemption, Period Two [Member]
Letters of Credit Facilities [Line Items]
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances		$ 20
Debt Instrument, Redemption, Period One [Member]
Letters of Credit Facilities [Line Items]
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances			$ 15
Federal Home Loan Bank [Member]
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	275			260
Letters of credit collateral amount	398			$ 326.8
Federal Home Loan Bank [Member] \| EAC
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	80
Federal Home Loan Bank [Member] \| ECIC
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	70
Federal Home Loan Bank [Member] \| EPIC
Letters of Credit Facilities [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 125

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income [Abstract]
Net unrealized gains on investments, before taxes	$ 141.4	$ 82.6
Deferred tax expense on net unrealized gains	(29.7)	(17.3)
Total accumulated other comprehensive income	$ 111.7	$ 65.3

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) $ / shares in Units, $ in Millions		9 Months Ended		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-options exercised		39,600	25,580	31,630
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units		114,416
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation award, shares issued	[1]	20,592
Share-based compensation options, exercise price on grant date	[1]	$ 29.59
Fair value of awards awarded on grant date	[1]	$ 0.6
Number of outstanding options or share units		266,740
Restricted Stock Units (RSUs) [Member] \| Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation award, shares issued	[2]	77,560
Share-based compensation options, exercise price on grant date	[2]	$ 37.81
Fair value of awards awarded on grant date	[2]	$ 2.9
Vesting rights for RSUs awarded		vest 25% on March 15, 2021, 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		275,961
Performance Shares [Member] \| Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation award, shares issued	[3]	105,180
Share-based compensation options, exercise price on grant date	[3]	$ 37.81
Fair value of awards awarded on grant date	[3]	$ 4
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 May 2020 were awarded to non-employee Directors of the Company and vest in full on May 28, 2021.
[2]	The RSUs awarded in March 2020 were awarded to certain employees of the Company and vest 25% on March 15, 2021, 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.
[3]	The PSUs awarded in March 2020 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		9 Months Ended
Earnings Per Share (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Net income available to stockholders - basic and diluted	$ 31.1	$ 32.8	$ 55.8	$ 125.4
Weighted average number of shares outstanding - basic	29,337,426	31,946,851	30,241,148	32,168,826
Effect of dilutive securities:
Dilutive securities	230,980	371,166	291,762	418,629
Weighted average number of shares outstanding - diluted	29,568,406	32,318,017	30,532,910	32,587,455
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	153,620	0	107,337	0
Performance Shares [Member]
Effect of dilutive securities:
Dilutive securities	195,860	255,663	224,126	278,641
Stock Option [Member]
Effect of dilutive securities:
Dilutive securities	27,490	80,889	39,184	79,954
Restricted Stock Units (RSUs) [Member]
Effect of dilutive securities:
Dilutive securities	7,630	34,614	28,452	60,034

Segment Reporting Segment Net I

Segment Reporting Segment Net Income Before Taxes (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Segment Reporting Information [Line Items]
Number of Reportable Segments			2
Premiums Written, Gross	$ 131.3	$ 166.5	$ 456.2	$ 553.1
Premiums Written, Net	129.6	165.2	452	549.1
Net premiums earned	144.4	175.8	463.8	526.1
Net investment income	18.5	22.3	58.3	65.5
Net realized and unrealized (losses) gains on investments	19.1	2.6	(2.3)	33.3
Other income (loss)	(0.1)	0.3	0.5	0.6
Revenues	181.9	201	520.3	625.5
Losses and loss adjustment expenses	77.1	92.9	254.5	268.2
Commission expense	19.4	21.9	59.9	67.7
Underwriting and general and administrative expenses	46.4	45.3	137.9	136.6
Interest and financing expenses	0	0	0	0.6
Other Expenses	0.7	0	0.7	0
Operating Expenses	143.6	160.1	453	473.1
Net (loss) income before income taxes	38.3	40.9	67.3	152.4
Employers Segment [Member]
Segment Reporting Information [Line Items]
Premiums Written, Gross	131.2	166.4	456.1	553
Premiums Written, Net	129.5	165.1	451.9	549
Net premiums earned	144.4	175.8	463.7	526.1
Net investment income	17.5	21.4	54.9	62.3
Net realized and unrealized (losses) gains on investments	19.2	2.6	0.1	30.3
Other income (loss)	(0.1)	0.3	0.5	0.6
Revenues	181	200.1	519.2	619.3
Losses and loss adjustment expenses	79.5	95.2	261.8	278.7
Commission expense	19.4	21.9	59.9	67.7
Underwriting and general and administrative expenses	38.6	36.2	116.2	111.4
Interest and financing expenses				0.6
Other Expenses	0.7		0.7
Operating Expenses	138.2	153.3	438.6	458.4
Net (loss) income before income taxes	42.8	46.8	80.6	160.9
Cerity Segment [Member]
Segment Reporting Information [Line Items]
Premiums Written, Gross	0.1	0.1	0.1	0.1
Premiums Written, Net	0.1	0.1	0.1	0.1
Net premiums earned	0	0	0.1	0
Net investment income	0.8	0.2	2.5	0.2
Net realized and unrealized (losses) gains on investments	(0.1)	0.1	(0.5)	0.1
Other income (loss)	0	0	0	0
Revenues	0.7	0.3	2.1	0.3
Losses and loss adjustment expenses	0.1	0	0.1	0
Commission expense	0	0	0	0
Underwriting and general and administrative expenses	3.8	4.1	11.9	11.7
Interest and financing expenses				0
Other Expenses	0		0
Operating Expenses	3.9	4.1	12	11.7
Net (loss) income before income taxes	(3.2)	(3.8)	(9.9)	(11.4)
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Premiums Written, Gross	0	0	0	0
Premiums Written, Net	0	0	0	0
Net premiums earned	0	0	0	0
Net investment income	0.2	0.7	0.9	3
Net realized and unrealized (losses) gains on investments	0	(0.1)	(1.9)	2.9
Other income (loss)	0	0	0	0
Revenues	0.2	0.6	(1)	5.9
Losses and loss adjustment expenses	(2.5)	(2.3)	(7.4)	(10.5)
Commission expense	0	0	0	0
Underwriting and general and administrative expenses	4	5	9.8	13.5
Interest and financing expenses				0
Other Expenses	0		0
Operating Expenses	1.5	2.7	2.4	3
Net (loss) income before income taxes	$ (1.3)	$ (2.1)	$ (3.4)	$ 2.9

Segment Reporting Geographic In

Segment Reporting Geographic Information (Details) $ in Millions	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)
CALIFORNIA
Revenue, Major Customer [Line Items]
Premiums In Force	$ 273.6	$ 329.8	$ 338.3	$ 357.1
Policies In force	40,567	43,079	43,465	41,988
FLORIDA
Revenue, Major Customer [Line Items]
Premiums In Force	$ 37	$ 36.3	$ 37	$ 41
Policies In force	6,680	5,822	5,688	5,833
NEW YORK
Revenue, Major Customer [Line Items]
Premiums In Force	$ 27.8	$ 31.7	$ 31.4	$ 23.9
Policies In force	6,625	5,679	5,120	3,663
AllOtherStates [Member]
Revenue, Major Customer [Line Items]
Premiums In Force	$ 254.5	$ 266.8	$ 257.8	$ 244.2
Policies In force	49,478	44,104	42,627	40,014
UNITED STATES
Revenue, Major Customer [Line Items]
Premiums In Force	$ 592.9	$ 664.6	$ 664.5	$ 666.2
Policies In force	103,350	98,684	96,900	91,498