Selective Insurance (SIGI) 10-K 11 Feb 22 2021 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Jan. 31, 2022	Jun. 30, 2021
Document and Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Document Transition Report	false
Entity File Number	001-33067
Entity Registrant Name	SELECTIVE INSURANCE GROUP, INC.
Entity Incorporation, State or Country Code	NJ
Entity Tax Identification Number	22-2168890
Entity Address, Address Line One	40 Wantage Avenue
Entity Address, City or Town	Branchville
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07890
City Area Code	973
Local Phone Number	948-3000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 4,787,831,538
Entity Common Stock, Shares Outstanding		60,186,063
Entity Central Index Key	0000230557
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for the 2022 Annual Meeting of Stockholders to be held on May 3, 2022, are incorporated by reference into Part III of this report.
Document Information [Line Items]
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Depositary Shares [Member]
Document Information [Line Items]
Security Exchange Name	NASDAQ
Trading Symbol	SIGIP
Title of 12(b) Security	Depositary Shares, each representing a 1/1,000th interest in a share of 4.60% Non-Cumulative Preferred Stock, Series B, without par value
Common Stock [Member]
Document Information [Line Items]
Security Exchange Name	NASDAQ
Trading Symbol	SIGI
Title of 12(b) Security	Common Stock, par value $2 per share

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Auditor [Line Items]
Auditor Name	KPMG LLP
Auditor Firm ID	185
Auditor Location	New York, New York

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
ASSETS
Fixed Income Securities, Held-to-maturity, Allowance for Credit Loss	$ (65)	$ (22)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss	28,785	16,824
Total HTM fixed income securities carrying value	28,850	16,846
Fixed Income Securities, Available-for-sale, at fair value	6,709,976	6,455,928
Commercial mortgage loans, at carrying value, Gross	95,795	46,306
Commercial mortgage loans, Allowance for Credit Loss	0	0
Commercial mortgage loans, net of allowance for credit losses	95,795	46,306
Equity securities - at fair value	335,537	310,367
Short-term investments	447,863	409,852
Other investments	409,032	266,322
Total investments (Notes 5 and 7)	8,026,988	7,505,599
Cash	455	394
Restricted cash	44,608	14,837
Accrued investment income	48,247	45,004
Premiums Receivable, Gross	958,787	857,014
Premium Receivable, Allowance for Credit Loss	(13,600)	(21,000)
Premiums Receivable, Net of allowance for credit losses	945,187	836,014
Reinsurance Recoverables, Gross	601,668	589,269
Reinsurance Recoverable, Allowance for Credit Loss	(1,600)	(1,777)
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments	600,068	587,492
Prepaid reinsurance premiums (Note 9)	183,007	170,531
Property, Plant and Equipment, Net	82,053	77,696
Deferred policy acquisition costs (Note 2)	326,915	288,578
Goodwill (Note 12)	7,849	7,849
Other assets	195,240	153,919
Current federal income tax (Note 14)	772	0
Total assets	10,461,389	9,687,913
LIABILITIES AND STOCKHOLDERS’ EQUITY
Reserve for loss and loss expense (Note 10)	4,580,903	4,260,355
Unearned premiums	1,803,207	1,618,271
Long-term debt (Note 11)	506,050	550,743
Current federal income tax (Note 14)	0	14,021
Deferred federal income tax (Note 14)	13,413	27,096
Accrued salaries and benefits	121,057	114,868
Other liabilities	453,874	363,670
Total liabilities	7,478,504	6,949,024
Stockholders’ Equity:
Preferred stock of $0 par value per share (Note 17): Authorized shares: 5,000,000; Issued shares: 8,000 with $25,000 liquidation preference per share - 2021; no shares issued or outstanding - 2020	200,000	200,000
Common stock of $2 par value per share Authorized shares: 360,000,000 Issued: 104,450,916 - 2021; 104,032,912 - 2020	208,902	208,066
Additional paid-in capital	464,347	438,985
Retained earnings	2,603,472	2,271,537
Accumulated other comprehensive income (Note 6)	115,099	220,186
Treasury Stock, at cost	(608,935)	(599,885)
Total stockholders’ equity	2,982,885	2,738,889
Commitments and contingencies (Notes 19 and 20)
Total liabilities and stockholders’ equity	$ 10,461,389	$ 9,687,913

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed Income Securities, Held-to-maturity, Fair Value	$ 29,460	$ 18,001
Fixed Income Securities, Available-for-sale, Allowance for Credit Loss	(9,724)	(3,969)
Fixed income securities, Available-For-Sale, Amortized Cost	6,490,753	6,073,517
Commercial mortgage loan, fair value	97,598	47,289
Equity securities, cost	308,840	301,551
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 253,427	$ 240,150
Series B [Member]
Preferred Stock, Liquidation Preference (in dollars per share)	$ 25,000
Preferred Stock [Member]
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Par or Stated Value (in dollars per share)	$ 0	$ 0
Preferred Stock, Shares Issued		8,000
Common Stock [Member]
Common Stock, Shares Authorized	360,000,000	360,000,000
Common Stock, Shares, Issued	104,450,916	104,032,912
Common Stock, Par or Stated Value (in dollars per share)	$ 2	$ 2
Treasury Stock, Common
Treasury Stock, Shares	44,266,534	44,127,109

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Net premiums earned	$ 3,017,253	$ 2,681,814	$ 2,597,171
Net investment income earned	326,589	227,107	222,543
Net realized and unrealized investment gains (losses)	17,599	(4,217)	14,422
Other income	17,723	17,570	12,355
Total revenues	3,379,164	2,922,274	2,846,491
Expenses:
Loss and loss expense incurred	1,813,984	1,635,823	1,551,491
Amortization of deferred policy acquisition costs	626,469	560,271	535,973
Other insurance expenses	375,931	366,941	358,069
Interest expense	29,165	30,839	33,668
Corporate expenses	28,305	25,412	30,900
Total expenses	2,873,854	2,619,286	2,510,101
Income before federal income tax	505,310	302,988	336,390
Federal income tax expense:
Current	87,335	60,059	60,640
Deferred	14,138	(3,426)	4,127
Total federal income tax expense	101,473	56,633	64,767
Net income	403,837	246,355	271,623
Preferred stock dividends	9,353	0	0
Net Income available to common stockholders	$ 394,484	$ 246,355	$ 271,623
Earnings per common share:
Net income available to common stockholders - Basic (in dollars per share)	$ 6.55	$ 4.12	$ 4.57
Net income available to common stockholders - Diluted (in dollars per share)	$ 6.50	$ 4.09	$ 4.53

Consolidation Statements of Com

Consolidation Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income	$ 403,837	$ 246,355	$ 271,623
Unrealized holding (losses) gains arising during year	119,598	133,104	168,021
Unrealized losses on securities with credit loss recognized in earnings	(7,159)	(6,459)	0
Amounts reclassified into net income: Held-to-maturity securities	(9)	(19)	(46)
Amounts reclassified into net income: Net realized losses on disposals and losses on intent-to-sell available-for-sale securities	(3,022)	(4,247)	(530)
Amounts reclassified into net income: Credit loss expense	5,418	(3,984)	0
Total unrealized (losses) gains on investment securities	124,370	134,857	168,505
Net actuarial gain (loss)	(17,093)	1,197	10,898
Amounts reclassified into net income: Net actuarial loss	2,190	2,382	2,099
Total defined benefit pension and post-retirement plans	19,283	3,579	(8,799)
Other comprehensive (loss) income	(105,087)	138,436	159,706
Comprehensive income	$ 298,750	$ 384,791	$ 431,329

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional paid-in capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings [Member]Accounting Standards Update 2016-02 [Member]	Retained Earnings [Member]Accounting Standards Update 2016-13 [Member]	Accumulated other comprehensive (loss) income [Member]	Treasury stock [Member]
Beginning of year at Dec. 31, 2018		$ 0	$ 205,697	$ 390,315	$ 1,858,414	$ 1,858,756	$ 342	$ 0	$ (77,956)	$ (584,668)
Dividend reinvestment plan			44	1,510
Preferred stock issuance costs				0
Preferred stock issuance costs		0
Stock purchase and compensation plans			1,227	26,696
Net income	$ 271,623				271,623
Dividends, Preferred Stock, Cash					0
Dividends to common stockholders					(49,850)
Other comprehensive (loss) income	159,706								159,706
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans										0
End of year at Dec. 31, 2019	$ 2,194,936	$ 0	206,968	418,521	2,080,529	2,081,964	0	1,435	81,750	(592,832)
Dividends declared per preferred share	$ 0
Dividends declared per common share	$ 0.83
Preferred stock, shares outstanding, beginning of period at Dec. 31, 2018	0
Preferred stock, shares outstanding, ending of period at Dec. 31, 2019	0
Preferred Stock, Shares Issued		0
Common Stock, shares outstanding, beginning of period at Dec. 31, 2018	58,948,554
Dividend reinvestment plan	22,087
Stock purchase and compensation plan	613,678
Acquisition of treasury stock	0
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation	123,166
Common Stock, shares outstanding, end of period at Dec. 31, 2019	59,461,153
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation										(8,164)
Dividend reinvestment plan			58	1,645
Preferred stock issuance costs				(5,416)
Preferred stock issuance costs		$ 200,000
Stock purchase and compensation plans			1,040	24,235
Net income	$ 246,355				246,355
Dividends, Preferred Stock, Cash					0
Dividends to common stockholders					(56,782)
Other comprehensive (loss) income	138,436								138,436
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans										0
End of year at Dec. 31, 2020	$ 2,738,889	$ 200,000	208,066	438,985	2,271,537	$ 2,271,537	$ 0	$ 0	220,186	(599,885)
Dividends declared per preferred share	$ 0
Dividends declared per common share	$ 0.94
Preferred stock, shares outstanding, ending of period at Dec. 31, 2020	8,000
Preferred Stock, Shares Issued		8,000
Dividend reinvestment plan	28,890
Stock purchase and compensation plan	519,863
Acquisition of treasury stock	0
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation	104,103
Common Stock, shares outstanding, end of period at Dec. 31, 2020	59,905,803
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation										(7,053)
Dividend reinvestment plan			46	1,707
Preferred stock issuance costs				0
Preferred stock issuance costs		$ 0
Stock purchase and compensation plans			790	23,655
Net income	$ 403,837				403,837
Dividends, Preferred Stock, Cash					9,353
Dividends to common stockholders					(62,549)
Other comprehensive (loss) income	(105,087)								(105,087)
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans	(3,400)									(3,404)
End of year at Dec. 31, 2021	$ 2,982,885	$ 200,000	$ 208,902	$ 464,347	$ 2,603,472				$ 115,099	(608,935)
Dividends declared per preferred share	$ 1,169.17
Dividends declared per common share	$ 1.03
Preferred stock, shares outstanding, ending of period at Dec. 31, 2021	8,000
Preferred Stock, Shares Issued		0
Dividend reinvestment plan	22,986
Stock purchase and compensation plan	395,018
Acquisition of treasury stock	(52,781)
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation	86,644
Common Stock, shares outstanding, end of period at Dec. 31, 2021	60,184,382
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation										$ (5,646)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net income	$ 403,837	$ 246,355	$ 271,623
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	55,109	59,350	55,205
Stock-based compensation expense	15,893	16,227	19,077
Undistributed gains of equity method investments	(69,873)	(12,408)	(12,773)
Distributions in excess of current year income of equity method investments	2,910	3,472	2,807
Net realized and unrealized (gains) losses	(17,599)	4,217	(14,422)
Loss on disposal of fixed assets	50	22	42
Changes in assets and liabilities:
Increase in reserve for loss and loss expense, net of reinsurance recoverable	307,972	181,839	149,232
Increase in unearned premiums, net of prepaid reinsurance	172,460	91,278	82,253
(Increase) decrease in net federal income taxes	(542)	7,708	7,721
Increase in premiums receivable	(109,173)	(13,171)	(53,383)
Increase in Deferred Policy Acquisition Costs	(38,337)	(17,392)	(18,574)
Increase in accrued investment income	(3,243)	(158)	(3,226)
Increase (decrease) in accrued salaries and benefits	7,216	(13,264)	(3,748)
Increase in other assets	(33,379)	(27,927)	(39,337)
Increase in other liabilities	78,121	27,897	34,998
Net cash provided by operating activities	771,422	554,045	477,495
Investing Activities
Purchase of fixed income securities, held-to-maturity	(16,250)	0	0
Purchase of fixed income securities, available-for-sale	(2,165,555)	(1,723,818)	(1,856,125)
Purchase of commercial mortgage loans	(50,204)	(46,506)	0
Purchase of other investments	(85,044)	(79,598)	(64,908)
Purchase of short-term investments	(4,345,140)	(5,762,725)	(6,087,909)
Sale of fixed income securities, available-for-sale	502,911	487,087	594,743
Proceeds from commercial mortgage loans	714	201	0
Sale of short-term investments	4,306,684	5,635,463	6,129,885
Redemption and maturities of fixed income securities, held-to-maturity	4,192	3,888	16,149
Redemption and maturities of fixed income securities, available-for-sale	1,217,555	1,019,132	626,686
Sale of equity securities	99,235	1,320	137,294
Sale of other investments	5,428	5,375	17,964
Distributions from other investments	17,497	24,884	19,972
Fixed asset disposals	0	0	9
Purchase of property and equipment	(22,163)	(22,064)	(30,986)
Net cash used in investing activities	(618,780)	(688,174)	(543,623)
Financing Activities
Dividends to preferred stockholders	(9,353)	0	0
Dividends to common stockholders	(60,136)	(54,486)	(47,675)
Acquisition of treasury stock	(9,050)	(7,053)	(8,164)
Net proceeds from stock purchase and compensation plans	7,976	8,411	8,243
Preferred stock issued, net of issuance costs	(479)	195,063	0
Proceeds from borrowings	0	587,000	355,757
Repayment of borrowings	(50,000)	(587,000)	(250,000)
Repayment of finance lease obligations	(1,768)	(550)	(977)
Net cash (used in) provided by financing activities	(122,810)	141,385	57,184
Net increase (decrease) in cash and restricted cash	29,832	7,256	(8,944)
Cash and restricted cash, beginning of year	15,231	7,975	16,919
Cash and restricted cash, end of year	45,063	15,231	7,975
Payments to Acquire Equity Securities, FV-NI	$ (88,640)	$ (230,813)	$ (46,397)

Organization

Organization	12 Months Ended
	Dec. 31, 2021
Organization [Abstract]
Organization	Organization Selective Insurance Group, Inc., through its subsidiaries, (collectively referred to as “we,” “us,” or “our”) offers standard commercial, standard personal, and excess and surplus ("E&S") lines property and casualty insurance products. Selective Insurance Group, Inc. (referred to as the “Parent”) was incorporated in New Jersey in 1977 and its corporate headquarters is located in Branchville, New Jersey. The Parent’s common and preferred stock are publicly traded on the Nasdaq Global Select Market under the symbols “SIGI” and "SIGIP," respectively. We have provided a glossary of terms as Exhibit 99.1 to this Form 10-K, which defines certain industry-specific and other terms that are used in this Form 10-K. We classify our business into four reportable segments, which are as follows: • Standard Commercial Lines – comprised of property and casualty insurance products and services provided in the standard marketplace to commercial enterprises, which are typically businesses, non-profit organizations, and local government agencies. • Standard Personal Lines – comprised of property and casualty insurance products and services, including flood insurance coverage, provided primarily to individuals acquiring coverage in the standard marketplace. • E&S Lines – comprised of property and casualty insurance products and services provided to customers who are unable to obtain coverage in the standard marketplace. • Investments – invests the premiums collected by our insurance operations, as well as amounts generated through our capital management strategies, which may include the issuance of debt and equity securities.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Signifcant Accounting Policies	Summary of Significant Accounting Policies (a) Principles of Consolidation The accompanying consolidated financial statements (“Financial Statements”) include the accounts of the Parent and its subsidiaries, and have been prepared in conformity with: (i) United States ("U.S.") generally accepted accounting principles ("GAAP"); and (ii) the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation. (b) Use of Estimates The preparation of our Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported financial statement balances, as well as the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. (c) Investments Portfolio Composition and Presentation in the Consolidated Balance Sheet Our investment portfolio is primarily comprised of fixed income investments. We also hold commercial mortgage loans ("CMLs"), equity securities, short-term investments, and other investments. A description of our portfolio holdings, and the related presentation in our Consolidated Balance Sheet, is provided below. Fixed Income Investments Our fixed income investments include our fixed income securities portfolio and our CML portfolio. Fixed Income Securities We hold the following types of securities in our fixed income securities portfolio: • U.S. government and government agency obligations; • Foreign government obligations; • Obligations of states and political subdivisions, including special revenue and general obligation bonds; • Corporate securities, which may include investment grade and below investment grade bonds, bank loan investments, redeemable preferred stock, and non-redeemable preferred stock with certain debt-like characteristics; • Collateralized loan obligations ("CLOs") and other asset-backed securities ("ABS"); • Residential mortgage-backed securities ("RMBS"); and • Commercial mortgage-backed securities ("CMBS"). We have designated substantially all of the holdings in our fixed income securities as available-for-sale ("AFS"). These securities are reported at fair value in our Consolidated Balance Sheet. The after-tax difference between fair value and cost or amortized cost is reflected in stockholders’ equity as a component of accumulated other comprehensive income (loss) ("AOCI"). The amortized cost of fixed income securities is adjusted for the amortization of premiums and the accretion of discounts over the expected life of the security using the effective yield method. Callable debt securities held at a premium are amortized to the earliest call date. Premiums and discounts arising from the purchase of RMBS, CMBS, CLO and other ABS are amortized over the expected life of the security based on future principal payments, giving additional consideration to prepayments. These prepayments are estimated based on historical and projected cash flows. Prepayment assumptions are reviewed quarterly and adjusted to reflect actual prepayments and changes in expectations. Future amortization of any premium and/or discount is adjusted to reflect the revised assumptions. Accrued interest on our fixed income securities is recorded as a component of “Accrued investment income” on our Consolidated Balance Sheet. If accrued interest is due but not paid within 90 days, we reverse the delinquent amount and record this reversal through earnings as a component of “Net investment income earned” on our Consolidated Statement of Income. CMLs CMLs are loans secured by commercial property, such as an office building, multi-family apartment complex, industrial warehouse, or shopping center. We may acquire investments in CMLs through (i) direct originations under a loan syndication arrangement or (ii) a marketplace purchase. We record our investment in CMLs on the settlement date of the loan. Our CMLs are classified as held-for-investment and reported at amortized cost, net of any allowance for credit losses ("ACL"), on our Consolidated Balance Sheet. Interest is recorded using the effective yield method and accrued interest on our CMLs is recorded as a component of “Accrued investment income” on our Consolidated Balance Sheet. Other Portfolio Holdings Equity securities may include common and non-redeemable preferred stocks. Equity securities with readily determinable fair values are reported at fair value. Equity securities without readily determinable fair values are reported at net asset value ("NAV") as a practical expedient. Short-term investments may include money market instruments, savings accounts, commercial paper, and fixed income securities purchased with a maturity of less than one year. We may also enter into reverse repurchase agreements that are included in short-term investments. These repurchase agreements are fully collateralized by high-quality, readily-marketable instruments that support the principal amount. At maturity, we receive principal and interest income on these agreements. Short-term investments are generally reported at fair value. Other investments are primarily comprised of alternative investments, which are limited partnership investments in private equity, private credit, and real estate strategies. These alternative investments are accounted for using the equity method, with income typically recognized on a one-quarter lag. Because these alternative investments are recorded under the equity method of accounting, with the underlying holdings carried at fair value, the valuation and income recognized on these investments may be impacted by volatility in the financial markets. In addition to our alternative investments, our other investment portfolio includes Federal Home Loan Bank stock (“FHLB Stock”) and tax credit investments. The FHLB Stock is reported at cost. Accounting for our tax credit investments is dependent on the type of credit we have purchased, as follows: • Federal low income housing tax credits are accounted for under the proportional amortization method; and • All other tax credits in our investment portfolio are accounted for using the equity method. For federal tax credits accounted for under the equity method, we use the deferral method for recognizing the benefit of the tax credit with the related deferred revenue being recognized in our Consolidated Income Statement as a component of "Federal income tax expense" proportionately over the life of the investment. We categorize distributions from our investments accounted for using the equity method on our Consolidated Statement of Cash Flows using the cumulative earnings approach. Under this approach, distributions received are classified as cash flows from operating activities until such time that the cumulative distributions exceed cumulative earnings for the investment. When such an excess occurs, the excess portion of the current period distribution is considered a return of investment and is classified as a cash flow from investing activities. We evaluate the alternative investments and tax credit investments included in our other investments portfolio to determine whether those investments are variable interest entities ("VIEs") and if so, whether consolidation is required. A VIE is an entity that either has equity investors that lack certain essential characteristics of a controlling financial interest or lack sufficient funds to finance its own activities without financial support provided by other entities. We consider several significant factors in determining if our investments are VIEs and if we are the primary beneficiary, including whether we have (i) the power to direct activities of the VIE, (ii) the ability to remove the decision maker of the VIE, (iii) the ability to participate in making decisions that are significant to the VIE, and (iv) the obligation to absorb losses and the right to receive benefits that could potentially be significant to the VIE. We have reviewed our alternative and tax credit investments and have concluded that they are VIEs, but that we are not the primary beneficiary and therefore, consolidation is not required. Presentation in the Consolidated Statement of Income Net Investment Income Earned Net investment income earned on our Consolidated Statement of Income includes the following: • Interest income, as well as amortization and accretion, on fixed income securities; • Interest income on CMLs; • Dividend income on equity securities; • Interest income on our short-term investments; and • Income recognized on our alternative and other investments accounted for under the equity method of accounting, except for federal tax credits, as discussed below. Income related to federal tax credits (either low income housing tax credits or other federal credits) is recorded in our Consolidated Statement of Income as a component of “Federal income tax expense” proportionately over the life of the investment. Net Realized and Unrealized Investment (Losses) Gains Net realized and unrealized investment gains (losses) on our Consolidated Statement of Income include the following: • Realized gains and losses on the disposal of holdings in our investment portfolio, which are determined on the basis of the cost of the specific investments sold; • Changes in unrealized gains or losses on our equity securities; • Losses on investments for which we have the intent to sell, which are discussed further below; and • Net credit loss expense or benefit resulting from changes in the ACL related to our investment portfolio, which is also discussed further below. Losses on securities for which we have the intent to sell and ACL on AFS Fixed Income Securities and Short-Term Investments We review our fixed income securities in an unrealized loss position to determine (i) if we have the intent to sell the security, or (ii) if it is more likely than not we will be required to sell the security before its anticipated recovery. If we determine that we have the intent or likely requirement to sell the security, we write down its amortized cost to its fair value. In writing down amortized cost, any amount previously recorded as an ACL is reversed and any incremental reduction in amortized cost is recorded directly to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. When fixed income securities are in an unrealized loss position and we do not record any losses on securities for which we intend to sell, we record an ACL for the portion of the unrealized loss due to an expected credit loss. We estimate expected credit losses on fixed income securities by performing a discounted cash flow (“DCF”). The ACL is equal to the excess of amortized cost over the greater of: (i) our estimate of the present value of expected future cash flows, or (ii) fair value. The ACL is recorded as a contra-asset reflected in the carrying value of the investment on the Consolidated Balance Sheet. The initial ACL and any subsequent changes are recorded to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. Any remaining unrealized loss is the non-credit amount and is recorded in AOCI. The ACL cannot exceed the unrealized loss of an AFS security and therefore it may fluctuate with changes in the fair value of the security. The ACL is written off against the amortized cost basis in the period in which it is determined uncollectible. Our DCF analyses calculate the present value of expected future cash flows using various models specific to the major security types in our portfolio. These models use security-specific information, as well as reasonable and forecasted macroeconomic data, to determine possible expected credit loss scenarios based on projected changes in the economy. The forecasted economic data incorporated into the models is based on the Federal Reserve Board’s annual supervisory stress test review on certain large banks and financial institutions. We also have the ability to incorporate internally-developed forecast information into the models as we deem appropriate. The discount rate used in a DCF is one of the following: • The current yield in effect at the reporting date to accrete the beneficial interest for RMBS, CMBS, CLO and other ABS that were not of high credit quality at acquisition; • The effective interest rate in effect as of the reporting date for non-fixed rate securities; and • The effective interest rate implicit in the security at the date of acquisition for all other securities. DCFs may include, but are not necessarily limited to: (i) generating cash flows for each tranche considering tranche-specific data, market data, and other pertinent information, such as the historical performance of the underlying collateral, including net operating income generated by underlying properties, conditional default rate assumptions, loan loss severity assumptions, consensus projections, prepayment projections, and actual pool and collateral information; (ii) identifying applicable benchmark yields; and (iii) applying market-based tranche specific spreads to determine an appropriate yield by incorporating collateral performance, tranche-level attributes, trades, bids, and offers. We do not record a valuation allowance on the accrued interest balance associated with our fixed income securities as we reverse delinquent amounts on a timely basis. We consider a fixed income security to be past due at the time any principal or interest payments become 90 days delinquent. ACL on CMLs We evaluate our CMLs on a quarterly basis for expected credit losses. If we hold a CML with a specific credit concern, we record an individual ACL on that loan. For all other CMLs, we record an ACL on the pool of loans based on lifetime expected credit losses. The ACL is recorded as a contra-asset reflected in the carrying value of our CMLs on the Consolidated Balance Sheet. Our initial ACL and any subsequent changes are recorded to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. We utilize a forecasting model to estimate lifetime expected credit losses at a loan level under multiple economic scenarios. The scenarios apply reasonable and forecasted macroeconomic data such as unemployment and inflation to project property-specific operating income and capitalization rates that are used to estimate the value of the future operating income stream. This information, coupled with historical data about mortgage loan performance, is used to project the probability of default, the amount of loss given a default, and the resulting lifetime expected loss. Losses on securities for which we have the intent to sell and Credit Losses on Other Investments If we determine that we intend to sell a holding in our investment portfolio and the expected proceeds are less than the recorded value of the investment, we will record a loss on those securities we intend to sell in earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. Additionally, we review our alternative investment portfolio for potential credit losses through quarterly fund reports and conversations with the general partners of the alternative investments concerning the following: • The current investment strategy; • Changes made or future changes to be made to the investment strategy; • Emerging issues that may affect the success of the strategy; and • The appropriateness of the valuation methodology used regarding the underlying investments. Our evaluation for potential credit loss on tax credits and FHLB Stock include a qualitative assessment of credit indicators, which include, but are not limited to, the following: • An adverse development of the expected receipt of remaining tax credits and other tax benefits; and • A significant deterioration in the financial condition or liquidity of the Federal Home Loan Bank. If we do not intend to sell a security, and we expect a credit loss on a holding in our other investments portfolio, we record a charge to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. (d) Fair Values of Financial Instruments Assets The fair values of our investments are generated using various valuation techniques and are placed into the fair value hierarchy considering the following: (i) the highest priority is given to quoted prices in active markets for identical assets (Level 1); (ii) the next highest priority is given to quoted prices in markets that are not active or inputs that are observable either directly or indirectly, including quoted prices for similar assets in markets that are not active and other inputs that can be derived principally from, or corroborated by, observable market data for substantially the full term of the assets (Level 2); and (iii) the lowest priority is given to unobservable inputs supported by little or no market activity and that reflect our assumptions about the exit price, including assumptions that market participants would use in pricing the asset (Level 3). An asset’s classification within the fair value hierarchy is based on the lowest level of significant input to its valuation. The techniques used to value our financial assets are as follows: Level 1 Pricing Security Type Methodology Equity Securities; U.S. Treasury Notes Equity and U.S. Treasury Note prices are received from an independent pricing service that are based on observable market transactions. We validate these prices against a second external pricing service, and if established market value comparison thresholds are breached, further analysis is performed to determine the price to be used. Short-Term Investments Short-term investments are recorded at fair value. Given the liquid nature of our short-term investments, we generally validate their fair value by way of active trades within approximately one week of the financial statement close. Level 2 Pricing We utilize a market approach for our Level 2 securities, using primarily matrix pricing models prepared by external pricing services. Matrix pricing models use mathematical techniques to value fixed income securities by relying on the securities' relationship to other benchmark quoted securities, and not relying exclusively on quoted prices for specific securities, as the specific securities are not always frequently traded. As a matter of policy, we consistently use one pricing service as our primary source and secondary pricing services if prices are not available from the primary pricing service. Fixed income security pricing is reviewed for reasonableness by (i) comparing our pricing to other third-party pricing services as well as benchmark indexed pricing, (ii) comparing fair value fluctuations between months for reasonableness, (iii) reviewing stale prices, and (iv) internally reviewing prices for reasonableness if a price from another third-party source is not available. If further analysis is needed, a challenge is sent to the pricing service for review and confirmation of the price. Further information on our Level 2 asset pricing is included in the following table: Security Type Methodology Corporate Securities including preferred stocks classified as Fixed Income Securities, and U.S. Government and Government Agencies Evaluations include obtaining relevant trade data, benchmark quotes and spreads, and incorporating this information into either spread-based or price-based evaluations as determined by the observed market data. Spread-based evaluations include: (i) creating a range of spreads for relevant maturities of each issuer based on the new issue market, secondary trading, and dealer quotes; and (ii) incorporating option adjusted spreads for issues that have early redemption features. Based on the findings in (i) and (ii) above, final spreads are derived and added to benchmark curves. Price-based evaluations include matching each issue to its best-known market maker and contacting firms that transact in these securities. Obligations of States and Political Subdivisions Evaluations are based on yield curves that are developed based on factors such as: (i) benchmarks to issues with interest rates near prevailing market rates; (ii) established trading spreads over widely-accepted market benchmarks; (iii) yields on new issues; and (iv) market information from third-party sources such as reportable trades, broker-dealers, or issuers. RMBS, CMBS, CLO and other ABS Evaluations are based on a DCF, including: (i) generating cash flows for each tranche considering tranche-specific data, market data, and other pertinent information, such as historical performance of the underlying collateral, including net operating income generated by the underlying properties, conditional default rate assumptions, loan loss severity assumptions, consensus projections, prepayment projections, and actual pool and loan level collateral information; (ii) identifying applicable benchmark yields; and (iii) applying market-based tranche-specific spreads to determine an appropriate yield by incorporating collateral performance, tranche-level attributes, trades, bids, and offers. Foreign Government Evaluations are performed using a DCF model and by incorporating observed market yields of benchmarks as inputs, adjusting for varied maturities. Level 3 Pricing Security Type Methodology CMLs Evaluations are performed by a third-party and are based on matrix pricing. For fixed rate loans, the matrix process uses a yield build up approach to create a pricing yield, with components for base yield, credit quality spread, property type spread, and a weighted average life spread. Floating rate loans are priced with a target quality spread over the swap curve. In addition to our CML portfolio, certain securities in our AFS fixed income portfolio are priced using unobservable inputs. These valuations are primarily based on broker quotes, or they are received from other third-party sources, for which there is a lack of transparency as to the inputs used to generate the valuation. The quantitative detail of these unobservable inputs is neither provided to us, nor reasonably available to us. Liabilities The techniques used to value our notes payable are as follows: Level 2 Pricing Security Type Methodology 7.25% Senior Notes; 6.70% Senior Notes; Based on matrix pricing models prepared by external pricing services. Borrowings from Federal Home Loan Banks Evaluations are performed using a DCF model based on current borrowing rates provided by the Federal Home Loan Banks that are consistent with the remaining term of the borrowing. (e) Allowance for Credit Losses on Premiums Receivable We estimate an ACL on our outstanding premiums receivable balance at each reporting date. In determining this allowance, we use a method that considers the aging of the receivable, based on the effective year of the related policy, along with our historical receivable loss experience. We also contemplate expected macroeconomic conditions over the expected collection period, which are short-term in nature because the majority of the balances are collected within two years of policy issuance. Changes in our ACL are charged to earnings as credit loss expense or benefit, which is a component of "Other insurance expenses" on our Consolidated Statements of Income, with an offsetting ACL recorded as a contra-asset reflected in the carrying value of the receivable. We charge write-offs against the allowance when we determine the account to be uncollectible after considering information obtained from our collection efforts. (f) Share-Based Compensation Share-based compensation consists of all share-based payment transactions in which an entity acquires goods or services by issuing (or offering to issue) its shares, share units, share options, or other equity instruments. The cost resulting from all share-based payment transactions are recognized in the Financial Statements based on the fair value of both equity and liability awards. The fair value is measured at grant date for equity awards, whereas the fair value for liability awards are remeasured at each reporting period. The fair value of both equity and liability awards is recognized over the requisite service period. The requisite service period is typically the lesser of the vesting period or the period of time from the grant date to the date of retirement eligibility. The expense recognized for share-based awards, which, in some cases, contain performance criteria, is based on the number of shares or units expected to be issued at the end of the performance period. We repurchase the Parent’s stock from our employees in connection with tax withholding obligations, as permitted under our stock-based compensation plans. This activity is disclosed in our Consolidated Statement of Stockholders' Equity. (g) Reinsurance The “Reinsurance recoverable” balance on our Consolidated Balance Sheet represents our estimate of amounts that will be recovered from reinsurers under our various treaties. Generally, amounts recoverable from reinsurers are recognized as assets at the same time and in a manner consistent with the paid and unpaid losses associated with the reinsured policies. We would consider a recoverable balance from a reinsurer to be past due if payment is not received by the first day following the invoice due date. We require collateral to secure reinsurance recoverable balances primarily from our reinsurance carriers that are not authorized, otherwise approved, or certified to do business in one or more of our ten insurance subsidiaries' domiciliary states. Our ten insurance subsidiaries are collectively referred to as the "Insurance Subsidiaries." The collateral received is typically in the form of a letter of credit, trust funds, or funds withheld against reinsurance recoverables. We estimate an ACL on our outstanding reinsurance recoverable balance at each reporting date. Credit risk is mitigated to the extent we have obtained collateral. As part of our estimation of the ACL, we reduce the recoverable balance by the amount of the collateral. We then pool the uncollateralized balances by similar risk characteristics, including the financial strength rating of the reinsurer, and use a probability-of-default methodology to calculate the allowance. Historical default rates are sourced from AM Best Company ("AM Best") and are coupled with severity assumptions in developing a baseline scenario. We then stress this scenario by incorporating forecasts of industry catastrophe losses and economic factors sourced through third-party data providers. In developing our best estimate of the allowance for credit losses, we consider our outlook as to the probability of each of these scenarios occurring. Changes in our ACL are charged to earnings as credit loss expense, which is a component of “Loss and loss expense incurred” on our Consolidated Statement of Income, with an offsetting ACL recorded as a contra-asset reflected in the carrying value of the recoverable balance. We charge write-offs against the ACL when we determine the recoverable balance to be uncollectible after considering information obtained from our efforts to collect amounts due or through a review of the financial condition of the reinsurer. (h) Property and Equipment Property and equipment used in operations, including certain costs incurred to develop or obtain computer software for internal use, are capitalized and recorded at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. The following estimated useful lives can be considered as general guidelines: Asset Category Years Computer hardware 3 Computer software 3 to 5 Software licenses 3 to 5 Internally developed software 5 Furniture and fixtures 10 Buildings and improvements 5 to 40 We recorded depreciation expense of $24.3 million, $21.5 million, and $18.7 million for 2021, 2020, and 2019, respectively. (i) Deferred Policy Acquisition Costs Deferred policy acquisition costs are limited to costs directly related to the successful acquisition of insurance contracts. Costs meeting this definition typically include, among other things, sales commissions paid to our distribution partners, premium taxes, and the portion of employee salaries and benefits directly related to time spent on acquired contracts. These costs are deferred and amortized over the life of the contracts. Accounting guidance requires a premium deficiency analysis to be performed at the level an entity acquires, services, and measures the profitability of its insurance contracts. We currently perform three premium deficiency analyses for our insurance operations, consistent with our reportable segments of Standard Commercial Lines, Standard Personal Lines, and E&S Lines. A combined ratio of over 100% does not necessarily indicate a premium deficiency, as any year's combined ratio includes a portion of underwriting expenses that are expensed at policy inception and therefore are not covered by the remaining unearned premium. In addition, investment income is not contemplated in the combined ratio calculation. There were no premium deficiencies for any of the reported years, as the sum of the anticipated loss and loss expense, unamortized acquisition costs, policyholder dividends, and other expenses for each segment did not exceed that segment’s related unearned premium and anticipated investment income. The investment yields assumed in the premium deficiency assessment for each reporting period, which were based on our actual average investment yield before tax as of the September 30 calculation date, were 4.3% for 2021, 3.0% for 2020, and 3.5% for 2019. (j) Goodwill Goodwill results from business acquisitions where the cost of assets and liabilities acquired exceeds the fair value of those assets and liabilities. A quantitative goodwill impairment analysis is performed if our quarterly qualitative analysis indicates that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. Goodwill is allocated to the reporting units for purposes of these analyses. Based on our analysis at December 31, 2021, goodwill was not impaired. (k) Reserve for Loss and Loss Expense Reserves for loss and loss expense includes case reserves on reported claims and reserves known as incurred but not reported ("IBNR") reserves. Case reserves are estimated on each individual claim, and based on claim-specific facts and circumstances known at the time. The case reserves may be adjusted upward or downward as the specific facts and circumstances change. IBNR reserves are established at more aggregated levels and include provisions for (i) claims not yet reported, (ii) future development on reported claims, (iii) previously closed claims that could be reopened in the future, and (iv) anticipated salvage and subrogation recoveries. We evaluate our reserves quarterly, through our comprehensive reserve review process and adjustments to recorded reserves are made accordingly. The primary input in evaluating reserve levels is the quarterly reserve review prepared by our internal actuaries, which provides comprehensive loss and loss expense projections. Our reviews are based primarily on our own loss experience, organized by line of business. Where sufficient statistical credibility exists, we may further segment the experience by coverage within line, or by geographic area. Generally accepted actuarial methodologies are applied to these reserve groups to produce ultimate loss and loss expense projections. Typically, we organize our experience by accident year and age, which lends itself to the application of various loss development methods. These methods rely on historical claims reporting and payment patterns to project ultimate loss or expense for open accident years. Consideration is also given to the prior loss estimate, particularly for longer-tailed lines of business, and the current accident year. For the current accident year, this expectation comes from our detailed actuarial planning process. The initial estimate is adjusted over time as actual experience emerges. These methods require numerous assumptions, such as the selection of loss and loss expense development factors and the weight applied to each individual projection method, among others. Therefore, no single method can be interpreted as definitive. Instead, ulti

Adoption of Accounting Pronounc

Adoption of Accounting Pronouncements	12 Months Ended
	Dec. 31, 2021
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]	Adoption of Accounting Pronouncements In December 2019, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2019-12, Income Taxes - Simplifying the Accounting for Income Taxes (“ASU 2019-12”). Among other items, ASU 2019-12 simplifies the accounting treatment of tax law changes and year-to-date losses in interim periods. An entity generally recognizes the effects of a change in tax law in the period of enactment; however, there is an exception for tax laws with delayed effective dates. Under current guidance, an entity may not adjust its annual effective tax rate for a tax law change until the period in which the law is effective. ASU 2019-12 provides that all effects of a tax law change, including adjustment of the estimated annual effective tax rate, are recognized in the period of enactment. For year-to-date losses in interim periods, an entity is required currently to estimate its annual effective tax rate for the full fiscal year at the end of each interim period and use that rate to calculate its income taxes on a year-to-date basis. When an interim period loss exceeds the anticipated loss for the year, the income tax benefit is limited to the amount that would be recognized if the year-to-date loss were the anticipated loss for the full year. ASU 2019-12 removes this limitation and an entity would compute its income tax benefit at each interim period based on its estimated annual effective tax rate. We adopted this guidance on January 1, 2021, and it did not have a material impact to our financial condition, cash flows, or results of operations. Pronouncements to be effective in the future In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) - Facilitation of the Effects of Reference Rate Reform on Financial Reporting (“ASU 2020-04”). ASU 2020-04 provides optional expedients and exceptions to the guidance in GAAP on contract modifications and hedge accounting to ease the financial reporting burdens related to the expected market transition away from the London Interbank Offered Rate (LIBOR) and other interbank offered rates to alternative reference rates. Companies can elect to adopt ASU 2020-04 as of the beginning of the interim period that includes March 2020, or any date thereafter through December 31, 2022. We are currently evaluating the impact of this guidance on our financial condition and results of operations.

Statements of Cash Flow

Statements of Cash Flow	12 Months Ended
	Dec. 31, 2021
Supplemental Cash Flow Information [Abstract]
Statements of Cash Flow	Statements of Cash Flows Supplemental cash flow information for the years ended December 31, 2021, 2020, and 2019 is as follows: ($ in thousands) 2021 2020 2019 Cash paid during the period for: Interest $ 28,930 30,464 25,089 Federal income tax 100,000 47,000 55,825 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases 7,935 9,498 8,138 Operating cash flows from financing leases 35 15 16 Financing cash flows from finance leases 1,768 550 977 Non-cash items: Corporate actions related to fixed income securities, AFS 1 56,365 55,446 61,369 Corporate actions related to fixed income securities, held-to-maturity ("HTM") 1 — 2,589 — Corporate actions related to equity securities 1 30,666 10,890 14,250 Conversion of AFS fixed income securities to equity securities 15,139 — — Assets acquired under finance lease arrangements 6,709 324 824 Assets acquired under operating lease arrangements 3,272 22,390 13,808 Non-cash purchase of property and equipment 472 590 89 1 Examples of corporate actions include like-kind exchanges, non-cash acquisitions, and stock-splits. The following table provides a reconciliation of cash and restricted cash reported within the Consolidated Balance Sheets that equate to the amount reported in the Consolidated Statements of Cash Flows: ($ in thousands) December 31, 2021 December 31, 2020 Cash $ 455 394 Restricted cash 44,608 14,837 Total cash and restricted cash shown in the Statements of Cash Flows $ 45,063 15,231 Amounts included in restricted cash represent cash received from the National Flood Insurance Program ("NFIP"), which is restricted to pay flood claims under the Write Your Own Program.

Investments

Investments	12 Months Ended
	Dec. 31, 2021
Investments [Abstract]
Investments	Investments (a) Net unrealized gains on investments included in OCI by asset class were as follows for the years ended December 31, 2021, 2020, and 2019: ($ in thousands) 2021 2020 2019 AFS securities: Fixed income securities $ 228,947 386,380 215,634 Total AFS securities 228,947 386,380 215,634 HTM securities: Fixed income securities (4) 7 31 Total HTM securities (4) 7 31 Short-term securities 20 6 23 Total net unrealized gains 228,963 386,393 215,688 Deferred income tax (48,082) (81,142) (45,294) Net unrealized gains, net of deferred income tax 180,881 305,251 170,394 Increase (decrease) in net unrealized gains in OCI, net of deferred income tax $ (124,370) 134,857 168,505 (b) Information regarding our AFS securities as of December 31, 2021 and December 31, 2020 were as follows: December 31, 2021 Cost/ Amortized Allowance for Unrealized Unrealized Fair ($ in thousands) Cost Credit Losses Gains Losses Value AFS fixed income securities: U.S. government and government agencies $ 127,974 — 3,629 (1,145) 130,458 Foreign government 15,420 (46) 609 (123) 15,860 Obligations of states and political subdivisions 1,121,422 (137) 68,258 (235) 1,189,308 Corporate securities 2,478,348 (6,682) 106,890 (4,953) 2,573,603 CLO and other ABS 1,343,687 (939) 14,350 (6,284) 1,350,814 RMBS 756,280 (1,909) 24,813 (2,932) 776,252 CMBS 647,622 (11) 27,752 (1,682) 673,681 Total AFS fixed income securities $ 6,490,753 (9,724) 246,301 (17,354) 6,709,976 December 31, 2020 Cost/ Amortized Allowance for Unrealized Unrealized Fair ($ in thousands) Cost Credit Losses Gains Losses Value AFS fixed income securities: U.S. government and government agencies $ 110,038 — 6,239 (137) 116,140 Foreign government 16,801 (1) 1,569 (3) 18,366 Obligations of states and political subdivisions 1,159,588 (4) 87,564 (11) 1,247,137 Corporate securities 2,152,203 (2,782) 180,971 (2,340) 2,328,052 CLO and other ABS 1,014,820 (592) 20,166 (7,843) 1,026,551 RMBS 999,485 (561) 53,065 (201) 1,051,788 CMBS 620,582 (29) 48,348 (1,007) 667,894 Total AFS fixed income securities $ 6,073,517 $ (3,969) 397,922 (11,542) 6,455,928 The following tables provide a roll forward of the allowance for credit losses on our AFS fixed income securities for the years indicated: 2021 Beginning Balance Current Provisions for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirements) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance ($ in thousands) Foreign Government $ 1 46 (1) — — 46 Obligations of states and political subdivisons 4 122 11 — — 137 Corporate Securities 2,782 5,785 (992) (723) (170) 6,682 CLO and other ABS 592 579 (211) (21) — 939 RMBS 561 1,593 (63) (182) — 1,909 CMBS 29 10 (28) — — 11 Total AFS fixed income securities $ 3,969 8,135 (1,284) (926) (170) 9,724 2020 Beginning Balance Current Provisions for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirements) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance ($ in thousands) Foreign Government $ — 19 — (18) — 1 Obligations of states and political subdivisons — 4 — — — 4 Corporate Securities — 3,645 — (781) (82) 2,782 CLO and other ABS — 722 — (113) (17) 592 RMBS — 623 — (62) — 561 CMBS — 29 — — — 29 Total AFS fixed income securities $ — 5,042 — (974) (99) 3,969 During 2021 or 2020, we did not have any write-offs or recoveries of our AFS fixed income securities and we did not purchase any assets with credit deterioration, so these items are not included in the tables above. As disclosed in Note 2. "Summary of Significant Accounting Policies," we do not evaluate accrued interest on our AFS securities for expected credit loss as we write-off these balances in a timely manner. Accrued interest on AFS securities was $46.3 million as of December 31, 2021, and $43.8 million as of December 31, 2020. We did not record any material write-offs of accrued interest during 2021 or 2020. (c) Quantitative information about unrealized losses on our AFS portfolio is provided below. December 31, 2021 Less than 12 months 12 months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized AFS fixed income securities: U.S. government and government agencies $ 34,857 (746) 7,827 (399) 42,684 (1,145) Foreign government 2,000 (84) 1,061 (39) 3,061 (123) Obligations of states and political subdivisions 25,837 (235) — — 25,837 (235) Corporate securities 300,549 (4,903) 2,520 (50) 303,069 (4,953) CLO and other ABS 663,976 (4,934) 53,368 (1,350) 717,344 (6,284) RMBS 236,010 (2,931) 20 (1) 236,030 (2,932) CMBS 112,899 (1,016) 20,326 (666) 133,225 (1,682) Total AFS fixed income securities $ 1,376,128 (14,849) 85,122 (2,505) 1,461,250 (17,354) December 31, 2020 Less than 12 months 12 months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized AFS fixed income securities: U.S. government and government agencies $ 11,519 (137) — — 11,519 (137) Foreign government 1,122 (3) — — 1,122 (3) Obligations of states and political subdivisions 2,223 (11) — — 2,223 (11) Corporate securities 65,187 (2,152) 2,400 (188) 67,587 (2,340) CLO and other ABS 261,746 (2,995) 165,661 (4,848) 427,407 (7,843) RMBS 18,227 (194) 1,181 (7) 19,408 (201) CMBS 55,482 (616) 16,093 (391) 71,575 (1,007) Total AFS fixed income securities $ 415,506 (6,108) 185,335 (5,434) 600,841 (11,542) We do not currently intend to sell any of the securities in the tables above, nor will we be required to sell any of these securities. The increase in gross unrealized losses during 2021 was driven by an increase in benchmark U.S. Treasury rates, partially offset by a tightening of credit spreads. Considering these factors and our review of these securities under our credit loss policy as described in Note 2. “Summary of Significant Accounting Policies” of this Form 10-K, we have concluded that no allowance for credit loss is required on these balances. This conclusion reflects our current judgment about the financial position and future prospects of the entity that issued the investment security and underlying collateral. (d) Fixed income securities at December 31, 2021, by contractual maturity are shown below. Mortgage-backed securities are included in the maturity tables using the estimated average life of each security. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Listed below are the contractual maturities of fixed income securities at December 31, 2021: AFS HTM ($ in thousands) Fair Value Carrying Value Fair Value Due in one year or less $ 500,579 1,384 1,401 Due after one year through five years 3,182,282 11,811 12,493 Due after five years through 10 years 2,316,389 15,590 15,566 Due after 10 years 710,726 — — Total fixed income securities $ 6,709,976 28,785 29,460 (e) The following table summarizes our other investment portfolio by strategy: Other Investments December 31, 2021 December 31, 2020 ($ in thousands) Carrying Remaining Maximum Exposure to Loss 1 Carrying Remaining Maximum 1 Alternative Investments Private equity $ 273,070 99,734 372,804 157,276 100,905 258,181 Private credit 63,138 92,674 155,812 54,017 98,330 152,347 Real assets 23,524 22,579 46,103 19,659 16,493 36,152 Total alternative investments 359,732 214,987 574,719 230,952 215,728 446,680 Other securities 49,300 — 49,300 35,370 — 35,370 Total other investments $ 409,032 214,987 624,019 266,322 215,728 482,050 1 In addition to the amounts in this table, previously recognized tax credits are subject to the risk of recapture. We do not consider this significant and therefore do not include in this table. We are contractually committed to make additional investments up to the remaining commitments stated above. We did not provide any non-contractual financial support during 2021 or 2020. The following is a description of our alternative investment strategies: Our private equity strategy includes the following: • Primary Private Equity : This strategy makes private equity investments, primarily in established large and middle market companies across diverse industries globally, with an emphasis on North America. • Secondary Private Equity : This strategy purchases seasoned private equity funds from investors desiring liquidity prior to normal fund termination. Investments are made across all sectors of the private equity market, including leveraged buyouts ("LBO"), venture capital, distressed securities, mezzanine financing, real estate, and infrastructure. • Venture Capital : In general, these investments are made principally by investing in equity securities of startup companies and small-to-medium sized privately-held corporations with strong long-term growth potential. This strategy makes private equity investments in seed stage, early stage, late stage, and growth equity partnerships. Our private credit strategy includes the following: • Direct Lending : This strategy provides privately negotiated loans to U.S. middle market companies. Typically, these are floating rate, senior secured loans diversified across industries. Loans are made to companies that may or may not have private equity sponsors to finance LBOs, recapitalizations, and acquisitions. • Mezzanine Financing : This strategy provides privately-negotiated fixed income securities, generally with an equity component, to LBO firms and private and publicly-traded large, mid, and small-cap companies to finance LBOs, recapitalizations, and acquisitions. • Opportunistic and Distressed Debt : This strategy makes investments in debt and equity securities of companies that are experiencing financial distress, operational issues, or dislocated pricing of publicly-traded securities. Investments include buying indebtedness of bankrupt or financially-troubled companies, small balance loan portfolios, special situations and capital structure arbitrage trades, commercial real estate mortgages, and similar non-U.S. securities and debt obligations. Our real assets strategy includes the following: • Infrastructure : This strategy invests in the equity or debt of cash flow generating assets, diversified across a variety of industries, including transportation, energy infrastructure, renewable power, such as wind and solar, social infrastructure, power generation, water, telecom, and other regulated entities principally located in North America and Western Europe. • Real Estate : This strategy invests in real estate in North America, Europe, and Asia via direct property ownership, joint ventures, mortgages, and investments in equity and debt instruments. Our alternative investment strategies may employ leverage and may use hedging to reduce foreign exchange or interest rate volatility. At this time, our alternative investment strategies do not include hedge funds. We typically cannot redeem our investments with the general partners of these investments; however, occasionally these partnership positions can be sold on the secondary market. Once liquidation is triggered by clauses within the limited partnership agreements or at the funds’ stated end date, we receive our final allocation of capital and any earned appreciation of the underlying investments, assuming we have not divested ourselves of our partnership interests prior to that time. We currently receive distributions from these alternative investments through the realization of the underlying investments of, or income generated by, the limited partnerships. The following tables show gross summarized financial information for our other investments portfolio, including the portion we do not own. As the majority of these investments report results to us on a one quarter lag, the summarized financial statement information is as of, and for the 12-month period ended, September 30: Balance Sheet Information December 31, ($ in millions) 2021 2020 Investments $ 107,347 55,145 Total assets 112,232 58,819 Total liabilities 12,371 6,744 Total partners’ capital 99,861 52,075 Income Statement Information 12 months ended September 30, ($ in millions) 2021 2020 2019 Net investment (loss) income $ 653 (26) (8) Realized gains 6,121 1,452 695 Net change in unrealized appreciation 26,877 4,898 5,543 Net income before tax $ 33,651 6,324 6,230 Alternative investment income included in "Net investment income earned" on our Consolidated Statements of Income 117.7 26.5 17.9 (f) We did not have exposure to any credit concentration risk of a single issuer greater than 10% of our stockholders' equity, other than to certain U.S. government agencies, as of December 31, 2021 or December 31, 2020. (g) We have pledged certain AFS fixed income securities as collateral related to our borrowing relationships with the Federal Home Loan Bank of Indianapolis ("FHLBI") and the Federal Home Loan Bank of New York ("FHLBNY"). In addition, certain securities were on deposit with various state and regulatory agencies at December 31, 2021 to comply with insurance laws. We retain all rights regarding all securities pledged as collateral. The following table summarizes the market value of these securities at December 31, 2021: ($ in millions) FHLBI Collateral FHLBNY Collateral State and Regulatory Deposits Total U.S. government and government agencies $ — — 22.3 22.3 Obligations of states and political subdivisions — — 4.0 4.0 RMBS 62.4 40.4 — 102.8 CMBS 6.3 14.1 — 20.4 Total pledged as collateral $ 68.7 54.5 26.3 149.5 (h) The components of pre-tax net investment income earned were as follows: ($ in thousands) 2021 2020 2019 Fixed income securities $ 209,709 203,926 203,255 CMLs 2,743 844 — Equity securities 15,920 9,286 6,996 Short-term investments 260 1,821 6,653 Other investments 118,060 26,922 18,778 Investment expenses (20,103) (15,692) (13,139) Net investment income earned $ 326,589 227,107 222,543 (i) The following tables summarize net realized and unrealized investment gains and losses for the periods indicated: ($ in thousands) 2021 2020 2019 Gross gains on sales $ 15,284 18,893 31,910 Gross losses on sales (8,140) (9,745) (5,195) Net realized gains on disposals 7,144 9,148 26,715 Net unrealized gains (losses) on equity securities 17,881 7,939 (8,649) Net credit loss (expense) on fixed maturities, AFS (6,858) (5,042) Net credit loss (expense) benefit on fixed maturities, HTM (49) 4 Losses on securities for which we have the intent to sell (519) (16,266) Net other-than-temporary-impairment ("OTTI") losses recognized in earnings (3,644) Net realized and unrealized gains (losses) $ 17,599 (4,217) 14,422 Unrealized (losses) recognized in income on equity securities, as reflected in the table above, included the following: ($ in thousands) 2021 2020 2019 Unrealized gains (losses) recognized in income on equity securities: On securities remaining in our portfolio at end of period $ 16,473 7,936 1,219 On securities sold in period 1,408 3 (9,868) Total unrealized gains (losses) recognized in income on equity securities $ 17,881 7,939 (8,649) Proceeds from the sales of AFS fixed income securities were $502.9 million, $487.1 million, and $594.7 million in 2021, 2020, and 2019, respectively. Proceeds from the sales of equity securities were $99.2 million, $1.3 million, and $137.3 million in 2021, 2020, and 2019, respectively.

Comprehensive Income

Comprehensive Income	12 Months Ended
	Dec. 31, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income	Comprehensive Income (a) The components of comprehensive income, both gross and net of tax, for 2021, 2020, and 2019 were as follows: 2021 ($ in thousands) Gross Tax Net Net income $ 505,310 101,473 403,837 Components of OCI: Unrealized (losses) gains on investment securities : Unrealized holding losses during the year (151,391) (31,793) (119,598) Unrealized losses on securities with credit loss recognized in earnings (9,061) (1,902) (7,159) Amounts reclassified into net income: HTM securities (11) (2) (9) Net realized gains on disposals and losses on intent-to-sell AFS securities (3,825) (803) (3,022) Credit loss expense 6,858 1,440 5,418 Total unrealized losses on investment securities (157,430) (33,060) (124,370) Defined benefit pension and post-retirement plans: Net actuarial gain 21,636 4,543 17,093 Amounts reclassified into net income: Net actuarial loss 2,772 582 2,190 Total defined benefit pension and post-retirement plans 24,408 5,125 19,283 Other comprehensive loss (133,022) (27,935) (105,087) Comprehensive income $ 372,288 73,538 298,750 2020 ($ in thousands) Gross Tax Net Net income $ 302,988 56,633 246,355 Components of OCI: Unrealized gains (losses) on investment securities : Unrealized holding gains during the year 168,487 35,383 133,104 Unrealized losses on securities with credit loss recognized in earnings (8,176) (1,717) (6,459) Amounts reclassified into net income: HTM securities (24) (5) (19) Net realized losses on disposals and losses on intent-to-sell AFS securities 5,376 1,129 4,247 Credit loss expense 5,042 1,058 3,984 Total unrealized gains on investment securities 170,705 35,848 134,857 Defined benefit pension and post-retirement plans: Net actuarial gain 1,515 318 1,197 Amounts reclassified into net income: Net actuarial loss 3,015 633 2,382 Total defined benefit pension and post-retirement plans 4,530 951 3,579 Other comprehensive income 175,235 36,799 138,436 Comprehensive income $ 478,223 93,432 384,791 2019 ($ in thousands) Gross Tax Net Net income $ 336,390 64,767 271,623 Components of OCI: Unrealized gains (losses) on investment securities : Unrealized holding gains during the year 212,683 44,662 168,021 Amounts reclassified into net income: HTM securities (58) (12) (46) Realized losses on disposals and OTTI of AFS securities 671 141 530 Total unrealized gains on investment securities 213,296 44,791 168,505 Defined benefit pension and post-retirement plans: Net actuarial loss (13,795) (2,897) (10,898) Amounts reclassified into net income: Net actuarial loss 2,657 558 2,099 Total defined benefit pension and post-retirement plans (11,138) (2,339) (8,799) Other comprehensive income 202,158 42,452 159,706 Comprehensive income $ 538,548 107,219 431,329 (b) The balances of, and changes in, each component of AOCI (net of taxes) as of December 31, 2021 and 2020 were as follows: Net Unrealized Gains (Losses) on Investment Securities Defined Benefit Pension and Post-retirement Plans ($ in thousands) Credit Loss Related 1 HTM Related All Other Investments Subtotal Total AOCI Balance, December 31, 2019 $ (71) 25 170,439 170,393 (88,643) 81,750 OCI before reclassifications (6,459) — 133,104 126,645 1,197 127,842 Amounts reclassified from AOCI 3,984 (19) 4,247 8,212 2,382 10,594 Net current period OCI (2,475) (19) 137,351 134,857 3,579 138,436 Balance, December 31, 2020 (2,546) 6 307,790 305,250 (85,064) 220,186 OCI before reclassifications (7,159) — (119,598) (126,757) 17,093 (109,664) Amounts reclassified from AOCI 5,418 (9) (3,022) 2,387 2,190 4,577 Net current period OCI (1,741) (9) (122,620) (124,370) 19,283 (105,087) Balance, December 31, 2021 $ (4,287) (3) 185,170 180,880 (65,781) 115,099 1 Represents change in unrealized loss on securities with credit loss recognized in earnings. The reclassifications out of AOCI are as follows: ($ in thousands) Year ended December 31, 2021 Year ended December 31, 2020 Affected Line Item in the Consolidated Statements of Income HTM related Unrealized gains on HTM disposals $ (14) (16) Net realized and unrealized investment gains (losses) Amortization of net unrealized gains on HTM securities 3 (8) Net investment income earned (11) (24) Income before federal income tax 2 5 Total federal income tax expense (9) (19) Net income Net realized (gains) losses on disposals and losses on intent-to-sell AFS securities Net realized (gains) losses on disposals and losses on intent-to-sell AFS securities (3,825) 5,376 Net realized and unrealized investment gains (losses) (3,825) 5,376 Income before federal income tax 803 (1,129) Total federal income tax expense (3,022) 4,247 Net income Credit loss related Credit loss expense 6,858 5,042 Net realized and unrealized investment gains (losses) 6,858 5,042 Income before federal income tax (1,440) (1,058) Total federal income tax expense 5,418 3,984 Net income Defined benefit pension and post-retirement life plans Net actuarial loss 638 647 Loss and loss expense incurred 2,134 2,368 Other insurance expenses Total defined benefit pension and post-retirement life 2,772 3,015 Income before federal income tax (582) (633) Total federal income tax expense 2,190 2,382 Net income Total reclassifications for the period $ 4,577 10,594 Net income

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The financial assets in our investment portfolio are primarily measured at fair value as disclosed on the Consolidated Balance Sheets. The following table presents the carrying amounts and estimated fair values of our financial liabilities as of December 31, 2021 and 2020: December 31, 2021 December 31, 2020 ($ in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial Liabilities Long-term debt: 7.25% Senior Notes $ 49,917 63,719 49,914 66,148 6.70% Senior Notes 99,520 127,574 99,499 127,886 5.375% Senior Notes 294,330 395,652 294,241 383,669 1.61% Borrowings from FHLBNY — — 25,000 25,182 1.56% Borrowings from FHLBNY — — 25,000 25,198 3.03% Borrowings from FHLBI 60,000 64,126 60,000 67,513 Subtotal long-term debt 503,767 651,071 553,654 695,596 Unamortized debt issuance costs (3,167) (3,419) Finance lease obligations 5,450 508 Total long-term debt $ 506,050 $ 550,743 For discussion regarding the fair value techniques of our financial instruments, refer to Note 2. "Summary of Significant Accounting Policies" of this Form 10-K. The following tables provide quantitative disclosures of our financial assets that were measured and recorded at fair value at December 31, 2021 and 2020: December 31, 2021 Fair Value Measurements Using ($ in thousands) Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 130,458 60,615 69,843 — Foreign government 15,860 — 15,860 — Obligations of states and political subdivisions 1,189,308 — 1,181,563 7,745 Corporate securities 2,573,603 — 2,459,476 114,127 CLO and other ABS 1,350,814 — 1,225,905 124,909 RMBS 776,252 — 776,007 245 CMBS 673,681 — 669,425 4,256 Total AFS fixed income securities 6,709,976 60,615 6,398,079 251,282 Equity securities: Common stock 1 333,449 249,846 — — Preferred stock 2,088 2,088 — — Total equity securities 335,537 251,934 — — Short-term investments 447,863 442,723 5,140 — Total assets measured at fair value $ 7,493,376 755,272 6,403,219 251,282 December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 116,140 40,960 75,180 — Foreign government 18,366 — 18,366 — Obligations of states and political subdivisions 1,247,137 — 1,244,243 2,894 Corporate securities 2,328,052 — 2,257,352 70,700 CLO and other ABS 1,026,551 — 970,176 56,375 RMBS 1,051,788 — 1,051,788 — CMBS 667,894 — 667,894 — Total AFS fixed income securities 6,455,928 40,960 6,284,999 129,969 Equity securities: Common stock 1 308,632 261,846 — — Preferred stock 1,735 1,735 — — Total equity securities 310,367 263,581 — — Short-term investments 409,852 405,400 4,452 — Total assets measured at fair value $ 7,176,147 709,941 6,289,451 129,969 1 Investments amounting to $83.6 million and $46.8 million at December 31, 2021 and December 31, 2020, respectively, were measured at fair value using the net asset value per share (or its practical expedient) and have not been classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value. The following tables provide a summary of the changes in the fair value of securities measured using Level 3 inputs and related quantitative information for the years indicated: 2021 ($ in thousands) Obligations of states and political subdivisions Corporate Securities CLO and Other ABS RMBS CMBS Total Fair value, December 31, 2020 2,894 70,700 56,375 — — 129,969 Total net (losses) gains for the period included in: OCI (239) 1,636 (520) — (196) 681 Net realized and unrealized (losses) gains (11) (50) (214) — 5 (270) Net investment income earned — 27 16 — 19 62 Purchases — 64,813 76,731 249 98 141,891 Sales — — — — — — Issuances — — — — — — Settlements — (544) (5,161) (4) (52) (5,761) Transfers into Level 3 5,101 981 11,344 — 4,382 21,808 Transfers out of Level 3 — (23,436) (13,662) — — (37,098) Fair value, December 31, 2021 $ 7,745 114,127 $ 124,909 245 4,256 251,282 Change in unrealized (losses) gains for the period included in earnings for assets held at period end (11) (50) (214) — 5 (270) Change in unrealized (losses) gains for the period included in OCI for assets held at period end (239) 1,636 (520) — (196) 681 2020 ($ in thousands) Obligations of states and political subdivisions Corporate Securities CLO and Other ABS Total Fair value, December 31, 2019 $ — 17,051 17,034 34,085 Total net (losses) gains for the period included in: OCI 4 (785) 1,883 1,102 Net realized and unrealized gains (losses) — (1,046) (237) (1,283) Net investment income earned — 21 6 27 Purchases — 46,150 25,785 71,935 Sales — — — — Issuances — — — — Settlements — (283) (2,638) (2,921) Transfers into Level 3 2,890 9,592 31,520 44,002 Transfers out of Level 3 — — (16,978) (16,978) Fair value, December 31, 2020 $ 2,894 70,700 56,375 129,969 Change in unrealized gains (losses) for the period included in earnings for assets held at period end — (1,046) (237) (1,283) Change in unrealized gains (losses) for the period included in OCI for assets held at period end 4 (785) 1,883 1,102 The following tables present quantitative information about the significant unobservable inputs utilized in the fair value measurements of Level 3 assets at December 31, 2021 and 2020: December 31, 2021 ($ in thousands) Assets Measured at Fair Value Valuation Techniques Unobservable Inputs Range Internal valuations: Corporate securities $ 54,135 Discounted Cash Flow Illiquidity Spread 0.3% - 3.0% (1.2)% CLO and other ABS 34,903 Discounted Cash Flow Illiquidity Spread 0.7%- 8.0% (2.1)% Total internal valuations 89,038 Other 1 162,244 Total Level 3 securities $ 251,282 December 31, 2020 ($ in thousands) Assets Measured at Fair Value Valuation Techniques Unobservable Inputs Range Internal valuations: Corporate securities $ 15,907 Discounted Cash Flow Illiquidity Spread 1.8% - 1.8% (1.8)% CLO and other ABS 27,005 Discounted Cash Flow Illiquidity Spread 1.2% - 3.1% (1.8)% Total internal valuations 42,912 Other 1 87,057 Total Level 3 securities $ 129,969 1 Other is comprised of broker quotes or other third-party pricing for which there is a lack of transparency as to the inputs used to develop the valuations. The quantitative details of these unobservable inputs is neither provided to us, nor reasonably available to us, and therefore are not included in the tables above. For the securities in the tables above valued using a discounted cash flow analysis, we apply an illiquidity spread in our determination of fair value. An increase in this assumption would result in a lower fair value measurement. The following tables provide quantitative information regarding our financial assets and liabilities that were not measured, but were disclosed at fair value at December 31, 2021 and 2020: December 31, 2021 Fair Value Measurements Using ($ in thousands) Assets/Liabilities Disclosed at Quoted Prices in Active Markets for Identical Assets/Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets HTM: Obligations of states and political subdivisions $ 3,576 — 3,576 — Corporate securities 25,884 — 25,884 — Total HTM fixed income securities $ 29,460 — 29,460 — CMLs $ 97,598 — — 97,598 Financial Liabilities Long-term debt: 7.25% Senior Notes $ 63,719 — 63,719 — 6.70% Senior Notes 127,574 — 127,574 — 5.375% Senior Notes 395,652 — 395,652 — 3.03% Borrowings from FHLBI 64,126 — 64,126 — Total long-term debt $ 651,071 — 651,071 — December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets/Liabilities Disclosed at Quoted Prices in Active Markets for Identical Assets/Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets HTM: Obligations of states and political subdivisions $ 4,795 — 4,795 — Corporate securities 13,206 — 13,206 — Total HTM fixed income securities $ 18,001 — 18,001 — CML $ 47,289 — — 47,289 Financial Liabilities Long-term debt: 7.25% Senior Notes $ 66,148 66,148 6.70% Senior Notes 127,886 127,886 5.375% Senior Notes 383,669 383,669 1.61% Borrowings from FHLBNY 25,182 — 25,182 — 1.56% Borrowings from FHLBNY 25,198 — 25,198 — 3.03% Borrowings from FHLBI 67,513 — 67,513 — Total long-term debt $ 695,596 — 695,596 —

Allowance for Credit Losses on

Allowance for Credit Losses on Premiums Receivable	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Premium Receivable, Allowance for Credit Loss	Allowance for Credit Losses on Premiums Receivable The following table provides a roll forward of the ACL on our premiums receivable balance for 2021 and 2020: ($ in thousands) December 31, 2021 December 31, 2020 Balance at beginning of year $ 21,000 6,400 Cumulative effect adjustment 1 — 1,058 Balance at beginning of year, as adjusted $ 21,000 7,458 Current period change for expected credit losses 1,291 16,751 Write-offs charged against the allowance for credit losses (9,343) (3,754) Recoveries 652 545 ACL, end of year $ 13,600 21,000 1 Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses .

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2021
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance Our Financial Statements reflect the effects of assumed and ceded reinsurance transactions. Assumed reinsurance refers to the acceptance of certain insurance risks that other insurance entities have underwritten. Ceded reinsurance involves transferring certain insurance risks (along with the related written and earned premiums) that we have underwritten to other insurance companies that agree to share these risks. The primary purpose of ceded reinsurance is to protect the Insurance Subsidiaries from potential losses in excess of the amount that we are prepared to accept. Our major treaties covering property, property catastrophe, and casualty business are excess of loss contracts. In addition, we have an intercompany quota share (proportional) pooling arrangement and other minor reinsurance treaties. As a Standard Commercial Lines and E&S Lines writer, we are subject to the Terrorism Risk Insurance Program Reauthorization Act ("TRIPRA"), which was extended by Congress to December 31, 2027. TRIPRA requires private insurers and the U. S. government to share the risk of loss on future acts of terrorism certified by the U.S. Secretary of the Treasury. Under TRIPRA, each participating insurer is responsible for paying a deductible of specified losses before federal assistance is available. This deductible is based on a percentage of the prior year’s applicable Standard Commercial Lines and E&S Lines premiums. In 2022, our deductible, before tax, is approximately $419 million. For losses above the deductible, the federal government will pay 80% of losses to an industry limit of $100 billion, and the insurer retains 20%. The Insurance Subsidiaries remain liable to policyholders to the extent that any reinsurer becomes unable to meet their contractual obligations. In addition to this direct counterparty credit risk, we have indirect counterparty credit risk as our reinsurers often enter into their own reinsurance programs, or retrocessions, as part of managing their exposure to large losses and improving their financial strength ratings. The credit quality of our reinsurers is also impacted by other factors, such as their reserve adequacy, investment portfolio, regulatory capital position, catastrophe aggregations, and risk management expertise. We evaluate and monitor the financial condition of our reinsurers under voluntary reinsurance arrangements to minimize our exposure to significant losses from reinsurer insolvencies. The following tables provide (i) a disaggregation of our reinsurance recoverable balance by financial strength rating, and (ii) an aging analysis of our past due reinsurance recoverable balances as of December 31, 2021 and 2020: December 31, 2021 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers A++ $ 38,601 $ 9 $ 38,610 A+ 339,857 1,520 341,377 A 95,675 1,227 96,902 A- 3,209 145 3,354 B++ — — — B+ — — — Total rated reinsurers $ 477,342 $ 2,901 $ 480,243 Non-rated reinsurers Federal and state pools $ 116,378 $ — $ 116,378 Other than federal and state pools 4,597 450 5,047 Total non-rated reinsurers $ 120,975 $ 450 $ 121,425 Total reinsurance recoverable, gross $ 598,317 $ 3,351 $ 601,668 Less: ACL (1,600) Total reinsurance recoverable, net $ 600,068 December 31, 2020 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers A++ $ 37,464 $ 102 $ 37,566 A+ 354,846 2,452 357,298 A 105,652 415 106,067 A- 2,139 — 2,139 B++ 56 324 380 B+ — — — Total rated reinsurers $ 500,157 $ 3,293 $ 503,450 Non-rated reinsurers Federal and state pools $ 82,575 $ — $ 82,575 Other than federal and state pools 2,676 568 3,244 Total non-rated reinsurers $ 85,251 $ 568 $ 85,819 Total reinsurance recoverable, gross $ 585,408 $ 3,861 $ 589,269 Less: ACL (1,777) Total reinsurance recoverable, net $ 587,492 The following table provides a rollforward of the allowance for credit losses on our reinsurance recoverable balance for 2021 and 2020: ($ in thousands) December 31, 2021 December 31, 2020 Balance at beginning of year $ 1,777 $ 4,400 Cumulative effect adjustment — (2,903) Balance at beginning of year, as adjusted $ 1,777 $ 1,497 Current period change for expected credit losses (177) 280 Write-offs charged against the allowance for credit losses — — Recoveries — — ACL, end of year $ 1,600 $ 1,777 The following table represents our total reinsurance balances segregated by reinsurer to illustrate our concentration of risk throughout our reinsurance portfolio: As of December 31, 2021 As of December 31, 2020 ($ in thousands) Reinsurance Balances % of Reinsurance Balance Reinsurance Balances % of Reinsurance Balance Total reinsurance recoverables, net of allowance for credit losses $ 600,068 $ 587,492 Total prepaid reinsurance premiums 183,007 170,531 Total reinsurance balance 783,075 758,023 Federal and state pools 1 : NFIP 223,845 29 % 178,532 25 % New Jersey Unsatisfied Claim Judgment Fund 49,738 6 52,053 6 Other 2,385 — 1,625 — Total federal and state pools 275,968 35 232,210 31 Remaining reinsurance balance $ 507,107 65 $ 525,813 69 Munich Re Group (AM Best rated "A+") $ 108,381 14 $ 117,028 15 Hannover Ruckversicherungs AG (AM Best rated "A+") 107,110 14 115,251 15 AXIS Reinsurance Company (AM Best rated "A") 70,814 9 78,617 10 Swiss Re Group (AM Best rated "A+") 29,186 4 33,249 4 Transatlantic Reinsurance Company (AM Best rated “A+”) 26,490 3 24,374 3 All other reinsurers 166,726 21 159,071 21 Total reinsurers 508,707 65 % 527,590 69 % Less: ACL (1,600) (1,777) Reinsurers, net of ACL 507,107 525,813 Less: collateral 2 (128,699) (130,169) Reinsurers, net of collateral $ 378,408 $ 395,644 1 Considered to have minimal risk of default. 2 Includes letters of credit, trust funds, and funds held against reinsurance recoverables. Under our reinsurance arrangements, which are prospective in nature, reinsurance premiums ceded are recorded as prepaid reinsurance and amortized over the remaining contract period in proportion to the reinsurance protection provided, or recorded periodically, as per the terms of the contract, in a direct relationship to the gross premium recording. Reinsurance recoveries are recognized as gross losses are incurred. The following table contains a listing of direct, assumed, and ceded reinsurance amounts for premiums written, premiums earned, and loss and loss expense incurred: ($ in thousands) 2021 2020 2019 Premiums written: Direct $ 3,656,537 3,204,512 3,084,451 Assumed 22,664 24,288 24,339 Ceded (489,488) (455,708) (429,366) Net $ 3,189,713 2,773,092 2,679,424 Premiums earned: Direct $ 3,472,715 3,108,687 2,993,157 Assumed 21,550 25,010 24,399 Ceded (477,012) (451,883) (420,385) Net $ 3,017,253 2,681,814 2,597,171 Loss and loss expense incurred: Direct $ 2,096,512 1,822,034 1,714,880 Assumed 13,813 17,201 22,879 Ceded (296,341) (203,412) (186,268) Net $ 1,813,984 1,635,823 1,551,491 Direct premiums written ("DPW") increased 14% in 2021 compared to 2020, and increased 4% in 2020 compared to 2019. The increase in our DPW growth rate was attributable to the following items (i) overall renewal pure price increases, (ii) strong retention, and (iii) new business growth. In addition, our strong growth in DPW in 2021 benefited from exposure growth driven by strong economic activity in the U.S., which resulted in our customers increasing their sales, payrolls, and exposure units, all of which favorably impacted our DPW. This increase included three percentage points from the $75 million return audit and endorsement premium accrual that was recorded in the first quarter of 2020 and a $19.7 million premium credit to our personal and commercial automobile policyholders in the second quarter of 2020. The return audit and endorsement premium accrual reflected lower exposure levels, which determine the premium we charge, attributable to the economic impacts of the COVID-19 pandemic and the anticipated decline in sales and payroll exposures on the general liability and workers compensation lines of business in 2020. The increase in direct premiums earned in 2021 compared to 2020 was elevated by the items discussed above for the DPW impacts. Ceded premiums written, ceded premiums earned, and ceded loss and loss expenses incurred related to our participation in the NFIP, to which we cede 100% of our NFIP flood premiums, losses, and loss expenses, were as follows: Ceded to NFIP ($ in thousands) 2021 2020 2019 Ceded premiums written $ (284,311) (274,042) (266,925) Ceded premiums earned (274,384) (271,598) (259,119) Ceded loss and loss expense incurred (215,224) (78,993) (71,676)

Reserve for Loss and Loss Expen

Reserve for Loss and Loss Expense	12 Months Ended
	Dec. 31, 2021
Insurance Loss Reserves [Abstract]
Reserve for Loss and Loss Expense	Reserve for Loss and Loss Expense (a) The table below provides a roll forward of reserves for loss and loss expense for beginning and ending reserve balances: ($ in thousands) 2021 2020 2019 Gross reserves for loss and loss expense, at beginning of year $ 4,260,355 4,067,163 3,893,868 Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year 1 554,269 547,066 537,388 Net reserves for loss and loss expense, at beginning of year 3,706,086 3,520,097 3,356,480 Incurred loss and loss expense for claims occurring in the: Current year 1,896,837 1,708,755 1,601,780 Prior years (82,853) (72,932) (50,289) Total incurred loss and loss expense 1,813,984 1,635,823 1,551,491 Paid loss and loss expense for claims occurring in the: Current year 676,331 642,586 579,527 Prior years 841,477 807,248 805,443 Total paid loss and loss expense 1,517,808 1,449,834 1,384,970 Net reserves for loss and loss expense, at end of year 4,002,262 3,706,086 3,523,001 Add: Reinsurance recoverable on unpaid loss and loss expense, at end of year 578,641 554,269 544,162 Gross reserves for loss and loss expense at end of year $ 4,580,903 4,260,355 4,067,163 1 2020 includes an adjustment of $2.9 million related to our adoption of ASU 2016-13, Financial Instruments - Credit Losses. Our net loss and loss expense reserves increased by $296.2 million in 2021, $183.1 million in 2020, and $166.5 million in 2019. The loss and loss expense reserves are net of anticipated recoveries for salvage and subrogation claims, which amounted to $87.0 million for 2021, $80.9 million for 2020, and $76.7 million for 2019. The increase in net loss and loss expense reserves in 2021 was primarily driven by increases in exposure due to premium growth. This increase in our net loss and loss expense reserves was partially offset by favorable prior year loss reserve development. In 2021, we experienced overall net favorable prior year loss reserve development of $82.9 million, compared to $72.9 million in 2020 and $50.3 million in 2019. The following table summarizes the prior year reserve development by line of business: (Favorable)/Unfavorable Prior Year Development ($ in millions) 2021 2020 2019 General Liability $ (29.0) (35.0) (5.0) Commercial Automobile 13.3 7.1 0.7 Workers Compensation (58.0) (60.0) (68.0) Businessowners' Policies (0.4) 3.9 1.9 Commercial Property (2.6) 9.2 5.1 Homeowners 1.8 7.7 7.5 Personal Automobile (0.2) (1.8) 4.4 E&S Casualty Lines (7.0) — 2.0 E&S Property Lines (0.8) (4.0) 1.0 Other — — 0.1 Total $ (82.9) (72.9) (50.3) The Insurance Subsidiaries had $82.9 million of favorable prior accident year reserve development during 2021, which included $81.0 million of net favorable casualty reserve development and $1.9 million of favorable property reserve development. The net favorable casualty reserve development was largely driven by the workers compensation and general liability lines of business. Workers compensation was impacted by continued favorable medical trends in accident years 2019 and prior, and general liability development was attributable to lower loss severities in accident years 2018 and prior. In addition, our E&S casualty lines experienced favorable reserve development of $7.0 million in 2021. Partially offsetting this net favorable reserve development was $15.0 million of unfavorable casualty reserve development in the commercial auto line of business ($13.3 million net of property reserve development), driven by unfavorable reserve development on loss severities in accident years 2016 through 2019. The Insurance Subsidiaries had $72.9 million of favorable prior accident year reserve development during 2020, which included $85.0 million of net favorable casualty reserve development and $12.1 million of unfavorable property reserve development. The net favorable casualty reserve development was largely driven by the workers compensation and general liability lines of business. Workers compensation was impacted by continued favorable medical trends in accident years 2018 and prior, and general liability development was attributable to lower loss severities in accident years 2017 and prior. Partially offsetting this net favorable reserve development was $10.0 million of unfavorable casualty reserve development in the commercial auto line of business ($7.1 million net of property reserve development), driven by unfavorable reserve development on loss severities in accident years 2016 through 2019, and higher than expected frequencies in accident year 2019. The Insurance Subsidiaries had $50.3 million of favorable prior accident year reserve development during 2019, which included $61.0 million of net favorable casualty reserve development and $10.7 million of unfavorable property reserve development. The net favorable casualty reserve development was largely driven by the workers compensation line of business, reflecting continued favorable medical trends in accident years 2017 and prior. (b) We have exposure to abuse or molestation claims within our general liability line of business, primarily through insurance policies that we issue to schools, religious institutions, daycares, and other social services. We also have exposure to abuse or molestation claims from recently enacted state laws that extend the statute of limitations or permit windows to be opened for abuse or molestation claims and lawsuits that were previously barred by statutes of limitations. The emergence of these claims is slow and highly unpredictable. There are significant uncertainties in estimating our exposure to abuse or molestation claims (for both case and IBNR reserves) resulting from (i) lack of relevant historical data, (ii) the delayed and inconsistent reporting patterns associated with these claims, (iii) the obligation of an insurer to defend a claim, (iv) the extent to which a party can prove the existence of coverage, and (v) uncertainty as to the number and identity of claimants. It is possible, as a result, that we may receive claims decades after the allegations occurred from coverages provided by us, including predecessor companies, that will require complex claims coverage determinations, potential litigation, and the need to collect from reinsurers under older reinsurance agreements. (c) Reserves established for liability insurance include exposure to asbestos and environmental claims. These claims have arisen primarily from insured exposures in municipal government, small non-manufacturing commercial risk, and homeowners policies. The emergence of these claims is slow and highly unpredictable. There are significant uncertainties in estimating our exposure to asbestos and environmental claims (for both case and IBNR reserves) resulting from (i) lack of relevant historical data, (ii) the delayed and inconsistent reporting patterns associated with these claims, and (iii) uncertainty as to the number and identity of claimants and complex legal and coverage issues. Legal issues that arise in asbestos and environmental cases include federal or state venue, choice of law, causation, admissibility of evidence, allocation of damages and contribution among joint defendants, successor and predecessor liability, and whether direct action against insurers can be maintained. Coverage issues that arise in asbestos and environmental cases include the interpretation and application of policy exclusions, the determination and calculation of policy limits, the determination of the ultimate amount of a loss, the extent to which a loss is covered by a policy, if at all, the obligation of an insurer to defend a claim, and the extent to which a party can prove the existence of coverage. Courts have reached different and sometimes inconsistent conclusions on these legal and coverage issues. Traditional accident year loss development methods cannot be applied because past loss history is not necessarily indicative of future behavior. Instead, we review the experience by calendar year and rely on alternative metrics, such as paid and incurred survival ratios. As a result, reserves for asbestos and environmental require a high degree of judgment. Because of the significant uncertainty in the estimate, we do not calculate an asbestos and environmental loss range. The following table details our loss and loss expense reserves for various asbestos and environmental claims showing gross and net of reinsurance: 2021 ($ in millions) Gross Net Asbestos $ 6.1 4.9 Landfill sites 12.1 7.6 Underground storage tanks 9.6 8.6 Total $ 27.8 21.1 Historically, our asbestos and environmental claims have been significantly lower in volume than many other Standard Commercial Lines carriers since, prior to the introduction of the absolute pollution exclusion endorsement in the mid-1980’s, we primarily wrote Standard Personal Lines, and therefore, our exposure to asbestos and environmental claims has been limited. The following table provides a roll forward of asbestos and environmental incurred loss and loss expense and related reserves thereon showing gross and net of reinsurance: 2021 2020 2019 ($ in thousands) Gross Net Gross Net Gross Net Asbestos Reserves for loss and loss expense at beginning of year $ 6,254 5,023 6,288 5,057 7,328 6,097 Incurred loss and loss expense 51 51 320 320 (375) (375) Less: loss and loss expense paid (190) (190) (354) (354) (665) (665) Reserves for loss and loss expense at the end of year $ 6,115 4,884 6,254 5,023 6,288 5,057 Environmental Reserves for loss and loss expense at beginning of year $ 22,276 16,398 22,413 16,532 22,692 16,686 Incurred loss and loss expense (613) (14) (447) (474) 723 609 Less: loss and loss expense paid (5) (193) 310 340 (1,002) (763) Reserves for loss and loss expense at the end of year $ 21,658 16,191 22,276 16,398 22,413 16,532 Total Asbestos and Environmental Claims Reserves for loss and loss expense at beginning of year $ 28,530 21,421 28,701 21,589 30,020 22,783 Incurred loss and loss expense (562) 37 (127) (154) 348 234 Less: loss and loss expense paid (195) (383) (44) (14) (1,667) (1,428) Reserves for loss and loss expense at the end of year $ 27,773 21,075 28,530 21,421 28,701 21,589 (d) The following is information about incurred and paid claims development as of December 31, 2021, net of reinsurance, as well as cumulative claim frequency and the associated IBNR liabilities. During the experience period we implemented a series of underwriting and claims-related initiatives, including claims management changes. These initiatives focused on general underwriting and claims improvements occurring naturally through our portfolio and may impact some relationships in the tables below. As a result, several historical patterns have changed and may no longer be appropriate to use as the sole basis for projections. All Lines (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 1,065,437 1,071,290 1,020,655 998,028 973,089 973,644 973,411 968,536 962,091 962,678 36,108 104,515 2013 1,044,142 1,062,045 1,047,230 1,021,007 1,002,316 987,763 984,858 973,739 957,958 40,736 91,756 2014 1,107,513 1,133,798 1,146,990 1,124,014 1,104,218 1,100,208 1,089,529 1,094,367 48,550 95,610 2015 1,114,081 1,130,513 1,144,830 1,138,313 1,119,441 1,108,860 1,103,592 56,165 94,874 2016 1,188,608 1,203,634 1,227,142 1,199,734 1,180,829 1,171,273 90,598 95,559 2017 1,270,110 1,313,372 1,313,585 1,288,526 1,268,941 122,313 99,424 2018 1,413,800 1,461,603 1,457,415 1,441,303 222,464 106,569 2019 1,483,945 1,523,041 1,526,566 383,970 103,271 2020 1,591,972 1,587,607 562,065 93,515 2021 1,784,661 932,590 89,801 Total 12,898,946 All Lines (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 378,067 555,819 651,544 743,742 810,135 856,195 879,372 898,269 905,816 913,478 2013 335,956 518,872 644,475 748,758 833,823 872,331 891,841 904,825 911,657 2014 405,898 614,075 736,154 855,959 936,425 981,868 1,002,157 1,020,961 2015 376,641 581,203 725,385 845,868 929,222 967,857 1,000,509 2016 387,272 617,958 764,331 892,390 983,852 1,025,264 2017 433,440 678,453 829,134 954,792 1,050,258 2018 511,271 779,466 942,893 1,083,556 2019 510,091 781,462 949,996 2020 572,302 831,976 2021 609,889 Total 9,397,544 All outstanding liabilities before 2012, net of reinsurance 372,496 Liabilities for loss and loss expenses, net of reinsurance 3,873,898 General Liability (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 238,979 245,561 215,083 194,144 175,305 175,268 180,659 182,085 178,285 179,197 12,796 10,052 2013 250,609 251,421 239,776 225,709 210,785 203,831 202,697 195,697 192,782 15,661 10,433 2014 244,312 249,946 257,132 239,333 234,082 237,125 229,679 230,247 21,413 10,677 2015 254,720 245,710 246,990 233,249 219,204 214,176 211,768 25,873 10,532 2016 277,214 272,048 277,986 263,245 252,733 246,643 41,647 10,763 2017 293,747 293,128 301,384 289,883 278,607 67,475 11,219 2018 317,934 336,326 345,224 332,013 126,438 11,641 2019 347,150 356,363 358,301 196,836 11,264 2020 361,554 360,302 252,458 9,076 2021 422,748 356,223 8,260 Total 2,812,608 General Liability (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 13,030 35,241 56,580 89,008 109,448 130,866 144,451 156,186 158,397 162,516 2013 12,789 35,113 72,127 104,587 139,114 153,628 163,764 169,847 172,983 2014 14,901 46,825 79,972 121,969 154,957 179,192 187,352 198,772 2015 14,665 39,978 78,668 116,804 144,216 157,071 173,697 2016 15,684 46,549 89,431 133,757 164,136 181,770 2017 17,366 49,470 92,355 131,980 167,002 2018 19,531 60,784 108,421 155,538 2019 18,097 58,284 100,206 2020 21,858 58,699 2021 28,069 Total 1,399,252 All outstanding liabilities before 2012, net of reinsurance 102,433 Liabilities for loss and loss expenses, net of reinsurance 1,515,789 Workers Compensation (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 203,864 208,036 199,360 195,197 188,596 187,359 183,314 178,774 177,658 177,706 20,697 11,628 2013 199,794 194,318 187,658 173,160 166,662 162,787 159,767 157,645 153,436 20,638 11,384 2014 199,346 187,065 182,579 172,515 164,420 160,646 159,604 161,021 21,285 10,495 2015 193,729 194,639 183,604 179,642 176,242 172,572 170,577 20,748 10,554 2016 196,774 184,946 176,248 166,009 156,540 155,210 24,850 10,585 2017 195,202 184,306 175,853 162,672 154,159 25,096 10,809 2018 193,894 193,818 181,151 173,428 34,218 11,129 2019 188,625 188,596 174,912 44,549 10,307 2020 168,643 168,594 61,878 7,495 2021 185,198 111,451 8,089 Total 1,674,241 Workers Compensation (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 40,911 86,909 108,211 122,755 132,052 139,477 143,281 146,739 148,750 151,273 2013 36,829 74,568 96,376 109,739 118,669 124,130 126,822 129,224 130,467 2014 35,924 78,944 100,876 113,626 119,392 124,077 127,858 130,726 2015 33,857 77,320 98,195 112,601 120,097 124,046 129,019 2016 34,525 78,531 98,037 109,166 115,159 119,800 2017 40,375 82,216 100,645 110,645 116,426 2018 41,122 84,780 105,903 119,904 2019 37,826 77,878 100,812 2020 29,559 68,277 2021 32,918 Total 1,099,622 All outstanding liabilities before 2012, net of reinsurance 241,987 Liabilities for loss and loss expenses, net of reinsurance 816,606 Commercial Automobile (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 179,551 191,947 183,527 184,289 184,367 186,128 184,633 185,357 184,477 184,411 467 24,431 2013 188,289 205,282 209,197 207,994 210,410 207,975 209,602 208,040 207,554 595 26,053 2014 200,534 212,725 216,824 219,925 218,172 217,334 216,461 214,992 875 28,079 2015 220,994 240,958 253,074 259,495 260,565 261,386 262,054 1,826 29,837 2016 255,187 274,367 285,302 285,304 290,359 291,674 3,226 31,754 2017 301,274 329,389 324,291 322,197 326,461 10,110 33,066 2018 347,908 352,487 345,547 350,310 23,671 35,714 2019 385,212 398,346 404,854 63,122 36,079 2020 381,654 381,163 121,558 30,095 2021 483,831 232,070 34,461 Total 3,107,304 Commercial Automobile (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 73,316 105,371 127,235 148,669 168,114 176,656 179,501 181,353 183,098 183,365 2013 76,469 109,893 140,015 169,850 189,626 200,750 202,622 205,064 206,162 2014 80,810 117,169 148,884 180,701 202,821 209,655 212,481 213,689 2015 91,347 132,260 175,866 211,515 238,142 249,905 255,600 2016 106,022 155,720 200,701 233,939 264,858 277,242 2017 117,287 178,823 220,422 262,349 296,600 2018 134,867 193,788 243,713 291,725 2019 149,538 221,590 283,410 2020 139,016 198,034 2021 187,200 Total 2,393,027 All outstanding liabilities before 2012, net of reinsurance 3,427 Liabilities for loss and loss expenses, net of reinsurance 717,704 Businessowners' Policies (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 54,342 48,029 46,303 44,172 44,077 43,747 43,418 43,717 43,444 43,534 198 5,545 2013 49,617 42,618 41,005 40,624 41,369 39,709 39,699 39,358 38,930 120 3,483 2014 55,962 60,949 62,548 59,806 58,517 58,093 57,302 57,483 746 4,067 2015 52,871 53,768 57,245 55,925 54,454 52,325 52,200 801 3,967 2016 52,335 53,792 54,993 53,835 53,367 53,147 1,010 3,851 2017 46,624 48,698 51,524 48,067 43,606 2,642 3,892 2018 55,024 57,202 62,427 60,393 7,655 4,256 2019 53,531 59,466 64,667 11,556 3,616 2020 71,836 73,680 11,225 5,364 2021 66,312 21,947 3,078 Total 553,952 Businessowners' Policies (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 22,199 31,833 35,089 37,215 38,766 40,627 41,326 41,356 42,075 42,061 2013 17,412 26,592 30,845 34,760 37,993 38,464 39,085 39,212 39,440 2014 28,914 40,584 44,911 49,460 52,940 55,458 55,708 55,729 2015 24,189 36,014 42,710 46,571 49,073 49,839 50,005 2016 24,655 36,848 39,973 45,308 48,786 50,536 2017 21,865 31,337 36,950 40,359 39,940 2018 29,995 39,791 44,316 48,144 2019 27,718 41,587 46,113 2020 43,376 57,210 2021 34,412 Total 463,590 All outstanding liabilities before 2012, net of reinsurance 9,139 Liabilities for loss and loss expenses, net of reinsurance 99,501 Commercial Property (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 118,464 114,224 115,375 116,658 117,102 117,170 117,225 117,220 117,200 117,277 4 8,519 2013 88,101 90,639 90,103 90,005 90,436 90,278 90,218 90,486 90,461 3 5,715 2014 141,192 136,249 136,820 138,751 138,155 136,212 136,237 136,151 10 6,517 2015 110,270 109,513 111,750 111,566 112,496 112,582 112,937 12 6,407 2016 121,927 126,185 125,937 124,487 123,567 123,005 23 6,743 2017 138,773 149,106 149,044 153,664 154,119 54 6,904 2018 183,177 190,834 192,558 194,016 98 8,289 2019 173,826 177,075 179,574 530 7,300 2020 232,060 225,278 4,314 10,116 2021 246,319 36,186 7,153 Total 1,579,137 Commercial Property (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 81,528 108,834 111,503 114,699 116,291 116,625 116,671 116,674 116,673 116,755 2013 60,244 87,874 90,446 90,350 90,840 90,696 90,646 90,917 90,891 2014 101,131 132,909 136,634 137,883 137,418 136,008 135,928 136,141 2015 79,048 106,182 109,829 110,994 110,969 112,117 112,410 2016 83,966 118,789 122,930 123,828 123,601 122,909 2017 99,047 142,338 148,589 152,018 153,750 2018 135,416 184,813 192,698 193,487 2019 130,891 172,768 177,825 2020 164,613 215,107 2021 161,757 Total 1,481,032 All outstanding liabilities before 2012, net of reinsurance 99 Liabilities for loss and loss expenses, net of reinsurance 98,204 Personal Automobile (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 113,771 114,921 109,832 109,324 110,294 110,300 109,795 109,701 109,634 109,546 5 22,333 2013 108,417 109,620 106,225 106,703 107,759 107,680 107,916 107,803 107,754 72 22,376 2014 102,250 109,325 106,757 107,452 106,821 107,104 107,106 107,566 79 22,509 2015 96,387 99,698 100,214 99,570 98,718 98,588 98,596 109 20,865 2016 92,727 98,032 100,202 101,140 99,544 99,858 357 19,826 2017 101,880 105,139 103,653 103,260 103,557 447 20,744 2018 111,594 113,569 112,030 112,418 2,100 22,682 2019 114,043 115,688 115,993 5,649 22,845 2020 95,625 94,532 17,790 17,501 2021 108,244 28,461 18,931 Total 1,058,064 Personal Automobile (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 63,704 82,729 94,842 102,977 107,890 109,355 109,447 109,482 109,554 109,539 2013 61,384 80,861 92,637 100,528 105,131 106,679 106,876 107,419 107,423 2014 62,519 83,739 92,589 99,173 104,055 105,709 106,478 107,108 2015 58,725 76,470 87,163 92,102 95,997 97,275 97,761 2016 57,961 76,823 86,752 94,372 98,080 98,977 2017 62,854 82,730 91,479 97,628 100,521 2018 69,721 89,628 99,982 107,026 2019 69,699 92,162 102,930 2020 53,407 68,691 2021 65,325 Total 965,301 All outstanding liabilities before 2012, net of reinsurance 5,713 Liabilities for loss and loss expenses, net of reinsurance 98,476 Homeowners (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 87,260 82,744 86,560 86,667 86,271 86,330 86,483 86,567 86,519 86,533 35 16,944 2013 73,670 72,528 71,494 72,145 71,714 72,148 72,318 71,948 71,955 38 7,750 2014 80,111 82,461 83,637 83,844 83,539 83,824 83,525 83,830 32 8,775 2015 76,637 76,400 76,559 74,723 74,978 74,673 74,682 478 7,750 2016 60,105 60,931 62,391 61,723 61,735 60,855 465 6,895 2017 59,167 67,978 70,365 70,064 68,938 570 7,386 2018 62,961 68,526 69,832 68,931 1,289 7,607 2019 64,306 72,772 73,816 3,027 7,001 2020 109,033 112,523 4,829 9,791 2021 82,425 15,963 6,298 Total 784,488 Homeowners (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 69,056 79,584 82,720 84,250 85,196 85,562 85,642 85,897 85,899 85,918 2013 50,664 65,528 67,838 69,775 71,776 72,197 72,433 72,446 72,447 2014 61,561 76,007 79,751 81,664 82,583 82,836 82,831 83,321 2015 52,589 70,078 72,202 72,927 74,079 74,052 74,096 2016 42,252 57,333 59,546 60,082 61,187 60,449 2017 45,466 63,290 67,193 67,767 68,078 2018 49,430 64,137 65,348 66,634 2019 49,680 67,631 69,911 2020 83,838 105,690 2021 59,054 Total 745,598 All outstanding liabilities before 2012, net of reinsurance 5,438 Liabilities for loss and loss expenses, net of reinsurance 44,328 E&S Casualty Lines (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 42,367 $ 42,621 43,175 46,149 46,165 45,988 46,444 44,622 44,348 44,083 1,911 2,064 2013 55,468 60,309 67,099 69,112 67,647 68,972 68,451 68,029 60,349 3,637 2,310 2014 55,316 63,505 69,929 71,719 71,206 71,153 70,846 74,270 4,115 2,131 2015 75,498 76,432 82,404 90,488 90,355 90,126 87,662 6,293 2,875 2016 94,451 96,416 104,655 105,120 104,730 102,476 19,208 2,968 2017 91,438 95,783 99,866 99,395 99,960 16,217 2,797 2018 98,324 103,004 103,184 104,983 25,673 2,762 2019 117,087 118,298 117,736 56,323 2,553 2020 103,872 103,137 71,650 1,595 2021 128,099 111,132 1,223 Total 922,755 E&S Casualty Lines (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 3,722 $ 7,914 16,430 25,064 32,343 36,278 38,298 39,832 40,615 41,299 2013 2,715 9,470 21,980 35,200 46,108 51,142 54,974 55,988 57,152 2014 2,353 12,234 25,571 43,877 53,780 60,092 64,698 66,661 2015 3,036 13,057 29,389 50,712 64,529 71,421 75,844 2016 3,720 16,195 33,950 56,581 69,448 75,004 2017 5,057 14,672 34,179 53,238 68,266 2018 5,509 21,337 39,174 57,962 2019 4,422 17,812 35,844 2020 3,695 13,064 2021 4,326 Total 495,422 All outstanding liabilities before 2012, net of reinsurance 2,843 Liabilities for loss and loss expenses, net of reinsurance 430,176 (e) The reconciliation of the net incurred and paid claims development tables to the liability for loss and loss expenses in the consolidated statement of financial position is as follows: (in thousands) December 31, 2021 Net outstanding liabilities: Standard Commercial Lines General liability $ 1,515,789 Workers compensation 816,606 Commercial automobile 717,704 Businessowners' policies 99,501 Commercial property 98,204 Other Standard Commercial Lines 22,866 Total Standard Commercial Lines net outstanding liabilities 3,270,670 Standard Personal Lines Personal automobile 98,476 Homeowners 44,328 Other Standard Personal Lines 12,261 Total Standard Personal Lines net outstanding liabilities 155,065 E&S Lines Casualty lines 430,176 Property lines 17,987 Total E&S Lines net outstanding liabilities 448,163 Total liabilities for unpaid loss and loss expenses, net of reinsurance 3,873,898 Reinsurance recoverable on unpaid claims: Standard Commercial Lines General liability 213,253 Workers compensation 196,670 Commercial automobile 15,480 Businessowners' policies 6,828 Commercial property 22,277 Other Standard Commercial Lines 2,136 Total Standard Commercial Lines reinsurance recoverable on unpaid loss 456,644 Standard Personal Lines Personal automobile 40,941 Homeowners 2,392 Other Standard Personal Lines 64,975 Total Standard Personal Lines reinsurance recoverable on unpaid loss 108,308 E&S Lines Casualty lines 11,672 Property lines 2,017 Total E&S Lines reinsurance recoverable on unpaid loss 13,689 Total reinsurance recoverable on unpaid loss 578,641 Unallocated loss expenses 128,364 Total gross liability for unpaid loss and loss expenses $ 4,580,903 (f) The table below reflects the historical average annual percentage payout of incurred claims by age. For example, the general liability line of business averages payout of 6.4% of its ultimate losses in the first year, 11.9% in the second year, and so forth. The following is supplementary information about average historical claims duration as of December 31, 2021: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Years 1 2 3 4 5 6 7 8 9 10 General liability 6.4% 11.9 15.6 17.6 14.4 9.8 6.6 5.0 1.9 1.6 Workers compensation 21.8 25.9 13.6 8.4 4.5 2.9 2.3 3.1 1.7 0.8 Commercial automobile 37.2 16.7 14.7 13.0 10.0 4.5 1.7 1.0 0.5 0.1 Businessowners’ policies 49.2 20.8 8.0 8.7 5.9 3.1 1.2 0.1 0.1 0.1 Commercial property 69.4 25.8 3.1 1.0 0.4 — — — — — Personal automobile 59.0 18.1 10.3 6.4 3.7 1.4 0.3 0.4 0.1 0.1 Homeowners 71.5 21.0 3.4 1.8 1.6 0.1 0.2 0.2 0.2 — E&S Lines - casualty 3.8 11.2 16.7 19.0 14.8 7.9 5.7 3.5 3.0 2.0

Indebtedness

Indebtedness	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Indebtedness	Indebtedness The table below provides a summary of our outstanding debt at December 31, 2021 and 2020: Outstanding Debt 2021 Carry Value Issuance Date Maturity Date Interest Rate Original Amount Unamortized Issuance Costs Debt Discount December 31, 2021 December 31, 2020 ($ in thousands) Description Long term (1) Senior Notes 3/1/2019 3/1/2049 5.375 % 300,000 $ 2,733 5,670 291,597 291,307 (2) FHLBI 12/16/2016 12/16/2026 3.03 % 60,000 — — 60,000 60,000 (3) FHLBNY 8/15/2016 8/16/2021 1.56 % 25,000 — — — 25,000 (3) FHLBNY 7/21/2016 7/21/2021 1.61 % 25,000 — — — 25,000 (4) Senior Notes 11/3/2005 11/1/2035 6.70 % 100,000 287 480 99,233 99,180 (5) Senior Notes 11/16/2004 11/15/2034 7.25 % 50,000 147 83 49,770 49,748 Finance lease obligations 5,450 508 Total long-term debt $ 3,167 6,233 506,050 550,743 On December 20, 2019, the Parent entered into a Credit Agreement (the “Line of Credit”) among the Parent, the lenders named therein (the “Lenders”), and Bank of Montreal, Chicago Branch, as Administrative Agent. Under the Line of Credit, the Lenders have agreed to provide the Parent with a $50 million revolving credit facility, which can be increased to $125 million with the consent of the Lenders. The Line of Credit will mature on December 20, 2022 and has an interest rate, which varies and is based on, among other factors, the Parent’s debt ratings. Our Line of Credit contains representations, warranties, and covenants that are customary for credit facilities of this type, including, without limitation, financial covenants under which we are obligated to maintain a minimum consolidated net worth, a maximum ratio of consolidated debt to total capitalization, and covenants limiting our ability to: (i) merge or liquidate; (ii) incur debt or liens; (iii) dispose of assets; (iv) make investments and acquisitions; and (v) engage in transactions with affiliates. The table below outlines information regarding certain covenants in the Line of Credit: Required as of Actual as of December 31, 2021 December 31, 2021 Consolidated net worth 1 Not less than $1.8 billion $2.9 billion Debt to total capitalization ratio 1 Not to exceed 35% 15.0% 1 Calculated in accordance with the Line of Credit. In addition to the above requirements, the Line of Credit contains a cross-default provision that provides that the Line of Credit will be in default if we fail to comply with any condition, covenant, or agreement (including payment of principal and interest when due on any debt with an aggregate principal amount of at least $20 million), which causes or permits the acceleration of principal. Additionally, the Line of Credit limits borrowings from the FHLBI and the FHLBNY to 10% of the respective member company's admitted assets for the previous year. Long-term Debt Activity (1) In the first quarter of 2019, we issued $300 million of 5.375% Senior Notes due 2049 at a discount of $5.9 million which, when coupled with debt issuance costs of approximately $3.3 million, resulted in net proceeds from the offering of $290.8 million. The 5.375% Senior Notes pay interest on March 1 and September 1 of each year. The first payment was made on September 1, 2019. A portion of the proceeds from this debt issuance was used to fully redeem the $185 million aggregate principal amount of our 5.875% Senior Notes due 2043, with the remaining $106 million being used for general corporate purposes. The 5.875% Senior Notes had pre-tax debt retirement costs of $4.2 million, or $3.3 million after tax, which was recorded in Interest expense on the Consolidated Statements of Income in the first quarter of 2019. There are no financial debt covenants to which we are required to comply in regards to the 5.375% Senior Notes. (2) In the first quarter of 2009, SICSC and SICSE, which are collectively referred to as the "Indiana Subsidiaries" as they are domiciled in Indiana, joined, and invested in, the FHLBI, which provides them with access to additional liquidity. The Indiana Subsidiaries’ aggregate investment in the FHLBI was $5.7 million at December 31, 2021 and December 31, 2020. Our investment provides us the ability to borrow approximately 20 times the total amount of the FHLBI common stock purchased with additional collateral, at comparatively low borrowing rates. The proceeds from the FHLBI borrowing on December 16, 2016 of $60 million were used to repay a $45 million borrowing from the FHLBI that was outstanding at the time, with the remaining $15 million used for general corporate purposes. All borrowings from the FHLBI require security. There are no financial debt covenants to which we are required to comply with in regards to these borrowings. For information on investments that are pledged as collateral for these borrowings, see Note 5. "Investments" above. (3) In the fourth quarter of 2015, SICA and Selective Insurance Company of New York ("SICNY") joined, and invested in, the FHLBNY, which provides them with access to additional liquidity. The aggregate investment for both subsidiaries was $0.8 million at December 31, 2021 and $3.1 million at December 31, 2020. Our investment provides us the ability to borrow approximately 20 times the total amount of the FHLBNY common stock purchased with additional collateral, at comparatively low borrowing rates. In 2016, SICA borrowed the following amounts from the FHLBNY: (i) $25 million in August 2016 at an interest rate of 1.56%, which was repaid on August 16, 2021; and (ii) $25 million in July 2016 at an interest rate of 1.61%, which was repaid on July 21, 2021. (4) In November 2005, we issued $100 million of 6.70% Senior Notes due 2035. These notes were issued at a discount of $0.7 million resulting in an effective yield of 6.754%. Net proceeds of approximately $50 million were used to fund an irrevocable trust that subsequently funded certain payment obligations in respect of our outstanding debt. The remainder of the proceeds was used for general corporate purposes. The agreements covering these notes contain a standard default cross-acceleration provision that provides the 6.70% Senior Notes will enter a state of default upon the failure to pay principal when due or upon any event or condition that results in an acceleration of principal of any other debt instrument in excess of $10 million that we have outstanding concurrently with the 6.70% Senior Notes. There are no financial debt covenants to which we are required to comply in regards to these notes. (5) In November 2004, we issued $50 million of 7.25% Senior Notes due 2034. These notes were issued at a discount of $0.1 million, resulting in an effective yield of 7.27%. We contributed $25 million of the bond proceeds to the Insurance Subsidiaries as capital. The remainder of the proceeds was used for general corporate purposes. The agreements covering these notes contain a standard default cross-acceleration provision that provides the 7.25% Senior Notes will enter a state of default upon the failure to pay principal when due or upon any event or condition that results in an acceleration of principal of any other debt instrument in excess of $10 million that we have outstanding concurrently with the 7.25% Senior Notes. There are no financial debt covenants to which we are required to comply in regards to these notes.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Segment Information	Segment Information We evaluate the results of our four reportable segments as follows: • Our Standard Commercial Lines, Standard Personal Lines, and E&S Lines are evaluated based on before and after-tax underwriting results (net premiums earned, incurred loss and loss expense, policyholders dividends, policy acquisition costs, and other underwriting expenses), return on equity ("ROE") contribution, and combined ratios. • Our Investments segment is primarily evaluated after-tax net investment income and its ROE contribution. After-tax net realized and unrealized gains and losses, which are not included in non-GAAP operating income, are also included in our Investment segment results. In computing each segment's results, we do not make adjustments for interest expense or corporate expenses. No segment has a separate investment portfolio or allocated assets. Our combined insurance operations are subject to certain geographic concentrations, particularly in the Eastern region of the country. In 2021, approximately 18% of NPW were related to insurance policies written in New Jersey. We also had a goodwill balance of $7.8 million at both December 31, 2021 and 2020 on our Consolidated Balance Sheet that relates to our Standard Commercial Lines reporting unit. The following summaries present revenues (net investment income and net realized and unrealized gains and losses on investments in the case of the Investments segment) and pre-tax income for the individual segments: Revenue by Segment Years ended December 31, ($ in thousands) 2021 2020 2019 Standard Commercial Lines: Net premiums earned: Commercial property $ 436,412 388,120 353,834 Workers compensation 306,428 278,062 311,370 General liability 807,158 694,019 669,895 Commercial automobile 724,398 615,181 554,256 Businessowners’ policies 110,622 110,210 105,252 Bonds 35,762 36,742 35,726 Other 23,105 20,850 19,281 Miscellaneous income 16,056 15,512 10,889 Total Standard Commercial Lines revenue 2,459,941 2,158,696 2,060,503 Standard Personal Lines: Net premiums earned: Personal automobile 163,007 165,020 172,606 Homeowners 122,526 125,405 127,543 Other 8,026 8,715 7,590 Miscellaneous income 1,667 2,058 1,466 Total Standard Personal Lines revenue 295,226 301,198 309,205 E&S Lines: Net premiums earned: Casualty lines 197,779 174,408 182,864 Property lines 82,030 65,082 56,954 Total E&S Lines revenue 279,809 239,490 239,818 Investments: Net investment income 326,589 227,107 222,543 Net realized and unrealized investment gains (losses) 17,599 (4,217) 14,422 Total Investments revenues 344,188 222,890 236,965 Total revenues $ 3,379,164 2,922,274 2,846,491 Income Before and After Federal Income Tax Years ended December 31, ($ in thousands) 2021 2020 2019 Standard Commercial Lines: Underwriting income, before federal income tax $ 198,596 151,731 145,990 Underwriting income, after federal income tax 156,891 119,867 115,332 Combined ratio 91.9 % 92.9 % 92.9 % ROE contribution 5.9 % 5.1 5.8 Standard Personal Lines: Underwriting income (loss), before federal income tax 3,966 (15,508) 8,260 Underwriting income (loss), after federal income tax 3,133 (12,251) 6,525 Combined ratio 98.6 % 105.2 % 97.3 % ROE contribution 0.1 % (0.5) 0.3 E&S Lines: Underwriting income (loss), before federal income tax 16,030 126 9,743 Underwriting income (loss), after federal income tax 12,664 100 7,697 Combined ratio 94.3 % 99.9 % 95.9 % ROE contribution 0.5 % — 0.4 Investments: Net investment income earned $ 326,589 227,107 222,543 Net realized and unrealized investment gains (losses) 17,599 (4,217) 14,422 Total investment segment income, before federal income tax 344,188 222,890 236,965 Tax on investment segment income 67,284 41,609 45,301 Total investment segment income, after federal income tax $ 276,904 181,281 191,664 ROE contribution of after-tax net investment income earned 9.9 % 7.8 9.6 Reconciliation of Segment Results to Income Before Federal Income Tax Years ended December 31, ($ in thousands) 2021 2020 2019 Underwriting income (loss) Standard Commercial Lines $ 198,596 151,731 145,990 Standard Personal Lines 3,966 (15,508) 8,260 E&S Lines 16,030 126 9,743 Investment income 344,188 222,890 236,965 Total all segments 562,780 359,239 400,958 Interest expense (29,165) (30,839) (33,668) Corporate expenses (28,305) (25,412) (30,900) Income, before federal income tax $ 505,310 302,988 336,390 Preferred stock dividends (9,353) — — Income available to common stockholders, before federal income tax $ 495,957 $ 302,988 $ 336,390

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	Earnings per Share The following table provides a reconciliation of the numerators and denominators of basic and diluted earnings per share ("EPS"): 2021 Income Shares Per Share ($ in thousands, except per share amounts) (Numerator) (Denominator) Amount Basic EPS: Net income available to common stockholders $ 394,484 60,183 $ 6.55 Effect of dilutive securities: Stock compensation plans — 484 Diluted EPS: Net income available to common stockholders $ 394,484 60,667 $ 6.50 2020 Income Shares Per Share ($ in thousands, except per share amounts) (Numerator) (Denominator) Amount Basic EPS: Net income available to common stockholders $ 246,355 59,862 $ 4.12 Effect of dilutive securities: Stock compensation plans — 431 Diluted EPS: Net income available to common stockholders $ 246,355 60,293 $ 4.09 2019 Income Shares Per Share ($ in thousands, except per share amounts) (Numerator) (Denominator) Amount Basic EPS: Net income available to common stockholders $ 271,623 59,421 $ 4.57 Effect of dilutive securities: Stock compensation plans — 583 Diluted EPS: Net income available to common stockholders $ 271,623 60,004 $ 4.53

Federal Income Taxes

Federal Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal Income Taxes	Federal Income Taxes (a) A reconciliation of federal income tax on income at the corporate rate (21.0%) to the effective tax rate is as follows: ($ in thousands) 2021 2020 2019 Tax at statutory rate $ 106,115 63,627 70,642 Tax-advantaged interest (4,514) (4,730) (4,909) Dividends received deduction (558) (514) (443) Executive compensation 2,469 2,246 2,985 Stock-based compensation (693) (1,846) (3,253) Other (1,346) (2,150) (255) Federal income tax expense 101,473 56,633 64,767 Income before federal income tax, less preferred stock dividends 495,957 302,988 336,390 Effective tax rate 20.5 % 18.7 % 19.3 % (b) The tax effects of the significant temporary differences that gave rise to deferred tax assets and liabilities were as follows: ($ in thousands) 2021 2020 Deferred tax assets: Net loss reserve discounting $ 60,227 54,240 Net unearned premiums 68,086 60,842 Employee benefits 2,787 8,943 Long-term incentive compensation plans 5,904 5,472 Temporary investment write-downs 4,314 6,037 Other 2,245 7,195 Total deferred tax assets 143,563 142,729 Deferred tax liabilities: Deferred policy acquisition costs 68,652 60,601 Unrealized gains on investment securities 48,082 81,142 Other investment-related items, net 27,044 14,760 Accelerated depreciation and amortization 13,198 13,322 Total deferred tax liabilities 156,976 169,825 Net deferred federal income tax liability $ (13,413) (27,096) After considering all evidence, both positive and negative, with respect to our federal tax loss carryback availability, expected levels of pre-tax financial statement income, and federal taxable income, we believe it is more likely than not that the existing deductible temporary differences will reverse during periods in which we generate net federal taxable income or have adequate federal carryback availability. As a result, we had no valuation allowance recognized for federal deferred tax assets at December 31, 2021 or 2020. We did not have unrecognized tax expense or benefit as of December 31, 2021.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 31, 2021
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans (a) Selective Insurance Retirement Savings Plan (“Retirement Savings Plan”) and the Selective Insurance Company of America Deferred Compensation Plan ("Deferred Compensation Plan") SICA offers a voluntary defined contribution 401(k) plan that is available to most of our employees and is a tax-qualified retirement plan subject to ERISA. In addition, SICA offers a Deferred Compensation Plan to a group of management or highly compensated employees as a method of recognizing and retaining such employees. Expenses recorded for these plans were $19.2 million in 2021, $18.6 million in 2020, and $17.3 million in 2019. (b) Retirement Income Plan SICA maintains a defined benefit pension plan, the Retirement Income Plan for Selective Insurance Company of America (the "Pension Plan"). This qualified, noncontributory plan is closed to new entrants and existing participants ceased accruing benefits after March 31, 2016. The following tables provide details on the Pension Plan for 2021 and 2020: December 31, Pension Plan ($ in thousands) 2021 2020 Change in Benefit Obligation: Benefit obligation, beginning of year $ 425,161 391,021 Interest cost 8,593 11,312 Actuarial (gains) losses (12,844) 35,276 Benefits paid (13,152) (12,448) Benefit obligation, end of year $ 407,758 425,161 Change in Fair Value of Assets: Fair value of assets, beginning of year $ 432,716 385,087 Actual return on plan assets, net of expenses 30,741 60,077 Benefits paid (13,152) (12,448) Fair value of assets, end of year $ 450,305 432,716 Funded status $ 42,547 7,555 Amounts Recognized in the Consolidated Balance Sheet: Net pension assets, end of year $ 42,547 7,555 Amounts Recognized in AOCI: Net actuarial loss $ 78,304 101,414 Other Information as of December 31: Accumulated benefit obligation $ 407,758 425,161 Weighted-Average Liability Assumptions as of December 31: Discount rate 2.98 % 2.68 When determining the most appropriate discount rate to be used in the valuation at December 31, 2021, we consider, among other factors, our expected payout patterns of the Pension Plan's obligations as well as our investment strategy. We ultimately select the rate that we believe best represents our estimate of the inherent interest rate at which our pension benefits can be effectively settled. The approach we utilize discounts the individual expected cash flows using the applicable spot rates derived from the yield curve over the projected cash flow period. Our discount rate increased 30 basis points, to 2.98% as of December 31, 2021, from 2.68% as of December 31, 2020, which drove the decrease in the benefit obligation for the period. Pension Plan ($ in thousands) 2021 2020 2019 Components of Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income: Net Periodic Benefit Cost (Benefit): Interest cost $ 8,593 11,312 13,506 Expected return on plan assets (22,976) (21,907) (21,114) Amortization of unrecognized actuarial loss 2,501 2,817 2,575 Total net periodic pension cost (benefit) 1 $ (11,882) (7,778) (5,033) Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Net actuarial (gain) loss $ (20,609) (2,894) 11,643 Reversal of amortization of net actuarial loss (2,501) (2,817) (2,575) Total recognized in other comprehensive income $ (23,110) (5,711) 9,068 Total recognized in net periodic benefit cost and other comprehensive income $ (34,992) (13,489) 4,035 1 The components of net periodic pension cost (benefit) are included within "Loss and loss expense incurred" and "Other insurance expenses" on the Consolidated Statements of Income. Pension Plan 2021 2020 2019 Weighted-Average Expense Assumptions for the years ended December 31: Discount rate 2.68 % 3.33 4.46 Interest rate 2.06 % 2.95 % 4.12 % Expected return on plan assets 5.40 5.80 6.50 Pension Plan Assets Assets of the Pension Plan are invested to adequately support the liability associated with the Pension Plan's defined benefit obligation. Our return objective is to exceed the returns of the plan's policy benchmark, which is the return the plan would have earned if the assets were invested according to the target asset class weightings and earned index returns shown below. In 2022, we will continue to phase in adjustments to the asset allocation to steadily close the gap between the duration of the assets and the duration of the liabilities, provided certain improved funding targets are achieved. Over time, the target and actual asset allocations may change based on the funded status of the Pension Plan and market return expectations. The Pension Plan’s target ranges, as well as the actual weighted average asset allocation by strategy, at December 31 were as follows: 2021 2020 Target Percentage Actual Percentage Actual Percentage Minimum Maximum Return seeking assets 1 50 % 70 % 66 % 64 % Liability hedging assets 70 % 80 % 33 % 35 % Short-term investments - - 1 % 1 % Total 100 % 100 % 100 % 100 % 1 Includes limited partnerships. The use of derivative instruments is permitted under certain circumstances for the Pension Plan portfolio, but may not be used for unrelated speculative purposes or to create exposures that are not permitted in the Pension Plan's investment guidelines. We currently invest in a U.S. Treasury overlay derivative strategy, within the funds in our liability hedging assets, to manage the interest rate duration mismatch between the assets and liabilities of the Pension Plan to help insulate the funded status of the plan. Considering the impact of this derivative overlay, the liability hedging assets provide for an approximate 79% hedge against the projected benefit obligation. The Pension Plan had no investments in the Parent’s common stock as of December 31, 2021 or 2020. For information regarding investments in funds of our related parties, refer to Note 18. "Related Party Transactions" below. The techniques used to determine the fair value of the Pension Plan's invested assets that appear on the following page are as follows: • The investments in the equities and liability hedging funds include collective investment funds and fund of funds that utilize a market approach wherein the published prices in the active market for identical assets are used. These investments are traded at their net asset value per share. These investments are classified as Level 1 in the fair value hierarchy. • The investments in private limited partnerships are valued utilizing net asset value as a practical expedient for fair value. These investments are not classified in the fair value hierarchy. • Short-term investments are recorded at fair value. Given that these investments are listed on active exchanges, coupled with their liquid nature, these investments are classified as Level 1 in the fair value hierarchy. • The deposit administration contract is recorded at cost, which approximates fair value. Given the liquid nature of the underlying investments in overnight cash deposits and other short-term duration products, we have determined that a correlation exists between the deposit administration contract and other short-term investments, such as money market funds. As such, this investment is classified as Level 2 in the fair value hierarchy. For discussion regarding the levels within the fair value hierarchy, see Note 2. "Summary of Significant Accounting Policies." In addition, refer to Note 5. "Investments" for discussion regarding the limited partnership investment strategies, excluding the secondary private equity and direct lending strategies as these investments are currently not part of the Pension Plan's investment portfolio. The following tables provide quantitative disclosures of the Pension Plan’s invested assets that are measured at fair value on a recurring basis: December 31, 2021 Fair Value Measurements at 12/31/21 Using ($ in thousands) Assets Measured at Fair Value At 12/31/21 Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Description Return seeking assets: Equities: Global equity $ 144,634 144,634 — — Diversified credit 66,165 66,165 — — Real assets 89,590 89,590 — — Total equities 300,389 300,389 — — Limited partnerships (at net asset value) 1 : Real assets 47 — — — Private equity 413 — — — Total limited partnerships 460 — — — Total return seeking assets 300,849 300,389 — — Liability hedging assets: Fixed income 86,183 86,183 — — U.S. Treasury overlay 65,304 65,304 — — Total liability hedging assets 151,487 151,487 — — Cash and short-term investments: Short-term investments 1,744 1,744 — — Deposit administration contracts 2,422 — 2,422 — Total cash and short-term investments 4,166 1,744 2,422 — Total invested assets $ 456,502 453,620 2,422 — December 31, 2020 Fair Value Measurements at 12/31/20 Using ($ in thousands) Assets Measured at Fair Value At 12/31/20 Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Description Return seeking assets: Equities: Global equity $ 142,320 142,320 — — Diversified credit 73,762 73,762 — — Real assets 61,585 61,585 — — Total equities 277,667 277,667 — — Limited partnerships (at net asset value) 1 : Real assets 73 — — — Private equity 400 — — — Private credit 29 — — — Total limited partnerships 502 — — — Total return seeking assets 278,169 277,667 — — Liability hedging assets: Fixed income 99,490 99,490 — — U.S. Treasury overlay 52,756 52,756 — — Total liability hedging assets 152,246 152,246 — — Cash and short-term investments: Short-term investments 3,273 3,273 — — Deposit administration contracts 2,073 — 2,073 — Total cash and short-term investments 5,346 3,273 2,073 — Total invested assets $ 435,761 433,186 2,073 — 1 In accordance with the FASB issued ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , certain investments that are measured at fair value using the net asset value per share (or its practical expedient) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total Pension Plan invested assets. Contributions We presently do not anticipate contributing to the Pension Plan in 2022, as we have no minimum required contribution amounts. Benefit Payments ($ in thousands) Pension Plan Benefits Expected to be Paid in Future Fiscal Years: 2022 $ 14,900 2023 16,099 2024 17,232 2025 18,296 2026 19,394 2026-2030 108,742

Share-Based Payments

Share-Based Payments	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-based Payment Arrangement [Text Block]	Share-Based Payments Active Plans As of December 31, 2021, the following four plans were available for the issuance of share-based payment awards: • The 2014 Omnibus Stock Plan, As Amended and Restated Effective as of May 2, 2018 (the "Stock Plan"); • The Cash Incentive Plan, As Amended and Restated as of May 1, 2014 (the "Cash Plan"); • The Employee Stock Purchase Plan, As Amended and Restated as of July 1, 2021 ("ESPP"); and • The Amended and Restated Stock Purchase Plan for Independent Insurance Agencies (2010), Amended and Restated as of November 1, 2020 (the "Agent Plan"). The following table provides information regarding the approval of these plans: Plan Approvals Stock Plan Approved effective as of May 1, 2014 by stockholders on April 23, 2014. Cash Plan Approved effective April 1, 2005 by stockholders on April 27, 2005. ESPP Approved effective July 1, 2009 by stockholders on April 29, 2009. Agent Plan Approved by stockholders on April 26, 2006. The types of awards that can be issued under each of these plans are as follows: Plan Types of Share-Based Payments Issued Stock Plan Qualified and nonqualified stock options, stock appreciation rights ("SARs"), restricted stock, restricted stock units ("RSUs"), stock grants, and other awards valued in whole or in part by reference to the Parent's common stock. The maximum exercise period for an option grant under this plan is 10 years from the date of the grant. Dividend equivalent units ("DEUs") are earned during the vesting period on RSU grants. The DEUs are reinvested in the Parent's common stock at fair value on each dividend payment date. The requisite service period for grants to employees under this plan is the lesser of: (i) the stated vested date, which is typically three years from issuance; or (ii) the date the employee becomes eligible to retire. Cash Plan Cash incentive units (“CIUs”). The initial dollar value of each CIU will be adjusted to reflect the percentage increase or decrease in the total shareholder return on the Parent's common stock over a specified performance period. In addition, for certain grants, the number of CIUs granted will be increased or decreased to reflect our performance on specified performance indicators compared to targeted peer companies. The requisite service period for grants under this plan is the lesser of: (i) the stated vested date, which is typically three years from issuance; or (ii) the date the employee becomes eligible to retire. ESPP Enables employees to purchase shares of the Parent’s common stock. The purchase price is the lower of: (i) 85% of the closing market price at the time the option is granted; or (ii) 85% of the closing price at the time the option is exercised. Shares are generally issued on June 30 and December 31 of each year. Agent Plan Quarterly offerings to purchase the Parent's common stock at a 10% discount with a one-year restricted period during which the shares purchased cannot be sold or transferred. Only our independent retail insurance agencies and wholesale general agencies, and certain eligible persons associated with the agencies, are eligible to participate in this plan. Shares authorized and available for issuance as of December 31, 2021 are as follows: Authorized Available for Issuance Awards Outstanding Stock Plan 4,750,000 2,713,667 660,697 ESPP 5,500,000 1,184,849 — Agent Plan 3,000,000 1,608,234 — Retired Plans The following plans are closed for the issuance of new awards, although awards outstanding continue in effect according to the terms of the applicable award agreements: December 31, 2021 Types of Share-Based Payments Issued Reserve Shares Awards Outstanding 1 Plan 2005 Omnibus Stock Plan ("2005 Stock Plan") Qualified and nonqualified stock options, SARs, restricted stock, RSUs, phantom stock, stock bonuses, and other awards in such amounts and with such terms and conditions as it determined, subject to the provisions of the 2005 Stock Plan. The maximum exercise period for an option grant under this plan is 10 years from the date of the grant. DEUs are earned during the vesting period on RSU grants. The DEUs are reinvested in the Parent's common stock at fair value on each dividend payment date. 1,958,306 32,906 Parent's Stock Compensation Plan for Non-employee Directors Directors could elect to receive a portion of their annual compensation in shares of the Parent's common stock. 44,468 44,468 1 Awards outstanding under the 2005 Stock Plan represent shares deferred by our non-employee directors. RSU Transactions A summary of the RSU transactions under our share-based payment plans is as follows: Number Weighted Average Unvested RSU awards at December 31, 2020 667,674 $ 61.02 Granted in 2021 249,293 64.03 Vested in 2021 (258,477) 57.10 Forfeited in 2021 (16,854) 62.61 Unvested RSU awards at December 31, 2021 641,636 $ 63.73 As of December 31, 2021, total unrecognized compensation expense related to unvested RSU awards granted under our Stock Plan was $10.1 million. That expense is expected to be recognized over a weighted-average period of 1.7 years. The total intrinsic value of RSUs vested was $17.2 million for 2021, $20.6 million for 2020, and $22.0 million for 2019. In connection with vested RSUs, the total value of the DEUs that vested was $0.6 million in 2021, $0.7 million in 2020, and $0.8 million in 2019. Option Transactions As of December 31, 2021 and 2020, we had no stock options outstanding under our 2005 Stock Plan. The total intrinsic value of options exercised was $1.3 million in 2020 and $5.2 million in 2019. CIU Transactions The liability recorded in connection with our Cash Plan was $11.0 million as of December 31, 2021, and $8.2 million as of December 31, 2020. The remaining cost associated with the CIUs is expected to be recognized over a weighted average period of 1.2 years. The CIU payments made in connection with the CIU vestings were $2.2 million in 2021, $2.3 million in 2020, and $18.4 million in 2019. There were structural changes to our Cash Plan in early 2017, and as a result, payments in 2021 and 2020 were comparatively lower than 2019. ESPP and Agent Plan Transactions A summary of ESPP and Agent Plan share issuances is as follows: 2021 2020 2019 ESPP Issuances 72,239 99,141 72,952 Agent Plan Issuances 50,999 69,238 47,888 Fair Value Measurements The grant date fair value of RSUs is based on the market price of our common stock on the grant date, adjusted for the present value of our expected dividend payments. The expense recognized for share-based awards is based on the number of shares or units expected to be issued at the end of the performance period and the grant date fair value. The grant date fair value of each option award is estimated using the Black Scholes option valuation model ("Black Scholes"). The following are the significant assumptions used in applying Black Scholes: (i) the risk-free interest rate, which is the implied yield currently available on U.S. Treasury zero-coupon issues with an equal remaining term; (ii) the expected term, which is based on historical experience of similar awards; (iii) the dividend yield, which is determined by dividing the expected per share dividend during the coming year by the grant date stock price; and (iv) the expected volatility, which is based on the volatility of the Parent's stock price over a historical period comparable to the expected term. In applying Black Scholes, we use the weighted average assumptions illustrated in the following table: ESPP 2021 2020 2019 Risk-free interest rate 0.07 % 0.76 2.33 Expected term 6 months 6 months 6 months Dividend yield 1.4 % 1.6 1.2 Expected volatility 28 % 37 26 The weighted-average fair value per share of options and stock, including RSUs granted under the Parent's stock plans, during 2021, 2020, and 2019 was as follows: 2021 2020 2019 RSUs $ 64.03 62.91 63.60 ESPP: Six month option 4.69 4.82 4.32 Discount of grant date market value 10.98 8.61 9.99 Total ESPP 15.67 13.43 14.31 Agent Plan: Discount of grant date market value 7.57 5.73 7.00 The fair value of the CIU liability is remeasured at each reporting period through the settlement date of the awards, which is three years from the date of grant, based on an amount expected to be paid. A Monte Carlo simulation is performed to approximate the projected fair value of the CIUs that, in accordance with the CIU agreements established under the Cash Plan, is adjusted to reflect our performance on specified indicators compared to targeted peer companies. Expense Recognition The following table provides share-based compensation expense in 2021, 2020, and 2019: ($ in millions) 2021 2020 2019 Share-based compensation expense, pre-tax $ 22.3 19.8 24.5 Income tax benefit, including the benefit related to stock grants that vested during the year (5.1) (5.7) (8.2) Share-based compensation expense, after-tax $ 17.2 14.1 16.3

Equity

Equity	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Equity Text Block	Preferred Stock We have 5,000,000 shares of preferred stock authorized, with no par value, of which (i) 300,000 shares are designated Series A junior preferred stock, which have not been issued, and (ii) 8,000 shares were issued as Series B in 2020 as discussed below. On December 2, 2020, we issued 8.0 million depository shares, each representing a 1/1,000th interest in a share of our perpetual 4.60% Non-Cumulative Preferred Stock, Series B, without par value, with a liquidation preference of $25,000 per share (equivalent to $25.00 per depository share) (“Preferred Stock”), for net proceeds of $194.6 million. Dividends are recorded when declared and, if declared are payable quarterly in arrears on the 15th day of March, June, September, and December. If a dividend is not declared and paid or made payable on all outstanding shares of the Preferred Stock for the latest completed dividend period, no dividends may be declared or paid on our common stock and we may not purchase, redeem, or otherwise acquire our outstanding common stock. The Preferred Stock is redeemable at our option in whole or in part, from time to time, on or after December 15, 2025 at a redemption price equal to $25,000 per share of Preferred Stock (equivalent to $25.00 per depository share), plus unpaid dividends attributable to the then current dividend period. Prior to December 15, 2025, the Preferred Stock is redeemable at the Company’s option, in whole but not in part, within 90 days of the occurrence of (a) a rating agency event at a redemption price equal to $25,500 per share of Preferred Stock (equivalent to $25.50 per depository share), plus unpaid dividends attributable to the current dividend period in circumstances where a rating agency changes its criteria used to assign equity credit to securities like the Preferred Stock; or (b) a regulatory capital event at a redemption price equal to $25,000 per share of Preferred Stock (equivalent to $25.00 per depository share), plus unpaid dividends attributable to the current dividend period in circumstances where a capital regulator such as a state insurance regulator changes or proposes to change capital adequacy rules. Share Repurchase Program On December 2, 2020, we announced that our Board authorized a $100 million share repurchase program, which has no set expiration or termination date. Our repurchase program does not obligate us to acquire any particular amount of our common stock. The timing and amount of any share repurchases under the authorization is determined by management at its discretion based on market conditions and other considerations. As of December 31, 2021, 52,781 shares were repurchased under the share repurchase program at a total cost of $3.4 million. These repurchases were all completed in the first quarter of 2021, and we did not repurchase any shares under our share repurchase program during the remainder of 2021. We have $96.6 million of remaining capacity under our share repurchase program.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions William M. Rue, a Director of the Parent, is Chairman of, and owns more than 10% of the equity of Rue Holding Company, which owns 100% of Chas. E. Rue & Son, Inc., t/a Rue Insurance, a general independent retail insurance agency ("Rue Insurance"). Rue Insurance is an appointed distribution partner of the Insurance Subsidiaries on terms and conditions similar to those of our other distribution partners, which includes the right to participate in the Agent Plan. Mr. Rue’s son is President, and an employee, of Rue Insurance, and owns more than 10% of the equity of Rue Holding Company. Mr. Rue’s daughter is an employee of Rue Insurance and owns less than 10% of the equity of Rue Holding Company. Our relationship with Rue Insurance has existed since 1928. Rue Insurance placed insurance policies with the Insurance Subsidiaries for its customers and itself. Direct premiums written associated with these policies were $12.8 million in 2021, and $11.0 million in both 2020 and 2019. In return, the Insurance Subsidiaries paid standard market commissions, including supplemental commissions, to Rue Insurance of $2.0 million in 2021, $1.8 million in 2020, and $2.0 million in 2019. Amounts due to Rue Insurance at December 31, 2021 and December 31, 2020 were $0.7 million and $0.2 million, respectively. All contracts and transactions with Rue Insurance were consummated in the ordinary course of business on an arm's-length basis. In 2005, we established a private foundation, now named The Selective Insurance Group Foundation (the "Foundation"), under Section 501(c)(3) of the Internal Revenue Code. The Board of the Foundation is comprised of some of the Parent's officers. We made $1.3 million of contributions to the Foundation in both 2021 and 2019, and $0.5 million in 2020. BlackRock, Inc., a leading publicly-traded investment management firm (“BlackRock”), has purchased our common shares in the ordinary course of its investment business and has previously filed Schedules 13G/A with the SEC. On January 27, 2022, BlackRock filed a Schedule 13G/A reporting beneficial ownership as of December 31, 2021, of 11.4% of our common stock. In connection with purchasing our common shares, BlackRock filed the necessary filings with insurance regulatory authorities. On the basis of those filings, BlackRock is deemed not to be a controlling person for the purposes of applicable insurance law. We are required to disclose related party information for our transactions with BlackRock. BlackRock is highly regulated, serves its clients as a fiduciary, and has a diverse platform of active (alpha) and index (beta) investment strategies across asset classes that enables it to tailor investment outcomes and asset allocation solutions for clients. BlackRock also offers the BlackRock Solutions ® investment and risk management technology platform, Aladdin ® , risk analytics, advisory, and technology services and solutions to a broad base of institutional and wealth management investors. We incurred expenses related to BlackRock for services rendered of $1.8 million in 2021, $2.0 million in 2020, and $2.2 million in 2019. Amounts payable for such services were $0.5 million at December 31, 2021, $1.3 million at December 31, 2020, and $1.1 million at December 31, 2019. As part of our overall investment diversification, we invest in various BlackRock funds from time to time. These funds accounted for less than 1% of our invested assets at December 31, 2021 and December 31, 2020, and are predominately reflected in "Equity securities" on our Consolidated Balance Sheet. During 2021, with regard to BlackRock funds, we (i) purchased $16.5 million in securities, (ii) sold $32.5 million, (iii) recognized net realized and unrealized losses of $0.6 million, and (iv) recorded $0.9 million in income. During 2020, we purchased (i) $62.2 million in securities, (ii) recognized net unrealized losses of $0.2 million, and (iii) recorded $0.4 million in income. We did not make any sales of BlackRock funds in 2020. During 2019, we purchased $21.7 million in securities, (ii) sold $59.5 million, (iii) recognized net realized and unrealized gains of $5.7 million, and (iv) recorded $0.8 million in income. There were no amounts payable on the settlement of these investment transactions at December 31, 2021 and December 31, 2020.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Lessee Disclosure [Text Block]	Leases We have various operating leases for office space, equipment, and fleet vehicles. In addition, we have various finance leases for computer hardware. Such lease agreements, which expire at various dates through 2032, are generally renewed or replaced by similar leases. The components of lease expense for the year ended December 31, 2021 and 2020 were as follows: ($ in thousands) 2021 2020 Operating lease cost, included in Other insurance expenses on the Consolidated Statements of Income $ 7,935 9,498 Finance lease cost: Amortization of assets, included in Other insurance expenses on the Consolidated Statements of Income 1,765 550 Interest on lease liabilities, included in Interest expense on the Consolidated Statements of Income 35 15 Total finance lease cost 1,800 565 Variable lease cost, included in Other insurance expenses on the Consolidated Statements of Income 291 758 Short-term lease cost, included in Other insurance expenses on the Consolidated Statements of Income $ 832 2,011 The following table provides supplemental information regarding our operating and finance leases. December 31, 2021 December 31, 2020 Weighted-average remaining lease term Operating leases 7 8 years Finance leases 2 2 Weighted-average discount rate Operating leases 2.1 2.3 % Finance leases 0.8 1.6 Operating and finance lease asset and liability balances are included within the following line items on the Consolidated Balance Sheets: ($ in thousands) December 31, 2021 December 31, 2020 Operating leases Other assets $ 35,644 40,215 Other liabilities 37,296 41,674 Finance leases Property and equipment - at cost, net of accumulated depreciation and amortization 5,446 502 Long-term debt $ 5,450 508 At December 31, 2021, the maturities of our lease liabilities were as follows: ($ in thousands) Finance Leases Operating Leases Total Year ended December 31, 2022 $ 2,350 7,235 9,585 2023 2,255 6,610 8,865 2024 795 5,992 6,787 2025 64 5,902 5,966 2026 41 5,967 6,008 Thereafter — 24,356 24,356 Total lease payments 5,505 56,062 61,567 Less: imputed interest 55 2,726 2,781 Less: leases that have not yet commenced — 16,040 16,040 Total lease liabilities $ 5,450 37,296 42,746 At December 31, 2020, the maturities of our lease liabilities for capital and operating leases were as follows: ($ in thousands) Finance Leases Operating Leases Total Year ended December 31, 2021 $ 330 8,372 8,702 2022 127 6,788 6,915 2023 56 5,411 5,467 2024 — 4,690 4,690 2025 — 3,572 3,572 Thereafter — 16,234 16,234 Total lease payments 513 45,067 45,580 Less: imputed interest 5 3,393 3,398 Less: leases that have not yet commenced — — — Total lease liabilities $ 508 41,674 42,182 Refer to Note 4 "Statements of Cash Flows" in this Form 10-K for supplemental cash and non-cash transactions included in the measurement of operating and finance lease liabilities.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies(a) We purchase annuities from life insurance companies to fulfill obligations under claim settlements that provide for periodic future payments to claimants. As of December 31, 2021, we had purchased such annuities with a present value of $31.6 million for settlement of claims on a structured basis for which we are contingently liable. To our knowledge, there are no material defaults from any of the issuers of such annuities. (b) As of December 31, 2021, we have made commitments that may require us to invest additional amounts into our investment portfolio, which are as follows: ($ in millions) Amount of Obligation Year of Expiration of Obligation Alternative and other investments $ 215.0 2036 Non-publicly traded collateralized loan obligations in our fixed income securities portfolio 59.8 2030 Non-publicly traded common stock within our equity portfolio 4.2 2027 CMLs 5.5 2023 Privately-placed corporate securities 4.3 Less than 1 year Total $ 288.8 There is no certainty that any such additional investment will be required. We expect to have the capacity to repay or refinance these obligations as they come due.

Litigation

Litigation	12 Months Ended
	Dec. 31, 2021
Loss Contingency, Information about Litigation Matters [Abstract]
Litigation	Litigation As of December 31, 2021, we do not believe we are involved in any legal action that could have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. In the ordinary course of conducting business, we are parties in various legal actions. Most are claims litigation involving our Insurance Subsidiaries as (i) liability insurers defending or providing indemnity for third-party claims brought against our customers, (ii) insurers defending first-party coverage claims brought against them, or (iii) liability insurers seeking declaratory judgment on our insurance coverage obligations. We account for such activity through the establishment of unpaid loss and loss expense reserves. In ordinary course claims litigation, we expect that any potential ultimate liability, after consideration of provisions made for potential losses and costs of defense, will not be material to our consolidated financial condition, results of operations, or cash flows. All of our commercial property and businessowners' policies require direct physical loss of or damage to property by a covered cause of loss. It also is our practice to include in, or attach to, all standard lines commercial property and businessowners' policies an exclusion that states that all loss or property damage caused by or resulting from any virus, bacterium, or other microorganism that induces or is capable of inducing physical distress, illness, or disease is not a covered cause of loss ("Virus Exclusion"). Whether COVID-19-related contamination, the existence of the COVID-19 pandemic, and the resulting COVID-19-related government shutdown orders cause physical loss of or damage to property is the subject of much public debate and first-party coverage litigation against some insurers, including us. The Virus Exclusion also is the subject of first-party coverage litigation against some insurers, including us. We cannot predict the outcome of litigation over these two coverage issues, including interpretation of provisions similar or identical to those in our insurance policies. From time to time, our Insurance Subsidiaries also are named as defendants in other legal actions, some of which assert claims for substantial amounts. Plaintiffs may style these actions as putative class actions and seek judicial certification of a state or national class for allegations involving our business practices, such as improper reimbursement of medical providers paid under workers compensation and personal and commercial automobile insurance policies or improper reimbursement for automobile parts. Similarly, our Insurance Subsidiaries can be named in individual actions seeking extra-contractual damages, punitive damages, or penalties, often alleging bad faith in the handling of insurance claims. We believe that we have valid defenses to these allegations and we account for such activity through the establishment of unpaid loss and loss expense reserves. In these other legal actions, we expect that any potential ultimate liability, after consideration of provisions made for estimated losses, will not be material to our consolidated financial condition. Nonetheless, litigation outcomes are inherently unpredictable and, because the amounts sought in certain of these actions are large or indeterminate, it is possible that any adverse outcomes could have a material adverse effect on our consolidated results of operations or cash flows in particular quarterly or annual periods.

Statutory Financial Information

Statutory Financial Information, Capital Requirements, and Restrictions on Dividends and Transfers of Funds	12 Months Ended
	Dec. 31, 2021
Insurance [Abstract]
Statutory Financial Information, Capital Requirments, and Retrictions on Dividends and Transfers of Funds	Statutory Financial Information, Capital Requirements, and Restrictions on Dividends and Transfers of Funds (a) Statutory Financial Information The Insurance Subsidiaries prepare their statutory financial statements in accordance with accounting principles prescribed or permitted by the various state insurance departments of domicile. Prescribed statutory accounting principles include state laws, regulations, and general administrative rules, as well as a variety of publications of the National Association of Insurance Commissioners (“NAIC"). Permitted statutory accounting principles encompass all accounting principles that are not prescribed; such principles differ from state to state, may differ from company to company within a state and may change in the future. The Insurance Subsidiaries do not utilize any permitted statutory accounting principles that affect the determination of statutory surplus, statutory net income, or risk-based capital (“RBC”). As of December 31, 2021, the various state insurance departments of domicile have adopted the March 2021 version of the NAIC Accounting Practices and Procedures manual in its entirety, as a component of prescribed or permitted practices. The following table provides statutory data for each of our Insurance Subsidiaries: State of Domicile Unassigned Surplus Statutory Surplus Statutory Net Income ($ in millions) 2021 2020 2021 2020 2021 2020 2019 SICA New Jersey $ 673.1 574.2 838.3 739.4 134.7 81.8 113.9 Selective Way Insurance Company ("SWIC") New Jersey 436.4 374.0 492.4 430.0 74.5 54.0 59.2 SICSC Indiana 166.3 148.6 200.6 182.8 24.2 20.8 23.9 SICSE Indiana 132.7 115.9 160.3 143.5 19.4 16.8 18.5 SICNY New York 127.0 111.7 154.7 139.4 18.6 15.3 17.0 Selective Insurance Company of New England ("SICNE") New Jersey 34.5 30.0 65.6 61.2 7.5 6.8 7.8 Selective Auto Insurance Company of New Jersey ("SAICNJ") New Jersey 90.4 70.0 135.2 114.9 16.7 12.9 14.9 Mesa Underwriters Specialty Insurance Company ("MUSIC") New Jersey 47.4 34.4 116.9 103.9 13.9 11.4 13.2 Selective Casualty Insurance Company ("SCIC") New Jersey 83.4 71.1 159.9 147.5 20.6 16.2 16.8 Selective Fire and Casualty Insurance Company ("SFCIC") New Jersey 34.2 29.2 67.1 62.1 8.2 6.4 7.5 Total $ 1,825.4 1,559.1 2,391.0 2,124.7 338.3 242.4 292.7 (b) Capital Requirements The Insurance Subsidiaries are required to maintain certain minimum amounts of statutory surplus to satisfy the requirements of their various state insurance departments of domicile. RBC requirements for property and casualty insurance companies are designed to assess capital adequacy and to raise the level of protection that statutory surplus provides for policyholders. The Insurance Subsidiaries' combined total adjusted capital exceeded the required level of capital as defined by the NAIC based on their 2021 statutory financial statements. In addition to statutory capital requirements, we are impacted by various rating agency requirements related to certain rating levels. These required capital levels may be higher than statutory requirements. (c) Restrictions on Dividends and Transfers of Funds Our ability to declare and pay dividends on the Parent's common stock is dependent on liquidity at the Parent coupled with the ability of the Insurance Subsidiaries to declare and pay dividends, if necessary, and/or the availability of other sources of liquidity to the Parent. In addition to regulatory restrictions on the availability of dividends that our Insurance Subsidiaries can pay to the Parent, the maximum amount of dividends the Parent can pay our shareholders is limited by certain New Jersey corporate law provisions that limit dividends if either: (i) the Parent would be unable to pay its debts as they became due in the usual course of business; or (ii) the Parent’s total assets would be less than its total liabilities. The Parent’s ability to pay dividends to shareholders also are impacted by (i) covenants in its Line of Credit that obligate it, among other things, to maintain a minimum consolidated net worth and a maximum ratio of consolidated debt to total capitalization, and (ii) the terms of our preferred stock that prohibit dividends to be declared or paid on our common stock if dividends are not declared and paid, or made payable, on all outstanding preferred stock for the latest completed dividend period. As of December 31, 2021, the Parent had an aggregate of $527.1 million in investments and cash available to fund future dividends and interest payments. These amounts are not subject to any regulatory restrictions other than the standard state insolvency restrictions noted above, whereas our consolidated retained earnings of $2.6 billion are predominately restricted due to regulations applicable to our Insurance Subsidiaries. In 2022, the Insurance Subsidiaries have the ability to provide for $322.0 million in annual dividends to the Parent; however, as regulated entities, these dividends are subject to certain restrictions, which are further discussed below. The Parent also has other potential sources of liquidity, such as: (i) borrowings from our Indiana Subsidiaries; (ii) debt issuances; (iii) common and preferred stock issuances; and (iv) borrowings under our Line of Credit. Borrowings from our Indiana Subsidiaries are governed by approved intercompany lending agreements with the Parent that provide for additional capacity of $109.9 million as of December 31, 2021, based on restrictions in these agreements that limit borrowings to 10% of the admitted assets of the Indiana Subsidiaries. For additional restrictions on the Parent's debt, see Note 11. "Indebtedness" in this Form 10-K. Insurance Subsidiaries Dividend Restrictions As noted above, the restriction on our net assets and retained earnings is predominantly driven by our Insurance Subsidiaries' ability to pay dividends to the Parent under applicable laws and regulations. Under the insurance laws of the domiciliary states of the Insurance Subsidiaries, New Jersey, Indiana, and New York, an insurer can potentially make an ordinary dividend payment if its statutory surplus following such dividend is reasonable in relation to its outstanding liabilities, is adequate to its financial needs, and the dividend does not exceed the insurer's unassigned surplus. In general, New Jersey defines an ordinary dividend as a dividend whose fair market value, together with other dividends made within the preceding 12 months, is less than the greater of 10% of the insurer's statutory surplus as of the preceding December 31, or the insurer's net income (excluding capital gains) for the 12-month period ending on the preceding December 31. Indiana's ordinary dividend calculation is consistent with New Jersey's, except that it does not exclude capital gains from net income. In general, New York defines an ordinary dividend as a dividend whose fair market value, together with other dividends made within the preceding 12 months, is less than the lesser of 10% of the insurer's statutory surplus, or 100% of adjusted net investment income. New Jersey and Indiana require notice of the declaration of any ordinary dividend distribution. During the notice period, the relevant state regulatory authority may disallow all or part of the proposed dividend if it determines that the dividend is not appropriate given the above considerations. New York does not require notice of ordinary dividends. Dividend payments exceeding ordinary dividends are referred to as extraordinary dividends and require review and approval by the applicable domiciliary insurance regulatory authority prior to payment. The table below provides the following information: (i) quantitative data regarding all Insurance Subsidiaries' dividends paid to the Parent in 2021, which was used for debt service, shareholder dividends, and general operating purposes; and (ii) the maximum ordinary dividends that can be paid to the Parent by the Insurance Subsidiaries in 2022, based on the 2021 statutory financial statements. Dividends Twelve Months ended December 31, 2021 2022 ($ in millions) State of Domicile Ordinary Dividends Paid Maximum Ordinary Dividends SICA New Jersey $ 66.0 $ 124.4 SWIC New Jersey 27.5 72.8 SICSC Indiana 10.0 24.2 SICSE Indiana 8.8 19.4 SICNY New York 4.0 15.5 SICNE New Jersey 3.0 7.5 SAICNJ New Jersey 0.7 16.8 MUSIC New Jersey 6.1 13.7 SCIC New Jersey 10.4 19.5 SFCIC New Jersey 3.5 8.2 Total $ 140.0 $ 322.0

Schedule I - Summary of Investm

Schedule I - Summary of Investments - Other Than Investments in Related Parties	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
Schedule I - Summary of Investments- Other than Investments in Related Parties	Types of investment ($ in thousands) Amortized Cost or Cost Fair Value Carrying Amount Fixed income securities: Held-to-maturity: Obligations of states and political subdivisions $ 3,442 3,576 3,440 Public utilities 1,345 1,368 1,352 All other corporate securities 24,067 24,516 23,993 Total fixed income securities, held-to-maturity 28,854 29,460 28,785 Available-for-sale: U.S. government and government agencies 127,974 130,458 130,458 Foreign government 15,420 15,860 15,860 Obligations of states and political subdivisions 1,121,422 1,189,308 1,189,308 Public utilities 119,980 122,329 122,329 All other corporate securities 2,358,369 2,451,274 2,451,274 Collateralized loan obligation securities and other asset-backed securities 1,343,687 1,350,814 1,350,814 Residential mortgage-backed securities 756,280 776,252 776,252 Commercial mortgage-backed securities 647,621 673,681 673,681 Total fixed income securities, available-for-sale 6,490,753 6,709,976 6,709,976 Equity securities: Common stock: Banks, trusts and insurance companies 45,537 44,086 44,086 Industrial, miscellaneous and all other 261,343 289,363 289,363 Nonredeemable preferred stock 1,960 2,088 2,088 Total equity securities 308,840 335,537 335,537 Commercial mortgage loans 95,795 95,795 Short-term investments 447,862 447,863 Other investments 409,032 409,032 Total investments $ 7,781,136 8,026,988 See accompanying Report of Independent Registered Public Accounting Firm in Item 8. "Financial Statements and Supplementary Data." of this Form 10-K.

Schedule II - Parent Corporatio

Schedule II - Parent Corporation Finanical Statements	12 Months Ended
	Dec. 31, 2021
Condensed Financial Information Disclosure [Abstract]
Schedule II- Parent Corporation Financial Statements	SCHEDULE II SELECTIVE INSURANCE GROUP, INC. (Parent Corporation) Balance Sheets December 31, ($ in thousands, except share amounts) 2021 2020 Assets: Fixed income securities, available-for-sale - at fair value (allowance for credit losses: $542 – 2021; $22 – 2020; amortized cost: $317,703 – 2021; $272,256 – 2020 $ 325,014 290,428 Equity securities 136,362 159,524 Short-term investments 56,042 36,425 Other investments 9,241 3,392 Cash 455 394 Investment in subsidiaries 2,954,725 2,754,012 Current federal income tax 7,208 11,040 Deferred federal income tax 4,487 2,218 Other assets 9,178 1,959 Total assets $ 3,502,712 3,259,392 Liabilities: Long-term debt $ 440,600 440,235 Intercompany notes payable 57,980 59,611 Accrued long-term stock compensation 10,965 8,238 Other liabilities 10,282 12,419 Total liabilities $ 519,827 520,503 Stockholders’ Equity: Preferred stock of $0 par value per share: Authorized shares: 5,000,000; Issued shares: 8,000 with $25,000 liquidation preference per share – 2021 and 2020 $ 200,000 200,000 Common stock of $2 par value per share: Authorized shares: 360,000,000 Issued: 104,450,916 – 2021; 104,032,912 – 2020 208,902 208,066 Additional paid-in capital 464,347 438,985 Retained earnings 2,603,472 2,271,537 Accumulated other comprehensive income 115,099 220,186 Treasury stock – at cost (shares: 44,266,534 – 2021; 44,127,109 – 2020) (608,935) (599,885) Total stockholders’ equity 2,982,885 2,738,889 Total liabilities and stockholders’ equity $ 3,502,712 3,259,392 See accompanying Report of Independent Registered Public Accounting Firm. Information should be read in conjunction with the Notes to Consolidated Financial Statements of Selective Insurance Group, Inc. and its subsidiaries. Both items are in Item 8. “Financial Statements and Supplementary Data.” of this Form 10-K. SCHEDULE II (continued) SELECTIVE INSURANCE GROUP, INC. (Parent Corporation) Statements of Income Year ended December 31, ($ in thousands) 2021 2020 2019 Revenues: Dividends from subsidiaries $ 140,018 104,992 110,004 Net investment income earned 15,454 7,579 7,301 Net realized and unrealized investment gains 1,898 1,756 207 Total revenues 157,370 114,327 117,512 Expenses: Interest expense 28,988 29,220 33,426 Other expenses 28,305 25,412 30,900 Total expenses 57,293 54,632 64,326 Income before federal income tax 100,077 59,695 53,186 Federal income tax (benefit) expense: Current (6,552) (10,987) (16,080) Deferred 12 473 3,606 Total federal income tax benefit (6,540) (10,514) (12,474) Net income before equity in undistributed income of subsidiaries 106,617 70,209 65,660 Equity in undistributed income of subsidiaries, net of tax 297,220 176,146 205,963 Net income $ 403,837 246,355 271,623 Preferred stock dividends 9,353 — — Net income available to common stockholders $ 394,484 246,355 271,623 See accompanying Report of Independent Registered Public Accounting Firm. Information should be read in conjunction with the Notes to Consolidated Financial Statements of Selective Insurance Group, Inc. and its subsidiaries. Both items are in Item 8. “Financial Statements and Supplementary Data.” of this Form 10-K. SCHEDULE II (continued) SELECTIVE INSURANCE GROUP, INC. (Parent Corporation) Statements of Cash Flows Year ended December 31, ($ in thousands) 2021 2020 2019 Operating Activities: Net income $ 403,837 246,355 271,623 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed income of subsidiaries, net of tax (297,220) (176,146) (205,963) Stock-based compensation expense 15,893 16,227 19,077 Net realized and unrealized investment gains (1,898) (1,756) (207) Undistributed (income) losses of equity method investments (1,859) 672 — Amortization – other 1,076 1,080 4,614 Changes in assets and liabilities: Increase (decrease) in accrued long-term stock compensation 2,727 (366) (12,970) Decrease in net federal income taxes 3,843 5,549 1,651 Increase in other assets (7,251) (317) (533) (Decrease) increase in other liabilities (1,742) (390) 3,919 Net cash provided by operating activities 117,406 90,908 81,211 Investing Activities: Purchase of fixed income securities, available-for-sale (113,829) (89,726) (153,482) Purchase of equity securities (5,676) (157,411) (10,824) Purchase of short-term investments (330,843) (523,961) (1,116,766) Purchase of other investments (4,949) (4,065) — Redemption and maturities of fixed income securities, available-for-sale 51,524 26,877 10,579 Sale of fixed income securities, available-for-sale 15,713 23,276 20,189 Sale of equity securities 31,204 — 10,828 Sale of short-term investments 311,225 523,813 1,116,253 Proceeds from other investments 959 — — Capital contribution to subsidiaries — (30,000) — Net cash used in investing activities (44,672) (231,197) (123,223) Financing Activities: Dividends to preferred stockholders (9,353) — — Dividends to common stockholders (60,136) (54,486) (47,675) Acquisition of treasury stock (9,050) (7,053) (8,164) Proceeds from borrowings — 50,000 290,757 Repayment of borrowings — (50,000) (185,000) Net proceeds from stock purchase and compensation plans 7,976 8,411 8,243 Preferred stock issued, net of issuance costs (479) 195,063 — Principal payment on borrowings from subsidiaries (1,631) (1,552) (16,354) Net cash (used in) provided by financing activities (72,673) 140,383 41,807 Net increase (decrease) in cash 61 94 (205) Cash, beginning of year 394 300 505 Cash, end of year $ 455 394 300 See accompanying Report of Independent Registered Public Accounting Firm. Information should be read in conjunction with the Notes to Consolidated Financial Statements of Selective Insurance Group, Inc. and its subsidiaries. Both items are in Item 8. “Financial Statements and Supplementary Data.” of this Form 10-K.

Schedule III - Supplementary In

Schedule III - Supplementary Insurance Information	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Abstract]
Schedule III- Supplementary Insurance Information	($ in thousands) Deferred Reserve Unearned premiums Net Net investment income 1 Loss Amortization Other operating expenses 2 Net Standard Commercial Lines Segment $ 279,850 3,832,151 1,346,809 2,443,885 — 1,426,768 539,606 278,915 2,593,018 Standard Personal Lines Segment 12,911 270,066 317,276 293,559 — 212,116 25,918 51,559 292,265 E&S Lines Segment 34,154 478,686 139,122 279,809 — 175,100 60,945 27,734 304,430 Investments Segment — — — — 344,188 — — — — Total $ 326,915 4,580,903 1,803,207 3,017,253 344,188 1,813,984 626,469 358,208 3,189,713 1 Includes “Net investment income earned” and “Net realized and unrealized investment gains (losses)” on the Consolidated Statements of Income. 2 “Other operating expenses” of $358,208 reconciles to the Consolidated Statements of Income as follows: Other insurance expenses $ 375,931 Other income (17,723) Total $ 358,208 See accompanying Report of Independent Registered Public Accounting Firm in Item 8. "Financial Statements and Supplementary Data." of this Form 10-K. Year ended December 31, 2020 ($ in thousands) Deferred Reserve Unearned premiums Net Net investment income 1 Loss Amortization Other operating expenses 2 Net Standard Commercial Lines Segment $ 246,494 3,596,340 1,196,243 2,143,184 — 1,245,627 474,322 271,504 2,230,636 Standard Personal Lines Segment 13,803 228,348 308,183 299,140 — 233,260 30,694 50,694 295,166 E&S Lines Segment 28,281 435,667 113,845 239,490 — 156,936 55,255 27,173 247,290 Investments Segment — — — — 222,890 — — — — Total $ 288,578 4,260,355 1,618,271 2,681,814 222,890 1,635,823 560,271 349,371 2,773,092 1 Includes “Net investment income earned” and “Net realized and unrealized investment gains (losses)” on the Consolidated Statements of Income. 2 “Other operating expenses” of $349,371 reconciles to the Consolidated Statements of Income as follows: Other insurance expenses $ 366,941 Other income (17,570) Total $ 349,371 See accompanying Report of Independent Registered Public Accounting Firm in Item 8. "Financial Statements and Supplementary Data." of this Form 10-K. Year ended December 31, 2019 ($ in thousands) Deferred Reserve Unearned premiums Net Net investment income 1 Loss Amortization Other operating expenses 2 Net Standard Commercial Lines Segment $ 226,464 3,436,363 1,108,009 2,049,614 — 1,187,856 445,661 270,107 2,137,071 Standard Personal Lines Segment 16,848 224,200 309,125 307,739 — 211,300 34,477 53,702 304,592 E&S Lines Segment 27,874 406,600 106,033 239,818 — 152,335 55,835 21,905 237,761 Investments Segment — — — — 236,965 — — — — Total $ 271,186 4,067,163 1,523,167 2,597,171 236,965 1,551,491 535,973 345,714 2,679,424 1 Includes “Net investment income earned” and “Net realized and unrealized investment gains (losses)” on the Consolidated Statements of Income. 2 “Other operating expenses” of $345,714 reconciles to the Consolidated Statements of Income as follows: Other insurance expenses $ 358,069 Other income (12,355) Total $ 345,714 See accompanying Report of Independent Registered Public Accounting Firm in Item 8. "Financial Statements and Supplementary Data." of this Form 10-K.

Schedule IV - Reinsurance

Schedule IV - Reinsurance	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]
Schedule IV - Reinsurance	($ thousands) Direct Amount Assumed from Other Companies Ceded to Other Companies Net Amount % of Amount Assumed to Net 2021 Premiums earned: Accident and health insurance $ 2 — 2 — — Property and liability insurance 3,472,713 21,550 477,010 3,017,253 1 % Total premiums earned 3,472,715 21,550 477,012 3,017,253 1 % 2020 Premiums earned: Accident and health insurance $ 13 — 13 — — Property and liability insurance 3,108,674 25,010 451,870 2,681,814 1 % Total premiums earned 3,108,687 25,010 451,883 2,681,814 1 % 2019 Premiums earned: Accident and health insurance $ 17 — 17 — — Property and liability insurance 2,993,140 24,399 420,368 2,597,171 1 % Total premiums earned 2,993,157 24,399 420,385 2,597,171 1 % See accompanying Report of Independent Registered Public Accounting Firm in Item 8. "Financial Statements and Supplementary Data." of this Form 10-K.

Schedule V - Allowance for Unco

Schedule V - Allowance for Uncollectible Premiums and Other Receivables	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule V - Allowance for Uncollectible Premiums and Other Receivables	($ in thousands) 2021 2020 2019 Balance, January $ 22,777 10,800 13,900 Cumulative effect adjustment — (1,845) — Balance at the beginning of the period, as adjusted 22,777 8,955 13,900 Additions 1,766 17,576 2,730 Deductions (9,343) (3,754) (5,830) Balance, December 31 $ 15,200 22,777 10,800 See accompanying Report of Independent Registered Public Accounting Firm in Item 8. "Financial Statements and Supplementary Data." of this Form 10-K.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Principles of Consolidation	Principles of ConsolidationThe accompanying consolidated financial statements (“Financial Statements”) include the accounts of the Parent and its subsidiaries, and have been prepared in conformity with: (i) United States ("U.S.") generally accepted accounting principles ("GAAP"); and (ii) the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). All significant intercompany accounts and transactions are eliminated in consolidation.
Use of Estimates	Use of EstimatesThe preparation of our Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported financial statement balances, as well as the disclosure of contingent assets and liabilities. Actual results could differ from those estimates.
Investments	Investments Portfolio Composition and Presentation in the Consolidated Balance Sheet Our investment portfolio is primarily comprised of fixed income investments. We also hold commercial mortgage loans ("CMLs"), equity securities, short-term investments, and other investments. A description of our portfolio holdings, and the related presentation in our Consolidated Balance Sheet, is provided below. Fixed Income Investments Our fixed income investments include our fixed income securities portfolio and our CML portfolio. Fixed Income Securities We hold the following types of securities in our fixed income securities portfolio: • U.S. government and government agency obligations; • Foreign government obligations; • Obligations of states and political subdivisions, including special revenue and general obligation bonds; • Corporate securities, which may include investment grade and below investment grade bonds, bank loan investments, redeemable preferred stock, and non-redeemable preferred stock with certain debt-like characteristics; • Collateralized loan obligations ("CLOs") and other asset-backed securities ("ABS"); • Residential mortgage-backed securities ("RMBS"); and • Commercial mortgage-backed securities ("CMBS"). We have designated substantially all of the holdings in our fixed income securities as available-for-sale ("AFS"). These securities are reported at fair value in our Consolidated Balance Sheet. The after-tax difference between fair value and cost or amortized cost is reflected in stockholders’ equity as a component of accumulated other comprehensive income (loss) ("AOCI"). The amortized cost of fixed income securities is adjusted for the amortization of premiums and the accretion of discounts over the expected life of the security using the effective yield method. Callable debt securities held at a premium are amortized to the earliest call date. Premiums and discounts arising from the purchase of RMBS, CMBS, CLO and other ABS are amortized over the expected life of the security based on future principal payments, giving additional consideration to prepayments. These prepayments are estimated based on historical and projected cash flows. Prepayment assumptions are reviewed quarterly and adjusted to reflect actual prepayments and changes in expectations. Future amortization of any premium and/or discount is adjusted to reflect the revised assumptions. Accrued interest on our fixed income securities is recorded as a component of “Accrued investment income” on our Consolidated Balance Sheet. If accrued interest is due but not paid within 90 days, we reverse the delinquent amount and record this reversal through earnings as a component of “Net investment income earned” on our Consolidated Statement of Income. CMLs CMLs are loans secured by commercial property, such as an office building, multi-family apartment complex, industrial warehouse, or shopping center. We may acquire investments in CMLs through (i) direct originations under a loan syndication arrangement or (ii) a marketplace purchase. We record our investment in CMLs on the settlement date of the loan. Our CMLs are classified as held-for-investment and reported at amortized cost, net of any allowance for credit losses ("ACL"), on our Consolidated Balance Sheet. Interest is recorded using the effective yield method and accrued interest on our CMLs is recorded as a component of “Accrued investment income” on our Consolidated Balance Sheet. Other Portfolio Holdings Equity securities may include common and non-redeemable preferred stocks. Equity securities with readily determinable fair values are reported at fair value. Equity securities without readily determinable fair values are reported at net asset value ("NAV") as a practical expedient. Short-term investments may include money market instruments, savings accounts, commercial paper, and fixed income securities purchased with a maturity of less than one year. We may also enter into reverse repurchase agreements that are included in short-term investments. These repurchase agreements are fully collateralized by high-quality, readily-marketable instruments that support the principal amount. At maturity, we receive principal and interest income on these agreements. Short-term investments are generally reported at fair value. Other investments are primarily comprised of alternative investments, which are limited partnership investments in private equity, private credit, and real estate strategies. These alternative investments are accounted for using the equity method, with income typically recognized on a one-quarter lag. Because these alternative investments are recorded under the equity method of accounting, with the underlying holdings carried at fair value, the valuation and income recognized on these investments may be impacted by volatility in the financial markets. In addition to our alternative investments, our other investment portfolio includes Federal Home Loan Bank stock (“FHLB Stock”) and tax credit investments. The FHLB Stock is reported at cost. Accounting for our tax credit investments is dependent on the type of credit we have purchased, as follows: • Federal low income housing tax credits are accounted for under the proportional amortization method; and • All other tax credits in our investment portfolio are accounted for using the equity method. For federal tax credits accounted for under the equity method, we use the deferral method for recognizing the benefit of the tax credit with the related deferred revenue being recognized in our Consolidated Income Statement as a component of "Federal income tax expense" proportionately over the life of the investment. We categorize distributions from our investments accounted for using the equity method on our Consolidated Statement of Cash Flows using the cumulative earnings approach. Under this approach, distributions received are classified as cash flows from operating activities until such time that the cumulative distributions exceed cumulative earnings for the investment. When such an excess occurs, the excess portion of the current period distribution is considered a return of investment and is classified as a cash flow from investing activities. We evaluate the alternative investments and tax credit investments included in our other investments portfolio to determine whether those investments are variable interest entities ("VIEs") and if so, whether consolidation is required. A VIE is an entity that either has equity investors that lack certain essential characteristics of a controlling financial interest or lack sufficient funds to finance its own activities without financial support provided by other entities. We consider several significant factors in determining if our investments are VIEs and if we are the primary beneficiary, including whether we have (i) the power to direct activities of the VIE, (ii) the ability to remove the decision maker of the VIE, (iii) the ability to participate in making decisions that are significant to the VIE, and (iv) the obligation to absorb losses and the right to receive benefits that could potentially be significant to the VIE. We have reviewed our alternative and tax credit investments and have concluded that they are VIEs, but that we are not the primary beneficiary and therefore, consolidation is not required. Presentation in the Consolidated Statement of Income Net Investment Income Earned Net investment income earned on our Consolidated Statement of Income includes the following: • Interest income, as well as amortization and accretion, on fixed income securities; • Interest income on CMLs; • Dividend income on equity securities; • Interest income on our short-term investments; and • Income recognized on our alternative and other investments accounted for under the equity method of accounting, except for federal tax credits, as discussed below. Income related to federal tax credits (either low income housing tax credits or other federal credits) is recorded in our Consolidated Statement of Income as a component of “Federal income tax expense” proportionately over the life of the investment. Net Realized and Unrealized Investment (Losses) Gains Net realized and unrealized investment gains (losses) on our Consolidated Statement of Income include the following: • Realized gains and losses on the disposal of holdings in our investment portfolio, which are determined on the basis of the cost of the specific investments sold; • Changes in unrealized gains or losses on our equity securities; • Losses on investments for which we have the intent to sell, which are discussed further below; and • Net credit loss expense or benefit resulting from changes in the ACL related to our investment portfolio, which is also discussed further below. Losses on securities for which we have the intent to sell and ACL on AFS Fixed Income Securities and Short-Term Investments We review our fixed income securities in an unrealized loss position to determine (i) if we have the intent to sell the security, or (ii) if it is more likely than not we will be required to sell the security before its anticipated recovery. If we determine that we have the intent or likely requirement to sell the security, we write down its amortized cost to its fair value. In writing down amortized cost, any amount previously recorded as an ACL is reversed and any incremental reduction in amortized cost is recorded directly to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. When fixed income securities are in an unrealized loss position and we do not record any losses on securities for which we intend to sell, we record an ACL for the portion of the unrealized loss due to an expected credit loss. We estimate expected credit losses on fixed income securities by performing a discounted cash flow (“DCF”). The ACL is equal to the excess of amortized cost over the greater of: (i) our estimate of the present value of expected future cash flows, or (ii) fair value. The ACL is recorded as a contra-asset reflected in the carrying value of the investment on the Consolidated Balance Sheet. The initial ACL and any subsequent changes are recorded to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. Any remaining unrealized loss is the non-credit amount and is recorded in AOCI. The ACL cannot exceed the unrealized loss of an AFS security and therefore it may fluctuate with changes in the fair value of the security. The ACL is written off against the amortized cost basis in the period in which it is determined uncollectible. Our DCF analyses calculate the present value of expected future cash flows using various models specific to the major security types in our portfolio. These models use security-specific information, as well as reasonable and forecasted macroeconomic data, to determine possible expected credit loss scenarios based on projected changes in the economy. The forecasted economic data incorporated into the models is based on the Federal Reserve Board’s annual supervisory stress test review on certain large banks and financial institutions. We also have the ability to incorporate internally-developed forecast information into the models as we deem appropriate. The discount rate used in a DCF is one of the following: • The current yield in effect at the reporting date to accrete the beneficial interest for RMBS, CMBS, CLO and other ABS that were not of high credit quality at acquisition; • The effective interest rate in effect as of the reporting date for non-fixed rate securities; and • The effective interest rate implicit in the security at the date of acquisition for all other securities. DCFs may include, but are not necessarily limited to: (i) generating cash flows for each tranche considering tranche-specific data, market data, and other pertinent information, such as the historical performance of the underlying collateral, including net operating income generated by underlying properties, conditional default rate assumptions, loan loss severity assumptions, consensus projections, prepayment projections, and actual pool and collateral information; (ii) identifying applicable benchmark yields; and (iii) applying market-based tranche specific spreads to determine an appropriate yield by incorporating collateral performance, tranche-level attributes, trades, bids, and offers. We do not record a valuation allowance on the accrued interest balance associated with our fixed income securities as we reverse delinquent amounts on a timely basis. We consider a fixed income security to be past due at the time any principal or interest payments become 90 days delinquent. ACL on CMLs We evaluate our CMLs on a quarterly basis for expected credit losses. If we hold a CML with a specific credit concern, we record an individual ACL on that loan. For all other CMLs, we record an ACL on the pool of loans based on lifetime expected credit losses. The ACL is recorded as a contra-asset reflected in the carrying value of our CMLs on the Consolidated Balance Sheet. Our initial ACL and any subsequent changes are recorded to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. We utilize a forecasting model to estimate lifetime expected credit losses at a loan level under multiple economic scenarios. The scenarios apply reasonable and forecasted macroeconomic data such as unemployment and inflation to project property-specific operating income and capitalization rates that are used to estimate the value of the future operating income stream. This information, coupled with historical data about mortgage loan performance, is used to project the probability of default, the amount of loss given a default, and the resulting lifetime expected loss. Losses on securities for which we have the intent to sell and Credit Losses on Other Investments If we determine that we intend to sell a holding in our investment portfolio and the expected proceeds are less than the recorded value of the investment, we will record a loss on those securities we intend to sell in earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income. Additionally, we review our alternative investment portfolio for potential credit losses through quarterly fund reports and conversations with the general partners of the alternative investments concerning the following: • The current investment strategy; • Changes made or future changes to be made to the investment strategy; • Emerging issues that may affect the success of the strategy; and • The appropriateness of the valuation methodology used regarding the underlying investments. Our evaluation for potential credit loss on tax credits and FHLB Stock include a qualitative assessment of credit indicators, which include, but are not limited to, the following: • An adverse development of the expected receipt of remaining tax credits and other tax benefits; and • A significant deterioration in the financial condition or liquidity of the Federal Home Loan Bank. If we do not intend to sell a security, and we expect a credit loss on a holding in our other investments portfolio, we record a charge to earnings as a component of “Net realized and unrealized investment gains (losses)” on our Consolidated Statement of Income.
Fair Value of Financial Instruments	Fair Values of Financial Instruments Assets The fair values of our investments are generated using various valuation techniques and are placed into the fair value hierarchy considering the following: (i) the highest priority is given to quoted prices in active markets for identical assets (Level 1); (ii) the next highest priority is given to quoted prices in markets that are not active or inputs that are observable either directly or indirectly, including quoted prices for similar assets in markets that are not active and other inputs that can be derived principally from, or corroborated by, observable market data for substantially the full term of the assets (Level 2); and (iii) the lowest priority is given to unobservable inputs supported by little or no market activity and that reflect our assumptions about the exit price, including assumptions that market participants would use in pricing the asset (Level 3). An asset’s classification within the fair value hierarchy is based on the lowest level of significant input to its valuation. The techniques used to value our financial assets are as follows: Level 1 Pricing Security Type Methodology Equity Securities; U.S. Treasury Notes Equity and U.S. Treasury Note prices are received from an independent pricing service that are based on observable market transactions. We validate these prices against a second external pricing service, and if established market value comparison thresholds are breached, further analysis is performed to determine the price to be used. Short-Term Investments Short-term investments are recorded at fair value. Given the liquid nature of our short-term investments, we generally validate their fair value by way of active trades within approximately one week of the financial statement close. Level 2 Pricing We utilize a market approach for our Level 2 securities, using primarily matrix pricing models prepared by external pricing services. Matrix pricing models use mathematical techniques to value fixed income securities by relying on the securities' relationship to other benchmark quoted securities, and not relying exclusively on quoted prices for specific securities, as the specific securities are not always frequently traded. As a matter of policy, we consistently use one pricing service as our primary source and secondary pricing services if prices are not available from the primary pricing service. Fixed income security pricing is reviewed for reasonableness by (i) comparing our pricing to other third-party pricing services as well as benchmark indexed pricing, (ii) comparing fair value fluctuations between months for reasonableness, (iii) reviewing stale prices, and (iv) internally reviewing prices for reasonableness if a price from another third-party source is not available. If further analysis is needed, a challenge is sent to the pricing service for review and confirmation of the price. Further information on our Level 2 asset pricing is included in the following table: Security Type Methodology Corporate Securities including preferred stocks classified as Fixed Income Securities, and U.S. Government and Government Agencies Evaluations include obtaining relevant trade data, benchmark quotes and spreads, and incorporating this information into either spread-based or price-based evaluations as determined by the observed market data. Spread-based evaluations include: (i) creating a range of spreads for relevant maturities of each issuer based on the new issue market, secondary trading, and dealer quotes; and (ii) incorporating option adjusted spreads for issues that have early redemption features. Based on the findings in (i) and (ii) above, final spreads are derived and added to benchmark curves. Price-based evaluations include matching each issue to its best-known market maker and contacting firms that transact in these securities. Obligations of States and Political Subdivisions Evaluations are based on yield curves that are developed based on factors such as: (i) benchmarks to issues with interest rates near prevailing market rates; (ii) established trading spreads over widely-accepted market benchmarks; (iii) yields on new issues; and (iv) market information from third-party sources such as reportable trades, broker-dealers, or issuers. RMBS, CMBS, CLO and other ABS Evaluations are based on a DCF, including: (i) generating cash flows for each tranche considering tranche-specific data, market data, and other pertinent information, such as historical performance of the underlying collateral, including net operating income generated by the underlying properties, conditional default rate assumptions, loan loss severity assumptions, consensus projections, prepayment projections, and actual pool and loan level collateral information; (ii) identifying applicable benchmark yields; and (iii) applying market-based tranche-specific spreads to determine an appropriate yield by incorporating collateral performance, tranche-level attributes, trades, bids, and offers. Foreign Government Evaluations are performed using a DCF model and by incorporating observed market yields of benchmarks as inputs, adjusting for varied maturities. Level 3 Pricing Security Type Methodology CMLs Evaluations are performed by a third-party and are based on matrix pricing. For fixed rate loans, the matrix process uses a yield build up approach to create a pricing yield, with components for base yield, credit quality spread, property type spread, and a weighted average life spread. Floating rate loans are priced with a target quality spread over the swap curve. In addition to our CML portfolio, certain securities in our AFS fixed income portfolio are priced using unobservable inputs. These valuations are primarily based on broker quotes, or they are received from other third-party sources, for which there is a lack of transparency as to the inputs used to generate the valuation. The quantitative detail of these unobservable inputs is neither provided to us, nor reasonably available to us. Liabilities The techniques used to value our notes payable are as follows: Level 2 Pricing Security Type Methodology 7.25% Senior Notes; 6.70% Senior Notes; Based on matrix pricing models prepared by external pricing services. Borrowings from Federal Home Loan Banks Evaluations are performed using a DCF model based on current borrowing rates provided by the Federal Home Loan Banks that are consistent with the remaining term of the borrowing.
Allowance for Uncollectible Accounts	Allowance for Credit Losses on Premiums Receivable We estimate an ACL on our outstanding premiums receivable balance at each reporting date. In determining this allowance, we use a method that considers the aging of the receivable, based on the effective year of the related policy, along with our historical receivable loss experience. We also contemplate expected macroeconomic conditions over the expected collection period, which are short-term in nature because the majority of the balances are collected within two years of policy issuance. Changes in our ACL are charged to earnings as credit loss expense or benefit, which is a component of "Other insurance expenses" on our Consolidated Statements of Income, with an offsetting ACL recorded as a contra-asset reflected in the carrying value of the receivable. We charge write-offs against the allowance when we determine the account to be uncollectible after considering information obtained from our collection efforts.
Share-Based Compensation	Share-Based CompensationShare-based compensation consists of all share-based payment transactions in which an entity acquires goods or services by issuing (or offering to issue) its shares, share units, share options, or other equity instruments. The cost resulting from all share-based payment transactions are recognized in the Financial Statements based on the fair value of both equity and liability awards. The fair value is measured at grant date for equity awards, whereas the fair value for liability awards are remeasured at each reporting period. The fair value of both equity and liability awards is recognized over the requisite service period. The requisite service period is typically the lesser of the vesting period or the period of time from the grant date to the date of retirement eligibility. The expense recognized for share-based awards, which, in some cases, contain performance criteria, is based on the number of shares or units expected to be issued at the end of the performance period. We repurchase the Parent’s stock from our employees in connection with tax withholding obligations, as permitted under our stock-based compensation plans. This activity is disclosed in our Consolidated Statement of Stockholders' Equity.
Reinsurance	ReinsuranceThe “Reinsurance recoverable” balance on our Consolidated Balance Sheet represents our estimate of amounts that will be recovered from reinsurers under our various treaties. Generally, amounts recoverable from reinsurers are recognized as assets at the same time and in a manner consistent with the paid and unpaid losses associated with the reinsured policies. We would consider a recoverable balance from a reinsurer to be past due if payment is not received by the first day following the invoice due date. We require collateral to secure reinsurance recoverable balances primarily from our reinsurance carriers that are not authorized, otherwise approved, or certified to do business in one or more of our ten insurance subsidiaries' domiciliary states. Our ten insurance subsidiaries are collectively referred to as the "Insurance Subsidiaries." The collateral received is typically in the form of a letter of credit, trust funds, or funds withheld against reinsurance recoverables.We estimate an ACL on our outstanding reinsurance recoverable balance at each reporting date. Credit risk is mitigated to the extent we have obtained collateral. As part of our estimation of the ACL, we reduce the recoverable balance by the amount of the collateral. We then pool the uncollateralized balances by similar risk characteristics, including the financial strength rating of the reinsurer, and use a probability-of-default methodology to calculate the allowance. Historical default rates are sourced from AM Best Company ("AM Best") and are coupled with severity assumptions in developing a baseline scenario. We then stress this scenario by incorporating forecasts of industry catastrophe losses and economic factors sourced through third-party data providers. In developing our best estimate of the allowance for credit losses, we consider our outlook as to the probability of each of these scenarios occurring.Changes in our ACL are charged to earnings as credit loss expense, which is a component of “Loss and loss expense incurred” on our Consolidated Statement of Income, with an offsetting ACL recorded as a contra-asset reflected in the carrying value of the recoverable balance. We charge write-offs against the ACL when we determine the recoverable balance to be uncollectible after considering information obtained from our efforts to collect amounts due or through a review of the financial condition of the reinsurer.
Property and Equipment	Property and Equipment Property and equipment used in operations, including certain costs incurred to develop or obtain computer software for internal use, are capitalized and recorded at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. The following estimated useful lives can be considered as general guidelines: Asset Category Years Computer hardware 3 Computer software 3 to 5 Software licenses 3 to 5 Internally developed software 5 Furniture and fixtures 10 Buildings and improvements 5 to 40
Deferred Policy Acquisition Costs	Deferred Policy Acquisition Costs Deferred policy acquisition costs are limited to costs directly related to the successful acquisition of insurance contracts. Costs meeting this definition typically include, among other things, sales commissions paid to our distribution partners, premium taxes, and the portion of employee salaries and benefits directly related to time spent on acquired contracts. These costs are deferred and amortized over the life of the contracts. Accounting guidance requires a premium deficiency analysis to be performed at the level an entity acquires, services, and measures the profitability of its insurance contracts. We currently perform three premium deficiency analyses for our insurance operations, consistent with our reportable segments of Standard Commercial Lines, Standard Personal Lines, and E&S Lines. A combined ratio of over 100% does not necessarily indicate a premium deficiency, as any year's combined ratio includes a portion of underwriting expenses that are expensed at policy inception and therefore are not covered by the remaining unearned premium. In addition, investment income is not contemplated in the combined ratio calculation.
Goodwill	GoodwillGoodwill results from business acquisitions where the cost of assets and liabilities acquired exceeds the fair value of those assets and liabilities. A quantitative goodwill impairment analysis is performed if our quarterly qualitative analysis indicates that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. Goodwill is allocated to the reporting units for purposes of these analyses. Based on our analysis at December 31, 2021, goodwill was not impaired.
Reserve for Loss and Loss Expense	Reserve for Loss and Loss ExpenseReserves for loss and loss expense includes case reserves on reported claims and reserves known as incurred but not reported ("IBNR") reserves. Case reserves are estimated on each individual claim, and based on claim-specific facts and circumstances known at the time. The case reserves may be adjusted upward or downward as the specific facts and circumstances change. IBNR reserves are established at more aggregated levels and include provisions for (i) claims not yet reported, (ii) future development on reported claims, (iii) previously closed claims that could be reopened in the future, and (iv) anticipated salvage and subrogation recoveries. We evaluate our reserves quarterly, through our comprehensive reserve review process and adjustments to recorded reserves are made accordingly. The primary input in evaluating reserve levels is the quarterly reserve review prepared by our internal actuaries, which provides comprehensive loss and loss expense projections. Our reviews are based primarily on our own loss experience, organized by line of business. Where sufficient statistical credibility exists, we may further segment the experience by coverage within line, or by geographic area. Generally accepted actuarial methodologies are applied to these reserve groups to produce ultimate loss and loss expense projections. Typically, we organize our experience by accident year and age, which lends itself to the application of various loss development methods. These methods rely on historical claims reporting and payment patterns to project ultimate loss or expense for open accident years. Consideration is also given to the prior loss estimate, particularly for longer-tailed lines of business, and the current accident year. For the current accident year, this expectation comes from our detailed actuarial planning process. The initial estimate is adjusted over time as actual experience emerges. These methods require numerous assumptions, such as the selection of loss and loss expense development factors and the weight applied to each individual projection method, among others. Therefore, no single method can be interpreted as definitive. Instead, ultimate loss and loss expenses are selected based on the various methods, considering the strengths and weaknesses of each as it applies to the specific line of business and accident year. Certain liabilities, by their nature, do not lend themselves to loss development methods. Examples include property catastrophes (low frequency/high severity, unique events), latent claims (where losses are incurred over an extended period of time), and unallocated loss expenses (loss expenses that cannot be attributed to a specific claim). Alternate development techniques are used for these liabilities, some of which are primarily exposure-based methods. These methods include individual claims reviews, calendar year counts and averages, aggregate benchmark measures, such as paid and incurred “survival ratios,” and others. These approaches often require additional assumptions and a greater amount of professional judgment. The result of the reserve review is a set of ultimate loss and loss expense estimates by line of business, including the current and prior accident years. The selected ultimate losses are separated into their components of claim frequency and severity, along with their associated trends, to provide additional insight. While these ultimate loss and loss expense estimates serve as the primary basis for determining the recorded IBNR reserves, other internal and external factors are considered in our overall reserve review. Internal factors include (i) changes to our underwriting and claims practices, (ii) supplemental data on claims reporting and settlement trends, (iii) exposure estimates for reported claims, (iv) potential large or complex claims, and (v) additional trends observed by claims personnel or defense counsel. External factors considered include (i) legislative and regulatory enactments, (ii) judicial trends and decisions, (iii) social trends, including the impacts of social inflation, and (iv) trends in general economic conditions, including the effects of inflation on medical costs, raw materials, and labor. The combination of IBNR estimates and case reserve estimates on individual claims results in our total reserves for loss and loss expense. These reserves are expected to be sufficient for settling loss and loss expense obligations under our policies on unpaid claims, including changes in the (i) volume of business written, (ii) claims frequency and severity, (iii) mix of business, (iv) claims processing, and (v) other items that management expects to affect our ultimate settlement of loss and loss expense. However, our loss and loss expense reserves are estimates of future events, the outcomes of which are not yet known. As with all estimates, they carry inherent uncertainty, which may be driven by internal factors, such as changes to our claims or underwriting operations, or external factors, such as changes in legislative, judicial, economic, or social trends. Actual outcomes are further impacted by inherent randomness, such as the actual number of accidents/incidents, or the occurrence or non-occurrence of a single large event. Because of these uncertainties, it is possible that actual outcomes will differ materially from the reserves established. While this risk cannot be eliminated, we review our reserves quarterly based on the information available at that time, and make adjustments to our ultimate loss and loss expense estimates accordingly. These changes in our ultimate loss and loss expense estimates are reflected in the Consolidated Statements of Income for the period in which such estimates are changed. Changes in the liability estimate could be material to the results of operations in future periods. Loss reserves are estimates, and as such, we also consider a range of possible loss and loss expense reserve estimates. This range is determined at the beginning of each year, using prior year-end data, and reflects the fact that there is no single precise method for estimating the required reserves, due to the many factors that may influence the amounts ultimately paid. We do not discount to present value that portion of our loss and loss expense reserves expected to be paid in future periods. Our loss and loss expense reserves implicitly include anticipated recoveries for salvage and subrogation claims. Claims are counted at the occurrence, line of business, and policy level. For example, if a single occurrence (e.g. an automobile accident) leads to a claim under an automobile and an associated umbrella policy, they are each counted separately. Conversely, multiple claimants under the same occurrence/line/policy would contribute only a single count. The claim counts provided are on a reported basis. A claim is considered reported when a reserve is established or a payment is made. Therefore, claims closed without payment are included in the count as long as there was an associated case reserve at some point in its life cycle.
Revenue Recognition	Revenue RecognitionPremiums written are recognized as revenue over the period that coverage is provided using the semi-monthly pro-rata method. Unearned premiums and prepaid reinsurance premiums represent that portion of premiums written that are applicable to the unexpired terms of policies in force.The Insurance Subsidiaries' net premiums written (“NPW”) include direct insurance policy writings, plus reinsurance assumed, less reinsurance ceded. The estimated premium on the workers compensation and general liability lines is referred to as audit premium. We estimate this premium, as it is anticipated to be either billed or returned on policies subsequent to expiration based on exposure levels (i.e. payroll or sales) when it is reasonably possible to do so based on historical trends adjusted for the uncertainty of future economic conditions. If we determine it is not reasonably possible to estimate this premium, we do not do so.
Dividends to Policyholders	Dividends to PolicyholdersWe establish reserves for dividends to policyholders on certain policies, most significantly workers compensation policies. These dividends are based on the policyholders' loss experience. Dividend reserves are established based on past experience, adjusted for the effects of current developments and anticipated trends. The expense for these dividends is recognized over a period that begins at policy inception and ends with the payment of the dividend. We report these dividends within "Other insurance expenses" on the Consolidated Statement of Income. We do not issue policies that entitle the policyholder to participate in the statutory earnings or surplus of our Insurance Subsidiaries.
Federal Income Tax	Federal Income TaxWe use the asset and liability method of accounting for income taxes. Current federal income taxes are recognized for the estimated taxes payable or refundable on tax returns for the current year. Deferred federal income taxes arise from the recognition of temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities. We consider all evidence, both positive and negative, with respect to our federal tax loss carryback availability, expected levels of pre-tax financial statement income, and federal taxable income, when evaluating whether the temporary differences will be realized. In projecting future taxable income, we begin with budgeted pre-tax income adjusted for estimated non-taxable items. The assumptions about future taxable income require significant judgment and are consistent with the plans and estimates we use to manage our businesses. A valuation allowance is established when it is more likely than not that some portion of the deferred tax asset will not be realized. A liability for uncertain tax positions is recorded when it is more likely than not that a tax position will not be sustained upon examination by taxing authorities. The effect of a change in tax rates is recognized in the period of enactment. If we were to be levied interest and penalties by the Internal Revenue Service, these amounts would be recognized as a component of “Total federal income tax expense” on the Consolidated Statement of Income.
Leases	LeasesWe have various operating leases for office space, equipment, and fleet vehicles. In addition, we have various finance leases for computer hardware. We determine if an arrangement is a lease on the commencement date of the contract. Lease assets represent our right to use an underlying asset for the lease term, and lease liabilities represent our obligation to make lease payments arising from the lease. The lease asset and liability are measured by the present value of the future minimum lease payments over the lease term. Our fleet vehicle leases include a residual value guarantee; however, the residual value guarantee is not probable of being owed. Therefore, there is no impact to the lease liability or lease asset. To measure the present value, we use the discount rate in the contract. If the discount rate is not readily determinable, our incremental borrowing rate is used. The lease asset is then adjusted to exclude lease incentives. We recognize variable lease payments in the periods in which the obligations for those payments are incurred. In calculating a lease liability, we include options to extend or terminate the lease if it is reasonably certain that we will exercise such option. Lease expense is calculated using the straight-line method. In addition, we have adopted accounting policy elections to: (i) aggregate lease and non-lease components into a single lease component; and (ii) expense short-term leases on a straight-line basis over the lease term.
Pension	Pension Our pension obligations and related costs are calculated using actuarial methods, within the framework of GAAP. Our pension benefit obligation is determined as the actuarial present value of the vested benefits to which employees are currently entitled, based on the average life expectancy of the employees. Our funding policy provides that payments to our pension trust shall be equal to the minimum funding requirements of the Employee Retirement Income Security Act of 1974 ("ERISA"), plus additional amounts that the Board of Directors (the "Board") of Selective Insurance Company of America (“SICA”) may approve from time to time. Two key assumptions, the benefit obligation discount rate and the expected return on plan assets, are important elements of expense and/or liability measurement. We evaluate these key assumptions annually unless facts indicate that a more frequent review is required. The discount rate enables us to state expected future cash flows at their present value on the measurement date. The purpose of the discount rate is to determine the interest rates inherent in the price at which pension benefits could be effectively settled. Our discount rate selection is based on high-quality, long-term corporate bonds. To determine the expected long-term rate of return on the plan assets, we consider the current and expected asset allocation, as well as historical and expected returns on each plan asset class. Other assumptions involve demographic factors such as retirement age and mortality. A portion of our plan assets is allocated to a liability hedging strategy through which we have an expectation that our plan assets will move in tandem with a portion of the plan liabilities, helping to mitigate funding ratio volatility.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Estimated Useful Life for Property and Equipment	Asset Category Years Computer hardware 3 Computer software 3 to 5 Software licenses 3 to 5 Internally developed software 5 Furniture and fixtures 10 Buildings and improvements 5 to 40

Statements of Cash Flow (Tables

Statements of Cash Flow (Tables)	12 Months Ended
	Dec. 31, 2021
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	($ in thousands) 2021 2020 2019 Cash paid during the period for: Interest $ 28,930 30,464 25,089 Federal income tax 100,000 47,000 55,825 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases 7,935 9,498 8,138 Operating cash flows from financing leases 35 15 16 Financing cash flows from finance leases 1,768 550 977 Non-cash items: Corporate actions related to fixed income securities, AFS 1 56,365 55,446 61,369 Corporate actions related to fixed income securities, held-to-maturity ("HTM") 1 — 2,589 — Corporate actions related to equity securities 1 30,666 10,890 14,250 Conversion of AFS fixed income securities to equity securities 15,139 — — Assets acquired under finance lease arrangements 6,709 324 824 Assets acquired under operating lease arrangements 3,272 22,390 13,808 Non-cash purchase of property and equipment 472 590 89
Schedule of Cash and Cash Equivalents	($ in thousands) December 31, 2021 December 31, 2020 Cash $ 455 394 Restricted cash 44,608 14,837 Total cash and restricted cash shown in the Statements of Cash Flows $ 45,063 15,231

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2021
Investment [Line Items]
Schedule of Unrealized Gains (Losses) On Investments	($ in thousands) 2021 2020 2019 AFS securities: Fixed income securities $ 228,947 386,380 215,634 Total AFS securities 228,947 386,380 215,634 HTM securities: Fixed income securities (4) 7 31 Total HTM securities (4) 7 31 Short-term securities 20 6 23 Total net unrealized gains 228,963 386,393 215,688 Deferred income tax (48,082) (81,142) (45,294) Net unrealized gains, net of deferred income tax 180,881 305,251 170,394 Increase (decrease) in net unrealized gains in OCI, net of deferred income tax $ (124,370) 134,857 168,505
Schedule of Available For Sale Securities	December 31, 2021 Cost/ Amortized Allowance for Unrealized Unrealized Fair ($ in thousands) Cost Credit Losses Gains Losses Value AFS fixed income securities: U.S. government and government agencies $ 127,974 — 3,629 (1,145) 130,458 Foreign government 15,420 (46) 609 (123) 15,860 Obligations of states and political subdivisions 1,121,422 (137) 68,258 (235) 1,189,308 Corporate securities 2,478,348 (6,682) 106,890 (4,953) 2,573,603 CLO and other ABS 1,343,687 (939) 14,350 (6,284) 1,350,814 RMBS 756,280 (1,909) 24,813 (2,932) 776,252 CMBS 647,622 (11) 27,752 (1,682) 673,681 Total AFS fixed income securities $ 6,490,753 (9,724) 246,301 (17,354) 6,709,976 December 31, 2020 Cost/ Amortized Allowance for Unrealized Unrealized Fair ($ in thousands) Cost Credit Losses Gains Losses Value AFS fixed income securities: U.S. government and government agencies $ 110,038 — 6,239 (137) 116,140 Foreign government 16,801 (1) 1,569 (3) 18,366 Obligations of states and political subdivisions 1,159,588 (4) 87,564 (11) 1,247,137 Corporate securities 2,152,203 (2,782) 180,971 (2,340) 2,328,052 CLO and other ABS 1,014,820 (592) 20,166 (7,843) 1,026,551 RMBS 999,485 (561) 53,065 (201) 1,051,788 CMBS 620,582 (29) 48,348 (1,007) 667,894 Total AFS fixed income securities $ 6,073,517 $ (3,969) 397,922 (11,542) 6,455,928
Schedule of debt securities, available-for-sale, allowance for credit losses	2021 Beginning Balance Current Provisions for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirements) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance ($ in thousands) Foreign Government $ 1 46 (1) — — 46 Obligations of states and political subdivisons 4 122 11 — — 137 Corporate Securities 2,782 5,785 (992) (723) (170) 6,682 CLO and other ABS 592 579 (211) (21) — 939 RMBS 561 1,593 (63) (182) — 1,909 CMBS 29 10 (28) — — 11 Total AFS fixed income securities $ 3,969 8,135 (1,284) (926) (170) 9,724 2020 Beginning Balance Current Provisions for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirements) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance ($ in thousands) Foreign Government $ — 19 — (18) — 1 Obligations of states and political subdivisons — 4 — — — 4 Corporate Securities — 3,645 — (781) (82) 2,782 CLO and other ABS — 722 — (113) (17) 592 RMBS — 623 — (62) — 561 CMBS — 29 — — — 29 Total AFS fixed income securities $ — 5,042 — (974) (99) 3,969
Schedule of Fair Value and Gross Pre-Tax Net Unrealized/Unrecognized Loss of Securities by Length of Time	December 31, 2021 Less than 12 months 12 months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized AFS fixed income securities: U.S. government and government agencies $ 34,857 (746) 7,827 (399) 42,684 (1,145) Foreign government 2,000 (84) 1,061 (39) 3,061 (123) Obligations of states and political subdivisions 25,837 (235) — — 25,837 (235) Corporate securities 300,549 (4,903) 2,520 (50) 303,069 (4,953) CLO and other ABS 663,976 (4,934) 53,368 (1,350) 717,344 (6,284) RMBS 236,010 (2,931) 20 (1) 236,030 (2,932) CMBS 112,899 (1,016) 20,326 (666) 133,225 (1,682) Total AFS fixed income securities $ 1,376,128 (14,849) 85,122 (2,505) 1,461,250 (17,354) December 31, 2020 Less than 12 months 12 months or longer Total ($ in thousands) Fair Unrealized Fair Unrealized Fair Unrealized AFS fixed income securities: U.S. government and government agencies $ 11,519 (137) — — 11,519 (137) Foreign government 1,122 (3) — — 1,122 (3) Obligations of states and political subdivisions 2,223 (11) — — 2,223 (11) Corporate securities 65,187 (2,152) 2,400 (188) 67,587 (2,340) CLO and other ABS 261,746 (2,995) 165,661 (4,848) 427,407 (7,843) RMBS 18,227 (194) 1,181 (7) 19,408 (201) CMBS 55,482 (616) 16,093 (391) 71,575 (1,007) Total AFS fixed income securities $ 415,506 (6,108) 185,335 (5,434) 600,841 (11,542)
Schedule of Investments Classified by Contractual Maturity Date	AFS HTM ($ in thousands) Fair Value Carrying Value Fair Value Due in one year or less $ 500,579 1,384 1,401 Due after one year through five years 3,182,282 11,811 12,493 Due after five years through 10 years 2,316,389 15,590 15,566 Due after 10 years 710,726 — — Total fixed income securities $ 6,709,976 28,785 29,460
Schedule of Other Investment Portfolio by Strategy and the Remaining Commitment Amount Associated With Each Strategy	Other Investments December 31, 2021 December 31, 2020 ($ in thousands) Carrying Remaining Maximum Exposure to Loss 1 Carrying Remaining Maximum 1 Alternative Investments Private equity $ 273,070 99,734 372,804 157,276 100,905 258,181 Private credit 63,138 92,674 155,812 54,017 98,330 152,347 Real assets 23,524 22,579 46,103 19,659 16,493 36,152 Total alternative investments 359,732 214,987 574,719 230,952 215,728 446,680 Other securities 49,300 — 49,300 35,370 — 35,370 Total other investments $ 409,032 214,987 624,019 266,322 215,728 482,050
Schedule of Aggregated Summarized Balance Sheet Financial Information For Partnerships In Our Alternative Investment Portfolio	Balance Sheet Information December 31, ($ in millions) 2021 2020 Investments $ 107,347 55,145 Total assets 112,232 58,819 Total liabilities 12,371 6,744 Total partners’ capital 99,861 52,075
Schedule of Aggregated Summarized Income Statement Financial Information For Partnerships In Our Alternative Investment Portfolio	Income Statement Information 12 months ended September 30, ($ in millions) 2021 2020 2019 Net investment (loss) income $ 653 (26) (8) Realized gains 6,121 1,452 695 Net change in unrealized appreciation 26,877 4,898 5,543 Net income before tax $ 33,651 6,324 6,230 Alternative investment income included in "Net investment income earned" on our Consolidated Statements of Income 117.7 26.5 17.9
Schedule Of Securities Pledged As Collateral	($ in millions) FHLBI Collateral FHLBNY Collateral State and Regulatory Deposits Total U.S. government and government agencies $ — — 22.3 22.3 Obligations of states and political subdivisions — — 4.0 4.0 RMBS 62.4 40.4 — 102.8 CMBS 6.3 14.1 — 20.4 Total pledged as collateral $ 68.7 54.5 26.3 149.5
Schedule of Components of Pre-Tax Net Investment Income Earned	($ in thousands) 2021 2020 2019 Fixed income securities $ 209,709 203,926 203,255 CMLs 2,743 844 — Equity securities 15,920 9,286 6,996 Short-term investments 260 1,821 6,653 Other investments 118,060 26,922 18,778 Investment expenses (20,103) (15,692) (13,139) Net investment income earned $ 326,589 227,107 222,543
Schedule of realized and unrealized gains (losses) on securities	($ in thousands) 2021 2020 2019 Gross gains on sales $ 15,284 18,893 31,910 Gross losses on sales (8,140) (9,745) (5,195) Net realized gains on disposals 7,144 9,148 26,715 Net unrealized gains (losses) on equity securities 17,881 7,939 (8,649) Net credit loss (expense) on fixed maturities, AFS (6,858) (5,042) Net credit loss (expense) benefit on fixed maturities, HTM (49) 4 Losses on securities for which we have the intent to sell (519) (16,266) Net other-than-temporary-impairment ("OTTI") losses recognized in earnings (3,644) Net realized and unrealized gains (losses) $ 17,599 (4,217) 14,422
Unrealized Gain (Loss) on Equity Securities	($ in thousands) 2021 2020 2019 Unrealized gains (losses) recognized in income on equity securities: On securities remaining in our portfolio at end of period $ 16,473 7,936 1,219 On securities sold in period 1,408 3 (9,868) Total unrealized gains (losses) recognized in income on equity securities $ 17,881 7,939 (8,649)

Comprehensive Income (Tables)

Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Schedule of Components of Comprehensive Income-Gross and Net of Tax	2021 ($ in thousands) Gross Tax Net Net income $ 505,310 101,473 403,837 Components of OCI: Unrealized (losses) gains on investment securities : Unrealized holding losses during the year (151,391) (31,793) (119,598) Unrealized losses on securities with credit loss recognized in earnings (9,061) (1,902) (7,159) Amounts reclassified into net income: HTM securities (11) (2) (9) Net realized gains on disposals and losses on intent-to-sell AFS securities (3,825) (803) (3,022) Credit loss expense 6,858 1,440 5,418 Total unrealized losses on investment securities (157,430) (33,060) (124,370) Defined benefit pension and post-retirement plans: Net actuarial gain 21,636 4,543 17,093 Amounts reclassified into net income: Net actuarial loss 2,772 582 2,190 Total defined benefit pension and post-retirement plans 24,408 5,125 19,283 Other comprehensive loss (133,022) (27,935) (105,087) Comprehensive income $ 372,288 73,538 298,750 2020 ($ in thousands) Gross Tax Net Net income $ 302,988 56,633 246,355 Components of OCI: Unrealized gains (losses) on investment securities : Unrealized holding gains during the year 168,487 35,383 133,104 Unrealized losses on securities with credit loss recognized in earnings (8,176) (1,717) (6,459) Amounts reclassified into net income: HTM securities (24) (5) (19) Net realized losses on disposals and losses on intent-to-sell AFS securities 5,376 1,129 4,247 Credit loss expense 5,042 1,058 3,984 Total unrealized gains on investment securities 170,705 35,848 134,857 Defined benefit pension and post-retirement plans: Net actuarial gain 1,515 318 1,197 Amounts reclassified into net income: Net actuarial loss 3,015 633 2,382 Total defined benefit pension and post-retirement plans 4,530 951 3,579 Other comprehensive income 175,235 36,799 138,436 Comprehensive income $ 478,223 93,432 384,791 2019 ($ in thousands) Gross Tax Net Net income $ 336,390 64,767 271,623 Components of OCI: Unrealized gains (losses) on investment securities : Unrealized holding gains during the year 212,683 44,662 168,021 Amounts reclassified into net income: HTM securities (58) (12) (46) Realized losses on disposals and OTTI of AFS securities 671 141 530 Total unrealized gains on investment securities 213,296 44,791 168,505 Defined benefit pension and post-retirement plans: Net actuarial loss (13,795) (2,897) (10,898) Amounts reclassified into net income: Net actuarial loss 2,657 558 2,099 Total defined benefit pension and post-retirement plans (11,138) (2,339) (8,799) Other comprehensive income 202,158 42,452 159,706 Comprehensive income $ 538,548 107,219 431,329
Schedule of Components of Accumulated Other Comprehensive Income	Net Unrealized Gains (Losses) on Investment Securities Defined Benefit Pension and Post-retirement Plans ($ in thousands) Credit Loss Related 1 HTM Related All Other Investments Subtotal Total AOCI Balance, December 31, 2019 $ (71) 25 170,439 170,393 (88,643) 81,750 OCI before reclassifications (6,459) — 133,104 126,645 1,197 127,842 Amounts reclassified from AOCI 3,984 (19) 4,247 8,212 2,382 10,594 Net current period OCI (2,475) (19) 137,351 134,857 3,579 138,436 Balance, December 31, 2020 (2,546) 6 307,790 305,250 (85,064) 220,186 OCI before reclassifications (7,159) — (119,598) (126,757) 17,093 (109,664) Amounts reclassified from AOCI 5,418 (9) (3,022) 2,387 2,190 4,577 Net current period OCI (1,741) (9) (122,620) (124,370) 19,283 (105,087) Balance, December 31, 2021 $ (4,287) (3) 185,170 180,880 (65,781) 115,099
Schedule of Reclassification out of Accumulated Other Comprehensive Income	($ in thousands) Year ended December 31, 2021 Year ended December 31, 2020 Affected Line Item in the Consolidated Statements of Income HTM related Unrealized gains on HTM disposals $ (14) (16) Net realized and unrealized investment gains (losses) Amortization of net unrealized gains on HTM securities 3 (8) Net investment income earned (11) (24) Income before federal income tax 2 5 Total federal income tax expense (9) (19) Net income Net realized (gains) losses on disposals and losses on intent-to-sell AFS securities Net realized (gains) losses on disposals and losses on intent-to-sell AFS securities (3,825) 5,376 Net realized and unrealized investment gains (losses) (3,825) 5,376 Income before federal income tax 803 (1,129) Total federal income tax expense (3,022) 4,247 Net income Credit loss related Credit loss expense 6,858 5,042 Net realized and unrealized investment gains (losses) 6,858 5,042 Income before federal income tax (1,440) (1,058) Total federal income tax expense 5,418 3,984 Net income Defined benefit pension and post-retirement life plans Net actuarial loss 638 647 Loss and loss expense incurred 2,134 2,368 Other insurance expenses Total defined benefit pension and post-retirement life 2,772 3,015 Income before federal income tax (582) (633) Total federal income tax expense 2,190 2,382 Net income Total reclassifications for the period $ 4,577 10,594 Net income

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Carrying Amounts and Estimated Fair Values of Financial Instruments	December 31, 2021 December 31, 2020 ($ in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial Liabilities Long-term debt: 7.25% Senior Notes $ 49,917 63,719 49,914 66,148 6.70% Senior Notes 99,520 127,574 99,499 127,886 5.375% Senior Notes 294,330 395,652 294,241 383,669 1.61% Borrowings from FHLBNY — — 25,000 25,182 1.56% Borrowings from FHLBNY — — 25,000 25,198 3.03% Borrowings from FHLBI 60,000 64,126 60,000 67,513 Subtotal long-term debt 503,767 651,071 553,654 695,596 Unamortized debt issuance costs (3,167) (3,419) Finance lease obligations 5,450 508 Total long-term debt $ 506,050 $ 550,743
Schedule of Quantitative Disclosures of our Financial Assets that were Measured at Fair Value	December 31, 2021 Fair Value Measurements Using ($ in thousands) Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 130,458 60,615 69,843 — Foreign government 15,860 — 15,860 — Obligations of states and political subdivisions 1,189,308 — 1,181,563 7,745 Corporate securities 2,573,603 — 2,459,476 114,127 CLO and other ABS 1,350,814 — 1,225,905 124,909 RMBS 776,252 — 776,007 245 CMBS 673,681 — 669,425 4,256 Total AFS fixed income securities 6,709,976 60,615 6,398,079 251,282 Equity securities: Common stock 1 333,449 249,846 — — Preferred stock 2,088 2,088 — — Total equity securities 335,537 251,934 — — Short-term investments 447,863 442,723 5,140 — Total assets measured at fair value $ 7,493,376 755,272 6,403,219 251,282 December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 116,140 40,960 75,180 — Foreign government 18,366 — 18,366 — Obligations of states and political subdivisions 1,247,137 — 1,244,243 2,894 Corporate securities 2,328,052 — 2,257,352 70,700 CLO and other ABS 1,026,551 — 970,176 56,375 RMBS 1,051,788 — 1,051,788 — CMBS 667,894 — 667,894 — Total AFS fixed income securities 6,455,928 40,960 6,284,999 129,969 Equity securities: Common stock 1 308,632 261,846 — — Preferred stock 1,735 1,735 — — Total equity securities 310,367 263,581 — — Short-term investments 409,852 405,400 4,452 — Total assets measured at fair value $ 7,176,147 709,941 6,289,451 129,969 1 Investments amounting to $83.6 million and $46.8 million at December 31, 2021 and December 31, 2020, respectively, were measured at fair value using the net asset value per share (or its practical expedient) and have not been classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value.
Schedule of Summary of the Changes in Fair Value of Securities Using Level 3 Inputs	2021 ($ in thousands) Obligations of states and political subdivisions Corporate Securities CLO and Other ABS RMBS CMBS Total Fair value, December 31, 2020 2,894 70,700 56,375 — — 129,969 Total net (losses) gains for the period included in: OCI (239) 1,636 (520) — (196) 681 Net realized and unrealized (losses) gains (11) (50) (214) — 5 (270) Net investment income earned — 27 16 — 19 62 Purchases — 64,813 76,731 249 98 141,891 Sales — — — — — — Issuances — — — — — — Settlements — (544) (5,161) (4) (52) (5,761) Transfers into Level 3 5,101 981 11,344 — 4,382 21,808 Transfers out of Level 3 — (23,436) (13,662) — — (37,098) Fair value, December 31, 2021 $ 7,745 114,127 $ 124,909 245 4,256 251,282 Change in unrealized (losses) gains for the period included in earnings for assets held at period end (11) (50) (214) — 5 (270) Change in unrealized (losses) gains for the period included in OCI for assets held at period end (239) 1,636 (520) — (196) 681 2020 ($ in thousands) Obligations of states and political subdivisions Corporate Securities CLO and Other ABS Total Fair value, December 31, 2019 $ — 17,051 17,034 34,085 Total net (losses) gains for the period included in: OCI 4 (785) 1,883 1,102 Net realized and unrealized gains (losses) — (1,046) (237) (1,283) Net investment income earned — 21 6 27 Purchases — 46,150 25,785 71,935 Sales — — — — Issuances — — — — Settlements — (283) (2,638) (2,921) Transfers into Level 3 2,890 9,592 31,520 44,002 Transfers out of Level 3 — — (16,978) (16,978) Fair value, December 31, 2020 $ 2,894 70,700 56,375 129,969 Change in unrealized gains (losses) for the period included in earnings for assets held at period end — (1,046) (237) (1,283) Change in unrealized gains (losses) for the period included in OCI for assets held at period end 4 (785) 1,883 1,102
Fair Value Measurement Inputs and Valuation Techniques	December 31, 2021 ($ in thousands) Assets Measured at Fair Value Valuation Techniques Unobservable Inputs Range Internal valuations: Corporate securities $ 54,135 Discounted Cash Flow Illiquidity Spread 0.3% - 3.0% (1.2)% CLO and other ABS 34,903 Discounted Cash Flow Illiquidity Spread 0.7%- 8.0% (2.1)% Total internal valuations 89,038 Other 1 162,244 Total Level 3 securities $ 251,282 December 31, 2020 ($ in thousands) Assets Measured at Fair Value Valuation Techniques Unobservable Inputs Range Internal valuations: Corporate securities $ 15,907 Discounted Cash Flow Illiquidity Spread 1.8% - 1.8% (1.8)% CLO and other ABS 27,005 Discounted Cash Flow Illiquidity Spread 1.2% - 3.1% (1.8)% Total internal valuations 42,912 Other 1 87,057 Total Level 3 securities $ 129,969 1 Other is comprised of broker quotes or other third-party pricing for which there is a lack of transparency as to the inputs used to develop the valuations. The quantitative details of these unobservable inputs is neither provided to us, nor reasonably available to us, and therefore are not included in the tables above.
Schedule of Quantitative Information of our Financial Assets and Liabilities that were Disclosed at Fair Value	December 31, 2021 Fair Value Measurements Using ($ in thousands) Assets/Liabilities Disclosed at Quoted Prices in Active Markets for Identical Assets/Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets HTM: Obligations of states and political subdivisions $ 3,576 — 3,576 — Corporate securities 25,884 — 25,884 — Total HTM fixed income securities $ 29,460 — 29,460 — CMLs $ 97,598 — — 97,598 Financial Liabilities Long-term debt: 7.25% Senior Notes $ 63,719 — 63,719 — 6.70% Senior Notes 127,574 — 127,574 — 5.375% Senior Notes 395,652 — 395,652 — 3.03% Borrowings from FHLBI 64,126 — 64,126 — Total long-term debt $ 651,071 — 651,071 — December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets/Liabilities Disclosed at Quoted Prices in Active Markets for Identical Assets/Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Financial Assets HTM: Obligations of states and political subdivisions $ 4,795 — 4,795 — Corporate securities 13,206 — 13,206 — Total HTM fixed income securities $ 18,001 — 18,001 — CML $ 47,289 — — 47,289 Financial Liabilities Long-term debt: 7.25% Senior Notes $ 66,148 66,148 6.70% Senior Notes 127,886 127,886 5.375% Senior Notes 383,669 383,669 1.61% Borrowings from FHLBNY 25,182 — 25,182 — 1.56% Borrowings from FHLBNY 25,198 — 25,198 — 3.03% Borrowings from FHLBI 67,513 — 67,513 — Total long-term debt $ 695,596 — 695,596 —

Allowance for Credit Losses o_2

Allowance for Credit Losses on Premiums Receivable (Tables)	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Premium Receivable, Allowance for Credit Loss	($ in thousands) December 31, 2021 December 31, 2020 Balance at beginning of year $ 21,000 6,400 Cumulative effect adjustment 1 — 1,058 Balance at beginning of year, as adjusted $ 21,000 7,458 Current period change for expected credit losses 1,291 16,751 Write-offs charged against the allowance for credit losses (9,343) (3,754) Recoveries 652 545 ACL, end of year $ 13,600 21,000

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2021
Reinsurance Disclosures [Abstract]
Reinsurance Recoverable, Credit Quality Indicator	December 31, 2021 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers A++ $ 38,601 $ 9 $ 38,610 A+ 339,857 1,520 341,377 A 95,675 1,227 96,902 A- 3,209 145 3,354 B++ — — — B+ — — — Total rated reinsurers $ 477,342 $ 2,901 $ 480,243 Non-rated reinsurers Federal and state pools $ 116,378 $ — $ 116,378 Other than federal and state pools 4,597 450 5,047 Total non-rated reinsurers $ 120,975 $ 450 $ 121,425 Total reinsurance recoverable, gross $ 598,317 $ 3,351 $ 601,668 Less: ACL (1,600) Total reinsurance recoverable, net $ 600,068 December 31, 2020 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers A++ $ 37,464 $ 102 $ 37,566 A+ 354,846 2,452 357,298 A 105,652 415 106,067 A- 2,139 — 2,139 B++ 56 324 380 B+ — — — Total rated reinsurers $ 500,157 $ 3,293 $ 503,450 Non-rated reinsurers Federal and state pools $ 82,575 $ — $ 82,575 Other than federal and state pools 2,676 568 3,244 Total non-rated reinsurers $ 85,251 $ 568 $ 85,819 Total reinsurance recoverable, gross $ 585,408 $ 3,861 $ 589,269 Less: ACL (1,777) Total reinsurance recoverable, net $ 587,492
Reinsurance Recoverable, Allowance for Credit Loss	($ in thousands) December 31, 2021 December 31, 2020 Balance at beginning of year $ 1,777 $ 4,400 Cumulative effect adjustment — (2,903) Balance at beginning of year, as adjusted $ 1,777 $ 1,497 Current period change for expected credit losses (177) 280 Write-offs charged against the allowance for credit losses — — Recoveries — — ACL, end of year $ 1,600 $ 1,777
Schedule of Total Reinsurance Balances Segregated By Reinsurer	As of December 31, 2021 As of December 31, 2020 ($ in thousands) Reinsurance Balances % of Reinsurance Balance Reinsurance Balances % of Reinsurance Balance Total reinsurance recoverables, net of allowance for credit losses $ 600,068 $ 587,492 Total prepaid reinsurance premiums 183,007 170,531 Total reinsurance balance 783,075 758,023 Federal and state pools 1 : NFIP 223,845 29 % 178,532 25 % New Jersey Unsatisfied Claim Judgment Fund 49,738 6 52,053 6 Other 2,385 — 1,625 — Total federal and state pools 275,968 35 232,210 31 Remaining reinsurance balance $ 507,107 65 $ 525,813 69 Munich Re Group (AM Best rated "A+") $ 108,381 14 $ 117,028 15 Hannover Ruckversicherungs AG (AM Best rated "A+") 107,110 14 115,251 15 AXIS Reinsurance Company (AM Best rated "A") 70,814 9 78,617 10 Swiss Re Group (AM Best rated "A+") 29,186 4 33,249 4 Transatlantic Reinsurance Company (AM Best rated “A+”) 26,490 3 24,374 3 All other reinsurers 166,726 21 159,071 21 Total reinsurers 508,707 65 % 527,590 69 % Less: ACL (1,600) (1,777) Reinsurers, net of ACL 507,107 525,813 Less: collateral 2 (128,699) (130,169) Reinsurers, net of collateral $ 378,408 $ 395,644 1 Considered to have minimal risk of default. 2 Includes letters of credit, trust funds, and funds held against reinsurance recoverables.
Schedule of List Of Direct, Assumed, And Ceded Reinsurance Amounts	($ in thousands) 2021 2020 2019 Premiums written: Direct $ 3,656,537 3,204,512 3,084,451 Assumed 22,664 24,288 24,339 Ceded (489,488) (455,708) (429,366) Net $ 3,189,713 2,773,092 2,679,424 Premiums earned: Direct $ 3,472,715 3,108,687 2,993,157 Assumed 21,550 25,010 24,399 Ceded (477,012) (451,883) (420,385) Net $ 3,017,253 2,681,814 2,597,171 Loss and loss expense incurred: Direct $ 2,096,512 1,822,034 1,714,880 Assumed 13,813 17,201 22,879 Ceded (296,341) (203,412) (186,268) Net $ 1,813,984 1,635,823 1,551,491
Schedule of Ceded Premiums and Losses Related to Flood Operations	Ceded to NFIP ($ in thousands) 2021 2020 2019 Ceded premiums written $ (284,311) (274,042) (266,925) Ceded premiums earned (274,384) (271,598) (259,119) Ceded loss and loss expense incurred (215,224) (78,993) (71,676)

Reserve for Loss and Loss Exp_2

Reserve for Loss and Loss Expense (Tables)	12 Months Ended
	Dec. 31, 2021
Insurance Loss Reserves [Abstract]
Schedule of Roll Forward of Reserve for Loss and Loss Expense	($ in thousands) 2021 2020 2019 Gross reserves for loss and loss expense, at beginning of year $ 4,260,355 4,067,163 3,893,868 Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year 1 554,269 547,066 537,388 Net reserves for loss and loss expense, at beginning of year 3,706,086 3,520,097 3,356,480 Incurred loss and loss expense for claims occurring in the: Current year 1,896,837 1,708,755 1,601,780 Prior years (82,853) (72,932) (50,289) Total incurred loss and loss expense 1,813,984 1,635,823 1,551,491 Paid loss and loss expense for claims occurring in the: Current year 676,331 642,586 579,527 Prior years 841,477 807,248 805,443 Total paid loss and loss expense 1,517,808 1,449,834 1,384,970 Net reserves for loss and loss expense, at end of year 4,002,262 3,706,086 3,523,001 Add: Reinsurance recoverable on unpaid loss and loss expense, at end of year 578,641 554,269 544,162 Gross reserves for loss and loss expense at end of year $ 4,580,903 4,260,355 4,067,163
Schedule of (Favorable)/ Unfavorable Prior Year Development	(Favorable)/Unfavorable Prior Year Development ($ in millions) 2021 2020 2019 General Liability $ (29.0) (35.0) (5.0) Commercial Automobile 13.3 7.1 0.7 Workers Compensation (58.0) (60.0) (68.0) Businessowners' Policies (0.4) 3.9 1.9 Commercial Property (2.6) 9.2 5.1 Homeowners 1.8 7.7 7.5 Personal Automobile (0.2) (1.8) 4.4 E&S Casualty Lines (7.0) — 2.0 E&S Property Lines (0.8) (4.0) 1.0 Other — — 0.1 Total $ (82.9) (72.9) (50.3)
Schedule of Exposure to Various Asbestos and Environmental Claims	2021 ($ in millions) Gross Net Asbestos $ 6.1 4.9 Landfill sites 12.1 7.6 Underground storage tanks 9.6 8.6 Total $ 27.8 21.1
Schedule of Roll Forward of Gross and Net Asbestos and Environmental Incurred Losses and Loss Expenses and Related Reserves	2021 2020 2019 ($ in thousands) Gross Net Gross Net Gross Net Asbestos Reserves for loss and loss expense at beginning of year $ 6,254 5,023 6,288 5,057 7,328 6,097 Incurred loss and loss expense 51 51 320 320 (375) (375) Less: loss and loss expense paid (190) (190) (354) (354) (665) (665) Reserves for loss and loss expense at the end of year $ 6,115 4,884 6,254 5,023 6,288 5,057 Environmental Reserves for loss and loss expense at beginning of year $ 22,276 16,398 22,413 16,532 22,692 16,686 Incurred loss and loss expense (613) (14) (447) (474) 723 609 Less: loss and loss expense paid (5) (193) 310 340 (1,002) (763) Reserves for loss and loss expense at the end of year $ 21,658 16,191 22,276 16,398 22,413 16,532 Total Asbestos and Environmental Claims Reserves for loss and loss expense at beginning of year $ 28,530 21,421 28,701 21,589 30,020 22,783 Incurred loss and loss expense (562) 37 (127) (154) 348 234 Less: loss and loss expense paid (195) (383) (44) (14) (1,667) (1,428) Reserves for loss and loss expense at the end of year $ 27,773 21,075 28,530 21,421 28,701 21,589
Schedule of Short-duration Insurance Contracts, Claims Development	All Lines (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 1,065,437 1,071,290 1,020,655 998,028 973,089 973,644 973,411 968,536 962,091 962,678 36,108 104,515 2013 1,044,142 1,062,045 1,047,230 1,021,007 1,002,316 987,763 984,858 973,739 957,958 40,736 91,756 2014 1,107,513 1,133,798 1,146,990 1,124,014 1,104,218 1,100,208 1,089,529 1,094,367 48,550 95,610 2015 1,114,081 1,130,513 1,144,830 1,138,313 1,119,441 1,108,860 1,103,592 56,165 94,874 2016 1,188,608 1,203,634 1,227,142 1,199,734 1,180,829 1,171,273 90,598 95,559 2017 1,270,110 1,313,372 1,313,585 1,288,526 1,268,941 122,313 99,424 2018 1,413,800 1,461,603 1,457,415 1,441,303 222,464 106,569 2019 1,483,945 1,523,041 1,526,566 383,970 103,271 2020 1,591,972 1,587,607 562,065 93,515 2021 1,784,661 932,590 89,801 Total 12,898,946 All Lines (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 378,067 555,819 651,544 743,742 810,135 856,195 879,372 898,269 905,816 913,478 2013 335,956 518,872 644,475 748,758 833,823 872,331 891,841 904,825 911,657 2014 405,898 614,075 736,154 855,959 936,425 981,868 1,002,157 1,020,961 2015 376,641 581,203 725,385 845,868 929,222 967,857 1,000,509 2016 387,272 617,958 764,331 892,390 983,852 1,025,264 2017 433,440 678,453 829,134 954,792 1,050,258 2018 511,271 779,466 942,893 1,083,556 2019 510,091 781,462 949,996 2020 572,302 831,976 2021 609,889 Total 9,397,544 All outstanding liabilities before 2012, net of reinsurance 372,496 Liabilities for loss and loss expenses, net of reinsurance 3,873,898 General Liability (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 238,979 245,561 215,083 194,144 175,305 175,268 180,659 182,085 178,285 179,197 12,796 10,052 2013 250,609 251,421 239,776 225,709 210,785 203,831 202,697 195,697 192,782 15,661 10,433 2014 244,312 249,946 257,132 239,333 234,082 237,125 229,679 230,247 21,413 10,677 2015 254,720 245,710 246,990 233,249 219,204 214,176 211,768 25,873 10,532 2016 277,214 272,048 277,986 263,245 252,733 246,643 41,647 10,763 2017 293,747 293,128 301,384 289,883 278,607 67,475 11,219 2018 317,934 336,326 345,224 332,013 126,438 11,641 2019 347,150 356,363 358,301 196,836 11,264 2020 361,554 360,302 252,458 9,076 2021 422,748 356,223 8,260 Total 2,812,608 General Liability (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 13,030 35,241 56,580 89,008 109,448 130,866 144,451 156,186 158,397 162,516 2013 12,789 35,113 72,127 104,587 139,114 153,628 163,764 169,847 172,983 2014 14,901 46,825 79,972 121,969 154,957 179,192 187,352 198,772 2015 14,665 39,978 78,668 116,804 144,216 157,071 173,697 2016 15,684 46,549 89,431 133,757 164,136 181,770 2017 17,366 49,470 92,355 131,980 167,002 2018 19,531 60,784 108,421 155,538 2019 18,097 58,284 100,206 2020 21,858 58,699 2021 28,069 Total 1,399,252 All outstanding liabilities before 2012, net of reinsurance 102,433 Liabilities for loss and loss expenses, net of reinsurance 1,515,789 Workers Compensation (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 203,864 208,036 199,360 195,197 188,596 187,359 183,314 178,774 177,658 177,706 20,697 11,628 2013 199,794 194,318 187,658 173,160 166,662 162,787 159,767 157,645 153,436 20,638 11,384 2014 199,346 187,065 182,579 172,515 164,420 160,646 159,604 161,021 21,285 10,495 2015 193,729 194,639 183,604 179,642 176,242 172,572 170,577 20,748 10,554 2016 196,774 184,946 176,248 166,009 156,540 155,210 24,850 10,585 2017 195,202 184,306 175,853 162,672 154,159 25,096 10,809 2018 193,894 193,818 181,151 173,428 34,218 11,129 2019 188,625 188,596 174,912 44,549 10,307 2020 168,643 168,594 61,878 7,495 2021 185,198 111,451 8,089 Total 1,674,241 Workers Compensation (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 40,911 86,909 108,211 122,755 132,052 139,477 143,281 146,739 148,750 151,273 2013 36,829 74,568 96,376 109,739 118,669 124,130 126,822 129,224 130,467 2014 35,924 78,944 100,876 113,626 119,392 124,077 127,858 130,726 2015 33,857 77,320 98,195 112,601 120,097 124,046 129,019 2016 34,525 78,531 98,037 109,166 115,159 119,800 2017 40,375 82,216 100,645 110,645 116,426 2018 41,122 84,780 105,903 119,904 2019 37,826 77,878 100,812 2020 29,559 68,277 2021 32,918 Total 1,099,622 All outstanding liabilities before 2012, net of reinsurance 241,987 Liabilities for loss and loss expenses, net of reinsurance 816,606 Commercial Automobile (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 179,551 191,947 183,527 184,289 184,367 186,128 184,633 185,357 184,477 184,411 467 24,431 2013 188,289 205,282 209,197 207,994 210,410 207,975 209,602 208,040 207,554 595 26,053 2014 200,534 212,725 216,824 219,925 218,172 217,334 216,461 214,992 875 28,079 2015 220,994 240,958 253,074 259,495 260,565 261,386 262,054 1,826 29,837 2016 255,187 274,367 285,302 285,304 290,359 291,674 3,226 31,754 2017 301,274 329,389 324,291 322,197 326,461 10,110 33,066 2018 347,908 352,487 345,547 350,310 23,671 35,714 2019 385,212 398,346 404,854 63,122 36,079 2020 381,654 381,163 121,558 30,095 2021 483,831 232,070 34,461 Total 3,107,304 Commercial Automobile (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 73,316 105,371 127,235 148,669 168,114 176,656 179,501 181,353 183,098 183,365 2013 76,469 109,893 140,015 169,850 189,626 200,750 202,622 205,064 206,162 2014 80,810 117,169 148,884 180,701 202,821 209,655 212,481 213,689 2015 91,347 132,260 175,866 211,515 238,142 249,905 255,600 2016 106,022 155,720 200,701 233,939 264,858 277,242 2017 117,287 178,823 220,422 262,349 296,600 2018 134,867 193,788 243,713 291,725 2019 149,538 221,590 283,410 2020 139,016 198,034 2021 187,200 Total 2,393,027 All outstanding liabilities before 2012, net of reinsurance 3,427 Liabilities for loss and loss expenses, net of reinsurance 717,704 Businessowners' Policies (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 54,342 48,029 46,303 44,172 44,077 43,747 43,418 43,717 43,444 43,534 198 5,545 2013 49,617 42,618 41,005 40,624 41,369 39,709 39,699 39,358 38,930 120 3,483 2014 55,962 60,949 62,548 59,806 58,517 58,093 57,302 57,483 746 4,067 2015 52,871 53,768 57,245 55,925 54,454 52,325 52,200 801 3,967 2016 52,335 53,792 54,993 53,835 53,367 53,147 1,010 3,851 2017 46,624 48,698 51,524 48,067 43,606 2,642 3,892 2018 55,024 57,202 62,427 60,393 7,655 4,256 2019 53,531 59,466 64,667 11,556 3,616 2020 71,836 73,680 11,225 5,364 2021 66,312 21,947 3,078 Total 553,952 Businessowners' Policies (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 22,199 31,833 35,089 37,215 38,766 40,627 41,326 41,356 42,075 42,061 2013 17,412 26,592 30,845 34,760 37,993 38,464 39,085 39,212 39,440 2014 28,914 40,584 44,911 49,460 52,940 55,458 55,708 55,729 2015 24,189 36,014 42,710 46,571 49,073 49,839 50,005 2016 24,655 36,848 39,973 45,308 48,786 50,536 2017 21,865 31,337 36,950 40,359 39,940 2018 29,995 39,791 44,316 48,144 2019 27,718 41,587 46,113 2020 43,376 57,210 2021 34,412 Total 463,590 All outstanding liabilities before 2012, net of reinsurance 9,139 Liabilities for loss and loss expenses, net of reinsurance 99,501 Commercial Property (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 118,464 114,224 115,375 116,658 117,102 117,170 117,225 117,220 117,200 117,277 4 8,519 2013 88,101 90,639 90,103 90,005 90,436 90,278 90,218 90,486 90,461 3 5,715 2014 141,192 136,249 136,820 138,751 138,155 136,212 136,237 136,151 10 6,517 2015 110,270 109,513 111,750 111,566 112,496 112,582 112,937 12 6,407 2016 121,927 126,185 125,937 124,487 123,567 123,005 23 6,743 2017 138,773 149,106 149,044 153,664 154,119 54 6,904 2018 183,177 190,834 192,558 194,016 98 8,289 2019 173,826 177,075 179,574 530 7,300 2020 232,060 225,278 4,314 10,116 2021 246,319 36,186 7,153 Total 1,579,137 Commercial Property (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 81,528 108,834 111,503 114,699 116,291 116,625 116,671 116,674 116,673 116,755 2013 60,244 87,874 90,446 90,350 90,840 90,696 90,646 90,917 90,891 2014 101,131 132,909 136,634 137,883 137,418 136,008 135,928 136,141 2015 79,048 106,182 109,829 110,994 110,969 112,117 112,410 2016 83,966 118,789 122,930 123,828 123,601 122,909 2017 99,047 142,338 148,589 152,018 153,750 2018 135,416 184,813 192,698 193,487 2019 130,891 172,768 177,825 2020 164,613 215,107 2021 161,757 Total 1,481,032 All outstanding liabilities before 2012, net of reinsurance 99 Liabilities for loss and loss expenses, net of reinsurance 98,204 Personal Automobile (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 113,771 114,921 109,832 109,324 110,294 110,300 109,795 109,701 109,634 109,546 5 22,333 2013 108,417 109,620 106,225 106,703 107,759 107,680 107,916 107,803 107,754 72 22,376 2014 102,250 109,325 106,757 107,452 106,821 107,104 107,106 107,566 79 22,509 2015 96,387 99,698 100,214 99,570 98,718 98,588 98,596 109 20,865 2016 92,727 98,032 100,202 101,140 99,544 99,858 357 19,826 2017 101,880 105,139 103,653 103,260 103,557 447 20,744 2018 111,594 113,569 112,030 112,418 2,100 22,682 2019 114,043 115,688 115,993 5,649 22,845 2020 95,625 94,532 17,790 17,501 2021 108,244 28,461 18,931 Total 1,058,064 Personal Automobile (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 63,704 82,729 94,842 102,977 107,890 109,355 109,447 109,482 109,554 109,539 2013 61,384 80,861 92,637 100,528 105,131 106,679 106,876 107,419 107,423 2014 62,519 83,739 92,589 99,173 104,055 105,709 106,478 107,108 2015 58,725 76,470 87,163 92,102 95,997 97,275 97,761 2016 57,961 76,823 86,752 94,372 98,080 98,977 2017 62,854 82,730 91,479 97,628 100,521 2018 69,721 89,628 99,982 107,026 2019 69,699 92,162 102,930 2020 53,407 68,691 2021 65,325 Total 965,301 All outstanding liabilities before 2012, net of reinsurance 5,713 Liabilities for loss and loss expenses, net of reinsurance 98,476 Homeowners (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 87,260 82,744 86,560 86,667 86,271 86,330 86,483 86,567 86,519 86,533 35 16,944 2013 73,670 72,528 71,494 72,145 71,714 72,148 72,318 71,948 71,955 38 7,750 2014 80,111 82,461 83,637 83,844 83,539 83,824 83,525 83,830 32 8,775 2015 76,637 76,400 76,559 74,723 74,978 74,673 74,682 478 7,750 2016 60,105 60,931 62,391 61,723 61,735 60,855 465 6,895 2017 59,167 67,978 70,365 70,064 68,938 570 7,386 2018 62,961 68,526 69,832 68,931 1,289 7,607 2019 64,306 72,772 73,816 3,027 7,001 2020 109,033 112,523 4,829 9,791 2021 82,425 15,963 6,298 Total 784,488 Homeowners (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Year Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 69,056 79,584 82,720 84,250 85,196 85,562 85,642 85,897 85,899 85,918 2013 50,664 65,528 67,838 69,775 71,776 72,197 72,433 72,446 72,447 2014 61,561 76,007 79,751 81,664 82,583 82,836 82,831 83,321 2015 52,589 70,078 72,202 72,927 74,079 74,052 74,096 2016 42,252 57,333 59,546 60,082 61,187 60,449 2017 45,466 63,290 67,193 67,767 68,078 2018 49,430 64,137 65,348 66,634 2019 49,680 67,631 69,911 2020 83,838 105,690 2021 59,054 Total 745,598 All outstanding liabilities before 2012, net of reinsurance 5,438 Liabilities for loss and loss expenses, net of reinsurance 44,328 E&S Casualty Lines (in thousands, except for claim counts) Incurred Loss and Allocated Loss Expenses, Net of Reinsurance As of December 31, 2021 Accident Year Unaudited IBNR Cumulative Number of Reported Claims 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 42,367 $ 42,621 43,175 46,149 46,165 45,988 46,444 44,622 44,348 44,083 1,911 2,064 2013 55,468 60,309 67,099 69,112 67,647 68,972 68,451 68,029 60,349 3,637 2,310 2014 55,316 63,505 69,929 71,719 71,206 71,153 70,846 74,270 4,115 2,131 2015 75,498 76,432 82,404 90,488 90,355 90,126 87,662 6,293 2,875 2016 94,451 96,416 104,655 105,120 104,730 102,476 19,208 2,968 2017 91,438 95,783 99,866 99,395 99,960 16,217 2,797 2018 98,324 103,004 103,184 104,983 25,673 2,762 2019 117,087 118,298 117,736 56,323 2,553 2020 103,872 103,137 71,650 1,595 2021 128,099 111,132 1,223 Total 922,755 E&S Casualty Lines (in thousands) Cumulative Paid Loss and Allocated Loss Expenses, Net of Reinsurance Accident Unaudited 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2012 $ 3,722 $ 7,914 16,430 25,064 32,343 36,278 38,298 39,832 40,615 41,299 2013 2,715 9,470 21,980 35,200 46,108 51,142 54,974 55,988 57,152 2014 2,353 12,234 25,571 43,877 53,780 60,092 64,698 66,661 2015 3,036 13,057 29,389 50,712 64,529 71,421 75,844 2016 3,720 16,195 33,950 56,581 69,448 75,004 2017 5,057 14,672 34,179 53,238 68,266 2018 5,509 21,337 39,174 57,962 2019 4,422 17,812 35,844 2020 3,695 13,064 2021 4,326 Total 495,422 All outstanding liabilities before 2012, net of reinsurance 2,843 Liabilities for loss and loss expenses, net of reinsurance 430,176
Schedule of Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability	(in thousands) December 31, 2021 Net outstanding liabilities: Standard Commercial Lines General liability $ 1,515,789 Workers compensation 816,606 Commercial automobile 717,704 Businessowners' policies 99,501 Commercial property 98,204 Other Standard Commercial Lines 22,866 Total Standard Commercial Lines net outstanding liabilities 3,270,670 Standard Personal Lines Personal automobile 98,476 Homeowners 44,328 Other Standard Personal Lines 12,261 Total Standard Personal Lines net outstanding liabilities 155,065 E&S Lines Casualty lines 430,176 Property lines 17,987 Total E&S Lines net outstanding liabilities 448,163 Total liabilities for unpaid loss and loss expenses, net of reinsurance 3,873,898 Reinsurance recoverable on unpaid claims: Standard Commercial Lines General liability 213,253 Workers compensation 196,670 Commercial automobile 15,480 Businessowners' policies 6,828 Commercial property 22,277 Other Standard Commercial Lines 2,136 Total Standard Commercial Lines reinsurance recoverable on unpaid loss 456,644 Standard Personal Lines Personal automobile 40,941 Homeowners 2,392 Other Standard Personal Lines 64,975 Total Standard Personal Lines reinsurance recoverable on unpaid loss 108,308 E&S Lines Casualty lines 11,672 Property lines 2,017 Total E&S Lines reinsurance recoverable on unpaid loss 13,689 Total reinsurance recoverable on unpaid loss 578,641 Unallocated loss expenses 128,364 Total gross liability for unpaid loss and loss expenses $ 4,580,903
Schedule of Short-duration Insurance Contracts, Schedule of Historical Claims Duration	Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance Years 1 2 3 4 5 6 7 8 9 10 General liability 6.4% 11.9 15.6 17.6 14.4 9.8 6.6 5.0 1.9 1.6 Workers compensation 21.8 25.9 13.6 8.4 4.5 2.9 2.3 3.1 1.7 0.8 Commercial automobile 37.2 16.7 14.7 13.0 10.0 4.5 1.7 1.0 0.5 0.1 Businessowners’ policies 49.2 20.8 8.0 8.7 5.9 3.1 1.2 0.1 0.1 0.1 Commercial property 69.4 25.8 3.1 1.0 0.4 — — — — — Personal automobile 59.0 18.1 10.3 6.4 3.7 1.4 0.3 0.4 0.1 0.1 Homeowners 71.5 21.0 3.4 1.8 1.6 0.1 0.2 0.2 0.2 — E&S Lines - casualty 3.8 11.2 16.7 19.0 14.8 7.9 5.7 3.5 3.0 2.0

Indebtedness (Tables)

Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Line of Credit Covenant Requirements	Required as of Actual as of December 31, 2021 December 31, 2021 Consolidated net worth 1 Not less than $1.8 billion $2.9 billion Debt to total capitalization ratio 1 Not to exceed 35% 15.0%
Schedule of Long-term Debt Instruments	Outstanding Debt 2021 Carry Value Issuance Date Maturity Date Interest Rate Original Amount Unamortized Issuance Costs Debt Discount December 31, 2021 December 31, 2020 ($ in thousands) Description Long term (1) Senior Notes 3/1/2019 3/1/2049 5.375 % 300,000 $ 2,733 5,670 291,597 291,307 (2) FHLBI 12/16/2016 12/16/2026 3.03 % 60,000 — — 60,000 60,000 (3) FHLBNY 8/15/2016 8/16/2021 1.56 % 25,000 — — — 25,000 (3) FHLBNY 7/21/2016 7/21/2021 1.61 % 25,000 — — — 25,000 (4) Senior Notes 11/3/2005 11/1/2035 6.70 % 100,000 287 480 99,233 99,180 (5) Senior Notes 11/16/2004 11/15/2034 7.25 % 50,000 147 83 49,770 49,748 Finance lease obligations 5,450 508 Total long-term debt $ 3,167 6,233 506,050 550,743

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of Revenue from Continuing Operations By Segment	Revenue by Segment Years ended December 31, ($ in thousands) 2021 2020 2019 Standard Commercial Lines: Net premiums earned: Commercial property $ 436,412 388,120 353,834 Workers compensation 306,428 278,062 311,370 General liability 807,158 694,019 669,895 Commercial automobile 724,398 615,181 554,256 Businessowners’ policies 110,622 110,210 105,252 Bonds 35,762 36,742 35,726 Other 23,105 20,850 19,281 Miscellaneous income 16,056 15,512 10,889 Total Standard Commercial Lines revenue 2,459,941 2,158,696 2,060,503 Standard Personal Lines: Net premiums earned: Personal automobile 163,007 165,020 172,606 Homeowners 122,526 125,405 127,543 Other 8,026 8,715 7,590 Miscellaneous income 1,667 2,058 1,466 Total Standard Personal Lines revenue 295,226 301,198 309,205 E&S Lines: Net premiums earned: Casualty lines 197,779 174,408 182,864 Property lines 82,030 65,082 56,954 Total E&S Lines revenue 279,809 239,490 239,818 Investments: Net investment income 326,589 227,107 222,543 Net realized and unrealized investment gains (losses) 17,599 (4,217) 14,422 Total Investments revenues 344,188 222,890 236,965 Total revenues $ 3,379,164 2,922,274 2,846,491
Schedule of Income from Continuing Operations before and after Federal Income Tax	Income Before and After Federal Income Tax Years ended December 31, ($ in thousands) 2021 2020 2019 Standard Commercial Lines: Underwriting income, before federal income tax $ 198,596 151,731 145,990 Underwriting income, after federal income tax 156,891 119,867 115,332 Combined ratio 91.9 % 92.9 % 92.9 % ROE contribution 5.9 % 5.1 5.8 Standard Personal Lines: Underwriting income (loss), before federal income tax 3,966 (15,508) 8,260 Underwriting income (loss), after federal income tax 3,133 (12,251) 6,525 Combined ratio 98.6 % 105.2 % 97.3 % ROE contribution 0.1 % (0.5) 0.3 E&S Lines: Underwriting income (loss), before federal income tax 16,030 126 9,743 Underwriting income (loss), after federal income tax 12,664 100 7,697 Combined ratio 94.3 % 99.9 % 95.9 % ROE contribution 0.5 % — 0.4 Investments: Net investment income earned $ 326,589 227,107 222,543 Net realized and unrealized investment gains (losses) 17,599 (4,217) 14,422 Total investment segment income, before federal income tax 344,188 222,890 236,965 Tax on investment segment income 67,284 41,609 45,301 Total investment segment income, after federal income tax $ 276,904 181,281 191,664 ROE contribution of after-tax net investment income earned 9.9 % 7.8 9.6
Schedule of Reconciliation of Segment Results to Income From Continuing Operations, Before Federal Income Tax	Reconciliation of Segment Results to Income Before Federal Income Tax Years ended December 31, ($ in thousands) 2021 2020 2019 Underwriting income (loss) Standard Commercial Lines $ 198,596 151,731 145,990 Standard Personal Lines 3,966 (15,508) 8,260 E&S Lines 16,030 126 9,743 Investment income 344,188 222,890 236,965 Total all segments 562,780 359,239 400,958 Interest expense (29,165) (30,839) (33,668) Corporate expenses (28,305) (25,412) (30,900) Income, before federal income tax $ 505,310 302,988 336,390 Preferred stock dividends (9,353) — — Income available to common stockholders, before federal income tax $ 495,957 $ 302,988 $ 336,390

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Reconciliation of Earnings Per Share	2021 Income Shares Per Share ($ in thousands, except per share amounts) (Numerator) (Denominator) Amount Basic EPS: Net income available to common stockholders $ 394,484 60,183 $ 6.55 Effect of dilutive securities: Stock compensation plans — 484 Diluted EPS: Net income available to common stockholders $ 394,484 60,667 $ 6.50 2020 Income Shares Per Share ($ in thousands, except per share amounts) (Numerator) (Denominator) Amount Basic EPS: Net income available to common stockholders $ 246,355 59,862 $ 4.12 Effect of dilutive securities: Stock compensation plans — 431 Diluted EPS: Net income available to common stockholders $ 246,355 60,293 $ 4.09 2019 Income Shares Per Share ($ in thousands, except per share amounts) (Numerator) (Denominator) Amount Basic EPS: Net income available to common stockholders $ 271,623 59,421 $ 4.57 Effect of dilutive securities: Stock compensation plans — 583 Diluted EPS: Net income available to common stockholders $ 271,623 60,004 $ 4.53

Federal Income Taxes (Tables)

Federal Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Federal Income Tax on Income at the Corporate Rate to the Effective Tax Rate	($ in thousands) 2021 2020 2019 Tax at statutory rate $ 106,115 63,627 70,642 Tax-advantaged interest (4,514) (4,730) (4,909) Dividends received deduction (558) (514) (443) Executive compensation 2,469 2,246 2,985 Stock-based compensation (693) (1,846) (3,253) Other (1,346) (2,150) (255) Federal income tax expense 101,473 56,633 64,767 Income before federal income tax, less preferred stock dividends 495,957 302,988 336,390 Effective tax rate 20.5 % 18.7 % 19.3 %
Schedule of Deferred Tax Assets and Liabilities	($ in thousands) 2021 2020 Deferred tax assets: Net loss reserve discounting $ 60,227 54,240 Net unearned premiums 68,086 60,842 Employee benefits 2,787 8,943 Long-term incentive compensation plans 5,904 5,472 Temporary investment write-downs 4,314 6,037 Other 2,245 7,195 Total deferred tax assets 143,563 142,729 Deferred tax liabilities: Deferred policy acquisition costs 68,652 60,601 Unrealized gains on investment securities 48,082 81,142 Other investment-related items, net 27,044 14,760 Accelerated depreciation and amortization 13,198 13,322 Total deferred tax liabilities 156,976 169,825 Net deferred federal income tax liability $ (13,413) (27,096)

Retirement Plans (Tables)

Retirement Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Schedule of Funded Status Of Retirement Income Plan And Retirement Life Plan	December 31, Pension Plan ($ in thousands) 2021 2020 Change in Benefit Obligation: Benefit obligation, beginning of year $ 425,161 391,021 Interest cost 8,593 11,312 Actuarial (gains) losses (12,844) 35,276 Benefits paid (13,152) (12,448) Benefit obligation, end of year $ 407,758 425,161 Change in Fair Value of Assets: Fair value of assets, beginning of year $ 432,716 385,087 Actual return on plan assets, net of expenses 30,741 60,077 Benefits paid (13,152) (12,448) Fair value of assets, end of year $ 450,305 432,716 Funded status $ 42,547 7,555
Schedule of Amounts Recognized in Consolidated Balance Sheet	Amounts Recognized in the Consolidated Balance Sheet: Net pension assets, end of year $ 42,547 7,555
Schedule of Amounts recognized in Accumulated Other than Comprehensive Income	Amounts Recognized in AOCI: Net actuarial loss $ 78,304 101,414
Schedule of Other Information as of December 31	Other Information as of December 31: Accumulated benefit obligation $ 407,758 425,161
Schedule of Components Of Net Periodic Benefit Cost And Other Amounts Recognized In Other Comprehensive Income	Pension Plan ($ in thousands) 2021 2020 2019 Components of Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income: Net Periodic Benefit Cost (Benefit): Interest cost $ 8,593 11,312 13,506 Expected return on plan assets (22,976) (21,907) (21,114) Amortization of unrecognized actuarial loss 2,501 2,817 2,575 Total net periodic pension cost (benefit) 1 $ (11,882) (7,778) (5,033) Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Net actuarial (gain) loss $ (20,609) (2,894) 11,643 Reversal of amortization of net actuarial loss (2,501) (2,817) (2,575) Total recognized in other comprehensive income $ (23,110) (5,711) 9,068 Total recognized in net periodic benefit cost and other comprehensive income $ (34,992) (13,489) 4,035
Schedule Of Weighted- Average Expense and Liability Assumptions	Weighted-Average Liability Assumptions as of December 31: Discount rate 2.98 % 2.68 Pension Plan 2021 2020 2019 Weighted-Average Expense Assumptions for the years ended December 31: Discount rate 2.68 % 3.33 4.46 Interest rate 2.06 % 2.95 % 4.12 % Expected return on plan assets 5.40 5.80 6.50
Schedule of Allocation of Plan Assets	2021 2020 Target Percentage Actual Percentage Actual Percentage Minimum Maximum Return seeking assets 1 50 % 70 % 66 % 64 % Liability hedging assets 70 % 80 % 33 % 35 % Short-term investments - - 1 % 1 % Total 100 % 100 % 100 % 100 %
Schedule of Quantitative Disclosures of our Financial Assets that were Measured at Fair Value	December 31, 2021 Fair Value Measurements Using ($ in thousands) Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 130,458 60,615 69,843 — Foreign government 15,860 — 15,860 — Obligations of states and political subdivisions 1,189,308 — 1,181,563 7,745 Corporate securities 2,573,603 — 2,459,476 114,127 CLO and other ABS 1,350,814 — 1,225,905 124,909 RMBS 776,252 — 776,007 245 CMBS 673,681 — 669,425 4,256 Total AFS fixed income securities 6,709,976 60,615 6,398,079 251,282 Equity securities: Common stock 1 333,449 249,846 — — Preferred stock 2,088 2,088 — — Total equity securities 335,537 251,934 — — Short-term investments 447,863 442,723 5,140 — Total assets measured at fair value $ 7,493,376 755,272 6,403,219 251,282 December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Measured at Fair Value Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 116,140 40,960 75,180 — Foreign government 18,366 — 18,366 — Obligations of states and political subdivisions 1,247,137 — 1,244,243 2,894 Corporate securities 2,328,052 — 2,257,352 70,700 CLO and other ABS 1,026,551 — 970,176 56,375 RMBS 1,051,788 — 1,051,788 — CMBS 667,894 — 667,894 — Total AFS fixed income securities 6,455,928 40,960 6,284,999 129,969 Equity securities: Common stock 1 308,632 261,846 — — Preferred stock 1,735 1,735 — — Total equity securities 310,367 263,581 — — Short-term investments 409,852 405,400 4,452 — Total assets measured at fair value $ 7,176,147 709,941 6,289,451 129,969 1 Investments amounting to $83.6 million and $46.8 million at December 31, 2021 and December 31, 2020, respectively, were measured at fair value using the net asset value per share (or its practical expedient) and have not been classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value.
Schedule of Expected Benefit Payments	Payments ($ in thousands) Pension Plan Benefits Expected to be Paid in Future Fiscal Years: 2022 $ 14,900 2023 16,099 2024 17,232 2025 18,296 2026 19,394 2026-2030 108,742
Retirement Income Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule of Quantitative Disclosures of our Financial Assets that were Measured at Fair Value	December 31, 2021 Fair Value Measurements at 12/31/21 Using ($ in thousands) Assets Measured at Fair Value At 12/31/21 Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Description Return seeking assets: Equities: Global equity $ 144,634 144,634 — — Diversified credit 66,165 66,165 — — Real assets 89,590 89,590 — — Total equities 300,389 300,389 — — Limited partnerships (at net asset value) 1 : Real assets 47 — — — Private equity 413 — — — Total limited partnerships 460 — — — Total return seeking assets 300,849 300,389 — — Liability hedging assets: Fixed income 86,183 86,183 — — U.S. Treasury overlay 65,304 65,304 — — Total liability hedging assets 151,487 151,487 — — Cash and short-term investments: Short-term investments 1,744 1,744 — — Deposit administration contracts 2,422 — 2,422 — Total cash and short-term investments 4,166 1,744 2,422 — Total invested assets $ 456,502 453,620 2,422 — December 31, 2020 Fair Value Measurements at 12/31/20 Using ($ in thousands) Assets Measured at Fair Value At 12/31/20 Quoted Prices in Active Markets for Identical Assets/ Liabilities Significant Other Observable Inputs Significant Unobservable Inputs Description Return seeking assets: Equities: Global equity $ 142,320 142,320 — — Diversified credit 73,762 73,762 — — Real assets 61,585 61,585 — — Total equities 277,667 277,667 — — Limited partnerships (at net asset value) 1 : Real assets 73 — — — Private equity 400 — — — Private credit 29 — — — Total limited partnerships 502 — — — Total return seeking assets 278,169 277,667 — — Liability hedging assets: Fixed income 99,490 99,490 — — U.S. Treasury overlay 52,756 52,756 — — Total liability hedging assets 152,246 152,246 — — Cash and short-term investments: Short-term investments 3,273 3,273 — — Deposit administration contracts 2,073 — 2,073 — Total cash and short-term investments 5,346 3,273 2,073 — Total invested assets $ 435,761 433,186 2,073 — 1 In accordance with the FASB issued ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , certain investments that are measured at fair value using the net asset value per share (or its practical expedient) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total Pension Plan invested assets.

Share-Based Payments (Tables)

Share-Based Payments (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Schedule Of Share-Based Compensation Plan Approval	Plan Approvals Stock Plan Approved effective as of May 1, 2014 by stockholders on April 23, 2014. Cash Plan Approved effective April 1, 2005 by stockholders on April 27, 2005. ESPP Approved effective July 1, 2009 by stockholders on April 29, 2009. Agent Plan Approved by stockholders on April 26, 2006.
Schedule of Types of Share-Based Payments Issued	Plan Types of Share-Based Payments Issued Stock Plan Qualified and nonqualified stock options, stock appreciation rights ("SARs"), restricted stock, restricted stock units ("RSUs"), stock grants, and other awards valued in whole or in part by reference to the Parent's common stock. The maximum exercise period for an option grant under this plan is 10 years from the date of the grant. Dividend equivalent units ("DEUs") are earned during the vesting period on RSU grants. The DEUs are reinvested in the Parent's common stock at fair value on each dividend payment date. The requisite service period for grants to employees under this plan is the lesser of: (i) the stated vested date, which is typically three years from issuance; or (ii) the date the employee becomes eligible to retire. Cash Plan Cash incentive units (“CIUs”). The initial dollar value of each CIU will be adjusted to reflect the percentage increase or decrease in the total shareholder return on the Parent's common stock over a specified performance period. In addition, for certain grants, the number of CIUs granted will be increased or decreased to reflect our performance on specified performance indicators compared to targeted peer companies. The requisite service period for grants under this plan is the lesser of: (i) the stated vested date, which is typically three years from issuance; or (ii) the date the employee becomes eligible to retire. ESPP Enables employees to purchase shares of the Parent’s common stock. The purchase price is the lower of: (i) 85% of the closing market price at the time the option is granted; or (ii) 85% of the closing price at the time the option is exercised. Shares are generally issued on June 30 and December 31 of each year. Agent Plan Quarterly offerings to purchase the Parent's common stock at a 10% discount with a one-year restricted period during which the shares purchased cannot be sold or transferred. Only our independent retail insurance agencies and wholesale general agencies, and certain eligible persons associated with the agencies, are eligible to participate in this plan.
Schedule of Share-Based Compensation Shares Authorized and Available for Issuance	Authorized Available for Issuance Awards Outstanding Stock Plan 4,750,000 2,713,667 660,697 ESPP 5,500,000 1,184,849 — Agent Plan 3,000,000 1,608,234 —
Schedule of Share-Based Compensation Retired Plans	December 31, 2021 Types of Share-Based Payments Issued Reserve Shares Awards Outstanding 1 Plan 2005 Omnibus Stock Plan ("2005 Stock Plan") Qualified and nonqualified stock options, SARs, restricted stock, RSUs, phantom stock, stock bonuses, and other awards in such amounts and with such terms and conditions as it determined, subject to the provisions of the 2005 Stock Plan. The maximum exercise period for an option grant under this plan is 10 years from the date of the grant. DEUs are earned during the vesting period on RSU grants. The DEUs are reinvested in the Parent's common stock at fair value on each dividend payment date. 1,958,306 32,906 Parent's Stock Compensation Plan for Non-employee Directors Directors could elect to receive a portion of their annual compensation in shares of the Parent's common stock. 44,468 44,468 1 Awards outstanding under the 2005 Stock Plan represent shares deferred by our non-employee directors.
Schedule of Summary of Restricted Stock Units Transactions under Share-Based Payment Plans	Number Weighted Average Unvested RSU awards at December 31, 2020 667,674 $ 61.02 Granted in 2021 249,293 64.03 Vested in 2021 (258,477) 57.10 Forfeited in 2021 (16,854) 62.61 Unvested RSU awards at December 31, 2021 641,636 $ 63.73
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted	2021 2020 2019 ESPP Issuances 72,239 99,141 72,952 Agent Plan Issuances 50,999 69,238 47,888
Schedule of Weighted Average Assumptions for Employee Stock Purchase Plan	ESPP 2021 2020 2019 Risk-free interest rate 0.07 % 0.76 2.33 Expected term 6 months 6 months 6 months Dividend yield 1.4 % 1.6 1.2 Expected volatility 28 % 37 26
Schedule of Weighted-Average Fair Value of Options and Stock Per Share	2021 2020 2019 RSUs $ 64.03 62.91 63.60 ESPP: Six month option 4.69 4.82 4.32 Discount of grant date market value 10.98 8.61 9.99 Total ESPP 15.67 13.43 14.31 Agent Plan: Discount of grant date market value 7.57 5.73 7.00
Schedule of Compensation Cost for Share-based Payment Arrangements	($ in millions) 2021 2020 2019 Share-based compensation expense, pre-tax $ 22.3 19.8 24.5 Income tax benefit, including the benefit related to stock grants that vested during the year (5.1) (5.7) (8.2) Share-based compensation expense, after-tax $ 17.2 14.1 16.3

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Components of Lease Expense	($ in thousands) 2021 2020 Operating lease cost, included in Other insurance expenses on the Consolidated Statements of Income $ 7,935 9,498 Finance lease cost: Amortization of assets, included in Other insurance expenses on the Consolidated Statements of Income 1,765 550 Interest on lease liabilities, included in Interest expense on the Consolidated Statements of Income 35 15 Total finance lease cost 1,800 565 Variable lease cost, included in Other insurance expenses on the Consolidated Statements of Income 291 758 Short-term lease cost, included in Other insurance expenses on the Consolidated Statements of Income $ 832 2,011
Supplemental Lease Information	December 31, 2021 December 31, 2020 Weighted-average remaining lease term Operating leases 7 8 years Finance leases 2 2 Weighted-average discount rate Operating leases 2.1 2.3 % Finance leases 0.8 1.6
Lease Assets and Liabilities	($ in thousands) December 31, 2021 December 31, 2020 Operating leases Other assets $ 35,644 40,215 Other liabilities 37,296 41,674 Finance leases Property and equipment - at cost, net of accumulated depreciation and amortization 5,446 502 Long-term debt $ 5,450 508
Maturities of Lease Liabilities	($ in thousands) Finance Leases Operating Leases Total Year ended December 31, 2022 $ 2,350 7,235 9,585 2023 2,255 6,610 8,865 2024 795 5,992 6,787 2025 64 5,902 5,966 2026 41 5,967 6,008 Thereafter — 24,356 24,356 Total lease payments 5,505 56,062 61,567 Less: imputed interest 55 2,726 2,781 Less: leases that have not yet commenced — 16,040 16,040 Total lease liabilities $ 5,450 37,296 42,746 At December 31, 2020, the maturities of our lease liabilities for capital and operating leases were as follows: ($ in thousands) Finance Leases Operating Leases Total Year ended December 31, 2021 $ 330 8,372 8,702 2022 127 6,788 6,915 2023 56 5,411 5,467 2024 — 4,690 4,690 2025 — 3,572 3,572 Thereafter — 16,234 16,234 Total lease payments 513 45,067 45,580 Less: imputed interest 5 3,393 3,398 Less: leases that have not yet commenced — — — Total lease liabilities $ 508 41,674 42,182

Commitments and Contingencies I

Commitments and Contingencies Investments Contractual Obligations (Tables)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Investments Classified by Contractual Maturity Date [Table Text Block]	($ in millions) Amount of Obligation Year of Expiration of Obligation Alternative and other investments $ 215.0 2036 Non-publicly traded collateralized loan obligations in our fixed income securities portfolio 59.8 2030 Non-publicly traded common stock within our equity portfolio 4.2 2027 CMLs 5.5 2023 Privately-placed corporate securities 4.3 Less than 1 year Total $ 288.8

Statutory Financial Informati_2

Statutory Financial Information, Capital Requirements, and Restrictions on Dividends and Transfers of Funds (Tables)	12 Months Ended
	Dec. 31, 2021
Insurance [Abstract]
Schedule of Insurance Subsidiaries Statutory Surplus Data	State of Domicile Unassigned Surplus Statutory Surplus Statutory Net Income ($ in millions) 2021 2020 2021 2020 2021 2020 2019 SICA New Jersey $ 673.1 574.2 838.3 739.4 134.7 81.8 113.9 Selective Way Insurance Company ("SWIC") New Jersey 436.4 374.0 492.4 430.0 74.5 54.0 59.2 SICSC Indiana 166.3 148.6 200.6 182.8 24.2 20.8 23.9 SICSE Indiana 132.7 115.9 160.3 143.5 19.4 16.8 18.5 SICNY New York 127.0 111.7 154.7 139.4 18.6 15.3 17.0 Selective Insurance Company of New England ("SICNE") New Jersey 34.5 30.0 65.6 61.2 7.5 6.8 7.8 Selective Auto Insurance Company of New Jersey ("SAICNJ") New Jersey 90.4 70.0 135.2 114.9 16.7 12.9 14.9 Mesa Underwriters Specialty Insurance Company ("MUSIC") New Jersey 47.4 34.4 116.9 103.9 13.9 11.4 13.2 Selective Casualty Insurance Company ("SCIC") New Jersey 83.4 71.1 159.9 147.5 20.6 16.2 16.8 Selective Fire and Casualty Insurance Company ("SFCIC") New Jersey 34.2 29.2 67.1 62.1 8.2 6.4 7.5 Total $ 1,825.4 1,559.1 2,391.0 2,124.7 338.3 242.4 292.7
Schedule of Insurance Subsidiaries Dividend Paid To Parent	Dividends Twelve Months ended December 31, 2021 2022 ($ in millions) State of Domicile Ordinary Dividends Paid Maximum Ordinary Dividends SICA New Jersey $ 66.0 $ 124.4 SWIC New Jersey 27.5 72.8 SICSC Indiana 10.0 24.2 SICSE Indiana 8.8 19.4 SICNY New York 4.0 15.5 SICNE New Jersey 3.0 7.5 SAICNJ New Jersey 0.7 16.8 MUSIC New Jersey 6.1 13.7 SCIC New Jersey 10.4 19.5 SFCIC New Jersey 3.5 8.2 Total $ 140.0 $ 322.0

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended			12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Depreciation expense				$ 24.3	$ 21.5	$ 18.7
Investment yields before tax assumed in premium deficiency assessment	4.30%	3.00%	3.50%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Property and Equipment) (Details)	12 Months Ended
	Dec. 31, 2021
Computer hardware [Member]
Property, Plant and Equipment, Estimated Useful Lives	3
Internally developed software [Member]
Property, Plant and Equipment, Estimated Useful Lives	5
Furniture and fixtures [Member]
Property, Plant and Equipment, Estimated Useful Lives	10
Maximum [Member] | Computer software [Member]
Property, Plant and Equipment, Estimated Useful Lives	5
Maximum [Member] | Software licenses [Member]
Property, Plant and Equipment, Estimated Useful Lives	5
Maximum [Member] | Building and improvements [Member]
Property, Plant and Equipment, Estimated Useful Lives	40
Minimum [Member] | Computer software [Member]
Property, Plant and Equipment, Estimated Useful Lives	3
Minimum [Member] | Software licenses [Member]
Property, Plant and Equipment, Estimated Useful Lives	3
Minimum [Member] | Building and improvements [Member]
Property, Plant and Equipment, Estimated Useful Lives	5

Statements of Cash Flow (Cash F

Statements of Cash Flow (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Interest	$ 28,930	$ 30,464	$ 25,089
Federal income tax	100,000	47,000	55,825
Operating cash flows from operating leases	7,935	9,498	8,138
Operating cash flows from financing leases	35	15	16
Financing cash flows from financing leases	1,768	550	977
Assets acquired under finance lease arrangements	6,709	324	824
Assets acquired under operating lease arrangements	3,272	22,390	13,808
Non-cash purchase of property and equipment	472	590	89
Available-for-sale Securities [Member]
Corporate actions related to securities	56,365	55,446	61,369
Held-to-maturity Securities [Member]
Corporate actions related to securities	0	2,589	0
Equity Securities [Member]
Corporate actions related to securities	30,666	10,890	14,250
Conversion of AFS fixed income securities to equity securities	$ 15,139	$ 0	$ 0

Statements of Cash Flow Stateme

Statements of Cash Flow Statements of Cash Flow (Cash and Restricted Cash) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Information [Abstract]
Cash	$ 455	$ 394
Restricted cash	44,608	14,837
Total cash and restricted cash shown in the Statements of Cash Flows	$ 45,063	$ 15,231	$ 7,975	$ 16,919

Investments (Unrealized Gains o

Investments (Unrealized Gains on Investments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net unrealized gains	$ 228,963	$ 386,393	$ 215,688
Deferred income tax expense	(48,082)	(81,142)	(45,294)
Net unrealized gains, net of deferred income tax	180,881	305,251	170,394
Total stockholders’ equity	2,982,885	2,738,889	2,194,936
Increase (decrease) in net unrealized gains in OCI, net of deferred income tax	(124,370)	(134,857)	(168,505)
Available-for-sale Securities [Member]
Net unrealized gains	228,947	386,380	215,634
Total HTM Securities [Member]
Net unrealized gains	(4)	7	31
Short-term Investments [Member]
Net unrealized gains	20	6	23
Retained Earnings [Member]
Total stockholders’ equity	$ 2,603,472	$ 2,271,537	$ 2,080,529	$ 1,858,414

Investments (Available-For-Sale

Investments (Available-For-Sale Securities Disclosure) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	$ (3,969)	$ 0
Accrued investment income	48,247	45,004
Current provision for securities without prior allowance	8,135	5,042
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(1,284)	0
Reduction for securities sold	(926)	(974)
Reduction for securities identified as intent (or requirement) to sell during the period	(170)	(99)
Debt Securities, Available-for-sale, Fair Value	6,709,976	6,455,928
Allowance for credit losses, ending balance at December 31, 2020	(9,724)	(3,969)
Fixed income securities, Available-For-Sale, Amortized Cost	6,490,753	6,073,517
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	246,301	397,922
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	17,354	11,542
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Accrued investment income	46,300	43,800
U.S. Government and Government Agencies [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	0
Debt Securities, Available-for-sale, Fair Value	130,458	116,140
Allowance for credit losses, ending balance at December 31, 2020	0	0
Fixed income securities, Available-For-Sale, Amortized Cost	127,974	110,038
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3,629	6,239
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,145	137
Foreign Government [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	(1)	0
Current provision for securities without prior allowance	46	19
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(1)	0
Reduction for securities sold	0	(18)
Reduction for securities identified as intent (or requirement) to sell during the period	0	0
Debt Securities, Available-for-sale, Fair Value	15,860	18,366
Allowance for credit losses, ending balance at December 31, 2020	(46)	(1)
Fixed income securities, Available-For-Sale, Amortized Cost	15,420	16,801
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	609	1,569
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	123	3
Obligations of States and Political Subdivisions [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	(4)	0
Current provision for securities without prior allowance	122	4
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	11	0
Reduction for securities sold	0	0
Reduction for securities identified as intent (or requirement) to sell during the period	0	0
Debt Securities, Available-for-sale, Fair Value	1,189,308	1,247,137
Allowance for credit losses, ending balance at December 31, 2020	(137)	(4)
Fixed income securities, Available-For-Sale, Amortized Cost	1,121,422	1,159,588
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	68,258	87,564
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	235	11
Corporate Securities [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	(2,782)	0
Current provision for securities without prior allowance	5,785	3,645
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(992)	0
Reduction for securities sold	(723)	(781)
Reduction for securities identified as intent (or requirement) to sell during the period	(170)	(82)
Debt Securities, Available-for-sale, Fair Value	2,573,603	2,328,052
Allowance for credit losses, ending balance at December 31, 2020	(6,682)	(2,782)
Fixed income securities, Available-For-Sale, Amortized Cost	2,478,348	2,152,203
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	106,890	180,971
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,953	2,340
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	(592)	0
Current provision for securities without prior allowance	579	722
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(211)	0
Reduction for securities sold	(21)	(113)
Reduction for securities identified as intent (or requirement) to sell during the period	0	(17)
Debt Securities, Available-for-sale, Fair Value	1,350,814	1,026,551
Allowance for credit losses, ending balance at December 31, 2020	(939)	(592)
Fixed income securities, Available-For-Sale, Amortized Cost	1,343,687	1,014,820
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	14,350	20,166
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	6,284	7,843
Residential Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	(561)	0
Current provision for securities without prior allowance	1,593	623
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(63)	0
Reduction for securities sold	(182)	(62)
Reduction for securities identified as intent (or requirement) to sell during the period	0	0
Debt Securities, Available-for-sale, Fair Value	776,252	1,051,788
Allowance for credit losses, ending balance at December 31, 2020	(1,909)	(561)
Fixed income securities, Available-For-Sale, Amortized Cost	756,280	999,485
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	24,813	53,065
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,932	201
Commercial Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	(29)	0
Current provision for securities without prior allowance	10	29
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(28)	0
Reduction for securities sold	0	0
Reduction for securities identified as intent (or requirement) to sell during the period	0	0
Debt Securities, Available-for-sale, Fair Value	673,681	667,894
Allowance for credit losses, ending balance at December 31, 2020	(11)	(29)
Fixed income securities, Available-For-Sale, Amortized Cost	647,622	620,582
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	27,752	48,348
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 1,682	$ 1,007

Investments (Number of Securiti

Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,376,128	$ 415,506
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	14,849
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	85,122	185,335
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		6,108
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,505	5,434
Debt Securities, Available-for-sale, Unrealized Loss Position	1,461,250	600,841
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	17,354	11,542
U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	34,857	11,519
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	746
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	7,827	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	399	0
Debt Securities, Available-for-sale, Unrealized Loss Position	42,684	11,519
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	1,145	137
Foreign Government [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,000	1,122
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	84
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,061	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	39	0
Debt Securities, Available-for-sale, Unrealized Loss Position	3,061	1,122
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	123	3
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	25,837	2,223
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	235
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		11
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	25,837	2,223
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	235	11
Corporate Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	300,549	65,187
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,903
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	2,520	2,400
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		2,152
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	50	188
Debt Securities, Available-for-sale, Unrealized Loss Position	303,069	67,587
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	4,953	2,340
Collateralized Loan Obligations and Other Asset-Backed Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	663,976	261,746
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,934
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	53,368	165,661
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		2,995
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,350	4,848
Debt Securities, Available-for-sale, Unrealized Loss Position	717,344	427,407
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	6,284	7,843
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	236,010	18,227
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,931
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	20	1,181
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		194
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	7
Debt Securities, Available-for-sale, Unrealized Loss Position	236,030	19,408
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2,932	201
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	112,899	55,482
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,016
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	20,326	16,093
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		616
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	666	391
Debt Securities, Available-for-sale, Unrealized Loss Position	133,225	71,575
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 1,682	$ 1,007

Investments (Fixed Maturity Sec

Investments (Fixed Maturity Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
AFS due in one year or less fair value	$ 500,579
AFS due after one year through five years fair value	3,182,282
AFS due after five years through 10 years fair value	2,316,389
AFS due after 10 years fair value	710,726
Fixed income securities, available-for-sale securities	6,709,976	$ 6,455,928
HTM due in one year or less carrying value	1,384
HTM due after one year through five years carrying value	11,811
HTM due after five years through 10 years carrying value	15,590
HTM due after 10 years carrying value	0
Total HTM fixed income securities carrying value	28,785	16,824
HTM due in one year or less fair value	1,401
HTM due after one year through five years fair value	12,493
HTM due after five years through 10 years fair value	15,566
HTM due after 10 years fair value	0
Total HTM fixed income securities fair value	$ 29,460	$ 18,001

Investments (Other Investment P

Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount Associated With Each Strategy) (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Carrying Value		$ 409,032	$ 266,322
Private Equity [Member]
Carrying Value		273,070	157,276
Remaining Commitment		99,734	100,905
Maximum Exposure to Loss	[1]	372,804	258,181
Private Credit Funds [Member]
Carrying Value		63,138	54,017
Remaining Commitment		92,674	98,330
Maximum Exposure to Loss	[1]	155,812	152,347
Real Assets [Member]
Carrying Value		23,524	19,659
Remaining Commitment		22,579	16,493
Maximum Exposure to Loss	[1]	46,103	36,152
Alternative Investments [Member]
Carrying Value		359,732	230,952
Remaining Commitment		214,987	215,728
Maximum Exposure to Loss	[1]	574,719	446,680
Other Securities [Member]
Carrying Value		49,300	35,370
Remaining Commitment		0	0
Maximum Exposure to Loss	[1]	49,300	35,370
Other Investment Portfolio [Member]
Carrying Value		409,032	266,322
Remaining Commitment		214,987	215,728
Maximum Exposure to Loss	[1]	$ 624,019	$ 482,050
[1]	In addition to the amounts in this table, previously recognized tax credits are subject to the risk of recapture. We do not consider this significant and therefore do not include in this table.

Investments (Aggregated Balance

Investments (Aggregated Balance Sheet Summarized Financial Information for Partnerships in our Alternative Investment Portfolio) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Assets	$ 112,232	$ 58,819
Equity Method Investment, Nonconsolidated Investee, Other
Partner's capital	99,861	52,075
Investments Accounted For Under The Equity Method [Member]
Investments	107,347	55,145
Liabilities	$ 12,371	$ 6,744

Investments (Aggregated Income

Investments (Aggregated Income Statement Summarized Financial Information for Partnerships in our Alternative Investment Portfolio) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 326,589		$ 227,107		$ 222,543
Investments Accounted For Under The Equity Method [Member]
Schedule of Equity Method Investments [Line Items]
Net investment (loss) income		$ 653,000		$ (26,000)		$ (8,000)
Realized gains		6,121,000		1,452,000		695,000
Net change in unrealized appreciation		26,877,000		4,898,000		5,543,000
Net Income before tax		33,651,000		6,324,000		6,230,000
Alternative Investments [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income earned		$ 117,700		$ 26,500		$ 17,900

Investments (Credit Concentrati

Investments (Credit Concentration Risk) (Details)	Dec. 31, 2021
Investments [Abstract]
Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government agencies	10.00%

Investments (Investments Pledge

Investments (Investments Pledged as Collateral) (Details) $ in Millions	Dec. 31, 2021USD ($)
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	$ 26.3
Securities pledged as collateral for reinsurance obligations	149.5
U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	22.3
Securities pledged as collateral for reinsurance obligations	22.3
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0
Assets Held by Insurance Regulators	4
Securities pledged as collateral for reinsurance obligations	4
Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	0
Securities pledged as collateral for reinsurance obligations	102.8
Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Assets Held by Insurance Regulators	0
Securities pledged as collateral for reinsurance obligations	20.4
Federal Home Loan Bank of New York [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	54.5
Federal Home Loan Bank of New York [Member] | U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0
Federal Home Loan Bank of New York [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	40.4
Federal Home Loan Bank of New York [Member] | Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	14.1
Federal Home Loan Bank of Indianapolis [Member] | Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	68.7
Federal Home Loan Bank of Indianapolis [Member] | U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0
Federal Home Loan Bank of Indianapolis [Member] | Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	0
Federal Home Loan Bank of Indianapolis [Member] | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	62.4
Federal Home Loan Bank of Indianapolis [Member] | Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	$ 6.3

Investments (Net Investment Inc

Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement [Line Items]
Net investment income earned	$ 326,589	$ 227,107	$ 222,543
Fixed Income Securities [Member]
Statement [Line Items]
Net investment income earned	209,709	203,926	203,255
Commercial Mortgage Loans [Member]
Statement [Line Items]
Net investment income earned	2,743	844	0
Equity Securities [Member]
Statement [Line Items]
Net investment income earned	15,920	9,286	6,996
Short-term Investments [Member]
Statement [Line Items]
Net investment income earned	260	1,821	6,653
Other Investment Portfolio [Member]
Statement [Line Items]
Net investment income earned	118,060	26,922	18,778
Investment Expenses [Member]
Statement [Line Items]
Net investment income earned	$ (20,103)	$ (15,692)	$ (13,139)

Investments Realized and Unreal

Investments Realized and Unrealized Gains (Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Gross gains on sales	$ 15,284	$ 18,893	$ 31,910
Gross losses on sales	(8,140)	(9,745)	(5,195)
Net realized investment gains (losses) on disposals	7,144	9,148	26,715
Net unrealized losses on equity securities	17,881	7,939	(8,649)
Losses on securities for which we have the intent to sell	(519)	(16,266)
OTTI Losses Gross			(3,644)
Net realized and unrealized investment gains (losses)	17,599	(4,217)	14,422
Sale of equity securities	99,235	1,320	$ 137,294
Losses on securities for which we have the intent to sell	(519)	(16,266)
Available-for-sale Securities [Member]
Credit loss expense on investment portfolio	(6,858)	(5,042)
Held-to-maturity Securities [Member]
Credit loss expense on investment portfolio	$ (49)	$ 4

Investments (Components of Net

Investments (Components of Net Realized and Unrealized Gains (Losses)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Unrealized Gain (Loss) on Investments recognized in income on equity securities remaining in our portfolio at end of period	$ 16,473	$ 7,936	$ 1,219
Unrealized gains (losses) recognized in income on equity securities that were sold in the respective period	1,408	3	(9,868)
Total unrealized (losses) recognized in income on equity securities	17,881	7,939	(8,649)
Sale of fixed income securities, available-for-sale	502,911	487,087	$ 594,743
Losses on securities for which we have the intent to sell	$ 519	$ 16,266

Comprehensive Income (Component

Comprehensive Income (Components of Comprehensive Income-Gross and Net of Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income before federal income tax	$ 505,310	$ 302,988	$ 336,390
Income Tax Expense (Benefit)	101,473	56,633	64,767
Net income	403,837	246,355	271,623
Unrealized holding (losses) gains during the period, Gross	151,391	168,487	212,683
Unrealized holding (losses) gains during the period, Tax	31,793	35,383	44,662
Unrealized holding (losses) gains arising during period, Net	119,598	133,104	168,021
Unrealized losses on securities with credit loss recognized in earnings; Gross	(9,061)	(8,176)
Unrealized losses on securities with credit loss recognized in earnings; Tax	(1,902)	(1,717)
Unrealized losses on securities with credit loss recognized in earnings	(7,159)	(6,459)	0
Amortization Of Net Unrealized Gains Losses On Held To Maturity Transferred From Available For Sale Before Tax	(11)	(24)	(58)
Amounts reclassified into net income: HTM securities, Tax	(2)	(5)	(12)
Amount reclassified into net income: HTM securities, Net	(9)	(19)	(46)
Net realized losses (gains) on disposals and losses on intent-to-sell of AFS securities, Gross	(3,825)	5,376	671
Net realized losses (gains) on disposals and losses on intent-to-sell of AFS securities, Tax	(803)	1,129	141
Net realized losses (gains) on disposals and losses on intent-to-sell of AFS securities	(3,022)	4,247	530
Credit loss expense, Gross	6,858	5,042
Credit loss expense, Tax	1,440	1,058
Credit loss expense, Net	5,418	3,984
Net unrealized gains (losses), Gross	(157,430)	170,705	213,296
Net unrealized gains (losses), Tax	(33,060)	35,848	44,791
Total unrealized (losses) gains on investment securities	124,370	134,857	168,505
Net actuarial gain (loss), Gross	21,636	1,515	(13,795)
Net actuarial gain (loss), Tax	4,543	318	(2,897)
Net actuarial (loss), Net	(17,093)	1,197	10,898
Amount reclassified into net income: Net actuarial loss, Gross	2,772	3,015	2,657
Amount reclassified into Net Income: Net actuarial loss, Tax	582	633	558
Amount reclassified into net income: Net actuarial loss, Net	2,190	2,382	2,099
Defined pension and other post-retirement benefit plans, Gross	24,408	4,530	(11,138)
Defined pension and other post-retirement benefit plans, Tax	5,125	951	(2,339)
Total defined benefit pension and post-retirement plans	19,283	3,579	(8,799)
Other Comprehensive Income (Loss), Gross	(133,022)	175,235	202,158
Other Comprehensive Income (Loss), Tax	(27,935)	36,799	42,452
Other comprehensive (loss) income	(105,087)	138,436	159,706
Comprehensive Income, Before Tax	372,288	478,223	538,548
Comprehensive Income, Tax	73,538	93,432	107,219
Comprehensive income	$ 298,750	$ 384,791	$ 431,329

Comprehensive Income (Compone_2

Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance December,	$ 220,186
Amount reclassified from AOCI, HTM	(9)	$ (19)	$ (46)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans	17,093	(1,197)	(10,898)
Amounts reclassified from AOCI,All other	(3,022)	4,247	530
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	19,283	3,579	(8,799)
Other comprehensive (loss) income	(105,087)	138,436	159,706
Balance December,	115,099	220,186
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance December,	(2,546)	(71)
Amounts reclassified into net income: Credit loss related	5,418	3,984
Other comprehensive (loss) income	(1,741)	(2,475)
Balance December,	(4,287)	(2,546)	(71)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
OCI before reclassifications	(7,159)	(6,459)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, December 31, 2018			(88,643)
Balance December,	(85,064)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans	17,093	1,197
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	2,190	2,382
Balance December,	(65,781)	(85,064)
Accumulated other comprehensive (loss) income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, December 31, 2018			81,750
Balance December,	220,186
OCI before reclassifications	(109,664)	127,842
Amount reclassified from AOCI	4,577	10,594
Other comprehensive (loss) income	(105,087)	138,436	159,706
Balance December,	115,099	220,186
Held-to-maturity Securities [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, December 31, 2018			25
Balance December,	6
OCI before reclassifications	0	0
Other comprehensive (loss) income	(9)	(19)
Balance December,	(3)	6
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, December 31, 2018			170,439
Balance December,	307,790
OCI before reclassifications	(119,598)	133,104
Amounts reclassified from AOCI,All other	(3,022)	4,247
Other comprehensive (loss) income	(122,620)	137,351
Balance December,	185,170	307,790
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, December 31, 2018			$ 170,393
Balance December,	305,250
OCI before reclassifications	(126,757)	126,645
Amount reclassified from AOCI	2,387	8,212
Other comprehensive (loss) income	(124,370)	134,857
Balance December,	$ 180,880	$ 305,250

Comprehensive Income (Reclassif

Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net realized and unrealized investment gains (losses)	$ 17,599	$ (4,217)	$ 14,422
Net investment income	326,589	227,107	222,543
Income before federal income tax	505,310	302,988	336,390
Income Tax Expense (Benefit)	101,473	56,633	64,767
Net income	403,837	246,355	271,623
Loss and loss expense incurred	1,813,984	1,635,823	1,551,491
Policy acquisition costs	375,931	366,941	358,069
Total defined benefit pension and post-retirement plans	19,283	3,579	$ (8,799)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Net income	4,577	10,594
Reclassification out of Accumulated Other Comprehensive Income [Member] | Retirement Income Plan [Member]
Income before federal income tax	2,772	3,015
Income Tax Expense (Benefit)	(582)	(633)
Net income	2,190	2,382
Loss and loss expense incurred	638	647
Policy acquisition costs	2,134	2,368
Held-to-maturity Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Net realized and unrealized investment gains (losses)	(14)	(16)
Net investment income	3	(8)
Income before federal income tax	(11)	(24)
Income Tax Expense (Benefit)	2	(5)
Net income	(9)	(19)
AOCI, Gain (Loss), Debt Securities, Available-for-sale, without Allowance for Credit Loss, Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Net realized and unrealized investment gains (losses)	(3,825)	5,376
Income before federal income tax	(3,825)	5,376
Income Tax Expense (Benefit)	803	(1,129)
Net income	(3,022)	4,247
AOCI, Gain (Loss), Debt Securities, Available-for-sale, with Allowance for Credit Loss, Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Net realized and unrealized investment gains (losses)	6,858	5,042
Income before federal income tax	6,858	5,042
Income Tax Expense (Benefit)	(1,440)	1,058
Net income	$ 5,418	$ 3,984

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Value and Estimated Fair Value of Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fixed Income Securities, Available-for-sale, at fair value	$ 6,709,976	$ 6,455,928
Equity securities	335,537	310,367
Short-term investments	447,863	409,852
Long-term debt	506,050	550,743
Unamortized Debt Issuance Costs	(3,167)
Finance Lease, Liability	5,450	508
Seven Point Twenty Five Percent Senior Notes [Member]
Long-term Debt, Fair Value	63,719	66,148
Unamortized Debt Issuance Costs	(147)
Six Point Seventy Percent Senior Notes [Member]
Long-term Debt, Fair Value	127,574	127,886
Unamortized Debt Issuance Costs	(287)
Five Point Three Hundred Seventy Five Percent Senior Notes [Member]
Long-term Debt, Fair Value	395,652	383,669
Unamortized Debt Issuance Costs	(2,733)
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Long-term Debt, Fair Value		25,182
Unamortized Debt Issuance Costs	0
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Long-term Debt, Fair Value		25,198
Unamortized Debt Issuance Costs	0
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Long-term Debt, Fair Value	64,126	67,513
Unamortized Debt Issuance Costs	0
Finance lease obligation [Member]
Finance Lease, Liability	5,450	508
Carrying Amount [Member]
Long-term debt	506,050	550,743
Carrying Amount [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Long-term debt	49,917	49,914
Carrying Amount [Member] | Six Point Seventy Percent Senior Notes [Member]
Long-term debt	99,520	99,499
Carrying Amount [Member] | Five Point Three Hundred Seventy Five Percent Senior Notes [Member]
Long-term debt	294,330	294,241
Carrying Amount [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Long-term debt	0	25,000
Carrying Amount [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Long-term debt	0	25,000
Carrying Amount [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Long-term debt	60,000	60,000
Carrying Amount [Member] | Long Term Debt Excluding Issuance Costs [Member]
Long-term debt	503,767	553,654
Carrying Amount [Member] | Unamortized Debt Issuance Costs [Member]
Unamortized Debt Issuance Costs	(3,167)	(3,419)
Carrying Amount [Member] | Finance lease obligation [Member]
Finance Lease, Liability	5,450	508
Fair Value [Member]
Long-term Debt, Fair Value	651,071	695,596
Fair Value [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Long-term Debt, Fair Value	63,719	66,148
Fair Value [Member] | Six Point Seventy Percent Senior Notes [Member]
Long-term Debt, Fair Value	127,574	127,886
Fair Value [Member] | Five Point Three Hundred Seventy Five Percent Senior Notes [Member]
Long-term Debt, Fair Value	395,652	383,669
Fair Value [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Long-term Debt, Fair Value	0	25,182
Fair Value [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Long-term Debt, Fair Value	0	25,198
Fair Value [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Long-term Debt, Fair Value	$ 64,126	$ 67,513

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Disclosures at Fair Value Assets) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments Net Asset Value		$ 83,600	$ 46,800
Fixed Income Securities, Available-for-sale, at fair value		6,709,976	6,455,928
Equity securities		335,537	310,367
Short-term investments		447,863	409,852
Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		(270)
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		6,709,976	6,455,928
Equity securities		335,537	310,367
Short-term investments		447,863	409,852
Total Assets		7,493,376	7,176,147
U.S. Government and Government Agencies and Authorities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		130,458	116,140
Foreign Government [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		15,860	18,366
Obligations of States and Political Subdivisions [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchases		0	0
Sales		0	0
Issuances		0	0
Settlements		0	0
Transfers into Level 3		5,101	2,890
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0	0
Total net (losses) gains for the period included in OCI		(239)	4
Period change unrealized gains (losses) in earnings		(11)	0
Period change unrealized gains (losses) in OCI		(239)	4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		7,745	2,894	$ 0
Obligations of States and Political Subdivisions [Member] | Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		0	0
Obligations of States and Political Subdivisions [Member] | Available-for-sale Securities [Member] | Gain (Loss) on Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		(11)	0
Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		1,189,308	1,247,137
Corporate Securities [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		27
Purchases		64,813	46,150
Sales		0	0
Issuances		0	0
Settlements		(544)	(283)
Transfers into Level 3		981	9,592
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		23,436	0
Total net (losses) gains for the period included in OCI		1,636	(785)
Period change unrealized gains (losses) in earnings		(50)	(1,046)
Period change unrealized gains (losses) in OCI		1,636	(785)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		114,127	70,700	17,051
Corporate Securities [Member] | Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		(50)	21
Corporate Securities [Member] | Available-for-sale Securities [Member] | Gain (Loss) on Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income			(1,046)
Corporate Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		2,573,603	2,328,052
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		16
Purchases		76,731	25,785
Sales		0	0
Issuances		0	0
Settlements		(5,161)	(2,638)
Transfers into Level 3		11,344	31,520
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		13,662	(16,978)
Total net (losses) gains for the period included in OCI		(520)	1,883
Period change unrealized gains (losses) in earnings		(214)	(237)
Period change unrealized gains (losses) in OCI		(520)	1,883
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		124,909	56,375	17,034
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		(214)	6
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Available-for-sale Securities [Member] | Gain (Loss) on Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income			(237)
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		1,350,814	1,026,551
Residential Mortgage Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		0
Purchases		249
Sales		0
Issuances		0
Settlements		(4)
Transfers into Level 3		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0
Total net (losses) gains for the period included in OCI		0
Period change unrealized gains (losses) in earnings		0
Period change unrealized gains (losses) in OCI		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		245	0
Residential Mortgage Backed Securities [Member] | Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		0
Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		776,252	667,894
Commercial Mortgage-backed Securities (CMBS) [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		19
Purchases		98
Sales		0
Issuances		0
Settlements		(52)
Transfers into Level 3		4,382
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		0
Total net (losses) gains for the period included in OCI		(196)
Period change unrealized gains (losses) in earnings		5
Period change unrealized gains (losses) in OCI		(196)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		4,256	0
Commercial Mortgage-backed Securities (CMBS) [Member] | Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		5
Commercial Mortgage-backed Securities (CMBS) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		673,681	1,051,788
Common Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[1]	333,449	308,632
Nonredeemable Preferred Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		2,088	1,735
Investments [Member] | Available-for-sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchases		141,891	71,935
Sales		0	0
Issuances		0	0
Settlements		(5,761)	(2,921)
Transfers into Level 3		21,808	44,002
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3		37,098	(16,978)
Total net (losses) gains for the period included in OCI		681	1,102
Period change unrealized gains (losses) in earnings		(270)	(1,283)
Period change unrealized gains (losses) in OCI		681	1,102
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value		251,282	129,969	$ 34,085
Investments [Member] | Available-for-sale Securities [Member] | Net Investment Income Earned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income		62	27
Investments [Member] | Available-for-sale Securities [Member] | Gain (Loss) on Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total net (losses) gains for the period included in net income			(1,283)
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		60,615	40,960
Equity securities		251,934	263,581
Short-term investments		442,723	405,400
Total Assets		755,272	709,941
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | U.S. Government and Government Agencies and Authorities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		60,615	40,960
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Commercial Mortgage-backed Securities (CMBS) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[1]	249,846	261,846
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Nonredeemable Preferred Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		2,088	1,735
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		6,398,079	6,284,999
Equity securities		0	0
Short-term investments		5,140	4,452
Total Assets		6,403,219	6,289,451
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government and Government Agencies and Authorities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		69,843	75,180
Significant Other Observable Inputs (Level 2) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		15,860	18,366
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		1,181,563	1,244,243
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		2,459,476	2,257,352
Significant Other Observable Inputs (Level 2) [Member] | Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		1,225,905	970,176
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		776,007	667,894
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage-backed Securities (CMBS) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		669,425	1,051,788
Significant Other Observable Inputs (Level 2) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[1]	0	0
Significant Other Observable Inputs (Level 2) [Member] | Nonredeemable Preferred Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		251,282	129,969
Equity securities		0	0
Short-term investments		0	0
Total Assets		251,282	129,969
Significant Unobservable Inputs (Level 3) [Member] | U.S. Government and Government Agencies and Authorities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Significant Unobservable Inputs (Level 3) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		0	0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		7,745	2,894
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		114,127	70,700
Significant Unobservable Inputs (Level 3) [Member] | Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		124,909	56,375
Significant Unobservable Inputs (Level 3) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		245	0
Significant Unobservable Inputs (Level 3) [Member] | Commercial Mortgage-backed Securities (CMBS) [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed Income Securities, Available-for-sale, at fair value		4,256	0
Significant Unobservable Inputs (Level 3) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	[1]	0	0
Significant Unobservable Inputs (Level 3) [Member] | Nonredeemable Preferred Stock [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities		$ 0	$ 0
[1]	Investments amounting to $83.6 million and $46.8 million at December 31, 2021 and December 31, 2020, respectively, were measured at fair value using the net asset value per share (or its practical expedient) and have not been classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total assets measured at fair value.

Fair Value Measurements (Change

Fair Value Measurements (Changes in Fair Value of Securities Using Level 3 Inputs) (Details) $ in Thousands	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Corporate Securities [Member] | Available-for-sale Securities [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 114,127	$ 70,700	$ 17,051
Corporate Securities [Member] | Valuation Technique, Discounted Cash Flow | Available-for-sale Securities [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	54,135	15,907
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Available-for-sale Securities [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	124,909	56,375	17,034
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Valuation Technique, Discounted Cash Flow | Available-for-sale Securities [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	34,903	27,005
Investments [Member] | Available-for-sale Securities [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Other Assets, Fair Value Disclosure	162,244	87,057
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	251,282	129,969	$ 34,085
Investments [Member] | Valuation Technique, Discounted Cash Flow | Available-for-sale Securities [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Assets, Fair Value Disclosure	$ 89,038	$ 42,912
Minimum [Member] | Corporate Securities [Member] | Measurement Input, Credit Spread | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	0.003	0.018
Minimum [Member] | Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Measurement Input, Credit Spread | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	0.007	0.012
Maximum [Member] | Corporate Securities [Member] | Measurement Input, Credit Spread | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	0.030	0.018
Maximum [Member] | Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Measurement Input, Credit Spread | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	0.080	0.031
Weighted Average | Corporate Securities [Member] | Measurement Input, Credit Spread | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	(0.012)	(0.018)
Weighted Average | Collateralized Loan Obligations and Other Asset-Backed Securities [Member] | Measurement Input, Credit Spread | Valuation Technique, Discounted Cash Flow
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Debt Securities, Available-for-sale, Measurement Input	(0.021)	(0.018)

Fair Value Measurements (Quan_2

Fair Value Measurements (Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	$ 29,460	$ 18,001
Commercial mortgage loan, fair value	97,598	47,289
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	0	0
Long-term Debt, Fair Value	0	0
Commercial mortgage loan, fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	29,460	18,001
Long-term Debt, Fair Value	651,071	695,596
Commercial mortgage loan, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	0	0
Long-term Debt, Fair Value	0	0
Commercial mortgage loan, fair value	97,598	47,289
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	3,576	4,795
Obligations of States and Political Subdivisions [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	0	0
Obligations of States and Political Subdivisions [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	3,576	4,795
Obligations of States and Political Subdivisions [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	0	0
Corporate Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	25,884	13,206
Corporate Securities [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	0	0
Corporate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	25,884	13,206
Corporate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total HTM fixed income securities fair value	0	0
Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	63,719	66,148
Seven Point Twenty Five Percent Senior Notes [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0
Seven Point Twenty Five Percent Senior Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	63,719	66,148
Seven Point Twenty Five Percent Senior Notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0
Six Point Seventy Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	127,574	127,886
Six Point Seventy Percent Senior Notes [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0
Six Point Seventy Percent Senior Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	127,574	127,886
Six Point Seventy Percent Senior Notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0
Five Point Three Hundred Seventy Five Percent Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	395,652	383,669
Five Point Three Hundred Seventy Five Percent Senior Notes [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0
Five Point Three Hundred Seventy Five Percent Senior Notes [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	395,652	383,669
Five Point Three Hundred Seventy Five Percent Senior Notes [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		25,182
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		0
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		25,182
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		0
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		25,198
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		0
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		25,198
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value		0
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	64,126	67,513
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0	0
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	64,126	67,513
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	0	0
Long-term Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 651,071	$ 695,596

Allowance for Credit Losses o_3

Allowance for Credit Losses on Premiums Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019
Premiums Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, net of write-offs	$ 13,500
Premium Receivable, Allowance for Credit Loss	13,600	$ 21,000		$ 6,400
Premiums Receivable [Member]
Premiums Receivable, Allowance for Credit Loss [Line Items]
Recoveries	652	545
Write-offs charged against the allowance for credit losses	(9,343)	(3,754)
Current period provision for expected credit losses	1,291	16,751
Premium Receivable, Allowance for Credit Loss	$ 13,600	21,000		7,458
Premiums Receivable [Member] | Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Premiums Receivable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss		$ 0	[1]	$ 1,058
[1]	Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses .

Reinsurance Recoverable, Credit

Reinsurance Recoverable, Credit Quality Indicator (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables on Unpaid Losses, Gross	$ 601,668	$ 589,269
Reinsurance Recoverable, Allowance for Credit Loss	(1,600)	(1,777)	$ (4,400)
Reinsurance Recoverables, net of allowance for credit losses	600,068	587,492
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments, Gross [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	598,317	585,408
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments, Gross [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	3,351	3,861
Total federal and state pools [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	116,378	82,575
Total federal and state pools [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	116,378	82,575
Total federal and state pools [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	0
Other Federal And State Pools [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	5,047	3,244
Other Federal And State Pools [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	4,597	2,676
Other Federal And State Pools [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	450	568
Total Non Rated Reinsurer [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	121,425	85,819
Total Non Rated Reinsurer [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	120,975	85,251
Total Non Rated Reinsurer [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	450	568
AM Best, A++ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	38,610	37,566
AM Best, A++ Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	38,601	37,464
AM Best, A++ Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	9	102
AM Best, A+ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	341,377	357,298
AM Best, A+ Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	339,857	354,846
AM Best, A+ Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	1,520	2,452
AM Best, A Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	96,902	106,067
AM Best, A Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	95,675	105,652
AM Best, A Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	1,227	415
AM Best, A- Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	3,354	2,139
AM Best, A- Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	3,209	2,139
AM Best, A- Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	145	0
AM Best, B++ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	380
AM Best, B++ Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	56
AM Best, B++ Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	324
AM Best, B+ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	0
AM Best, B+ Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	0
AM Best, B+ Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0	0
AM Best Rated Reinsurer [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	480,243	503,450
AM Best Rated Reinsurer [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	477,342	500,157
AM Best Rated Reinsurer [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	$ 2,901	$ 3,293

Reinsurance Allowance for Credi

Reinsurance Allowance for Credit Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Reinsurance Recoverable, Allowance for Credit Loss, Beginning Balance	$ 1,777	$ 4,400
Reinsurance Recoverable, Allowance for Credit Loss, Ending Balance	1,600	1,777
Current period provision for expected credit losses	(177)	280
Write-offs charged against the allowance for credit losses	0	0
Recoveries	0	0
Current period provision for expected credit losses	(177)	280
Write-offs charged against the allowance for credit losses	0	0
Recoveries	0	0
Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Reinsurance Recoverable, Allowance for Credit Loss, Beginning Balance	1,777	1,497
Reinsurance Recoverable, Allowance for Credit Loss, Ending Balance		1,777
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments, Gross [Member] | Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Reinsurance Recoverable, Allowance for Credit Loss, Beginning Balance	$ 0	(2,903)
Reinsurance Recoverable, Allowance for Credit Loss, Ending Balance		$ 0

Reinsurance (Total Reinsurance

Reinsurance (Total Reinsurance Balances Segregated By Reinsurer) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Terrorism Risk Insurance Program Companys Estimated Deductible		$ 419,000
Terrorism Risk Insurance Program Reimbursed Percentage Maximum		80.00%
Terrorism Risk Insurance Program Annual Cap		$ 100,000,000
Terrorism Risk Insurance Program Insurer Retainer		20.00%
Total prepaid reinsurance premiums		$ 183,007	$ 170,531
Total reinsurance balance		783,075	758,023
Less: collateral	[1]	(128,699)	(130,169)
Reinsurance Recoverable, Allowance for Credit Loss		(1,600)	(1,777)	$ (4,400)
Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments		600,068	587,492
National Flood Insurance Program [Member]
Total reinsurance balance	[2]	$ 223,845	$ 178,532
% of Net Unsecured Reinsurance	[2]	29.00%	25.00%
NJ Unsatisfied Claim Judgment Fund [Member]
Total reinsurance balance	[2]	$ 49,738	$ 52,053
% of Net Unsecured Reinsurance	[2]	6.00%	6.00%
Other Federal And State Pools [Member]
Total reinsurance balance	[2]	$ 2,385	$ 1,625
% of Net Unsecured Reinsurance	[2]	0.00%	0.00%
Total Federal And State Pools [Member]
Total reinsurance balance	[2]	$ 275,968	$ 232,210
% of Net Unsecured Reinsurance	[2]	35.00%	31.00%
Remaining Unsecured Reinsurance [Member]
Total reinsurance balance		$ 508,707	$ 527,590
% of Net Unsecured Reinsurance		65.00%	69.00%
Remaining Reinsurance, after Allowance for Credit Loss		$ 507,107	$ 525,813
Munich Re Group [Member]
Total reinsurance balance		$ 108,381	$ 117,028
% of Net Unsecured Reinsurance		14.00%	15.00%
Hanover Ruckversicherungs AG [Member]
Total reinsurance balance		$ 107,110	$ 115,251
% of Net Unsecured Reinsurance		14.00%	15.00%
AXIS Reinsurance Company [Member]
Total reinsurance balance		$ 70,814	$ 78,617
% of Net Unsecured Reinsurance		9.00%	10.00%
Swiss Re Group [Member]
Total reinsurance balance		$ 29,186	$ 33,249
% of Net Unsecured Reinsurance		4.00%	4.00%
Transatlantic Reinsurance Company [Member]
Total reinsurance balance		$ 26,490	$ 24,374
% of Net Unsecured Reinsurance		3.00%	3.00%
All Other Reinsurers [Member]
Total reinsurance balance		$ 166,726	$ 159,071
% of Net Unsecured Reinsurance		21.00%	21.00%
Remaining Unsecured Reinsurance, Net of Collateral [Member]
Total reinsurance balance		$ 378,408	$ 395,644
[1]	Includes letters of credit, trust funds, and funds held against reinsurance recoverables.
[2]	Considered to have minimal risk of default.

Reinsurance (List of direct, as

Reinsurance (List of direct, assumed and ceded Reinsurance Amounts) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Premiums Written:
Direct premiums written	$ 3,656,537	$ 3,204,512	$ 3,084,451
Assumed	22,664	24,288	24,339
Ceded premiums written	(489,488)	(455,708)	(429,366)
Net	3,189,713	2,773,092	2,679,424
Direct premiums written	3,656,537	3,204,512	3,084,451
Premiums Earned:
Direct	3,472,715	3,108,687	2,993,157
Assumed	21,550	25,010	24,399
Ceded premiums earned	(477,012)	(451,883)	(420,385)
Total Net Premiums Earned	3,017,253	2,681,814	2,597,171
Loss and loss expense incurred:
Direct	2,096,512	1,822,034	1,714,880
Assumed	13,813	17,201	22,879
Ceded loss and loss expense	(296,341)	(203,412)	(186,268)
Net	$ 1,813,984	$ 1,635,823	$ 1,551,491
Increase in DPW from Prior Year	14.00%	4.00%
Return audit and midterm endorsement premium [Member] | COVID-19 [Member]
Premiums Written:
Direct premiums written	$ 75,000
Direct premiums written	75,000
Commercial & Personal Automobile [Member] | COVID-19 [Member]
Premiums Written:
Direct premiums written	19,700
Direct premiums written	$ 19,700

Reinsurance (Ceded Premiums and

Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Percentage of NFIP claims ceded to the federal government	100.00%
Ceded premiums written	$ (489,488)	$ (455,708)	$ (429,366)
Ceded premiums earned	(477,012)	(451,883)	(420,385)
Ceded loss and loss expense	(296,341)	(203,412)	(186,268)
National Flood Insurance Program [Member]
Ceded premiums written	(284,311)	(274,042)	(266,925)
Ceded premiums earned	(274,384)	(271,598)	(259,119)
Ceded loss and loss expense	$ (215,224)	$ (78,993)	$ (71,676)

Reserve for Loss and Loss Exp_3

Reserve for Loss and Loss Expense (Rollforward of Reserve for Loss and Loss Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019	Jan. 01, 2020
Gross reserve for loss and loss expense, at beginning of year	$ 4,260,355		$ 4,067,163		$ 3,893,868
Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year	554,269	[1]	544,162		537,388
Net reserves for loss and loss expense, at beginning of year	3,706,086		3,523,001		3,356,480
Incurred loss and loss expense for claims occurring in the current year	1,896,837		1,708,755		1,601,780
Prior Year Claims and Claims Adjustment Expense	(82,853)		(72,932)
Total incurred loss and loss expense	1,813,984		1,635,823		1,551,491
Paid loss and loss expense for claims occurring in current year	676,331		642,586		579,527
Paid loss and loss expense for claims occurring in prior years	841,477		807,248		805,443
Total paid loss and loss expense	1,517,808		1,449,834		1,384,970
Net reserves for loss and loss expense, at end of year	4,002,262		3,706,086		3,523,001
Add: reinsurance recoverable on unpaid loss and loss expense, at end of year	578,641		554,269	[1]	544,162
Gross reserve for loss and loss expense, at end of year	4,580,903		4,260,355		4,067,163
Increase of net loss and loss expense reserves	296,200		183,100		166,500
Anticipated recoveries for salvage and subrogation claims	87,000		80,900		76,700
Accounting Standards Update 2016-13 [Member]
Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year			547,066
Net reserves for loss and loss expense, at beginning of year			$ 3,520,097
Net reserves for loss and loss expense, at end of year					3,520,097
Add: reinsurance recoverable on unpaid loss and loss expense, at end of year					547,066
Equity Impact on Cumulative Effect Adjustment						$ 0
Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Prior Year Claims and Claims Adjustment Expense					$ 50,289
Equity Impact on Cumulative Effect Adjustment	$ 2,900
[1]	ncludes an adjustment of $2.9 million related to our adoption of ASU 2016-13, Financial Instruments - Credit Losses.

Reserve for Loss and Loss Exp_4

Reserve for Loss and Loss Expense (Reserve Loss Development) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Favorable or adverse loss development	$ (82,853)	$ (72,932)
Favorable or unfavorable loss development [Member]
Favorable or adverse loss development	(82,900)	(72,900)	$ (50,300)
Favorable or unfavorable loss development [Member] | Casualty Insurance Product Line [Member]
Favorable or adverse loss development	(81,000)	(85,000)	(61,000)
Favorable or unfavorable loss development [Member] | Casualty Insurance Product Line [Member] | Commercial Automobile [Member]
Favorable or adverse loss development	15,000	10,000
Favorable or unfavorable loss development [Member] | Property Insurance [Member]
Favorable or adverse loss development	1,900	12,100	10,700
Favorable or unfavorable loss development [Member] | Property Insurance [Member] | Commercial Automobile [Member]
Favorable or adverse loss development	13,300	7,100
Favorable or unfavorable loss development [Member] | General Liability [Member]
Favorable or adverse loss development	(29,000)	(35,000)	(5,000)
Favorable or unfavorable loss development [Member] | Commercial Automobile [Member]
Favorable or adverse loss development	13,300	7,100	700
Favorable or unfavorable loss development [Member] | Workers Compensation [Member]
Favorable or adverse loss development	(58,000)	(60,000)	(68,000)
Favorable or unfavorable loss development [Member] | Business Owners' Policies [Member]
Favorable or adverse loss development	(400)	3,900	1,900
Favorable or unfavorable loss development [Member] | Commercial Property [Member]
Favorable or adverse loss development	(2,600)	9,200	5,100
Favorable or unfavorable loss development [Member] | Homeowners [Member]
Favorable or adverse loss development	1,800	7,700	7,500
Favorable or unfavorable loss development [Member] | Personal Automobile [Member]
Favorable or adverse loss development	(200)	(1,800)	4,400
Favorable or unfavorable loss development [Member] | E&S Casualty Lines [Member]
Favorable or adverse loss development	(7,000)	0	2,000
Favorable or unfavorable loss development [Member] | E&S Property Lines [Member]
Favorable or adverse loss development	(800)	(4,000)	1,000
Favorable or unfavorable loss development [Member] | Insurance, Other [Member]
Favorable or adverse loss development	$ 0	$ 0	$ 100

Reserve for Loss and Loss Exp_5

Reserve for Loss and Loss Expense (Exposure to Environmental Claims) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Loss and Loss expense reserves, Gross	$ 27,773	$ 28,530	$ 28,701	$ 30,020
Liability for Asbestos and Environmental Claims, Net	21,075	$ 21,421	$ 21,589	$ 22,783
Net outstanding liabilities	12,898,946
Asbestos Claim [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Loss and Loss expense reserves, Gross	6,100
Liability for Asbestos and Environmental Claims, Net	4,900
Landfill Sites Related Claims [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Loss and Loss expense reserves, Gross	12,100
Liability for Asbestos and Environmental Claims, Net	7,600
Leaking Underground Storage Tanks Claims [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Loss and Loss expense reserves, Gross	9,600
Liability for Asbestos and Environmental Claims, Net	$ 8,600

Reserve for Loss and Loss Exp_6

Reserve for Loss and Loss Expense (Roll Forward of Gross and Net Asbestos and Net Environmental Incurred Losses and Loss Expenses and Related Reserves) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Reserve for loss and loss expense at beginning of year, gross	$ 28,530	$ 28,701	$ 30,020
Incurred loss and loss expense, Gross	(562)	(127)	348
Less: loss and loss expense paid, Gross	(195)	(44)	(1,667)
Reserve for loss and loss expense at the end of year, gross	27,773	28,530	28,701
Reserve for loss and loss expense at beginning of year, net	21,421	21,589	22,783
Incurred loss and loss expense, Net	37	(154)	234
Less: loss and loss expense paid, Net	(383)	(14)	(1,428)
Reserve for loss and loss expense at the end of year, net	21,075	21,421	21,589
Asbestos [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Reserve for loss and loss expense at beginning of year, gross	6,254	6,288	7,328
Incurred loss and loss expense, Gross	51	320	(375)
Less: loss and loss expense paid, Gross	(190)	(354)	(665)
Reserve for loss and loss expense at the end of year, gross	6,115	6,254	6,288
Reserve for loss and loss expense at beginning of year, net	5,023	5,057	6,097
Incurred loss and loss expense, Net	51	320	(375)
Less: loss and loss expense paid, Net	(190)	(354)	(665)
Reserve for loss and loss expense at the end of year, net	4,884	5,023	5,057
Enviromental [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Reserve for loss and loss expense at beginning of year, gross	22,276	22,413	22,692
Incurred loss and loss expense, Gross	(613)	(447)	723
Less: loss and loss expense paid, Gross	(5)	310	(1,002)
Reserve for loss and loss expense at the end of year, gross	21,658	22,276	22,413
Reserve for loss and loss expense at beginning of year, net	16,398	16,532	16,686
Incurred loss and loss expense, Net	(14)	(474)	609
Less: loss and loss expense paid, Net	(193)	340	(763)
Reserve for loss and loss expense at the end of year, net	$ 16,191	$ 16,398	$ 16,532

Reserve for Loss and Loss Exp_7

Reserve for Loss and Loss Expense (Claims Development) (Details) $ in Thousands	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Claims Development [Line Items]
Net outstanding liabilities	$ 12,898,946
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	9,397,544
Liability for Unpaid Claims and Claims Adjustment Expense, Net	3,873,898
Reserve for loss and loss expense	4,580,903	$ 4,260,355
Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	372,496
Short-duration Insurance Contracts, Accident Year 2012 [Member]
Claims Development [Line Items]
Net outstanding liabilities	962,678	962,091	$ 968,536	$ 973,411	$ 973,644	$ 973,089	$ 998,028	$ 1,020,655	$ 1,071,290	$ 1,065,437
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 36,108
Short-duration Insurance Contract, Cumulative Number of Reported Claims	104,515
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 913,478	905,816	898,269	879,372	856,195	810,135	743,742	651,544	555,819	378,067
Short-duration Insurance Contracts, Accident Year 2013 [Member]
Claims Development [Line Items]
Net outstanding liabilities	957,958	973,739	984,858	987,763	1,002,316	1,021,007	1,047,230	1,062,045	1,044,142
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 40,736
Short-duration Insurance Contract, Cumulative Number of Reported Claims	91,756
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 911,657	904,825	891,841	872,331	833,823	748,758	644,475	518,872	335,956
Short-duration Insurance Contracts, Accident Year 2014[Member]
Claims Development [Line Items]
Net outstanding liabilities	1,094,367	1,089,529	1,100,208	1,104,218	1,124,014	1,146,990	1,133,798	1,107,513
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 48,550
Short-duration Insurance Contract, Cumulative Number of Reported Claims	95,610
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,020,961	1,002,157	981,868	936,425	855,959	736,154	614,075	405,898
Short-duration Insurance Contracts, Accident Year 2015 [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,103,592	1,108,860	1,119,441	1,138,313	1,144,830	1,130,513	1,114,081
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 56,165
Short-duration Insurance Contract, Cumulative Number of Reported Claims	94,874
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,000,509	967,857	929,222	845,868	725,385	581,203	376,641
Short-duration Insurance Contracts, Accident Year 2016 [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,171,273	1,180,829	1,199,734	1,227,142	1,203,634	1,188,608
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 90,598
Short-duration Insurance Contract, Cumulative Number of Reported Claims	95,559
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,025,264	983,852	892,390	764,331	617,958	387,272
Short-duration Insurance Contracts, Accident Year 2017 [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,268,941	1,288,526	1,313,585	1,313,372	1,270,110
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 122,313
Short-duration Insurance Contract, Cumulative Number of Reported Claims	99,424
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,050,258	954,792	829,134	678,453	433,440
Short-duration Insurance Contract, Accident Year 2018 [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,441,303	1,457,415	1,461,603	1,413,800
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 222,464
Short-duration Insurance Contract, Cumulative Number of Reported Claims	106,569
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,083,556	942,893	779,466	511,271
Short-Duration Insurance Contract, Accident Year 2019 [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,526,566	1,523,041	1,483,945
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 383,970
Short-duration Insurance Contract, Cumulative Number of Reported Claims	103,271
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 949,996	781,462	510,091
Short-Duration Insurance Contract, Accident Year 2020
Claims Development [Line Items]
Net outstanding liabilities	1,587,607	1,591,972
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 562,065
Short-duration Insurance Contract, Cumulative Number of Reported Claims	93,515
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 831,976	572,302
Short-Duration Insurance Contract, Accident Year 2021
Claims Development [Line Items]
Net outstanding liabilities	1,784,661
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 932,590
Short-duration Insurance Contract, Cumulative Number of Reported Claims	89,801
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 609,889
Standard Commercial Lines [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	2,812,608
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	1,399,252
Liability for Unpaid Claims and Claims Adjustment Expense, Net	1,515,789
Standard Commercial Lines [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,674,241
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	1,099,622
Liability for Unpaid Claims and Claims Adjustment Expense, Net	816,606
Standard Commercial Lines [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	3,107,304
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	2,393,027
Liability for Unpaid Claims and Claims Adjustment Expense, Net	717,704
Standard Commercial Lines [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	553,952
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	463,590
Liability for Unpaid Claims and Claims Adjustment Expense, Net	99,501
Standard Commercial Lines [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,579,137
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	1,481,032
Liability for Unpaid Claims and Claims Adjustment Expense, Net	98,204
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | General Liability [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	102,433
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	241,987
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	3,427
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	9,139
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	99
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	179,197	178,285	182,085	180,659	175,268	175,305	194,144	215,083	245,561	238,979
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 12,796
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,052
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 162,516	158,397	156,186	144,451	130,866	109,448	89,008	56,580	35,241	13,030
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	177,706	177,658	178,774	183,314	187,359	188,596	195,197	199,360	208,036	203,864
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 20,697
Short-duration Insurance Contract, Cumulative Number of Reported Claims	11,628,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 151,273	148,750	146,739	143,281	139,477	132,052	122,755	108,211	86,909	40,911
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	184,411	184,477	185,357	184,633	186,128	184,367	184,289	183,527	191,947	179,551
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 467
Short-duration Insurance Contract, Cumulative Number of Reported Claims	24,431,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 183,365	183,098	181,353	179,501	176,656	168,114	148,669	127,235	105,371	73,316
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	43,534	43,444	43,717	43,418	43,747	44,077	44,172	46,303	48,029	54,342
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 198
Short-duration Insurance Contract, Cumulative Number of Reported Claims	5,545,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 42,061	42,075	41,356	41,326	40,627	38,766	37,215	35,089	31,833	22,199
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	117,277	117,200	117,220	117,225	117,170	117,102	116,658	115,375	114,224	118,464
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 4
Short-duration Insurance Contract, Cumulative Number of Reported Claims	8,519,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 116,755	116,673	116,674	116,671	116,625	116,291	114,699	111,503	108,834	81,528
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	192,782	195,697	202,697	203,831	210,785	225,709	239,776	251,421	250,609
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 15,661
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,433
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 172,983	169,847	163,764	153,628	139,114	104,587	72,127	35,113	12,789
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	153,436	157,645	159,767	162,787	166,662	173,160	187,658	194,318	199,794
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 20,638
Short-duration Insurance Contract, Cumulative Number of Reported Claims	11,384,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 130,467	129,224	126,822	124,130	118,669	109,739	96,376	74,568	36,829
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	207,554	208,040	209,602	207,975	210,410	207,994	209,197	205,282	188,289
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 595
Short-duration Insurance Contract, Cumulative Number of Reported Claims	26,053,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 206,162	205,064	202,622	200,750	189,626	169,850	140,015	109,893	76,469
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	38,930	39,358	39,699	39,709	41,369	40,624	41,005	42,618	49,617
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 120
Short-duration Insurance Contract, Cumulative Number of Reported Claims	3,483,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 39,440	39,212	39,085	38,464	37,993	34,760	30,845	26,592	17,412
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	90,461	90,486	90,218	90,278	90,436	90,005	90,103	90,639	88,101
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 3
Short-duration Insurance Contract, Cumulative Number of Reported Claims	5,715,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 90,891	90,917	90,646	90,696	90,840	90,350	90,446	87,874	60,244
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014[Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	230,247	229,679	237,125	234,082	239,333	257,132	249,946	244,312
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 21,413
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,677
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 198,772	187,352	179,192	154,957	121,969	79,972	46,825	14,901
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014[Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	161,021	159,604	160,646	164,420	172,515	182,579	187,065	199,346
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 21,285
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,495,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 130,726	127,858	124,077	119,392	113,626	100,876	78,944	35,924
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014[Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	214,992	216,461	217,334	218,172	219,925	216,824	212,725	200,534
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 875
Short-duration Insurance Contract, Cumulative Number of Reported Claims	28,079,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 213,689	212,481	209,655	202,821	180,701	148,884	117,169	80,810
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014[Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	57,483	57,302	58,093	58,517	59,806	62,548	60,949	55,962
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 746
Short-duration Insurance Contract, Cumulative Number of Reported Claims	4,067,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 55,729	55,708	55,458	52,940	49,460	44,911	40,584	28,914
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014[Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	136,151	136,237	136,212	138,155	138,751	136,820	136,249	141,192
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 10
Short-duration Insurance Contract, Cumulative Number of Reported Claims	6,517,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 136,141	135,928	136,008	137,418	137,883	136,634	132,909	101,131
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	211,768	214,176	219,204	233,249	246,990	245,710	254,720
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 25,873
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,532
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 173,697	157,071	144,216	116,804	78,668	39,978	14,665
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	170,577	172,572	176,242	179,642	183,604	194,639	193,729
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 20,748
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,554,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 129,019	124,046	120,097	112,601	98,195	77,320	33,857
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	262,054	261,386	260,565	259,495	253,074	240,958	220,994
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 1,826
Short-duration Insurance Contract, Cumulative Number of Reported Claims	29,837,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 255,600	249,905	238,142	211,515	175,866	132,260	91,347
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	52,200	52,325	54,454	55,925	57,245	53,768	52,871
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 801
Short-duration Insurance Contract, Cumulative Number of Reported Claims	3,967,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 50,005	49,839	49,073	46,571	42,710	36,014	24,189
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	112,937	112,582	112,496	111,566	111,750	109,513	110,270
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 12
Short-duration Insurance Contract, Cumulative Number of Reported Claims	6,407,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 112,410	112,117	110,969	110,994	109,829	106,182	79,048
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	246,643	252,733	263,245	277,986	272,048	277,214
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 41,647
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,763
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 181,770	164,136	133,757	89,431	46,549	15,684
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	155,210	156,540	166,009	176,248	184,946	196,774
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 24,850
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,585,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 119,800	115,159	109,166	98,037	78,531	34,525
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	291,674	290,359	285,304	285,302	274,367	255,187
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 3,226
Short-duration Insurance Contract, Cumulative Number of Reported Claims	31,754,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 277,242	264,858	233,939	200,701	155,720	106,022
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	53,147	53,367	53,835	54,993	53,792	52,335
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 1,010
Short-duration Insurance Contract, Cumulative Number of Reported Claims	3,851,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 50,536	48,786	45,308	39,973	36,848	24,655
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	123,005	123,567	124,487	125,937	126,185	121,927
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 23
Short-duration Insurance Contract, Cumulative Number of Reported Claims	6,743,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 122,909	123,601	123,828	122,930	118,789	83,966
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	278,607	289,883	301,384	293,128	293,747
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 67,475
Short-duration Insurance Contract, Cumulative Number of Reported Claims	11,219
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 167,002	131,980	92,355	49,470	17,366
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	154,159	162,672	175,853	184,306	195,202
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 25,096
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,809,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 116,426	110,645	100,645	82,216	40,375
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	326,461	322,197	324,291	329,389	301,274
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 10,110
Short-duration Insurance Contract, Cumulative Number of Reported Claims	33,066,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 296,600	262,349	220,422	178,823	117,287
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	43,606	48,067	51,524	48,698	46,624
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 2,642
Short-duration Insurance Contract, Cumulative Number of Reported Claims	3,892,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 39,940	40,359	36,950	31,337	21,865
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	154,119	153,664	149,044	149,106	138,773
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 54
Short-duration Insurance Contract, Cumulative Number of Reported Claims	6,904,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 153,750	152,018	148,589	142,338	99,047
Standard Commercial Lines [Member] | Short-duration Insurance Contract, Accident Year 2018 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	332,013	345,224	336,326	317,934
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 126,438
Short-duration Insurance Contract, Cumulative Number of Reported Claims	11,641
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 155,538	108,421	60,784	19,531
Standard Commercial Lines [Member] | Short-duration Insurance Contract, Accident Year 2018 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	173,428	181,151	193,818	193,894
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 34,218
Short-duration Insurance Contract, Cumulative Number of Reported Claims	11,129,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 119,904	105,903	84,780	41,122
Standard Commercial Lines [Member] | Short-duration Insurance Contract, Accident Year 2018 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	350,310	345,547	352,487	347,908
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 23,671
Short-duration Insurance Contract, Cumulative Number of Reported Claims	35,714,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 291,725	243,713	193,788	134,867
Standard Commercial Lines [Member] | Short-duration Insurance Contract, Accident Year 2018 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	60,393	62,427	57,202	55,024
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 7,655
Short-duration Insurance Contract, Cumulative Number of Reported Claims	4,256,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 48,144	44,316	39,791	29,995
Standard Commercial Lines [Member] | Short-duration Insurance Contract, Accident Year 2018 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	194,016	192,558	190,834	183,177
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net	$ 98
Short-duration Insurance Contract, Cumulative Number of Reported Claims	8,289,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 193,487	192,698	184,813	135,416
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	358,301	356,363	347,150
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 196,836
Short-duration Insurance Contract, Cumulative Number of Reported Claims	11,264
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 100,206	58,284	18,097
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	174,912	188,596	188,625
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 44,549
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,307,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 100,812	77,878	37,826
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	404,854	398,346	385,212
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 63,122
Short-duration Insurance Contract, Cumulative Number of Reported Claims	36,079,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 283,410	221,590	149,538
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	64,667	59,466	53,531
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 11,556
Short-duration Insurance Contract, Cumulative Number of Reported Claims	3,616,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 46,113	41,587	27,718
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	179,574	177,075	173,826
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net	$ 530
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,300,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 177,825	172,768	130,891
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	360,302	361,554
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 252,458
Short-duration Insurance Contract, Cumulative Number of Reported Claims	9,076
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 58,699	21,858
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	168,594	168,643
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 61,878
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,495,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 68,277	29,559
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	381,163	381,654
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 121,558
Short-duration Insurance Contract, Cumulative Number of Reported Claims	30,095,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 198,034	139,016
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	73,680	71,836
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 11,225
Short-duration Insurance Contract, Cumulative Number of Reported Claims	5,364,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 57,210	43,376
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	225,278	232,060
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net	$ 4,314
Short-duration Insurance Contract, Cumulative Number of Reported Claims	10,116,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 215,107	164,613
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2021 | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	422,748
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 356,223
Short-duration Insurance Contract, Cumulative Number of Reported Claims	8,260
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 28,069
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2021 | Workers Compensation [Member]
Claims Development [Line Items]
Net outstanding liabilities	185,198
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 111,451
Short-duration Insurance Contract, Cumulative Number of Reported Claims	8,089,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 32,918
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2021 | Commercial Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	483,831
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 232,070
Short-duration Insurance Contract, Cumulative Number of Reported Claims	34,461,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 187,200
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2021 | Business Owners' Policies [Member]
Claims Development [Line Items]
Net outstanding liabilities	66,312
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 21,947
Short-duration Insurance Contract, Cumulative Number of Reported Claims	3,078,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 34,412
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2021 | Commercial Property [Member]
Claims Development [Line Items]
Net outstanding liabilities	246,319
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 36,186
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,153,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 161,757
Standard Personal Lines | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	1,058,064
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	965,301
Liability for Unpaid Claims and Claims Adjustment Expense, Net	98,476
Standard Personal Lines | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	784,488
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	745,598
Liability for Unpaid Claims and Claims Adjustment Expense, Net	44,328
Standard Personal Lines | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	5,713
Standard Personal Lines | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | Homeowners [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	5,438
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	109,546	109,634	109,701	109,795	110,300	110,294	109,324	109,832	114,921	113,771
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 5
Short-duration Insurance Contract, Cumulative Number of Reported Claims	22,333,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 109,539	109,554	109,482	109,447	109,355	107,890	102,977	94,842	82,729	63,704
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	86,533	86,519	86,567	86,483	86,330	86,271	86,667	86,560	82,744	87,260
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 35
Short-duration Insurance Contract, Cumulative Number of Reported Claims	16,944,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 85,918	85,899	85,897	85,642	85,562	85,196	84,250	82,720	79,584	69,056
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	107,754	107,803	107,916	107,680	107,759	106,703	106,225	109,620	108,417
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 72
Short-duration Insurance Contract, Cumulative Number of Reported Claims	22,376,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 107,423	107,419	106,876	106,679	105,131	100,528	92,637	80,861	61,384
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	71,955	71,948	72,318	72,148	71,714	72,145	71,494	72,528	73,670
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 38
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,750,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 72,447	72,446	72,433	72,197	71,776	69,775	67,838	65,528	50,664
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2014[Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	107,566	107,106	107,104	106,821	107,452	106,757	109,325	102,250
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 79
Short-duration Insurance Contract, Cumulative Number of Reported Claims	22,509,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 107,108	106,478	105,709	104,055	99,173	92,589	83,739	62,519
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2014[Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	83,830	83,525	83,824	83,539	83,844	83,637	82,461	80,111
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 32
Short-duration Insurance Contract, Cumulative Number of Reported Claims	8,775,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 83,321	82,831	82,836	82,583	81,664	79,751	76,007	61,561
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	98,596	98,588	98,718	99,570	100,214	99,698	96,387
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net	$ 109
Short-duration Insurance Contract, Cumulative Number of Reported Claims	20,865,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 97,761	97,275	95,997	92,102	87,163	76,470	58,725
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	74,682	74,673	74,978	74,723	76,559	76,400	76,637
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 478
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,750,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 74,096	74,052	74,079	72,927	72,202	70,078	52,589
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	99,858	99,544	101,140	100,202	98,032	92,727
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 357
Short-duration Insurance Contract, Cumulative Number of Reported Claims	19,826,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 98,977	98,080	94,372	86,752	76,823	57,961
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	60,855	61,735	61,723	62,391	60,931	60,105
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 465
Short-duration Insurance Contract, Cumulative Number of Reported Claims	6,895,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 60,449	61,187	60,082	59,546	57,333	42,252
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	103,557	103,260	103,653	105,139	101,880
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 447
Short-duration Insurance Contract, Cumulative Number of Reported Claims	20,744,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 100,521	97,628	91,479	82,730	62,854
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	68,938	70,064	70,365	67,978	59,167
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 570
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,386,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 68,078	67,767	67,193	63,290	45,466
Standard Personal Lines | Short-duration Insurance Contract, Accident Year 2018 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	112,418	112,030	113,569	111,594
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 2,100
Short-duration Insurance Contract, Cumulative Number of Reported Claims	22,682,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 107,026	99,982	89,628	69,721
Standard Personal Lines | Short-duration Insurance Contract, Accident Year 2018 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	68,931	69,832	68,526	62,961
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 1,289
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,607,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 66,634	65,348	64,137	49,430
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	115,993	115,688	114,043
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 5,649
Short-duration Insurance Contract, Cumulative Number of Reported Claims	22,845,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 102,930	92,162	69,699
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	73,816	72,772	64,306
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 3,027
Short-duration Insurance Contract, Cumulative Number of Reported Claims	7,001,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 69,911	67,631	49,680
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2020 | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	94,532	95,625
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 17,790
Short-duration Insurance Contract, Cumulative Number of Reported Claims	17,501,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 68,691	53,407
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2020 | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	112,523	109,033
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 4,829
Short-duration Insurance Contract, Cumulative Number of Reported Claims	9,791,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 105,690	83,838
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2021 | Personal Automobile [Member]
Claims Development [Line Items]
Net outstanding liabilities	108,244
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 28,461
Short-duration Insurance Contract, Cumulative Number of Reported Claims	18,931,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 65,325
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2021 | Homeowners [Member]
Claims Development [Line Items]
Net outstanding liabilities	82,425
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 15,963
Short-duration Insurance Contract, Cumulative Number of Reported Claims	6,298,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 59,054
E&S Lines [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	922,755
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	495,422
Liability for Unpaid Claims and Claims Adjustment Expense, Net	430,176
E&S Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2012 [Member] | General Liability [Member]
Claims Development [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	2,843
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	44,083	44,348	44,622	46,444	45,988	46,165	46,149	43,175	42,621	42,367
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 1,911
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,064,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 41,299	40,615	39,832	38,298	36,278	32,343	25,064	16,430	7,914	$ 3,722
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	60,349	68,029	68,451	68,972	67,647	69,112	67,099	60,309	55,468
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 3,637
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,310,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 57,152	55,988	54,974	51,142	46,108	35,200	21,980	9,470	$ 2,715
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014[Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	74,270	70,846	71,153	71,206	71,719	69,929	63,505	55,316
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 4,115
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,131,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 66,661	64,698	60,092	53,780	43,877	25,571	12,234	$ 2,353
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	87,662	90,126	90,355	90,488	82,404	76,432	75,498
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 6,293
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,875,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 75,844	71,421	64,529	50,712	29,389	13,057	$ 3,036
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	102,476	104,730	105,120	104,655	96,416	94,451
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 19,208
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,968,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 75,004	69,448	56,581	33,950	16,195	$ 3,720
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	99,960	99,395	99,866	95,783	91,438
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 16,217
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,797,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 68,266	53,238	34,179	14,672	$ 5,057
E&S Lines [Member] | Short-duration Insurance Contract, Accident Year 2018 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	104,983	103,184	103,004	98,324
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 25,673
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,762,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 57,962	39,174	21,337	$ 5,509
E&S Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	117,736	118,298	117,087
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 56,323
Short-duration Insurance Contract, Cumulative Number of Reported Claims	2,553,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 35,844	17,812	$ 4,422
E&S Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	103,137	103,872
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 71,650
Short-duration Insurance Contract, Cumulative Number of Reported Claims	1,595,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 13,064	$ 3,695
E&S Lines [Member] | Short-Duration Insurance Contract, Accident Year 2021 | General Liability [Member]
Claims Development [Line Items]
Net outstanding liabilities	128,099
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	$ 111,132
Short-duration Insurance Contract, Cumulative Number of Reported Claims	1,223,000
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 4,326

Reserve for Loss and Loss Exp_8

Reserve for Loss and Loss Expense (Reconciliation of Claims Development to Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020		Dec. 31, 2019	Dec. 31, 2018
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	$ 3,873,898
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	578,641	$ 554,269	[1]	$ 544,162	$ 537,388
Unallocated loss expenses	128,364
Gross liability for unpaid loss and loss expenses	4,580,903	$ 4,260,355		$ 4,067,163	$ 3,893,868
Standard Commercial Lines [Member] | General Liability [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	1,515,789
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	213,253
Standard Commercial Lines [Member] | Workers Compensation [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	816,606
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	196,670
Standard Commercial Lines [Member] | Commercial Automobile [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	717,704
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	15,480
Standard Commercial Lines [Member] | Business Owners' Policies [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	99,501
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	6,828
Standard Commercial Lines [Member] | Commercial Property [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	98,204
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	22,277
Standard Commercial Lines [Member] | Other Commercial [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	22,866
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	2,136
Standard Commercial Lines [Member] | Total Standard Commercial Lines [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	3,270,670
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	456,644
Standard Personal Lines | Personal Automobile [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	98,476
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	40,941
Standard Personal Lines | Homeowners [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	44,328
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	2,392
Standard Personal Lines | Other Personal [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	12,261
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	64,975
Standard Personal Lines | Standard Personal Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	155,065
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	108,308
E&S Lines [Member] | General Liability [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	430,176
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	11,672
E&S Lines [Member] | Total E&S Lines [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	448,163
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	13,689
E&S Lines [Member] | Standard Commercial Lines [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Net	17,987
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	$ 2,017
[1]	ncludes an adjustment of $2.9 million related to our adoption of ASU 2016-13, Financial Instruments - Credit Losses.

Reserve for Loss and Loss Exp_9

Reserve for Loss and Loss Expense (Historical Claims Duration) (Details) $ in Thousands	Dec. 31, 2021USD ($)
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Net outstanding liabilities	$ 12,898,946
Standard Commercial Lines [Member] | General Liability [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	6.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	11.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	15.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	17.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	14.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	9.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	6.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	5.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	1.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	1.60%
Standard Commercial Lines [Member] | Workers Compensation [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	21.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	25.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	13.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	8.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	4.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	2.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	2.30%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	3.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	1.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.80%
Standard Commercial Lines [Member] | Commercial Automobile [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	37.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	16.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	14.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	13.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	10.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	4.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	1.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.10%
Standard Commercial Lines [Member] | Business Owners' Policies [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	49.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	20.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	8.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	8.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	5.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	3.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	1.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	0.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.10%
Standard Commercial Lines [Member] | Commercial Property [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	69.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	25.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	3.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	1.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	0.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%
Standard Personal Lines | Personal Automobile [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	59.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	18.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	10.30%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	6.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	3.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	1.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	0.30%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	0.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.10%
Standard Personal Lines | Homeowners [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	71.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	21.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	3.40%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	1.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	1.60%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	0.10%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	0.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	0.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	0.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	0.00%
E&S Lines [Member] | General Liability [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Short-duration Insurance Contracts, Historical Claims Duration, Year One	3.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Two	11.20%
Short-duration Insurance Contracts, Historical Claims Duration, Year Three	16.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Four	19.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Five	14.80%
Short-duration Insurance Contracts, Historical Claims Duration, Year Six	7.90%
Short-duration Insurance Contracts, Historical Claims Duration, Year Seven	5.70%
Short-duration Insurance Contracts, Historical Claims Duration, Year Eight	3.50%
Short-duration Insurance Contracts, Historical Claims Duration, Year Nine	3.00%
Short-duration Insurance Contracts, Historical Claims Duration, Year Ten	2.00%

Indebtedness Indebtedness (Sche

Indebtedness Indebtedness (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Schedule of Debt Instruments [Line Items]
Long-term debt	$ 506,050	$ 550,743
Unamortized Debt Issuance Costs	3,167
Unamortized Debt Discount	6,233
Finance Lease, Liability	$ 5,450	508
Five Point Three Hundred Seventy Five Percent Senior Notes [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	5.375%
Long-term Debt, Gross	$ 300,000
Unamortized Debt Issuance Costs	2,733
Unamortized Debt Discount	5,670
Long-term Debt	$ 291,597	291,307
Five Point Eight Hundred Seventy Five Percent Senior Notes [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	5.875%
Long-term Debt, Gross	$ 185,000
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	3.03%
Long-term Debt, Gross	$ 60,000
Unamortized Debt Issuance Costs	0
Unamortized Debt Discount	0
Long-term Debt	$ 60,000	60,000
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	1.56%
Long-term Debt, Gross	$ 25,000
Unamortized Debt Issuance Costs	0
Unamortized Debt Discount	0
Long-term Debt	$ 0	25,000
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	1.61%
Long-term Debt, Gross	$ 25,000
Unamortized Debt Issuance Costs	0
Unamortized Debt Discount	0
Long-term Debt	$ 0	25,000
Six Point Seventy Percent Senior Notes [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	6.70%
Long-term Debt, Gross	$ 100,000
Unamortized Debt Issuance Costs	287
Unamortized Debt Discount	480
Long-term Debt	$ 99,233	99,180
Seven Point Twenty Five Percent Senior Notes [Member]
Schedule of Debt Instruments [Line Items]
Interest Rate	7.25%
Long-term Debt, Gross	$ 50,000
Unamortized Debt Issuance Costs	147
Unamortized Debt Discount	83
Long-term Debt	49,770	49,748
Finance lease obligation [Member]
Schedule of Debt Instruments [Line Items]
Finance Lease, Liability	$ 5,450	$ 508

Indebtedness (Narrative) (Detai

Indebtedness (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2005	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2004
Maximum borrowing percentage		10.00%
Borrowing threshold of FHLBI		20
Debt Issuance Costs, Gross		$ 3,300
Long-term debt		506,050	$ 550,743
Five Point Three Hundred Seventy Five Percent Senior Notes [Member]
Long-term Debt, Gross		$ 300,000
Interest Rate		5.375%
Discount for notes issued		$ 5,900
Net proceeds from the issuance		290,800
Five Point Eight Hundred Seventy Five Percent Senior Notes [Member]
Long-term Debt, Gross		$ 185,000
Interest Rate		5.875%
Debt Retirement Costs Before Tax		$ 4,200
Debt Retirement Costs Net of Tax		3,300
Proceeds From Debt Issuance After Redemption		106,000
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Long-term Debt, Gross		$ 60,000
Interest Rate		3.03%
Federal Home Loan Bank Advances			45,000
Net proceeds from the issuance			15,000
Six Point Seventy Percent Senior Notes due 2035 [Member]
Long-term Debt, Gross		$ 100,000
Interest Rate		6.70%
Acceleration of principal		$ 10,000
Discount for notes issued	$ 700
Effective yield	6.754%
Net proceeds from the issuance	$ 50,000
Seven Point Twenty Five Percent Senior Notes due 2034 [Member]
Long-term Debt, Gross		$ 50,000
Interest Rate		7.25%
Acceleration of principal		$ 10,000
Discount for notes issued				$ 100
Effective yield				7.27%
Bond proceeds to Insurance Subsidiaries as capital				$ 25,000
Line of Credit expires Dec.20, 2022 [Member]
Line of credit borrowing capacity		50,000
Line of credit, maximum borrowing capacity		125,000
Acceleration of principal		$ 20,000
Maximum borrowing percentage		10.00%
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Long-term Debt, Gross		$ 25,000
Interest Rate		1.61%
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Long-term Debt, Gross		$ 25,000
Interest Rate		1.56%
Federal Home Loan Bank of Indianapolis [Member]
Aggregate investment in FHLBI		$ 5,700	5,700
Federal Home Loan Bank of New York [Member]
Aggregate investment in FHLBI		$ 800	$ 3,100

Indebtedness (Covenants in the

Indebtedness (Covenants in the Line of Credit) (Details) $ in Thousands	Dec. 31, 2021USD ($)
Debt Disclosure [Abstract]
Consolidated Net Worth Requirement	$ 1,800,000
Consolidated Net Worth, Actual	$ 2,900,000
Debt-to-capitalization ratio, required	35.00%
Debt-to-capitalization ratio, actual	15.00%

Segment Information (Narrative)

Segment Information (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Segment Reporting [Abstract]
Number of Operating Segments	4
Goodwill	$ 7,849	$ 7,849
Percentage of net premiums written related to insurance policies written in New Jersey	18.00%

Segment Information (Revenue Fr

Segment Information (Revenue From Continuing Operations by Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Net premiums earned	$ 3,017,253	$ 2,681,814	$ 2,597,171
Other income	17,723	17,570	12,355
Net investment income	326,589	227,107	222,543
Net realized and unrealized investment gains (losses)	17,599	(4,217)	14,422
Total investment revenues	344,188	222,890	236,965
Total revenues	3,379,164	2,922,274	2,846,491
Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Other income	16,056	15,512	10,889
Total revenues	2,459,941	2,158,696	2,060,503
Standard Personal Lines
Revenue from External Customer [Line Items]
Other income	1,667	2,058	1,466
Total revenues	295,226	301,198	309,205
E&S Lines [Member]
Revenue from External Customer [Line Items]
Total revenues	279,809	239,490	239,818
Commercial Automobile [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	436,412	388,120	353,834
Workers Compensation [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	306,428	278,062	311,370
General Liability [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	807,158	694,019	669,895
Commercial Property [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	724,398	615,181	554,256
Business Owners' Policies [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	110,622	110,210	105,252
Bonds Segment [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	35,762	36,742	35,726
Other Commercial [Member] | Standard Commercial Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	23,105	20,850	19,281
Personal Automobile [Member] | Standard Personal Lines
Revenue from External Customer [Line Items]
Net premiums earned	163,007	165,020	172,606
Homeowners [Member] | Standard Personal Lines
Revenue from External Customer [Line Items]
Net premiums earned	122,526	125,405	127,543
Other Personal [Member] | Standard Personal Lines
Revenue from External Customer [Line Items]
Net premiums earned	8,026	8,715	7,590
Casualty Insurance Product Line [Member] | E&S Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	197,779	174,408	182,864
Property Insurance [Member] | E&S Lines [Member]
Revenue from External Customer [Line Items]
Net premiums earned	$ 82,030	$ 65,082	$ 56,954

Segment Information (Income Fro

Segment Information (Income From Continuing Operations, Before and After Federal Income Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net investment income	$ 326,589	$ 227,107	$ 222,543
Net realized and unrealized investment gains (losses)	17,599	(4,217)	14,422
Tax on investment income	67,284	41,609	45,301
Total investment income, after federal income tax	276,904	181,281	191,664
Total investment revenues	344,188	222,890	236,965
Standard Commercial Lines [Member]
Underwriting gain (loss), before federal income tax	198,596	151,731	145,990
Underwriting gain (loss), after federal income tax	$ 156,891	$ 119,867	$ 115,332
Combined Ratio	91.90%	92.90%	92.90%
Return on Equity	5.90%	5.10%	5.80%
Standard Personal Lines
Underwriting gain (loss), before federal income tax	$ 3,966	$ (15,508)	$ 8,260
Underwriting gain (loss), after federal income tax	$ 3,133	$ (12,251)	$ 6,525
Combined Ratio	98.60%	105.20%	97.30%
Return on Equity	0.10%	(0.50%)	0.30%
E&S Lines [Member]
Underwriting gain (loss), before federal income tax	$ 16,030	$ 126	$ 9,743
Underwriting gain (loss), after federal income tax	$ 12,664	$ 100	$ 7,697
Combined Ratio	94.30%	99.90%	95.90%
Return on Equity	0.50%	0.00%	0.40%
Investments SIGI
Return on Equity	9.90%	7.80%	9.60%

Segment Information (Reconcilia

Segment Information (Reconciliation of Segment Results to Income from Continuing Operations, before Federal Income Tax) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total investment revenues	$ 344,188	$ 222,890	$ 236,965
Interest expense	(29,165)	(30,839)	(33,668)
Corporate expenses	(28,305)	(25,412)	(30,900)
Income before federal income tax	505,310	302,988	336,390
Preferred Stock Dividends, Income Statement Impact	(9,353)	0	0
Income available to common stockholders, before tax	495,957	302,988	336,390
Standard Commercial Lines [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	198,596	151,731	145,990
Standard Personal Lines
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	3,966	(15,508)	8,260
E&S Lines [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	16,030	126	9,743
Operating Segments [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total all segments	$ 562,780	$ 359,239	$ 400,958

Earnings Per Share (Reconciliat

Earnings Per Share (Reconciliation of EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Basic EPS: [Abstract]
Net income, basic shares	60,183	59,862	59,421
Basic net income per share	$ 6.55	$ 4.12	$ 4.57
Effect of dilutive securities: [Abstract]
Stock compensation plans, shares	484	431	583
Earnings Per Share, Diluted [Abstract]
Shares net income, Diluted	60,667	60,293	60,004
Diluted net income per share	$ 6.50	$ 4.09	$ 4.53
Net Income available to common stockholders	$ 394,484	$ 246,355	$ 271,623

Federal Income Taxes (Reconcili

Federal Income Taxes (Reconciliation of Federal Income Tax on Income at the Corporate Rate to the Effective Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tax at statutory rate	$ 106,115	$ 63,627	$ 70,642
Tax-advantaged interest	(4,514)	(4,730)	(4,909)
Dividends received deduction	(558)	(514)	(443)
Federal Income Tax Expense Benefit Related to Executive Compensation	2,469	2,246	2,985
Federal Income Tax Expense (Benefit) Related to Stock-based Compensation	(693)	(1,846)	(3,253)
Other	(1,346)	(2,150)	(255)
Total federal income tax expense	101,473	56,633	64,767
Income available to common stockholders, before tax	$ 495,957	$ 302,988	$ 336,390
Effective Income Tax Rate Reconciliation, Percent	20.50%	18.70%	19.30%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%

Federal Income Taxes (Deferred

Federal Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Net loss reserve discounting	$ 60,227	$ 54,240
Net unearned premiums	68,086	60,842
Employee benefits	2,787	8,943
Long-term incentive compensation plans	5,904	5,472
Temporary investment write-downs	4,314	6,037
Other	2,245	7,195
Total deferred tax assets	143,563	142,729
Deferred policy acquisition costs	68,652	60,601
Unrealized gains on investment securities	48,082	81,142
Other investment-related items, net	27,044	14,760
Accelerated depreciation and amortization	13,198	13,322
Deferred Tax Liabilities, Total	156,976	169,825
Deferred Income Tax Liabilities, Net	(13,413)	(27,096)
Deferred tax liability
Deferred Income Tax Liabilities, Net	$ (13,413)	$ (27,096)

Retirement Plans (Retirement Sa

Retirement Plans (Retirement Savings Plan) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retirement Savings Plan [Member]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 19.2	$ 18.6	$ 17.3

Retirement Plans (Funded Status

Retirement Plans (Funded Status of Retirement Income Plan and Retirement Life Plan) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Retirement Income Plan [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.98%	2.68%
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	[1]	$ (11,882)	$ (7,778)	$ (5,033)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year		425,161	391,021
Interest cost		8,593	11,312	13,506
Actuarial losses (gains)		(12,844)	35,276
Benefits paid fair value		(13,152)	(12,448)
Benefit obligation, end of year		407,758	425,161	391,021
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of assets, beginning of year		432,716	385,087
Actual return on plan assets, net of expenses		30,741	60,077
Fair value of assets, end of year		450,305	432,716	385,087
Funded status		42,547	7,555
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Net pension asset (liability), end of year		42,547	7,555
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract]
Net actuarial loss		78,304	101,414
Weighted-Average Liability Asumptions
Accumulated benefit obligation		407,758	425,161
Retirement Life Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Contributions by the employer to funded plans		$ 19,200	$ 18,600	$ 17,300
[1]	The components of net periodic pension cost (benefit) are included within "Loss and loss expense incurred" and "Other insurance expenses" on the Consolidated Statements of Income.

Retirement Plans (Components of

Retirement Plans (Components of Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net actuarial loss (gain)		$ (21,636)	$ (1,515)	$ 13,795
Reversal of amortization of net actuarial loss		$ (2,772)	$ (3,015)	(2,657)
Retirement Income Plan [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		2.98%	2.68%
Interest cost		$ 8,593	$ 11,312	13,506
Expected return on plan assets		(22,976)	(21,907)	(21,114)
Amortization of unrecognized actuarial loss		2,501	2,817	2,575
Total net periodic cost	[1]	(11,882)	(7,778)	(5,033)
Net actuarial loss (gain)		(20,609)	(2,894)	11,643
Reversal of amortization of net actuarial loss		(2,501)	(2,817)	(2,575)
Total recognized in other comprehensive income		(23,110)	(5,711)	9,068
Total recognized in net periodic benefit cost and OCI		$ (34,992)	$ (13,489)	$ 4,035
[1]	The components of net periodic pension cost (benefit) are included within "Loss and loss expense incurred" and "Other insurance expenses" on the Consolidated Statements of Income.

Retirement Plans (Weighted-Aver

Retirement Plans (Weighted-Average Expense Assumptions) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Discount rate	2.06%	2.95%	4.12%
Change in Defined Benefit Plan Discount Rate	$ 30
Retirement Income Plan [Member]
Discount rate	2.68%	3.33%	4.46%
Expected return on plan assets	5.40%	5.80%	6.50%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.98%	2.68%

Retirement Plans (Plan's Alloca

Retirement Plans (Plan's Allocated Target Ranges and Actual Weighted Average Asset Allocation by Investment Categories) (Details)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Percent Hedge Against Projected Benefit Obligation		79.00%
Actual percentage		100.00%	100.00%
Return Seeking Assets [Member]
Actual percentage	[1]	66.00%	64.00%
Liability Hedging Assets [Member]
Actual percentage		33.00%	35.00%
Short-term Investments [Member]
Actual percentage		1.00%	1.00%
Minimum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		100.00%
Minimum [Member] | Return Seeking Assets [Member]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description		50
Minimum [Member] | Liability Hedging Assets [Member]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description		70
Minimum [Member] | Short-term Investments [Member]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description		-
Maximum [Member]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage		100.00%
Maximum [Member] | Return Seeking Assets [Member]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description		70
Maximum [Member] | Liability Hedging Assets [Member]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description		80
Maximum [Member] | Short-term Investments [Member]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description		-
[1]	Includes limited partnerships.

Retirement Plans (Quantitative

Retirement Plans (Quantitative Disclosures of Retirement Income Plan's Invested Assets that are Measured at Fair Value on a Recurring Basis) (Details) - Retirement Income Plan [Member] - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total Assets		$ 450,305	$ 432,716	$ 385,087
Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		456,502	435,761
Total Equities [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		300,389	277,667
Return Seeking Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		300,849	278,169
Liability Hedging Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		151,487	152,246
Cash And Short Term Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		4,166	5,346
Alternative Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	460	502
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		453,620	433,186
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Total Equities [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		300,389	277,667
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Return Seeking Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		300,389	277,667
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Liability Hedging Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		151,487	152,246
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Cash And Short Term Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		1,744	3,273
Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		2,422	2,073
Significant Other Observable Inputs (Level 2) [Member] | Total Equities [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Other Observable Inputs (Level 2) [Member] | Return Seeking Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Other Observable Inputs (Level 2) [Member] | Liability Hedging Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Other Observable Inputs (Level 2) [Member] | Cash And Short Term Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		2,422	2,073
Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Unobservable Inputs (Level 3) [Member] | Total Equities [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Unobservable Inputs (Level 3) [Member] | Return Seeking Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Unobservable Inputs (Level 3) [Member] | Liability Hedging Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Significant Unobservable Inputs (Level 3) [Member] | Cash And Short Term Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Global Equity [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		144,634	142,320
Global Equity [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		144,634	142,320
Global Equity [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Global Equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Diversified Credit [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		66,165	73,762
Diversified Credit [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		66,165	73,762
Diversified Credit [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Diversified Credit [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Real Assets Equity [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		89,590	61,585
Real Assets Equity [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		89,590	61,585
Real Assets Equity [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Real Assets Equity [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Real Assets [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	47	73
Real Assets [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Real Assets [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Real Assets [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Private Equity Funds [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	413	400
Private Equity Funds [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Private Equity Funds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Private Equity Funds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Private Credit Funds [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]		29
Private Credit Funds [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]		0
Private Credit Funds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]		0
Private Credit Funds [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]		0
Alternative Investments [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Alternative Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Alternative Investments [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	[1]	0	0
Fixed Income Securities [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		86,183	99,490
Fixed Income Securities [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		86,183	99,490
Fixed Income Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Fixed Income Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
US Treasury Securities [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		65,304	52,756
US Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		65,304	52,756
US Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
US Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Short-term Investments [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		1,744	3,273
Short-term Investments [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		1,744	3,273
Short-term Investments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Short-term Investments [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Deposit Administration Contracts [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		2,422	2,073
Deposit Administration Contracts [Member] | Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		0	0
Deposit Administration Contracts [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		2,422	2,073
Deposit Administration Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value, recurring [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets		$ 0	$ 0
[1]	In accordance with the FASB issued ASU 2015-07, Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) , certain investments that are measured at fair value using the net asset value per share (or its practical expedient) have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to total Pension Plan invested assets.

Retirement Plans (Benefit Payme

Retirement Plans (Benefit Payments) (Details) - Retirement Income Plan [Member] $ in Thousands	Dec. 31, 2021USD ($)
2021	$ 14,900
2022	16,099
2023	17,232
2024	18,296
2025	19,394
2026 - 2030	$ 108,742

Share-Based Payments (Summary o

Share-Based Payments (Summary of Shares Available for Issuance) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Dividend Equivalent Units [Member]
Schedule of Share-Based Compensation Shares Available for Issuance [Line Items]
Total intrinsic value of shares vested	$ 0.6	$ 0.7	$ 0.8
Omnibus Stock Plan 2014 [Member]
Schedule of Share-Based Compensation Shares Available for Issuance [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	4,750,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2,713,667
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	660,697
Employee Stock [Member]
Schedule of Share-Based Compensation Shares Available for Issuance [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	5,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,184,849
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	0
Agent Stock Purchase Plan [Member]
Schedule of Share-Based Compensation Shares Available for Issuance [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	3,000,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,608,234
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	0

Shared-Based Payments (Summary

Shared-Based Payments (Summary of Retired Plans) (Details)	Dec. 31, 2021shares
Omnibus Stock Plan [Member]
Schedule of Share-Based Compensation Retired Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,958,306
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	32,906	[1]
Stock Compensation Plan For Non Employee Directors [Member]
Schedule of Share-Based Compensation Retired Plans [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	44,468
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	44,468	[1]
[1]	Awards outstanding under the 2005 Stock Plan represent shares deferred by our non-employee directors.

Share-Based Payments (Summary_2

Share-Based Payments (Summary of the Restricted Stock Unit Transactions under Share-Based Payment Plans) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Incentive Plan [Member]
Weighted average remaining expense life	1 year 2 months 12 days
Share Based Compensation Liability Awards Amount Of Liability	$ 11	$ 8.2
Cash incentive unit payments made	$ 2.2	$ 2.3	$ 18.4
Restricted Stock Units (RSUs) [Member]
Unvested RSU awards at December 31, 2020, number of shares	667,674
Granted in 2021, number of shares	249,293
Vested in 2021, number of shares	(258,477)
Forfeited in 2021, number of shares	(16,854)
Unvested RSU awards at December 31, 2021, number of shares	641,636	667,674
Unvested RSU awards at December 31, 2020, weighted average grant date fair value	$ 61.02
Granted in 2021, weighted average grant date market value	64.03	$ 62.91	$ 63.60
Vested in 2021, weighted average grant date value	57.10
Forfeited in 2021, weighted average grant date fair value	62.61
Unvested RSU awards at December 31, 2021, weighted average grant date fair value	$ 63.73	$ 61.02
Total unrecognized compensation cost related to unvested RSU awards	$ 10.1
Weighted average remaining expense life	1 year 8 months 12 days
Total intrinsic value of shares vested	$ 17.2	$ 20.6	$ 22
Dividend Equivalent Units [Member]
Total intrinsic value of shares vested	$ 0.6	$ 0.7	$ 0.8

Share-Based Payments (Summary_3

Share-Based Payments (Summary of Stock Option Transactions under Share-Based Payment Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Total intrinsic value of options exercised	$ 1.3	$ 5.2

Shared-Based Payments (Summar_2

Shared-Based Payments (Summary of ESPP and ASPP Shares Issued) (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items]
Stock Issued During Period Shares	395,018	519,863	613,678
Employee Stock [Member]
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items]
Stock Issued During Period Shares	72,239	99,141	72,952
Agent Stock Purchase Plan [Member]
Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items]
Stock Issued During Period Shares	50,999	69,238	47,888

Share-Based Payments (Weighted

Share-Based Payments (Weighted Average Assumptions for Employee Stock Purchase Plan and Other Options) (Details) - Employee Stock Purchase Plan [Member]	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Risk-free interest rate	0.07%	0.76%	2.33%
Expected term	6 months	6 months	6 months
Dividend yield	1.40%	1.60%	1.20%
Expected volatility	28.00%	37.00%	26.00%

Share-Based Payments (Weighted-

Share-Based Payments (Weighted-Average Fair Value of Options and Stock Per Share) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock Units (RSUs) [Member]
Stock, weighted average grant date fair value	$ 64.03	$ 62.91	$ 63.60
Employee Stock Purchase Plan [Member]
Options, weighted average grant date fair value	4.69	4.82	4.32
Discount of grant date market value	10.98	8.61	9.99
Total ESPP	15.67	13.43	14.31
Agent Stock Purchase Plan [Member]
Stock, weighted average grant date fair value	$ 7.57	$ 5.73	$ 7

Shared-Based Payments (Summar_3

Shared-Based Payments (Summary of Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disclosure of Share-Based Compensation Expenses [Abstract]
Share-based compensation expense, pre-tax	$ 22.3	$ 19.8	$ 24.5
Income tax benefit, including the benefit related to stock grants that vested during the year	(5.1)	(5.7)	(8.2)
Share-based Compensation Expense, Net of Tax	$ 17.2	$ 14.1	$ 16.3

Preferred Stock Text Block List

Preferred Stock Text Block List (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Preferred Stock Shares Issued	8,000,000
Preferred Stock, Liquidation Preference, Value	$ 25
Preferred stock issued, net of issuance costs	$ (479)	$ 195,063	$ 0
Equity Text Block	Preferred Stock We have 5,000,000 shares of preferred stock authorized, with no par value, of which (i) 300,000 shares are designated Series A junior preferred stock, which have not been issued, and (ii) 8,000 shares were issued as Series B in 2020 as discussed below. On December 2, 2020, we issued 8.0 million depository shares, each representing a 1/1,000th interest in a share of our perpetual 4.60% Non-Cumulative Preferred Stock, Series B, without par value, with a liquidation preference of $25,000 per share (equivalent to $25.00 per depository share) (“Preferred Stock”), for net proceeds of $194.6 million. Dividends are recorded when declared and, if declared are payable quarterly in arrears on the 15th day of March, June, September, and December. If a dividend is not declared and paid or made payable on all outstanding shares of the Preferred Stock for the latest completed dividend period, no dividends may be declared or paid on our common stock and we may not purchase, redeem, or otherwise acquire our outstanding common stock. The Preferred Stock is redeemable at our option in whole or in part, from time to time, on or after December 15, 2025 at a redemption price equal to $25,000 per share of Preferred Stock (equivalent to $25.00 per depository share), plus unpaid dividends attributable to the then current dividend period. Prior to December 15, 2025, the Preferred Stock is redeemable at the Company’s option, in whole but not in part, within 90 days of the occurrence of (a) a rating agency event at a redemption price equal to $25,500 per share of Preferred Stock (equivalent to $25.50 per depository share), plus unpaid dividends attributable to the current dividend period in circumstances where a rating agency changes its criteria used to assign equity credit to securities like the Preferred Stock; or (b) a regulatory capital event at a redemption price equal to $25,000 per share of Preferred Stock (equivalent to $25.00 per depository share), plus unpaid dividends attributable to the current dividend period in circumstances where a capital regulator such as a state insurance regulator changes or proposes to change capital adequacy rules. Share Repurchase Program On December 2, 2020, we announced that our Board authorized a $100 million share repurchase program, which has no set expiration or termination date. Our repurchase program does not obligate us to acquire any particular amount of our common stock. The timing and amount of any share repurchases under the authorization is determined by management at its discretion based on market conditions and other considerations. As of December 31, 2021, 52,781 shares were repurchased under the share repurchase program at a total cost of $3.4 million. These repurchases were all completed in the first quarter of 2021, and we did not repurchase any shares under our share repurchase program during the remainder of 2021. We have $96.6 million of remaining capacity under our share repurchase program.
Rating Agency Event [Member]
Class of Stock [Line Items]
Depositary Share Price	$ 25.50
Preferred Stock, Redemption Price Per Share	25,500
Regulatory Capital Event [Member]
Class of Stock [Line Items]
Depositary Share Price	25
Preferred Stock, Redemption Price Per Share	$ 25,000
Proceeds from preferred stock offering; less issuance costs [Member]
Class of Stock [Line Items]
Preferred stock issued, net of issuance costs	$ 194,600
Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued		8,000
Series A [Member]
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	300,000	300,000
Series B [Member]
Class of Stock [Line Items]
Depositary Share Price	$ 25
Preferred Stock, Dividend Rate, Percentage	4.60%

Equity (Details)

Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Treasury Stock[Line Items]
Stock Repurchase Program, Authorized Amount	$ 100,000
Treasury Stock, Shares, Acquired	52,781	0	0
Treasury Stock, Value, Acquired, Cost Method	$ 3,400
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 96,600
Equity Text Block	Preferred Stock We have 5,000,000 shares of preferred stock authorized, with no par value, of which (i) 300,000 shares are designated Series A junior preferred stock, which have not been issued, and (ii) 8,000 shares were issued as Series B in 2020 as discussed below. On December 2, 2020, we issued 8.0 million depository shares, each representing a 1/1,000th interest in a share of our perpetual 4.60% Non-Cumulative Preferred Stock, Series B, without par value, with a liquidation preference of $25,000 per share (equivalent to $25.00 per depository share) (“Preferred Stock”), for net proceeds of $194.6 million. Dividends are recorded when declared and, if declared are payable quarterly in arrears on the 15th day of March, June, September, and December. If a dividend is not declared and paid or made payable on all outstanding shares of the Preferred Stock for the latest completed dividend period, no dividends may be declared or paid on our common stock and we may not purchase, redeem, or otherwise acquire our outstanding common stock. The Preferred Stock is redeemable at our option in whole or in part, from time to time, on or after December 15, 2025 at a redemption price equal to $25,000 per share of Preferred Stock (equivalent to $25.00 per depository share), plus unpaid dividends attributable to the then current dividend period. Prior to December 15, 2025, the Preferred Stock is redeemable at the Company’s option, in whole but not in part, within 90 days of the occurrence of (a) a rating agency event at a redemption price equal to $25,500 per share of Preferred Stock (equivalent to $25.50 per depository share), plus unpaid dividends attributable to the current dividend period in circumstances where a rating agency changes its criteria used to assign equity credit to securities like the Preferred Stock; or (b) a regulatory capital event at a redemption price equal to $25,000 per share of Preferred Stock (equivalent to $25.00 per depository share), plus unpaid dividends attributable to the current dividend period in circumstances where a capital regulator such as a state insurance regulator changes or proposes to change capital adequacy rules. Share Repurchase Program On December 2, 2020, we announced that our Board authorized a $100 million share repurchase program, which has no set expiration or termination date. Our repurchase program does not obligate us to acquire any particular amount of our common stock. The timing and amount of any share repurchases under the authorization is determined by management at its discretion based on market conditions and other considerations. As of December 31, 2021, 52,781 shares were repurchased under the share repurchase program at a total cost of $3.4 million. These repurchases were all completed in the first quarter of 2021, and we did not repurchase any shares under our share repurchase program during the remainder of 2021. We have $96.6 million of remaining capacity under our share repurchase program.

Related Party Transactions (Nar

Related Party Transactions (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments	$ 8,026,988	$ 7,505,599
Direct premiums written	3,656,537	3,204,512	$ 3,084,451
Contributions to the Selective Insurance Group Foundation	1,300	500	1,300
Costs and Expenses, Related Party - BlackRock	1,800	2,000	2,200
Due to Related Parties	$ 500	1,300
Related Party Insurance Agency [Member]
Equity ownership percentage of director of parent of general independent retail insurance agency	10.00%
Equity Ownership Percentage Of Son Of Director Of Parent	10.00%
Direct premiums written	$ 12,800	12,800	11,000
Commissions paid to Rue Insurance	2,000	1,800	2,000
Due to Related Parties, Current	$ 700	200
BlackRock Inc [Member]
Percentage Common Stock Owned by Related Party	11.40%
Related Party Transaction, Purchases from Related Party	$ 16,500	62,200	21,700
Sale of Related Party Investments	32,500
Net realized and unrealized gain (loss)	(600)	200	(5,700)
Investment Income (Loss), Net	900	400
Retirement Income Plan [Member] | BlackRock Inc [Member]
Investments	209,900	191,800
Related Party Transaction, Purchases from Related Party	18,000	56,700	19,700
Sale of Related Party Investments	18,100	44,900	44,100
Investment Income (Loss), Net	$ 18,200	$ 35,800	$ 36,700

Leases Components of Lease Expe

Leases Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Lease Expense [Line Items]
Operating lease cost	$ 7,935	$ 9,498
Finance lease cost: Amortization of assets	1,765	550
Finance lease cost: Interest on lease liabilities	35	15
Total finance lease cost	1,800	565
Variable lease cost	291	758
Short-term lease cost	$ 832	$ 2,011

Leases Supplemental Lease Infor

Leases Supplemental Lease Information (Details)	Dec. 31, 2021	Dec. 31, 2020
Supplemental Lease Information [Line Items]
Weighted average remaining lease term, operating leases	7 years	8 years
Weighted average remaining lease term, finance leases	2 years	2 years
Weighted average discount rate, operating leases	2.10%	2.30%
Weighted average discount rate, finance leases	0.80%	1.60%

Leases Lease Assets and Liabili

Leases Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Lease Assets and Liabilities [Abstract]
Operating leases, Other assets	$ 35,644	$ 40,215
Finance leases, Property and equipment - at cost, net of accumulated depreciation and amortization	5,446	502
Finance lease, Long-term debt	$ 5,450	$ 508
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Other liabilities	Other liabilities
Finance Lease, Right-of-Use Asset, Accumulated Amortization	Property, Plant and Equipment, Net	Property, Plant and Equipment, Net
Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Long-term debt (Note 11)	Long-term debt (Note 11)
Other Liabilities [Member]
Lease Assets and Liabilities [Abstract]
Operating leases, Other liabilities	$ 37,296	$ 41,674
Operating Lease, Liability	$ 37,296	$ 41,674

Leases Maturities of Lease Liab

Leases Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finance Lease Liability, Due Year One	$ 2,350	$ 330
Finance Lease Liability, Due Year Two	2,255	127
Finance Lease Liability, Due Year Three	795	56
Finance Lease Liability, Due Year Four	64	0
Finance Lease Liability, Due Year Five	41	0
Total finance leases due thereafter	0	0
Finance Lease Liability, total payments	5,505	513
Finance Lease imputed interest	55	5
Finance Lease Liability Not Yet Commenced	0	0
Finance Lease, Liability	5,450	508
Operating Lease Liability, Due Year One	7,235	8,372
Operating Lease Liability, Due Year Two	6,610	6,788
Operating Lease Liability, Due Year Three	5,992	5,411
Operating Lease Liability, Due Year Four	5,902	4,690
Operating Lease Liability, Due Year Five	5,967	3,572
Total operating lease due thereafter	24,356	16,234
Operating Lease Liability, total payments	56,062	45,067
Operating Lease imputed interest	2,726	3,393
Operating Lease Liability Not Yet Commenced	16,040	0
Total Lease Liability, Due Year One	9,585	8,702
Total Lease Liability, Due Year Two	8,865	6,915
Total Lease Liability, Due Year Three	6,787	5,467
Total Lease Liability, Due Year Four	5,966	4,690
Total Lease Liability, Due Year Five	6,008	3,572
Total Lease Due Thereafter	24,356	16,234
Total Lease Liability, total payments	61,567	45,580
Total imputed interest	2,781	3,398
Total lease liability not yet commenced	16,040	0
Total lease liability	42,746	42,182
Other Liabilities [Member]
Operating Lease, Liability	37,296	41,674
Operating Lease, Liability	$ 37,296	$ 41,674

Commitments and Contingencies (

Commitments and Contingencies (Narrative) (Details) $ in Thousands	Dec. 31, 2021USD ($)
Total contractually obligated investments
Contractual Obligation Additional Investment in Alternative or Other Investments	$ 288,800
Alternative and Other Investments
Contractual Obligation Additional Investment in Alternative or Other Investments	215,000
Non-publicly traded collateralized loan obligations in our fixed income securities portfolio
Contractual Obligation	59,800
Non-publicly traded common stock within our equity portfolio
Contractual Obligation	4,200
Commercial Mortgage Loans SIGI
Contractual Obligation	5,500
Privately placed corporate securities
Contractual Obligation	$ 4,300

Commitments and Contingencies S

Commitments and Contingencies Stuctured Settlement Annuity (Details) $ in Millions	Dec. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Purchase Amount Of Annuities	$ 31.6

Statutory Financial Informati_3

Statutory Financial Information, Capital Requirements and Restrictions on Dividends and Transfers of Funds (Statutory Financial Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statutory unassigned surplus	$ 1,825.4	$ 1,559.1
Statutory surplus	2,391	2,124.7
Statutory net income	338.3	242.4	$ 292.7
Selective Insurace Company of America (SICA) [Member]
Statutory unassigned surplus	673.1	574.2
Statutory surplus	838.3	739.4
Statutory net income	134.7	81.8	113.9
Selective Way Insurance Company (SWIC) [Member]
Statutory unassigned surplus	436.4	374
Statutory surplus	492.4	430
Statutory net income	74.5	54	59.2
Selective Insurance Company of South Carolina (SICSC) [Member]
Statutory unassigned surplus	166.3	148.6
Statutory surplus	200.6	182.8
Statutory net income	24.2	20.8	23.9
Selective Insurance Company of the Southeast (SICSE) [Member]
Statutory unassigned surplus	132.7	115.9
Statutory surplus	160.3	143.5
Statutory net income	19.4	16.8	18.5
Selective Insurance Company of New York (SICNY) [Member]
Statutory unassigned surplus	127	111.7
Statutory surplus	154.7	139.4
Statutory net income	18.6	15.3	17
Selective Insurance Company of New England (SICNE) [Member]
Statutory unassigned surplus	34.5	30
Statutory surplus	65.6	61.2
Statutory net income	7.5	6.8	7.8
Selective Auto Insurance Company of New Jersey (SAICNJ) [Member]
Statutory unassigned surplus	90.4	70
Statutory surplus	135.2	114.9
Statutory net income	16.7	12.9	14.9
Mesa Underwriting Specialty Insurance Company (MUSIC) [Member]
Statutory unassigned surplus	47.4	34.4
Statutory surplus	116.9	103.9
Statutory net income	13.9	11.4	13.2
Selective Casualty Insurance Company (SCIC) [Member]
Statutory unassigned surplus	83.4	71.1
Statutory surplus	159.9	147.5
Statutory net income	20.6	16.2	16.8
Selective Fire and Casualty Insurance Company (SFCIC) [Member]
Statutory unassigned surplus	34.2	29.2
Statutory surplus	67.1	62.1
Statutory net income	$ 8.2	$ 6.4	$ 7.5

Statutory Financial Informati_4

Statutory Financial Information, Capital Requirements, and Restrictions on Dividends and Transfers of Funds (Dividends) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Retained Earnings	$ 2,603,472	$ 2,271,537
Ordinary dividends paid	140,000
Insurance subsidiaries ability to provide annual dividends	$ 322,000
Maximum borrowing percentage	10.00%
New Jersey Dividend Restriction	10.00%
New York Dividend Restriction on Insurer's Statutory Surplus	10.00%
New York Dividend Restriction on Adjusted Net Investment Income	100.00%
Selective Insurace Company of America (SICA) [Member]
Ordinary dividends paid	$ 66,000
Insurance subsidiaries ability to provide annual dividends	124,400
Selective Way Insurance Company (SWIC) [Member]
Ordinary dividends paid	27,500
Insurance subsidiaries ability to provide annual dividends	72,800
Selective Insurance Company of South Carolina (SICSC) [Member]
Ordinary dividends paid	10,000
Insurance subsidiaries ability to provide annual dividends	24,200
Selective Insurance Company of the Southeast (SICSE) [Member]
Ordinary dividends paid	8,800
Insurance subsidiaries ability to provide annual dividends	19,400
Selective Insurance Company of New York (SICNY) [Member]
Ordinary dividends paid	4,000
Insurance subsidiaries ability to provide annual dividends	15,500
Selective Insurance Company of New England (SICNE) [Member]
Ordinary dividends paid	3,000
Insurance subsidiaries ability to provide annual dividends	7,500
Selective Auto Insurance Company of New Jersey (SAICNJ) [Member]
Ordinary dividends paid	700
Insurance subsidiaries ability to provide annual dividends	16,800
Mesa Underwriting Specialty Insurance Company (MUSIC) [Member]
Ordinary dividends paid	6,100
Insurance subsidiaries ability to provide annual dividends	13,700
Selective Casualty Insurance Company (SCIC) [Member]
Ordinary dividends paid	10,400
Insurance subsidiaries ability to provide annual dividends	19,500
Selective Fire and Casualty Insurance Company (SFCIC) [Member]
Ordinary dividends paid	3,500
Insurance subsidiaries ability to provide annual dividends	8,200
Parent Company [Member]
Investments and Cash Available to fund future dividend and interest payments	527,100
Retained Earnings	2,600,000
Additional Borrowing Capacity for Parent	$ 109,900

Schedule I - Summary of Inves_2

Schedule I - Summary of Investments - Other Than Investments in Related Parties (Details) $ in Thousands	Dec. 31, 2021USD ($)
Amortized Cost or Cost	$ 7,781,136
Carrying Amount	8,026,988
Short-term Investments [Member]
Amortized Cost or Cost	447,862
Carrying Amount	447,863
Other Investments [Member]
Amortized Cost or Cost	409,032
Carrying Amount	409,032
Held-to-maturity Securities [Member] | Obligations of States and Political Subdivisions [Member]
Amortized Cost or Cost	3,442
Fair Value	3,576
Carrying Amount	3,440
Held-to-maturity Securities [Member] | Public Utilities
Amortized Cost or Cost	1,345
Fair Value	1,368
Carrying Amount	1,352
Held-to-maturity Securities [Member] | All other corporate securities
Amortized Cost or Cost	24,067
Fair Value	24,516
Carrying Amount	23,993
Held-to-maturity Securities [Member] | Fixed Income Securities [Member]
Amortized Cost or Cost	28,854
Fair Value	29,460
Carrying Amount	28,785
AFS Fixed Income Securities [Member] | US Government Agencies Debt Securities [Member]
Amortized Cost or Cost	127,974
Fair Value	130,458
Carrying Amount	130,458
AFS Fixed Income Securities [Member] | Foreign Government
Amortized Cost or Cost	15,420
Fair Value	15,860
Carrying Amount	15,860
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member]
Amortized Cost or Cost	1,121,422
Fair Value	1,189,308
Carrying Amount	1,189,308
AFS Fixed Income Securities [Member] | Public Utilities
Amortized Cost or Cost	119,980
Fair Value	122,329
Carrying Amount	122,329
AFS Fixed Income Securities [Member] | All other corporate securities
Amortized Cost or Cost	2,358,369
Fair Value	2,451,274
Carrying Amount	2,451,274
AFS Fixed Income Securities [Member] | CLO and Other ABS
Amortized Cost or Cost	1,343,687
Fair Value	1,350,814
Carrying Amount	1,350,814
AFS Fixed Income Securities [Member] | Commercial Mortgage-backed Securities (CMBS) [Member]
Amortized Cost or Cost	756,280
Fair Value	776,252
Carrying Amount	776,252
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member]
Amortized Cost or Cost	647,621
Fair Value	673,681
Carrying Amount	673,681
AFS Fixed Income Securities [Member] | Fixed Income Securities [Member]
Amortized Cost or Cost	6,490,753
Fair Value	6,709,976
Carrying Amount	6,709,976
Equity Securities [Member] | Banks, trusts, and insurance companies
Amortized Cost or Cost	45,537
Fair Value	44,086
Carrying Amount	44,086
Equity Securities [Member] | Industrial, miscellaneous and all other
Amortized Cost or Cost	261,343
Fair Value	289,363
Carrying Amount	289,363
Equity Securities [Member] | Preferred Stock [Member]
Amortized Cost or Cost	1,960
Fair Value	2,088
Carrying Amount	2,088
Equity Securities [Member] | Equity Securities [Member]
Amortized Cost or Cost	308,840
Fair Value	335,537
Carrying Amount	335,537
Commercial Mortgage Loans [Member]
Amortized Cost or Cost	95,795
Carrying Amount	$ 95,795

Parent Corporation Balance Shee

Parent Corporation Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Fixed Income Securities, Available-for-sale, at fair value	$ 6,709,976	$ 6,455,928
Equity securities	335,537	310,367
Short-term investments	447,863	409,852
Other investments	409,032	266,322
Cash	455	394
Current federal income tax	772	0
Other assets	195,240	153,919
Total assets	10,461,389	9,687,913
Liabilities:
Long-term debt	506,050	550,743
Other liabilities	453,874	363,670
Total liabilities	7,478,504	6,949,024
Stockholders’ Equity:
Preferred stock of $0 par value per share (Note 17): Authorized shares: 5,000,000; Issued shares: 8,000 with $25,000 liquidation preference per share - 2021; no shares issued or outstanding - 2020	200,000	200,000
Common stock of $2 par value per share Authorized shares: 360,000,000 Issued: 104,450,916 - 2021; 104,032,912 - 2020	208,902	208,066
Additional paid-in capital	464,347	438,985
Retained earnings	2,603,472	2,271,537
Accumulated other comprehensive income	115,099	220,186
Treasury Stock, at cost	(608,935)	(599,885)
Total stockholders’ equity	2,982,885	2,738,889	$ 2,194,936
Total liabilities and stockholders’ equity	10,461,389	9,687,913
Parent Company [Member]
ASSETS
Fixed Income Securities, Available-for-sale, at fair value	325,014	290,428
Equity securities	136,362	159,524
Short-term investments	56,042	36,425
Other investments	9,241	3,392
Cash	455	394	$ 300	$ 505
Investment in subsidiaries	2,954,725	2,754,012
Current federal income tax	7,208	11,040
Deferred federal income tax	4,487	2,218
Other assets	9,178	1,959
Total assets	3,502,712	3,259,392
Liabilities:
Long-term debt	440,600	440,235
Intercompany notes payable	57,980	59,611
Accrued long-term stock compensation	10,965	8,238
Other liabilities	10,282	12,419
Total liabilities	519,827	520,503
Stockholders’ Equity:
Preferred stock of $0 par value per share (Note 17): Authorized shares: 5,000,000; Issued shares: 8,000 with $25,000 liquidation preference per share - 2021; no shares issued or outstanding - 2020	200,000	200,000
Common stock of $2 par value per share Authorized shares: 360,000,000 Issued: 104,450,916 - 2021; 104,032,912 - 2020	208,902	208,066
Additional paid-in capital	464,347	438,985
Retained earnings	2,603,472	2,271,537
Accumulated other comprehensive income	115,099	220,186
Treasury Stock, at cost	(608,935)	(599,885)
Total stockholders’ equity	2,982,885	2,738,889
Total liabilities and stockholders’ equity	$ 3,502,712	$ 3,259,392

Parent Corporation Balance Sh_2

Parent Corporation Balance Sheets (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fixed Income Securities, Available-for-sale, Allowance for Credit Loss	$ (9,724)	$ (3,969)	$ 0
Fixed income securities, Available-For-Sale, Amortized Cost	$ 6,490,753	$ 6,073,517
Series B [Member]
Preferred Stock, Liquidation Preference (in dollars per share)	$ 25,000
Treasury Stock, Common
Treasury Stock, Shares	44,266,534	44,127,109
Common Stock [Member]
Common Stock, Par or Stated Value (in dollars per share)	$ 2	$ 2
Common Stock, Shares Authorized	360,000,000	360,000,000
Common Stock, Shares, Issued	104,450,916	104,032,912
Preferred Stock [Member]
Preferred Stock, Par or Stated Value (in dollars per share)	$ 0	$ 0
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued		8,000
Parent Company [Member]
Fixed Income Securities, Available-for-sale, Allowance for Credit Loss	$ 542
Fixed income securities, Available-For-Sale, Amortized Cost	$ 317,703

Parent Corporation Statements o

Parent Corporation Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues:
Net investment income earned	$ 326,589	$ 227,107	$ 222,543
Total revenues	3,379,164	2,922,274	2,846,491
Expenses:
Interest expense	29,165	30,839	33,668
Total expenses	2,873,854	2,619,286	2,510,101
Income before federal income tax	505,310	302,988	336,390
Federal income tax (benefit) expense:
Current	87,335	60,059	60,640
Deferred	14,138	(3,426)	4,127
Total federal income tax benefit	101,473	56,633	64,767
Net income	403,837	246,355	271,623
Preferred stock dividends	9,353	0	0
Net Income available to common stockholders	394,484	246,355	271,623
Parent Company [Member]
Revenues:
Dividends from subsidaries	140,018	104,992	110,004
Net investment income earned	15,454	7,579	7,301
Net realized and unrealized investment gains	1,898	1,756	207
Total revenues	157,370	114,327	117,512
Expenses:
Interest expense	28,988	29,220	33,426
Other expenses	28,305	25,412	30,900
Total expenses	57,293	54,632	64,326
Income before federal income tax	100,077	59,695	53,186
Federal income tax (benefit) expense:
Current	(6,552)	(10,987)	(16,080)
Deferred	12	473	3,606
Total federal income tax benefit	(6,540)	(10,514)	(12,474)
Net income before equity in undistributed income of subsidiaries	106,617	70,209	65,660
Equity In Undistributed Income Of Continuing Subsidiaries, Net Of Tax	297,220	176,146	205,963
Net income	403,837	246,355	271,623
Preferred stock dividends	9,353	0	0
Net Income available to common stockholders	$ 394,484	$ 246,355	$ 271,623

Parent Corporation Statements_2

Parent Corporation Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net income	$ 403,837	$ 246,355	$ 271,623
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Stock-based compensation expense	15,893	16,227	19,077
Undistributed losses of equity method investments	(69,873)	(12,408)	(12,773)
Amortization - other	55,109	59,350	55,205
Changes in assets and liabilities:
Decrease in net federal income taxes	(542)	7,708	7,721
Increase in other assets	(33,379)	(27,927)	(39,337)
(Decrease) increase in other liabilities	78,121	27,897	34,998
Investing Activities
Purchase of fixed income securities, available-for-sale	(2,165,555)	(1,723,818)	(1,856,125)
Purchase of short-term investments	(4,345,140)	(5,762,725)	(6,087,909)
Purchase of other investments	(85,044)	(79,598)	(64,908)
Redemption and maturities of fixed income securities, available-for-sale	1,217,555	1,019,132	626,686
Sale of fixed income securities, available-for-sale	502,911	487,087	594,743
Sale of equity securities	99,235	1,320	137,294
Sale of short-term investments	4,306,684	5,635,463	6,129,885
Proceeds from Sale of Other Investments	959	0	0
Financing Activities
Dividends to preferred stockholders	(9,353)	0	0
Dividends to common stockholders	(60,136)	(54,486)	(47,675)
Acquisition of treasury stock	(9,050)	(7,053)	(8,164)
Net proceeds from stock purchase and compensation plans	7,976	8,411	8,243
Preferred stock issued, net of issuance costs	(479)	195,063	0
Cash, beginning of year	394
Cash, end of year	455	394
Payments to Acquire Equity Securities, FV-NI	(88,640)	(230,813)	(46,397)
Parent Company [Member]
Operating Activities
Net income	403,837	246,355	271,623
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in undistributed income of subsidiaries, net of tax	(297,220)	(176,146)	(205,963)
Stock-based compensation expense	15,893	16,227	19,077
Net realized and unrealized investment gains	(1,898)	(1,756)	(207)
Undistributed losses of equity method investments	(1,859)	672	0
Amortization - other	1,076	1,080	4,614
Changes in assets and liabilities:
Increase (decrease) in accrued long-term stock compensation	2,727	(366)	(12,970)
Decrease in net federal income taxes	3,843	5,549	1,651
Increase in other assets	(7,251)	(317)	(533)
(Decrease) increase in other liabilities	(1,742)	(390)	3,919
Net cash provided by operating activities	117,406	90,908	81,211
Investing Activities
Purchase of fixed income securities, available-for-sale	(113,829)	(89,726)	(153,482)
Purchase of short-term investments	(330,843)	(523,961)	(1,116,766)
Purchase of other investments	(4,949)	(4,065)	0
Redemption and maturities of fixed income securities, available-for-sale	51,524	26,877	10,579
Sale of fixed income securities, available-for-sale	15,713	23,276	20,189
Sale of equity securities	31,204	0	10,828
Sale of short-term investments	311,225	523,813	1,116,253
Capital contribution to subsidiaries	0	(30,000)	0
Net cash used in investing activities	(44,672)	(231,197)	(123,223)
Financing Activities
Dividends to preferred stockholders	(9,353)	0	0
Dividends to common stockholders	(60,136)	(54,486)	(47,675)
Acquisition of treasury stock	(9,050)	(7,053)	(8,164)
Proceeds from borrowings	0	50,000	290,757
Repayment of borrowings	0	(50,000)	(185,000)
Net proceeds from stock purchase and compensation plans	7,976	8,411	8,243
Preferred stock issued, net of issuance costs	(479)	195,063	0
Principal payments of borrowings from subsidiaries	(1,631)	(1,552)	(16,354)
Net cash (used in) provided by financing activities	(72,673)	140,383	41,807
Net increase (decrease) in cash	61	94	(205)
Cash, beginning of year	394	300	505
Cash, end of year	455	394	300
Payments to Acquire Equity Securities, FV-NI	$ (5,676)	$ (157,411)	$ (10,824)

Schedule III - Supplementary _2

Schedule III - Supplementary Insurance Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Deferred policy acquisition costs		$ 326,915		$ 288,578		$ 271,186
Reserve for loss and loss expenses		4,580,903		4,260,355		4,067,163
Unearned premiums		1,803,207		1,618,271		1,523,167
Net premiums earned		3,017,253		2,681,814		2,597,171
Net investment income	[1]	344,188		222,890		236,965
Loss and loss expense incurred		1,813,984		1,635,823		1,551,491
Amortization of deferred policy acquisition costs		626,469		560,271		535,973
Other operating expenses		358,208	[2]	349,371	[3]	345,714	[4]
Net premiums written		3,189,713		2,773,092		2,679,424
Other insurance expenses		375,931		366,941		358,069
Other income		17,723		17,570		12,355
Standard Commercial Lines [Member]
Deferred policy acquisition costs		279,850		246,494		226,464
Reserve for loss and loss expenses		3,832,151		3,596,340		3,436,363
Unearned premiums		1,346,809		1,196,243		1,108,009
Net premiums earned		2,443,885		2,143,184		2,049,614
Net investment income		0		0		0
Loss and loss expense incurred		1,426,768		1,245,627		1,187,856
Amortization of deferred policy acquisition costs		539,606		474,322		445,661
Other operating expenses		278,915		271,504		270,107
Net premiums written		2,593,018		2,230,636		2,137,071
Other income		16,056		15,512		10,889
E&S Lines [Member]
Deferred policy acquisition costs		34,154		28,281		27,874
Reserve for loss and loss expenses		478,686		435,667		406,600
Unearned premiums		139,122		113,845		106,033
Net premiums earned		279,809		239,490		239,818
Net investment income		0		0		0
Loss and loss expense incurred		175,100		156,936		152,335
Amortization of deferred policy acquisition costs		60,945		55,255		55,835
Other operating expenses		27,734		27,173		21,905
Net premiums written		304,430		247,290		237,761
Miscellaneous Income [Member]
Other income		17,723		17,570		12,355
Standard Personal Lines
Deferred policy acquisition costs		12,911		13,803		16,848
Reserve for loss and loss expenses		270,066		228,348		224,200
Unearned premiums		317,276		308,183		309,125
Net premiums earned		293,559		299,140		307,739
Net investment income		0		0		0
Loss and loss expense incurred		212,116		233,260		211,300
Amortization of deferred policy acquisition costs		25,918		30,694		34,477
Other operating expenses		51,559		50,694		53,702
Net premiums written		292,265		295,166		304,592
Other income		1,667		2,058		1,466
Investments SIGI
Deferred policy acquisition costs		0		0		0
Reserve for loss and loss expenses		0		0		0
Unearned premiums		0		0		0
Net premiums earned		0		0		0
Net investment income	[1]	344,188		222,890		236,965
Loss and loss expense incurred		0		0		0
Amortization of deferred policy acquisition costs		0		0		0
Other operating expenses		0		0		0
Net premiums written		$ 0		$ 0		$ 0
[1]	Includes “Net investment income earned” and “Net realized and unrealized investment gains (losses)” on the Consolidated Statements of Income.
[2]	“Other operating expenses” of $358,208 reconciles to the Consolidated Statements of Income
[3]	“Other operating expenses” of $349,371 reconciles to the Consolidated Statements of Income
[4]	“Other operating expenses” of $345,714 reconciles to the Consolidated Statements of Income

Schedule IV - Reinsurance (Deta

Schedule IV - Reinsurance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Direct Amount	$ 3,472,715	$ 3,108,687	$ 2,993,157
Assumed From Other Companies	21,550	25,010	24,399
Ceded to Other Companies	477,012	451,883	420,385
Net premiums earned	$ 3,017,253	$ 2,681,814	$ 2,597,171
Percentage of Amount Assumed to Net	1.00%	1.00%	1.00%
Accident and Health Insurance Segment [Member]
Direct Amount	$ 2	$ 13	$ 17
Assumed From Other Companies	0	0	0
Ceded to Other Companies	2	13	17
Net premiums earned	$ 0	$ 0	$ 0
Percentage of Amount Assumed to Net	0.00%	0.00%	0.00%
Property and liability insurance [Member]
Direct Amount	$ 3,472,713	$ 3,108,674	$ 2,993,140
Assumed From Other Companies	21,550	25,010	24,399
Ceded to Other Companies	477,010	451,870	420,368
Net premiums earned	$ 3,017,253	$ 2,681,814	$ 2,597,171
Percentage of Amount Assumed to Net	1.00%	1.00%	1.00%

Schedule V - Allowance for Un_2

Schedule V - Allowance for Uncollectible Premiums and Other Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020
Balance, January 1	$ 22,777	$ 10,800	$ 13,900
Balance, December 31	15,200	22,777	10,800
Additions	1,766	17,576	2,730
Deductions	(9,343)	(3,754)	(5,830)
Accounting Standards Update 2016-13 [Member]
Balance, January 1		1,845	0
Balance, December 31			1,845
Cumulative effect adjustment				$ 0
Accounting Standards Update 2016-13 [Member] | Premiums Receivable [Member]
Balance, January 1	$ 22,777	8,955	13,900
Balance, December 31		$ 22,777	$ 8,955