Selective Insurance (SIGI) 10-Q 28 Oct 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 15, 2021
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,123,535
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000230557
Current Fiscal Year End Date	--12-31
Noncumulative Preferred Stock
Document Information [Line Items]
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
Trading Symbol	SIGIP
Security Exchange Name	NASDAQ
Common Stock [Member]
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $2 per share
Trading Symbol	SIGI
Security Exchange Name	NASDAQ

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
ASSETS
Fixed income securities, held-to-maturity, net of allowance for credit losses	$ 25,323	$ 16,846
Fixed income securities, held-to-maturity, allowance for credit losses	(71)	(22)
Total HTM fixed income securities carrying value	25,252	16,824
Fixed income securities, available-for-sale, at fair value	6,677,070	6,455,928
Commercial mortgage loans, carrying value, Gross	83,993	46,306
Less: allowance for credit losses	0	0
Commercial mortgage loans, net of allowance for credit losses	83,993	46,306
Equity Securities, fair value	324,186	310,367
Short-term investments	355,937	409,852
Other investments	392,788	266,322
Total investments (Note 4 and 5)	7,859,226	7,505,599
Cash	477	394
Restricted cash	34,312	14,837
Interest and dividends due or accrued	46,082	45,004
Premiums receivable	1,001,331	857,014
Less: allowance for credit losses (Note 6)	(16,500)	(21,000)
Premiums receivable, net of allowance for credit losses	984,831	836,014
Reinsurance recoverable	687,812	589,269
Allowance for credit losses	(1,595)	(1,777)
Reinsurance recoverables, net of allowance for credit losses	686,217	587,492
Prepaid reinsurance premiums	187,969	170,531
Current federal income tax	1,220	0
Property and equipment, at cost, net of accumulated depreciation and amortization	75,014	77,696
Deferred policy acquisition costs	333,995	288,578
Goodwill	7,849	7,849
Other assets	224,982	153,919
Total assets	10,442,174	9,687,913
Liabilities And Stockholders' Equity
Reserve for loss and loss expense (Note 8)	4,610,340	4,260,355
Unearned premiums	1,847,273	1,618,271
Long-term Debt	500,904	550,743
Current federal income tax	0	14,021
Deferred federal income tax	3,215	27,096
Accrued salaries and benefits	113,708	114,868
Other liabilities	444,638	363,670
Total liabilities	7,520,078	6,949,024
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: 104,389,125 - 2021; 104,032,912 - 2020	208,778	208,066
Additional paid-in capital	458,143	438,985
Retained Earnings	2,523,810	2,271,537
Accumulated Other Comprehensive Income (Note 11)	140,224	220,186
Treasury Stock, at cost. Shares: 44,265,590 - 2021; 44,127,109 - 2020. (Note 12)	(608,859)	(599,885)
Total stockholders' equity	2,922,096	2,738,889
Commitments and contingencies
Total liabilities and stockholders' equity	$ 10,442,174	$ 9,687,913

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Net premiums earned	$ 767,247	$ 694,541	$ 2,232,725	$ 1,976,915
Net investment income earned	93,032	68,185	246,479	158,596
Net realized and unrealized investment gains (losses)	177	7,721	15,353	(24,296)
Other income	4,588	6,119	14,912	12,627
Total revenues	865,044	776,566	2,509,469	2,123,842
Expenses:
Loss and loss expense incurred	505,269	447,802	1,340,293	1,252,075
Amortization of deferred policy acquisition costs	160,868	142,291	464,276	415,723
Other insurance expenses	94,759	89,530	278,531	269,477
Interest expense	7,242	7,781	21,967	23,310
Corporate expenses	4,270	3,905	22,936	19,310
Total expenses	772,408	691,309	2,128,003	1,979,895
Income before federal income tax	92,636	85,257	381,466	143,947
Federal income tax expense:
Current	18,878	17,412	79,319	25,948
Deferred	53	(2,030)	(2,711)	(1,295)
Total federal income tax expense	18,931	15,382	76,608	24,653
Net income	73,705	69,875	304,858	119,294
Preferred stock dividends	2,300	0	7,053	0
Net Income available to common stockholders	$ 71,405	$ 69,875	$ 297,805	$ 119,294
Earnings per common share:
Net income available to common stockholders - Basic	$ 1.19	$ 1.17	$ 4.95	$ 1.99
Net income available to common stockholders - Diluted	$ 1.18	$ 1.16	$ 4.92	$ 1.98

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income	$ 73,705	$ 69,875	$ 304,858	$ 119,294
Unrealized holding (losses) gains arising during period	(27,875)	29,889	(81,402)	104,771
Unrealized (losses) gains on securities with credit loss recognized in earnings	(1,851)	7,299	(2,906)	(14,751)
Amounts reclassified into net income: Held-to-maturity securities	1	0	(3)	(5)
Amounts reclassified into net income: Net realized (gains) losses on disposals and intent-to-sell AFS securities	(1,024)	(406)	(501)	7,210
Amounts reclassified into net income: Credit loss (benefit) expense	1,054	(2,254)	3,207	6,328
Total Unrealized (Losses) Gains on Investment Securities, Net	(29,695)	34,528	(81,605)	103,553
Amount reclassified into net income: Net actuarial loss	548	596	1,643	1,787
Total defined benefit pension and post-retirement plans, Net	548	596	1,643	1,787
Other Comprehensive (loss) income	(29,147)	35,124	(79,962)	105,340
Comprehensive Income	$ 44,558	$ 104,999	$ 224,896	$ 224,634

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional paid-in capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Accounting Standards Update 2016-13 [Member]	Retained Earnings [Member]Cumulative Effect, Period of Adoption, Adjustment	Accumulated other comprehensive income (loss) [Member]	Treasury stock [Member]	Preferred Stock
Preferred Stock, Shares Outstanding	0
Beginning of year at Dec. 31, 2019		$ 206,968	$ 418,521	$ 2,080,529	$ 1,435	$ 2,081,964	$ 81,750	$ (592,832)	$ 0
Issuance of preferred stock									0
Dividend reinvestment plan		44	1,216
Stock purchase and compensation plans		911	19,137
Net income	$ 119,294			119,294
Dividends to preferred stockholders				0
Dividends to common stockholders				(41,661)
Other comprehensive (loss) income	105,340						105,340
Acquisition of treasury stock - shares acquired related to employee-share based compensation plans								(7,039)
End of period at Sep. 30, 2020	$ 2,393,613	207,923	438,874	2,159,597			187,090	(599,871)	$ 0
Dividends declared per share to preferred stockholders	$ 0
Dividends declared per share to common stockholders	$ 0.69
Stock Issued During Period, Shares, New Issues									0
Common stock, shares outstanding, beginning of period at Dec. 31, 2019	59,461,153
Dividend reinvestment plan, shares	21,900
Stock purchase and compensation plan, shares	455,537
Acquisition of treasury stock, share repurchase authorization	0
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans	(103,888)
Common stock, shares outstanding, end of period at Sep. 30, 2020	59,834,702
Preferred Stock, Shares Outstanding	0
Beginning of year at Jun. 30, 2020		207,875	435,019	2,103,629	0	2,103,629	151,966	(599,814)	$ 0
Issuance of preferred stock									0
Dividend reinvestment plan		14	401
Stock purchase and compensation plans		34	3,454
Net income	$ 69,875			69,875
Dividends to preferred stockholders				0
Dividends to common stockholders				(13,907)
Other comprehensive (loss) income	35,124						35,124
Acquisition of treasury stock - share repurchase authorization								0
Acquisition of treasury stock - shares acquired related to employee-share based compensation plans								(57)
End of period at Sep. 30, 2020	$ 2,393,613	207,923	438,874	2,159,597			187,090	(599,871)	$ 0
Dividends declared per share to preferred stockholders	$ 0
Dividends declared per share to common stockholders	$ 0.23
Stock Issued During Period, Shares, New Issues									0
Common stock, shares outstanding, beginning of period at Jun. 30, 2020	59,811,742
Dividend reinvestment plan, shares	7,026
Stock purchase and compensation plan, shares	16,936
Acquisition of treasury stock, share repurchase authorization	0
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans	(1,002)
Common stock, shares outstanding, end of period at Sep. 30, 2020	59,834,702
Preferred Stock, Shares Outstanding	0
Preferred Stock, Shares Outstanding	8,000
Beginning of year at Dec. 31, 2020	$ 2,738,889	208,066	438,985	2,271,537	0	2,271,537	220,186	(599,885)	$ 200,000
Issuance of preferred stock									0
Dividend reinvestment plan		34	1,261
Stock purchase and compensation plans		678	17,897
Net income	304,858			304,858
Dividends to preferred stockholders				(7,053)
Dividends to common stockholders				(45,532)
Other comprehensive (loss) income	(79,962)						(79,962)
Acquisition of treasury stock - share repurchase authorization	(3,400)							(3,404)
Acquisition of treasury stock - shares acquired related to employee-share based compensation plans								(5,570)
End of period at Sep. 30, 2021	$ 2,922,096	208,778	458,143	2,523,810			140,224	(608,859)	$ 200,000
Dividends declared per share to preferred stockholders	$ 881.67
Dividends declared per share to common stockholders	$ 0.75
Stock Issued During Period, Shares, New Issues									0
Common stock, shares outstanding, beginning of period at Dec. 31, 2020	59,905,803
Dividend reinvestment plan, shares	17,152
Stock purchase and compensation plan, shares	339,061
Acquisition of treasury stock, share repurchase authorization	(52,781)
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans	(85,700)
Common stock, shares outstanding, end of period at Sep. 30, 2021	60,123,535
Preferred Stock, Shares Outstanding	8,000
Beginning of year at Jun. 30, 2021		208,742	454,459	2,467,596	$ 0	$ 2,467,596	169,371	(608,801)	$ 200,000
Issuance of preferred stock									0
Dividend reinvestment plan		10	416
Stock purchase and compensation plans		26	3,268
Net income	$ 73,705			73,705
Dividends to preferred stockholders				(2,300)
Dividends to common stockholders				(15,191)
Other comprehensive (loss) income	(29,147)						(29,147)
Acquisition of treasury stock - share repurchase authorization								0
Acquisition of treasury stock - shares acquired related to employee-share based compensation plans								(58)
End of period at Sep. 30, 2021	$ 2,922,096	$ 208,778	$ 458,143	$ 2,523,810			$ 140,224	$ (608,859)	$ 200,000
Dividends declared per share to preferred stockholders	$ 287.50
Dividends declared per share to common stockholders	$ 0.25
Stock Issued During Period, Shares, New Issues									0
Common stock, shares outstanding, beginning of period at Jun. 30, 2021	60,106,236
Dividend reinvestment plan, shares	5,096
Stock purchase and compensation plan, shares	12,946
Acquisition of treasury stock, share repurchase authorization	0
Acquisition of treasury stock - shares acquired related to employee share-based compensation plans	(743)
Common stock, shares outstanding, end of period at Sep. 30, 2021	60,123,535
Preferred Stock, Shares Outstanding	8,000

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net income	$ 304,858	$ 119,294
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	40,706	44,435
Stock-based compensation expense	13,431	13,935
Undistributed gains of equity method investments	(65,215)	(5,146)
Distributions in excess of current year income of equity method investments	2,750	3,136
Net realized and unrealized (gains) losses	(15,353)	24,296
Loss on disposal of fixed assets	50	17
Changes in assets and liabilities:
Increase in reserve for loss and loss expense, net of reinsurance recoverable	251,260	190,796
Increase in unearned premiums, net of prepaid reinsurance	211,564	114,672
Increase in net federal income taxes	(17,866)	(10,775)
Increase in premiums receivable	(148,817)	(28,239)
Increase in deferred policy acquisition costs	(45,417)	(21,523)
Increase in interest and dividends due or accrued	(1,249)	(1,507)
Decrease in accrued salaries and benefits	(1,160)	(33,677)
Increase in other assets	(22,045)	(23,388)
Increase (decrease) in other liabilities	35,806	(5,443)
Net Cash Provided by Operating Activities	543,303	380,883
Investing Activities
Purchase of fixed income securities, held-to-maturity	(11,250)	0
Purchase of fixed income securities, available-for-sale	(1,660,798)	(1,373,226)
Purchase of commercial mortgage loans	(38,129)	(29,800)
Payments to Acquire Equity Securities, FV-NI	82,223	87,307
Purchase of other investments	(63,661)	(61,051)
Purchase of short-term investments	(3,443,597)	(4,475,128)
Sale of fixed income securities, available-for-sale	384,586	411,263
Proceeds from commercial mortgage loans	442	109
Sale of short-term investments	3,497,243	4,377,024
Redemption and maturities of fixed income securities, held-to-maturity	2,735	1,646
Redemption and maturities of fixed income securities, available-for-sale	910,741	738,238
Proceeds from Sale of Equity Securities, FV-NI	85,373	1,320
Sale of other investments	5,377	3,879
Distributions from other investments	10,524	12,890
Purchase of property and equipment	(15,123)	(17,858)
Net Cash Used in Investing Activities	(417,760)	(498,001)
Financing Activities
Dividends to preferred stockholders	(7,053)	0
Dividends to common stockholders	(43,756)	(39,972)
Acquisition of treasury stock	(8,974)	(7,039)
Net proceeds from stock purchase and compensation plans	4,575	5,478
Preferred stock issued, net of issuance costs	(479)	0
Proceeds from borrowings	0	487,000
Repayments of borrowings	(50,000)	(320,000)
Repayments of finance lease obligations	(298)	(429)
Net Cash (used in) provided by Financing Activities	(105,985)	125,038
Cash and restricted cash, beginning of year	15,231	7,975
Cash and restricted cash, end of period	34,789	15,895
Net increase in cash and restricted cash	$ 19,558	$ 7,920

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed income securities, held-to-maturity, fair value	$ 26,037	$ 18,001
Fixed Income Securities, Available-for-sale, Allowance for Credit Loss	(7,169)	(3,969)
Fixed income securities, available-for-sale, amortized cost	6,401,167	6,073,517
Commercial mortgage loan, fair value	86,001	47,289
Equity Securities, cost	299,541	301,551
Property and equipment, accumulated depreciation and amortization	$ 256,826	$ 240,150
Preferred Stock, Shares Outstanding	8,000	8,000
Preferred Stock
Preferred stock, Par or Stated Value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized	5,000,000	5,000,000
Series B
Preferred Stock, Liquidation Preference (in dollars per share)	$ 25,000	$ 25,000
Preferred stock, shares issued	8,000	8,000
Preferred Stock, Shares Outstanding	8,000	8,000
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	104,389,125	104,032,912
Treasury stock [Member]
Treasury stock, shares	44,265,590	44,127,109

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2021
Basis of Presentation And Significant Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe words "Company,” “we,” “us,” or “our” refer to Selective Insurance Group, Inc. (the "Parent") and its subsidiaries, except as expressly indicated or the context requires otherwise. We have prepared our interim unaudited consolidated financial statements (“Financial Statements”) in conformity with U.S. generally accepted accounting principles (“GAAP”) and the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) regarding interim financial reporting. These require us to make estimates and assumptions that affect the reported financial statement balances and the disclosure of contingent assets and liabilities. Actual results could differ from those estimates. All significant intercompany accounts and transactions between the Parent and its subsidiaries are eliminated in consolidation.Our Financial Statements reflect all adjustments that, in our opinion, are normal, recurring, and necessary for a fair presentation of our results of operations and financial condition. Our Financial Statements cover the third quarters ended September 30, 2021 (“Third Quarter 2021”) and September 30, 2020 (“Third Quarter 2020”) and the nine-month periods ended September 30, 2021 (“Nine Months 2021”) and September 30, 2020 (“Nine Months 2020”). Our Financial Statements do not include all information and disclosures required by GAAP and the SEC for audited annual financial statements. Because results of operations for any interim period are not necessarily indicative of results for a full year, our Financial Statements should be read in conjunction with the consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2020 (“2020 Annual Report”) filed with the SEC.

Accounting Pronouncements

Accounting Pronouncements	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Accounting Pronouncements	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 Flows

Statements of Cash Flows	9 Months Ended
	Sep. 30, 2021
Supplemental Cash Flow Information [Abstract]
Statements of Cash Flows	Statements of Cash Flows Supplemental cash flow information was as follows: Nine Months ended September 30, ($ in thousands) 2021 2020 Cash paid during the period for: Interest $ 23,278 24,449 Federal income tax 93,000 34,000 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases 6,480 7,077 Operating cash flows from financing leases 5 13 Financing cash flows from finance leases 298 429 Non-cash items: Corporate actions related to fixed income securities, AFS 1 50,501 32,580 Corporate actions related to fixed income securities, HTM 1 — 2,596 Corporate actions related to equity securities 1 527 890 Assets acquired under finance lease arrangements 183 119 Assets acquired under operating lease arrangements 273 22,104 Non-cash purchase of property and equipment — 9 1 Examples of corporate actions include exchanges, non-cash acquisitions, and stock splits. The following table reconciles cash and restricted cash reported in the Consolidated Balance Sheets to the Consolidated Statements of Cash Flows: ($ in thousands) September 30, 2021 December 31, 2020 Cash $ 477 394 Restricted cash 34,312 14,837 Total cash and restricted cash shown in the Consolidated Statements of Cash Flows $ 34,789 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	9 Months Ended
	Sep. 30, 2021
Investments [Abstract]
Investments	Investments (a) Information about our AFS securities as of September 30, 2021, and December 31, 2020, was as follows: September 30, 2021 ($ in thousands) Cost/ Allowance for Credit Losses Unrealized Unrealized Fair AFS fixed income securities: U.S. government and government agencies $ 128,415 — 3,600 (957) 131,058 Foreign government 14,567 (47) 695 (75) 15,140 Obligations of states and political subdivisions 1,094,619 (99) 71,507 (103) 1,165,924 Corporate securities 2,420,904 (4,719) 131,442 (3,101) 2,544,526 Collateralized loan obligations ("CLO") and other asset-backed securities ("ABS") 1,326,348 (926) 18,896 (4,517) 1,339,801 Residential mortgage-backed securities ("RMBS") 785,840 (1,363) 33,361 (1,056) 816,782 Commercial mortgage-backed securities ("CMBS") 630,474 (15) 34,465 (1,085) 663,839 Total AFS fixed income securities $ 6,401,167 (7,169) 293,966 (10,894) 6,677,070 December 31, 2020 ($ in thousands) Cost/ Allowance for Credit Losses Unrealized Unrealized Fair 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 periods indicated: Quarter ended September 30, 2021 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ 49 — (2) — — 47 Obligations of states and political subdivisions 38 61 — — — 99 Corporate securities 3,477 1,307 64 (49) (80) 4,719 CLO and other ABS 1,399 46 (517) (2) — 926 RMBS 1,034 248 125 (44) — 1,363 CMBS 14 4 (3) — — 15 Total AFS fixed income securities $ 6,011 1,666 (333) (95) (80) 7,169 Quarter ended September 30, 2020 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ 28 — (2) (19) — 7 Obligations of states and political subdivisions 17 9 (11) — — 15 Corporate securities 8,077 1,016 (3,455) (265) (15) 5,358 CLO and other ABS 1,389 — (210) (51) (7) 1,121 RMBS 831 — (157) (27) — 647 CMBS 53 — (21) — — 32 Total AFS fixed income securities $ 10,395 1,025 (3,856) (362) (22) 7,180 Nine Months ended September 30, 2021 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ 1 47 (1) — — 47 Obligations of states and political subdivisions 4 84 11 — — 99 Corporate securities 2,782 3,413 (765) (570) (141) 4,719 CLO and other ABS 592 573 (219) (20) — 926 RMBS 561 1,018 (95) (121) — 1,363 CMBS 29 4 (18) — — 15 Total AFS fixed income securities $ 3,969 5,139 (1,087) (711) (141) 7,169 Nine Months ended September 30, 2020 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ — 26 — (19) — 7 Obligations of states and political subdivisions — 15 — — — 15 Corporate securities — 6,100 — (659) (83) 5,358 CLO and other ABS — 1,237 — (109) (7) 1,121 RMBS — 690 — (43) — 647 CMBS — 32 — — — 32 Total AFS fixed income securities $ — 8,100 — (830) (90) 7,180 For information on our methodology and significant inputs used to measure expected credit losses, our accounting policy for recognizing write-offs of uncollectible amounts, and our treatment of accrued interest, refer to Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2020 Annual Report. Accrued interest on AFS securities was $44.9 million as of September 30, 2021, and $43.8 million as of December 31, 2020. We did not record any material write-offs during 2021 or 2020. (b) Quantitative information about unrealized losses on our AFS portfolio is provided below. September 30, 2021 Less than 12 months 12 months or longer Total ($ in thousands) Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized AFS fixed income securities: U.S. government and government agencies $ 34,717 (940) 156 (17) 34,873 (957) Foreign government 3,114 (75) — — 3,114 (75) Obligations of states and political subdivisions 7,936 (103) — — 7,936 (103) Corporate securities 236,164 (3,067) 2,412 (34) 238,576 (3,101) CLO and other ABS 515,458 (3,723) 57,153 (794) 572,611 (4,517) RMBS 111,648 (1,055) 20 (1) 111,668 (1,056) CMBS 75,714 (941) 8,286 (144) 84,000 (1,085) Total AFS fixed income securities $ 984,751 (9,904) 68,027 (990) 1,052,778 (10,894) December 31, 2020 Less than 12 months 12 months or longer Total ($ in thousands) Fair Unrealized Fair Value Unrealized Fair Value 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 reflected in the tables above, nor do we expect that we will be required to sell any of these securities. The decrease in gross unrealized losses during Nine Months 2021 was driven by a tightening of credit spreads, partially offset by an increase in longer-dated benchmark United States Treasury rates. Considering these factors and our review of these securities under our credit loss policy as described in Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2020 Annual Report, 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. (c) Fixed income securities at September 30, 2021 are summarized below by contractual maturity. Mortgage-backed securities are reflected in the table 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. AFS HTM ($ in thousands) Fair Value Carrying Value Fair Value Due in one year or less $ 511,751 32 33 Due after one year through five years 3,389,351 14,548 15,340 Due after five years through 10 years 2,101,275 10,672 10,664 Due after 10 years 674,693 — — Total fixed income securities $ 6,677,070 25,252 26,037 (d) The following table summarizes our other investment portfolio by strategy: Other Investments September 30, 2021 December 31, 2020 ($ in thousands) Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Alternative Investments Private equity $ 257,160 103,792 360,952 157,276 100,905 258,181 Private credit 62,462 91,991 154,453 54,017 98,330 152,347 Real assets 22,870 23,466 46,336 19,659 16,493 36,152 Total alternative investments 342,492 219,249 561,741 230,952 215,728 446,680 Other securities 50,296 — 50,296 35,370 — 35,370 Total other investments $ 392,788 219,249 612,037 266,322 215,728 482,050 1 The maximum exposure to loss includes both the carry value of these investments and the related remaining commitments. In addition, tax credits that have been previously recognized in Other securities are subject to the risk of recapture, which we do not consider significant. We are contractually committed to make additional investments up to the remaining commitments stated above. We have not provided any non-contractual financial support at any time during 2021 or 2020. The following table shows gross summarized financial information for our other investments portfolio, including the portion we do not own. The majority of these investments are carried under the equity method of accounting and report results to us on a one-quarter lag. The following table provides (i) the gross summarized financial statement information for these investments for the three and nine-months ended June 30, and (ii) the portion of these results included in our Third Quarter and Nine Months results: Income Statement Information Quarter ended September 30, Nine Months ended September 30, ($ in millions) 2021 2020 2021 2020 Net investment income $ 60.4 83.4 $ 550.3 92.9 Realized gains 1,857.6 731.3 4,026.2 1,075.0 Net change in unrealized appreciation 11,188.2 2,230.4 20,767.9 571.6 Net income $ 13,106.2 3,045.1 $ 25,344.4 1,739.5 Alternative investment income included in "Net investment income earned" on our Consolidated Statements of Income $ 42.8 18.7 $ 92.9 8.9 (e) Certain of our insurance subsidiaries, as members of the Federal Home Loan Bank of Indianapolis ("FHLBI") and the Federal Home Loan Bank of New York ("FHLBNY"), have pledged certain AFS fixed income securities as collateral. Additionally, to comply with insurance laws, certain of our insurance subsidiaries have deposited certain securities with various state and regulatory agencies at September 30, 2021. We retain all rights regarding all securities pledged as collateral. The following table summarizes the market value of these securities at September 30, 2021: ($ in millions) FHLBI Collateral FHLBNY Collateral State and Total U.S. government and government agencies $ — — 22.1 22.1 Obligations of states and political subdivisions — — 4.0 4.0 RMBS 67.8 44.8 — 112.6 CMBS 6.6 14.6 — 21.2 Total pledged as collateral $ 74.4 59.4 26.1 159.9 (f) We did not have exposure to any credit concentration risk of a single issuer greater than 10% of our stockholders' equity, other than certain U.S. government-backed investments, as of September 30, 2021, or December 31, 2020. (g) The components of pre-tax net investment income earned were as follows: Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Fixed income securities $ 51,683 51,285 $ 157,114 152,617 Commercial mortgage loans ("CMLs") 683 245 1,892 463 Equity securities 2,955 1,948 8,425 5,523 Short-term investments 64 244 204 1,830 Other investments 42,865 18,671 93,158 9,167 Investment expenses (5,218) (4,208) (14,314) (11,004) Net investment income earned $ 93,032 68,185 $ 246,479 158,596 The increases in net investment income earned in Third Quarter and Nine Months 2021 compared to the prior year periods were driven by the alternative investments in our other investments portfolio. The results principally reflect unrealized gains on our private equity holdings that benefited from the upward movement in private market valuations in the three and nine-month periods ending June 30, 2021, as our results on these holdings are recorded on a one-quarter lag. (h) The following table summarizes net realized and unrealized gains and losses for the periods indicated: Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Gross gains on sales $ 7,151 2,975 $ 12,906 15,129 Gross losses on sales (2,505) (2,402) (8,787) (7,841) Net realized gains on disposals 4,646 573 4,119 7,288 Net unrealized (losses) gains on equity securities (3,111) 4,338 15,830 (7,098) Net credit loss (expense) benefit on fixed income securities, AFS (1,334) 2,853 (4,059) (8,011) Net credit loss benefit (expense) on fixed income securities, HTM 6 3 (54) 4 Net credit loss benefit (expense) on CMLs — (2) — (220) Losses on securities for which we have the intent to sell (30) (44) (483) (16,259) Net realized and unrealized gains (losses) $ 177 7,721 $ 15,353 (24,296) Unrealized gains (losses) recognized in income on equity securities, as reflected in the table above, include the following: Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Unrealized gains (losses) recognized in income on equity securities: On securities remaining in our portfolio at period end $ 269 4,338 $ 14,767 (7,101) On securities sold during period (3,380) — 1,063 3 Total unrealized (losses) gains recognized in income on equity securities $ (3,111) 4,338 $ 15,830 (7,098) The improvement in net realized and unrealized gains in Nine Months 2021 compared to Nine Months 2020 was primarily driven by (i) unrealized gains on our equity securities compared to unrealized losses last year, driven by COVID-19-related market disruption, and (ii) lower intent-to-sell losses given the significant trading flexibility we allowed our investment managers given last year's market conditions.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 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 September 30, 2021, and December 31, 2020: September 30, 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 64,955 49,914 66,148 6.70% Senior Notes 99,514 127,279 99,499 127,886 5.375% Senior Notes 294,307 382,961 294,241 383,669 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 65,109 60,000 67,513 Subtotal long-term debt 503,738 640,304 553,654 695,596 Unamortized debt issuance costs (3,228) (3,419) Finance lease obligations 394 508 Total long-term debt $ 500,904 550,743 For a discussion of the fair value hierarchy and techniques used to value our financial assets and liabilities, refer to Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2020 Annual Report. The following tables provide quantitative disclosures of our financial assets that were measured and recorded at fair value at September 30, 2021, and December 31, 2020: September 30, 2021 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Significant Other Significant Unobservable Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 131,058 59,264 71,794 — Foreign government 15,140 — 15,140 — Obligations of states and political subdivisions 1,165,924 — 1,157,920 8,004 Corporate securities 2,544,526 — 2,434,240 110,286 CLO and other ABS 1,339,801 — 1,277,372 62,429 RMBS 816,782 — 816,782 — CMBS 663,839 — 663,839 — Total AFS fixed income securities 6,677,070 59,264 6,437,087 180,719 Equity securities: Common stock 1 322,074 225,911 — — Preferred stock 2,112 2,112 — — Total equity securities 324,186 228,023 — — Short-term investments 355,937 355,937 — — Total assets measured at fair value $ 7,357,193 643,224 6,437,087 180,719 December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Significant Significant Unobservable 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 $96.2 million at September 30, 2021, and $46.8 million at December 31, 2020, were measured at fair value using net asset value per share (or its practical expedient) and are not classified in the fair value hierarchy. These investments are not redeemable and the timing of liquidations of the underlying assets is unknown at each reporting period. The fair value amounts in this table enables reconciliation of the fair value hierarchy to total assets measured at fair value. The following table provides a summary of Level 3 changes in Nine Months 2021 and Nine Months 2020: September 30, 2021 ($ in thousands) Obligations of States and Political Subdivisions Corporate Securities CLO and Other ABS Total Fair value, December 31, 2020 $ 2,894 70,700 56,375 129,969 Total net (losses) gains for the period included in: OCI 9 2,607 206 2,822 Net realized and unrealized (losses) gains — (185) (35) (220) Net investment income earned — 14 9 23 Purchases — 43,833 19,041 62,874 Sales — — — — Issuances — — — — Settlements — (210) (1,750) (1,960) Transfers into Level 3 5,101 981 3,226 9,308 Transfers out of Level 3 — (7,454) (14,643) (22,097) Fair value, September 30, 2021 $ 8,004 110,286 62,429 180,719 Change in unrealized losses for the period included in earnings for assets held at period end — (185) (35) (220) Change in unrealized gains for the period included in OCI for assets held at period end 9 2,607 206 2,822 September 30, 2020 ($ in thousands) Obligation of state 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 (36) (2,415) 732 (1,719) Net realized and unrealized (losses) gains — (456) (247) (703) Net investment income earned — — 3 3 Purchases — 19,002 11,751 30,753 Sales — — — — Issuances — — — — Settlements — (138) (1,030) (1,168) Transfers into Level 3 2,890 4,592 26,401 33,883 Transfers out of Level 3 — — (9,924) (9,924) Fair value, September 30, 2020 $ 2,854 37,636 44,720 85,210 Change in unrealized gains (losses) for the period included in earnings for assets held at period end — (456) (247) (703) Change in unrealized gains (losses) for the period included in OCI for assets held at period end (36) (2,415) 732 (1,719) The following tables provide quantitative information regarding our financial assets and liabilities that were disclosed at fair value at September 30, 2021, and December 31, 2020: September 30, 2021 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Significant Other Significant Financial Assets HTM: Obligations of states and political subdivisions $ 3,619 — 3,619 — Corporate securities 22,418 — 22,418 — Total HTM fixed income securities $ 26,037 — 26,037 — CMLs $ 86,001 — — 86,001 Financial Liabilities Long-term debt: 7.25% Senior Notes $ 64,955 — 64,955 — 6.70% Senior Notes 127,279 — 127,279 — 5.375% Senior Notes 382,961 — 382,961 — 3.03% borrowings from FHLBI 65,109 — 65,109 — Total long-term debt $ 640,304 — 640,304 — December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Significant Other Significant 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 — CMLs $ 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 Uncollectible Pre

Allowance for Uncollectible Premiums Receivable (Notes)	9 Months Ended
	Sep. 30, 2021
Premiums Receivable [Abstract]
Allowance for Uncollectible Premiums Receivable Note [Text Block]	Premiums Receivable The following table provides a roll forward of the allowance for credit losses on our premiums receivable balance for the periods indicated: Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Balance at beginning of period $ 18,300 $ 21,000 $ 21,000 $ 6,400 Cumulative effect adjustment 1 — — — 1,058 Balance at beginning of period, as adjusted $ 18,300 $ 21,000 $ 21,000 $ 7,458 Current period provision for expected credit losses 180 802 1,721 16,369 Write-offs charged against the allowance for credit losses (2,154) (996) (6,554) (3,272) Recoveries 174 194 333 445 Allowance for credit losses, end of period $ 16,500 $ 21,000 $ 16,500 $ 21,000 1 Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses . In Nine Months 2020, we recognized an additional allowance for credit losses of $13.5 million, net of write-offs and recoveries. We based this increase on an evaluation of the recoverability of our premiums receivable in light of (i) the billing accommodations we announced during the first quarter of 2020 and (ii) the impact of certain state regulations that provided for deferral of payments without cancellation for a period up to 90 days and increased earned but uncollected premiums. The billing accommodations included individualized payment flexibility and suspending the effect of policy cancellations, late payment notices, and late or reinstatement fees. The heightened credit risk experienced in 2020 led us to increase the allowance for credit losses to $21.0 million last year. During Nine Months 2021, we realized a portion of the anticipated write-offs, which reduced our allowance. The reduction was partially offset by the additional provision established on current-year premiums, which resulted in the end of period allowance of $16.5 million.

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2021
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance 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 September 30, 2021, and December 31, 2020: September 30, 2021 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers A++ $ 39,325 $ 13 $ 39,338 A+ 338,912 887 339,799 A 96,071 439 96,510 A- 3,166 271 3,437 B++ — — — B+ — — — Total rated reinsurers $ 477,474 $ 1,610 $ 479,084 Non-rated reinsurers Federal and state pools $ 204,001 $ — $ 204,001 Other than federal and state pools 4,698 29 4,727 Total non-rated reinsurers $ 208,699 $ 29 $ 208,728 Total reinsurance recoverable, gross $ 686,173 $ 1,639 $ 687,812 Less: allowance for credit losses 1 (1,595) Total reinsurance recoverable, net $ 686,217 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: allowance for credit losses 1 (1,777) Total reinsurance recoverable, net $ 587,492 1 Represents our current expectation of credit losses on total current and past due reinsurance recoverables, and is not identifiable by reinsurer. The $98.7 million increase in "Total reinsurance recoverable, net," was primarily driven by losses ceded to the NFIP due to seasonal catastrophic storms, mainly Hurricane Ida, and subsequent flooding. See below for further discussion on ceded premiums written, ceded premiums earned, and ceded loss and loss expenses incurred related to our participation in the NFIP. For a discussion of the methodology used to evaluate our estimate of expected credit losses, refer to Note 2. "Summary of Significant Accounting Policies" in Item 8. "Financial Statements and Supplementary Data." of our 2020 Annual Report. The following table provides a rollforward of the allowance for credit losses on our reinsurance recoverable balance for the periods indicated: ($ in thousands) Quarter ended September 30, Nine Months ended September 30, 2021 2020 2021 2020 Balance at beginning of period $ 1,777 2,396 $ 1,777 4,400 Cumulative effect adjustment 1 — — — (2,903) Balance at beginning of period, as adjusted $ 1,777 2,396 $ 1,777 1,497 Current period provision for expected credit losses (182) (565) (182) 334 Write-offs charged against the allowance for credit losses — — — — Recoveries — — — — Allowance for credit losses, end of period $ 1,595 1,831 $ 1,595 1,831 1 Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses . The following table contains a listing of direct, assumed, and ceded reinsurance amounts for premiums written, premiums earned, and loss and loss expenses incurred for the periods indicated. For more information about reinsurance, refer to Note 9. “Reinsurance” in Item 8. “Financial Statements and Supplementary Data.” of our 2020 Annual Report. Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Premiums written: Direct $ 932,752 839,275 $ 2,796,296 2,420,350 Assumed 7,136 5,450 17,541 17,902 Ceded (126,982) (125,217) (369,548) (346,665) Net $ 812,906 719,508 $ 2,444,289 2,091,587 Premiums earned: Direct $ 877,620 803,957 $ 2,568,445 2,292,495 Assumed 6,304 6,147 16,391 18,375 Ceded (116,677) (115,563) (352,111) (333,955) Net $ 767,247 694,541 $ 2,232,725 1,976,915 Loss and loss expenses incurred: Direct $ 655,483 530,192 $ 1,557,063 1,407,000 Assumed 4,143 4,232 10,807 13,430 Ceded (154,357) (86,622) (227,577) (168,355) Net $ 505,269 447,802 $ 1,340,293 1,252,075 Direct premiums written ("DPW") increased $375.9 million, or 16%, in Nine Months 2021 compared to Nine Months 2020 from (i) overall renewal pure price increases, (ii) strong retention, and (iii) new business growth. This increase included four percentage points from the $75 million return audit and endorsement premium accrual that was recorded in the first quarter of 2020 and a $19.7 million premium credit to automobile policyholders in the second quarter of 2020. The return audit and endorsement premium accrual recorded in 2020 reflected lower exposure levels, which determine the premium we charge, attributable to the economic impacts of the COVID-19 pandemic and the anticipated decline in sales and payroll exposures on the general liability and workers compensation lines of business in 2020. Ceded premiums written, ceded premiums earned, and ceded loss and loss expenses incurred related to our participation in the NFIP, to which we cede 100% of our NFIP flood premiums, losses, and loss expenses, were as follows: Ceded to NFIP Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Ceded premiums written $ (77,697) (77,318) $ (218,520) (213,592) Ceded premiums earned (69,197) (68,427) (203,549) (202,656) Ceded loss and loss expenses incurred (153,713) (48,132) (174,861) (66,219)

Reserve for Loss and Loss Expen

Reserve for Loss and Loss Expense	9 Months Ended
	Sep. 30, 2021
Insurance Loss Reserves [Abstract]
Reserve for Loss and Loss Expense	Reserve for Loss and Loss Expense The table below provides a roll forward of reserve for loss and loss expense balances: Nine Months ended September 30, ($ in thousands) 2021 2020 Gross reserve for loss and loss expense, at beginning of year $ 4,260,355 4,067,163 Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year 1 554,269 547,066 Net reserve for loss and loss expense, at beginning of year 3,706,086 3,520,097 Incurred loss and loss expense for claims occurring in the: Current year 1,408,240 1,295,285 Prior years (67,947) (43,210) Total incurred loss and loss expense 1,340,293 1,252,075 Paid loss and loss expense for claims occurring in the: Current year 430,288 421,981 Prior years 675,782 646,974 Total paid loss and loss expense 1,106,070 1,068,955 Net reserve for loss and loss expense, at end of period 3,940,309 3,703,217 Add: Reinsurance recoverable on unpaid loss and loss expense, at end of period 670,031 590,059 Gross reserve for loss and loss expense at end of period $ 4,610,340 4,293,276 1 Nine Months 2020 includes an adjustment of $2.9 million related to our adoption of ASU 2016-13, Financial Instruments - Credit Losses . Prior year reserve development in Nine Months 2021 was favorable by $67.9 million, which included $66.0 million of casualty reserve development. The favorable casualty reserve development included $29.0 million in our general liability line of business, $28.0 million in our workers compensation line of business, $7.0 million in our Excess and Surplus ("E&S") casualty lines of business, and $2.0 million in our businessowners' policies line of business. Prior year reserve development in Nine Months 2020 was favorable by $43.2 million, which included $50.0 million of casualty reserve development, partially offset by $6.8 million of unfavorable property reserve development. The favorable casualty reserve development included $40.0 million in our workers compensation line of business and $20 million in our general liability line of business, partially offset by $10.0 million of unfavorable reserve development in our commercial automobile line of business.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 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 on before and after-tax underwriting results (net premiums earned, incurred loss and loss expense, policyholder dividends, policy acquisition costs, and other underwriting expenses), return on equity ("ROE") contribution, and combined ratios. • Our Investments segment is primarily evaluated on 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 Investments segment results. In computing each segment's results, we do not make adjustments for interest expense or corporate expenses, nor do we allocate assets. The following summaries present revenues (net investment income and net realized and unrealized gains and losses on investments for the Investments segment) and pre-tax income for the individual segments: Revenue by Segment Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Standard Commercial Lines: Net premiums earned: Commercial property $ 111,981 97,997 $ 320,904 287,279 Workers compensation 78,318 75,595 230,845 204,207 General liability 205,904 181,459 596,717 509,312 Commercial automobile 185,610 160,937 535,519 449,162 Businessowners' policies 23,025 27,605 80,963 82,157 Bonds 8,850 9,226 26,436 28,075 Other 5,883 5,266 17,082 15,477 Miscellaneous income 4,168 5,521 13,670 11,107 Total Standard Commercial Lines revenue 623,739 563,606 1,822,136 1,586,776 Standard Personal Lines: Net premiums earned: Personal automobile 40,575 42,458 122,977 123,134 Homeowners 30,633 31,395 91,801 94,537 Other 2,154 2,123 5,698 6,066 Miscellaneous income 420 598 1,242 1,520 Total Standard Personal Lines revenue 73,782 76,574 221,718 225,257 E&S Lines: Net premiums earned: Casualty lines 52,983 43,650 144,458 130,444 Property lines 21,331 16,830 59,325 47,065 Total E&S Lines revenue 74,314 60,480 203,783 177,509 Investments: Net investment income 93,032 68,185 246,479 158,596 Net realized and unrealized investment gains (losses) 177 7,721 15,353 (24,296) Total Investments revenue 93,209 75,906 261,832 134,300 Total revenues $ 865,044 776,566 $ 2,509,469 2,123,842 Income Before and After Federal Income Tax Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Standard Commercial Lines: Underwriting gain, before federal income tax $ 17,413 42,718 $ 154,850 76,574 Underwriting gain, after federal income tax 13,756 33,746 122,332 60,493 Combined ratio 97.2 % 92.3 91.4 95.1 ROE contribution 2.1 5.7 6.2 3.5 Standard Personal Lines: Underwriting gain (loss), before federal income tax $ (11,146) (14,404) $ 2,193 (20,342) Underwriting gain (loss), after federal income tax (8,805) (11,379) 1,732 (16,070) Combined ratio 115.2 % 119.0 99.0 109.1 ROE contribution (1.3) (1.9) 0.1 (0.9) E&S Lines: Underwriting gain (loss), before federal income tax $ 4,672 (7,277) $ 7,494 (3,965) Underwriting gain (loss), after federal income tax 3,691 (5,748) 5,920 (3,132) Combined ratio 93.7 % 112.0 96.3 102.2 ROE contribution 0.5 (1.0) 0.3 (0.2) Investments: Net investment income $ 93,032 68,185 $ 246,479 158,596 Net realized and unrealized investment gains (losses) 177 7,721 15,353 (24,296) Total investments segment income, before federal income tax 93,209 75,906 261,832 134,300 Tax on investments segment income 18,379 14,676 51,229 24,338 Total investments segment income, after federal income tax $ 74,830 61,230 $ 210,603 109,962 ROE contribution of after-tax net investment income 11.0 9.4 10.1 7.5 Reconciliation of Segment Results to Income Before Federal Income Tax Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Underwriting gain Standard Commercial Lines $ 17,413 42,718 $ 154,850 76,574 Standard Personal Lines (11,146) (14,404) 2,193 (20,342) E&S Lines 4,672 (7,277) 7,494 (3,965) Investment income 93,209 75,906 261,832 134,300 Total all segments 104,148 96,943 426,369 186,567 Interest expense (7,242) (7,781) (21,967) (23,310) Corporate expenses (4,270) (3,905) (22,936) (19,310) Income, before federal income tax $ 92,636 85,257 $ 381,466 143,947 Preferred stock dividends (2,300) — (7,053) — Income available to common stockholders, before federal income tax $ 90,336 85,257 $ 374,413 143,947

Retirement Plans

Retirement Plans	9 Months Ended
	Sep. 30, 2021
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans The primary pension plan for our employees is the Retirement Income Plan for Selective Insurance Company of America (the “Pension Plan”). Selective Insurance Company of America (“SICA”) also sponsors the Supplemental Excess Retirement Plan (the “Excess Plan”) and a life insurance benefit plan. All plans are closed to new entrants, and benefits ceased accruing under the Pension Plan and the Excess Plan after March 31, 2016. For more information about SICA's retirement plans, see Note 15. “Retirement Plans” in Item 8. “Financial Statements and Supplementary Data.” of our 2020 Annual Report. The following tables provide information about the Pension Plan: Pension Plan Pension Plan Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Net Periodic Pension Cost (Benefit): Interest cost $ 2,148 2,828 $ 6,445 8,484 Expected return on plan assets (5,744) (5,477) (17,232) (16,430) Amortization of unrecognized net actuarial loss 626 704 1,876 2,112 Total net periodic pension benefit 1 $ (2,970) (1,945) $ (8,911) (5,834) 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 Nine Months ended September 30, 2021 2020 Weighted-Average Expense Assumptions: Discount rate 2.68 % 3.33 % Effective interest rate for calculation of interest cost 2.06 2.95 Expected return on plan assets 5.40 5.80

Comprehensive Income

Comprehensive Income	3 Months Ended
	Sep. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Comprehensive Income	Comprehensive Income The following are the components of comprehensive income, both gross and net of tax, for Third Quarter and Nine Months 2021 and 2020: Third Quarter 2021 ($ in thousands) Gross Tax Net Net income $ 92,636 18,931 73,705 Components of OCI: Unrealized losses on investment securities : Unrealized holding losses during the period (35,285) (7,410) (27,875) Unrealized losses on securities with credit loss recognized in earnings (2,343) (492) (1,851) Amounts reclassified into net income: HTM securities 1 — 1 Net realized gains on disposals and losses on intent-to-sell AFS securities (1,296) (272) (1,024) Credit loss expense 1,334 280 1,054 Total unrealized losses on investment securities (37,589) (7,894) (29,695) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 693 145 548 Total defined benefit pension and post-retirement plans 693 145 548 Other comprehensive loss (36,896) (7,749) (29,147) Comprehensive income $ 55,740 11,182 44,558 Third Quarter 2020 ($ in thousands) Gross Tax Net Net income $ 85,257 15,382 69,875 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during the period 37,836 7,947 29,889 Unrealized gains on securities with credit loss recognized in earnings 9,239 1,940 7,299 Amounts reclassified into net income: HTM securities (1) (1) — Net realized gains on disposals and losses on intent-to-sell AFS securities (515) (109) (406) Credit loss benefit (2,853) (599) (2,254) Total unrealized gains on investment securities 43,706 9,178 34,528 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 754 158 596 Total defined benefit pension and post-retirement plans 754 158 596 Other comprehensive income 44,460 9,336 35,124 Comprehensive income $ 129,717 24,718 104,999 Nine Months 2021 ($ in thousands) Gross Tax Net Net income $ 381,466 76,608 304,858 Components of OCI: Unrealized losses on investment securities : Unrealized holding losses during the period (103,040) (21,638) (81,402) Unrealized losses on securities with credit loss recognized in earnings (3,678) (772) (2,906) Amounts reclassified into net income: HTM securities (4) (1) (3) Net realized gains on disposals and losses on intent-to-sell AFS securities (634) (133) (501) Credit loss expense 4,059 852 3,207 Total unrealized losses on investment securities (103,297) (21,692) (81,605) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 2,079 436 1,643 Total defined benefit pension and post-retirement plans 2,079 436 1,643 Other comprehensive loss (101,218) (21,256) (79,962) Comprehensive income $ 280,248 55,352 224,896 Nine Months 2020 ($ in thousands) Gross Tax Net Net income $ 143,947 24,653 119,294 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during the period 132,623 27,852 104,771 Unrealized losses on securities with credit loss recognized in earnings (18,672) (3,921) (14,751) Amounts reclassified into net income: HTM securities (7) (2) (5) Net realized losses on disposals and losses on intent-to-sell AFS securities 9,126 1,916 7,210 Credit loss expense 8,010 1,682 6,328 Total unrealized gains on investment securities 131,080 27,527 103,553 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 2,261 474 1,787 Total defined benefit pension and post-retirement plans 2,261 474 1,787 Other comprehensive income 133,341 28,001 105,340 Comprehensive income $ 277,288 52,654 224,634 The following are the balances and changes in each component of AOCI (net of taxes) as of September 30, 2021: September 30, 2021 Defined Benefit Net Unrealized (Losses) Gains on Investment Securities Total AOCI ($ in thousands) Credit Loss Related 1 HTM All Investments Balance, December 31, 2020 $ (2,546) 6 307,790 305,250 (85,064) 220,186 OCI before reclassifications (2,906) — (81,402) (84,308) — (84,308) Amounts reclassified from AOCI 3,207 (3) (501) 2,703 1,643 4,346 Net current period OCI 301 (3) (81,903) (81,605) 1,643 (79,962) Balance, September 30, 2021 $ (2,245) 3 225,887 223,645 (83,421) 140,224 1 Represents change in unrealized loss on securities with credit loss recognized in earnings. The reclassifications out of AOCI were as follows: Quarter ended September 30, Nine Months ended September 30, Affected Line Item in the Unaudited Consolidated Statements of Income ($ in thousands) 2021 2020 2021 2020 HTM related Unrealized (gains) losses on HTM disposals $ (1) 4 $ (1) 5 Net realized and unrealized investment gains (losses) Amortization of net unrealized losses (gains) on HTM securities 2 (5) (3) (12) Net investment income earned 1 (1) (4) (7) Income before federal income tax — 1 1 2 Total federal income tax expense 1 — (3) (5) Net income Net realized (gains) losses on disposals and intent-to-sell AFS securities Net realized (gains) losses on disposals and intent-to-sell AFS securities (1,296) (515) (634) 9,126 Net realized and unrealized investment gains (losses) (1,296) (515) (634) 9,126 Income before federal income tax 272 109 133 (1,916) Total federal income tax expense (1,024) (406) (501) 7,210 Net income Credit loss related Credit loss expense (benefit) 1,334 (2,853) 4,059 8,010 Net realized and unrealized investment gains (losses) 1,334 (2,853) 4,059 8,010 Income before federal income tax (280) 599 (852) (1,682) Total federal income tax expense 1,054 (2,254) 3,207 6,328 Net income Defined benefit pension and post-retirement life plans Net actuarial loss 159 162 478 486 Loss and loss expense incurred 534 592 1,601 1,775 Other insurance expenses Total defined benefit pension and post-retirement life 693 754 2,079 2,261 Income before federal income tax (145) (158) (436) (474) Total federal income tax expense 548 596 1,643 1,787 Net income Total reclassifications for the period $ 579 (2,064) $ 4,346 15,320 Net income

Equity

Equity	9 Months Ended
	Sep. 30, 2021
Equity [Abstract]
Treasury Stock	EquityOn December 2, 2020, we announced that our Board of Directors 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, and the repurchase program may be suspended or discontinued at any time at our discretion. The timing and amount of any share repurchases under the authorization will be determined by management at its discretion based on market conditions and other considerations. As of September 30, 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 in the second or third quarters of 2021. We have $96.6 million of remaining capacity under our share repurchase program.

Litigation

Litigation	9 Months Ended
	Sep. 30, 2021
Loss Contingency, Information about Litigation Matters [Abstract]
Litigation	Litigation As of September 30, 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.

Statements of Cash Flows (Table

Statements of Cash Flows (Tables)	9 Months Ended
	Sep. 30, 2021
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Nine Months ended September 30, ($ in thousands) 2021 2020 Cash paid during the period for: Interest $ 23,278 24,449 Federal income tax 93,000 34,000 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases 6,480 7,077 Operating cash flows from financing leases 5 13 Financing cash flows from finance leases 298 429 Non-cash items: Corporate actions related to fixed income securities, AFS 1 50,501 32,580 Corporate actions related to fixed income securities, HTM 1 — 2,596 Corporate actions related to equity securities 1 527 890 Assets acquired under finance lease arrangements 183 119 Assets acquired under operating lease arrangements 273 22,104 Non-cash purchase of property and equipment — 9 1 Examples of corporate actions include exchanges, non-cash acquisitions, and stock splits.
Schedule of Cash and Restricted Cash	($ in thousands) September 30, 2021 December 31, 2020 Cash $ 477 394 Restricted cash 34,312 14,837 Total cash and restricted cash shown in the Consolidated Statements of Cash Flows $ 34,789 15,231

Investments (Tables)

Investments (Tables)	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021
Schedule of Investments [Line Items]
Schedule of Available-for-sale Securities		September 30, 2021 ($ in thousands) Cost/ Allowance for Credit Losses Unrealized Unrealized Fair AFS fixed income securities: U.S. government and government agencies $ 128,415 — 3,600 (957) 131,058 Foreign government 14,567 (47) 695 (75) 15,140 Obligations of states and political subdivisions 1,094,619 (99) 71,507 (103) 1,165,924 Corporate securities 2,420,904 (4,719) 131,442 (3,101) 2,544,526 Collateralized loan obligations ("CLO") and other asset-backed securities ("ABS") 1,326,348 (926) 18,896 (4,517) 1,339,801 Residential mortgage-backed securities ("RMBS") 785,840 (1,363) 33,361 (1,056) 816,782 Commercial mortgage-backed securities ("CMBS") 630,474 (15) 34,465 (1,085) 663,839 Total AFS fixed income securities $ 6,401,167 (7,169) 293,966 (10,894) 6,677,070 December 31, 2020 ($ in thousands) Cost/ Allowance for Credit Losses Unrealized Unrealized Fair 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
Debt Securities, Available-for-sale, Allowance for Credit Loss [Table Text Block]	Quarter ended September 30, 2021 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ 49 — (2) — — 47 Obligations of states and political subdivisions 38 61 — — — 99 Corporate securities 3,477 1,307 64 (49) (80) 4,719 CLO and other ABS 1,399 46 (517) (2) — 926 RMBS 1,034 248 125 (44) — 1,363 CMBS 14 4 (3) — — 15 Total AFS fixed income securities $ 6,011 1,666 (333) (95) (80) 7,169 Quarter ended September 30, 2020 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ 28 — (2) (19) — 7 Obligations of states and political subdivisions 17 9 (11) — — 15 Corporate securities 8,077 1,016 (3,455) (265) (15) 5,358 CLO and other ABS 1,389 — (210) (51) (7) 1,121 RMBS 831 — (157) (27) — 647 CMBS 53 — (21) — — 32 Total AFS fixed income securities $ 10,395 1,025 (3,856) (362) (22) 7,180 Nine Months ended September 30, 2021 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ 1 47 (1) — — 47 Obligations of states and political subdivisions 4 84 11 — — 99 Corporate securities 2,782 3,413 (765) (570) (141) 4,719 CLO and other ABS 592 573 (219) (20) — 926 RMBS 561 1,018 (95) (121) — 1,363 CMBS 29 4 (18) — — 15 Total AFS fixed income securities $ 3,969 5,139 (1,087) (711) (141) 7,169 Nine Months ended September 30, 2020 ($ in thousands) Beginning Balance Current Provision for Securities without Prior Allowance Increase (Decrease) on Securities with Prior Allowance, excluding intent (or Requirement) to Sell Securities Reductions for Securities Sold Reductions for Securities Identified as Intent (or Requirement) to Sell during the Period Ending Balance Foreign government $ — 26 — (19) — 7 Obligations of states and political subdivisions — 15 — — — 15 Corporate securities — 6,100 — (659) (83) 5,358 CLO and other ABS — 1,237 — (109) (7) 1,121 RMBS — 690 — (43) — 647 CMBS — 32 — — — 32 Total AFS fixed income securities $ — 8,100 — (830) (90) 7,180
Schedule of Fair Value and Gross Pre-Tax Net Unrealized Loss of Securities by Length of Time, AFS		September 30, 2021 Less than 12 months 12 months or longer Total ($ in thousands) Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized AFS fixed income securities: U.S. government and government agencies $ 34,717 (940) 156 (17) 34,873 (957) Foreign government 3,114 (75) — — 3,114 (75) Obligations of states and political subdivisions 7,936 (103) — — 7,936 (103) Corporate securities 236,164 (3,067) 2,412 (34) 238,576 (3,101) CLO and other ABS 515,458 (3,723) 57,153 (794) 572,611 (4,517) RMBS 111,648 (1,055) 20 (1) 111,668 (1,056) CMBS 75,714 (941) 8,286 (144) 84,000 (1,085) Total AFS fixed income securities $ 984,751 (9,904) 68,027 (990) 1,052,778 (10,894) December 31, 2020 Less than 12 months 12 months or longer Total ($ in thousands) Fair Unrealized Fair Value Unrealized Fair Value 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 Fixed Maturity Securities By Contractual Maturities		AFS HTM ($ in thousands) Fair Value Carrying Value Fair Value Due in one year or less $ 511,751 32 33 Due after one year through five years 3,389,351 14,548 15,340 Due after five years through 10 years 2,101,275 10,672 10,664 Due after 10 years 674,693 — — Total fixed income securities $ 6,677,070 25,252 26,037
Schedule of Other Investment Portfolio By Strategy And Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy		Other Investments September 30, 2021 December 31, 2020 ($ in thousands) Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Carrying Value Remaining Commitment Maximum Exposure to Loss 1 Alternative Investments Private equity $ 257,160 103,792 360,952 157,276 100,905 258,181 Private credit 62,462 91,991 154,453 54,017 98,330 152,347 Real assets 22,870 23,466 46,336 19,659 16,493 36,152 Total alternative investments 342,492 219,249 561,741 230,952 215,728 446,680 Other securities 50,296 — 50,296 35,370 — 35,370 Total other investments $ 392,788 219,249 612,037 266,322 215,728 482,050 1 The maximum exposure to loss includes both the carry value of these investments and the related remaining commitments. In addition, tax credits that have been previously recognized in Other securities are subject to the risk of recapture, which we do not consider significant.
Schedule of Aggregated Summarized Income Statement Financial Information For Partnerships In Our Alternative Investment Portfolio		Income Statement Information Quarter ended September 30, Nine Months ended September 30, ($ in millions) 2021 2020 2021 2020 Net investment income $ 60.4 83.4 $ 550.3 92.9 Realized gains 1,857.6 731.3 4,026.2 1,075.0 Net change in unrealized appreciation 11,188.2 2,230.4 20,767.9 571.6 Net income $ 13,106.2 3,045.1 $ 25,344.4 1,739.5 Alternative investment income included in "Net investment income earned" on our Consolidated Statements of Income $ 42.8 18.7 $ 92.9 8.9
Schedule of Securities Pledged As Collateral		($ in millions) FHLBI Collateral FHLBNY Collateral State and Total U.S. government and government agencies $ — — 22.1 22.1 Obligations of states and political subdivisions — — 4.0 4.0 RMBS 67.8 44.8 — 112.6 CMBS 6.6 14.6 — 21.2 Total pledged as collateral $ 74.4 59.4 26.1 159.9
Schedule of Pre-Tax Net Investment Income Earned		Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Fixed income securities $ 51,683 51,285 $ 157,114 152,617 Commercial mortgage loans ("CMLs") 683 245 1,892 463 Equity securities 2,955 1,948 8,425 5,523 Short-term investments 64 244 204 1,830 Other investments 42,865 18,671 93,158 9,167 Investment expenses (5,218) (4,208) (14,314) (11,004) Net investment income earned $ 93,032 68,185 $ 246,479 158,596
Schedule of realized and unrealized gains (losses) on securities	Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Gross gains on sales $ 7,151 2,975 $ 12,906 15,129 Gross losses on sales (2,505) (2,402) (8,787) (7,841) Net realized gains on disposals 4,646 573 4,119 7,288 Net unrealized (losses) gains on equity securities (3,111) 4,338 15,830 (7,098) Net credit loss (expense) benefit on fixed income securities, AFS (1,334) 2,853 (4,059) (8,011) Net credit loss benefit (expense) on fixed income securities, HTM 6 3 (54) 4 Net credit loss benefit (expense) on CMLs — (2) — (220) Losses on securities for which we have the intent to sell (30) (44) (483) (16,259) Net realized and unrealized gains (losses) $ 177 7,721 $ 15,353 (24,296)
Unrealized Gain (Loss) on Equity Securities		Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Unrealized gains (losses) recognized in income on equity securities: On securities remaining in our portfolio at period end $ 269 4,338 $ 14,767 (7,101) On securities sold during period (3,380) — 1,063 3 Total unrealized (losses) gains recognized in income on equity securities $ (3,111) 4,338 $ 15,830 (7,098)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Schedule of Carrying Values and Estimated Fair Values of Financial Liabilities	September 30, 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 64,955 49,914 66,148 6.70% Senior Notes 99,514 127,279 99,499 127,886 5.375% Senior Notes 294,307 382,961 294,241 383,669 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 65,109 60,000 67,513 Subtotal long-term debt 503,738 640,304 553,654 695,596 Unamortized debt issuance costs (3,228) (3,419) Finance lease obligations 394 508 Total long-term debt $ 500,904 550,743
Schedule of Quantitative Disclosures of Our Financial Assets That Were Measured At Fair Value	September 30, 2021 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Significant Other Significant Unobservable Description Measured on a recurring basis: AFS fixed income securities: U.S. government and government agencies $ 131,058 59,264 71,794 — Foreign government 15,140 — 15,140 — Obligations of states and political subdivisions 1,165,924 — 1,157,920 8,004 Corporate securities 2,544,526 — 2,434,240 110,286 CLO and other ABS 1,339,801 — 1,277,372 62,429 RMBS 816,782 — 816,782 — CMBS 663,839 — 663,839 — Total AFS fixed income securities 6,677,070 59,264 6,437,087 180,719 Equity securities: Common stock 1 322,074 225,911 — — Preferred stock 2,112 2,112 — — Total equity securities 324,186 228,023 — — Short-term investments 355,937 355,937 — — Total assets measured at fair value $ 7,357,193 643,224 6,437,087 180,719 December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets Quoted Prices in Significant Significant Unobservable 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
Schedule of Changes in Fair Value of Securities Using Level 3 Inputs	September 30, 2021 ($ in thousands) Obligations of States and Political Subdivisions Corporate Securities CLO and Other ABS Total Fair value, December 31, 2020 $ 2,894 70,700 56,375 129,969 Total net (losses) gains for the period included in: OCI 9 2,607 206 2,822 Net realized and unrealized (losses) gains — (185) (35) (220) Net investment income earned — 14 9 23 Purchases — 43,833 19,041 62,874 Sales — — — — Issuances — — — — Settlements — (210) (1,750) (1,960) Transfers into Level 3 5,101 981 3,226 9,308 Transfers out of Level 3 — (7,454) (14,643) (22,097) Fair value, September 30, 2021 $ 8,004 110,286 62,429 180,719 Change in unrealized losses for the period included in earnings for assets held at period end — (185) (35) (220) Change in unrealized gains for the period included in OCI for assets held at period end 9 2,607 206 2,822 September 30, 2020 ($ in thousands) Obligation of state 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 (36) (2,415) 732 (1,719) Net realized and unrealized (losses) gains — (456) (247) (703) Net investment income earned — — 3 3 Purchases — 19,002 11,751 30,753 Sales — — — — Issuances — — — — Settlements — (138) (1,030) (1,168) Transfers into Level 3 2,890 4,592 26,401 33,883 Transfers out of Level 3 — — (9,924) (9,924) Fair value, September 30, 2020 $ 2,854 37,636 44,720 85,210 Change in unrealized gains (losses) for the period included in earnings for assets held at period end — (456) (247) (703) Change in unrealized gains (losses) for the period included in OCI for assets held at period end (36) (2,415) 732 (1,719)
Schedule of Quantitative Information of Our Financial Assets and Liabilities That Were Disclosed at Fair Value	September 30, 2021 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Significant Other Significant Financial Assets HTM: Obligations of states and political subdivisions $ 3,619 — 3,619 — Corporate securities 22,418 — 22,418 — Total HTM fixed income securities $ 26,037 — 26,037 — CMLs $ 86,001 — — 86,001 Financial Liabilities Long-term debt: 7.25% Senior Notes $ 64,955 — 64,955 — 6.70% Senior Notes 127,279 — 127,279 — 5.375% Senior Notes 382,961 — 382,961 — 3.03% borrowings from FHLBI 65,109 — 65,109 — Total long-term debt $ 640,304 — 640,304 — December 31, 2020 Fair Value Measurements Using ($ in thousands) Assets/ Quoted Prices in Significant Other Significant 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 — CMLs $ 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 Uncollectible P_2

Allowance for Uncollectible Premiums Receivable (Tables)	9 Months Ended
	Sep. 30, 2021
Premiums Receivable [Abstract]
Premium Receivable, Allowance for Credit Loss [Table Text Block]	Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Balance at beginning of period $ 18,300 $ 21,000 $ 21,000 $ 6,400 Cumulative effect adjustment 1 — — — 1,058 Balance at beginning of period, as adjusted $ 18,300 $ 21,000 $ 21,000 $ 7,458 Current period provision for expected credit losses 180 802 1,721 16,369 Write-offs charged against the allowance for credit losses (2,154) (996) (6,554) (3,272) Recoveries 174 194 333 445 Allowance for credit losses, end of period $ 16,500 $ 21,000 $ 16,500 $ 21,000

Reinsurance (Tables)

Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2021
Reinsurance Disclosures [Abstract]
Reinsurance Recoverable, Credit Quality Indicator [Table Text Block]	September 30, 2021 ($ in thousands) Current Past Due Total Reinsurance Recoverables Financial strength rating of rated reinsurers A++ $ 39,325 $ 13 $ 39,338 A+ 338,912 887 339,799 A 96,071 439 96,510 A- 3,166 271 3,437 B++ — — — B+ — — — Total rated reinsurers $ 477,474 $ 1,610 $ 479,084 Non-rated reinsurers Federal and state pools $ 204,001 $ — $ 204,001 Other than federal and state pools 4,698 29 4,727 Total non-rated reinsurers $ 208,699 $ 29 $ 208,728 Total reinsurance recoverable, gross $ 686,173 $ 1,639 $ 687,812 Less: allowance for credit losses 1 (1,595) Total reinsurance recoverable, net $ 686,217 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: allowance for credit losses 1 (1,777) Total reinsurance recoverable, net $ 587,492
Reinsurance Recoverable, Allowance for Credit Loss [Table Text Block]	($ in thousands) Quarter ended September 30, Nine Months ended September 30, 2021 2020 2021 2020 Balance at beginning of period $ 1,777 2,396 $ 1,777 4,400 Cumulative effect adjustment 1 — — — (2,903) Balance at beginning of period, as adjusted $ 1,777 2,396 $ 1,777 1,497 Current period provision for expected credit losses (182) (565) (182) 334 Write-offs charged against the allowance for credit losses — — — — Recoveries — — — — Allowance for credit losses, end of period $ 1,595 1,831 $ 1,595 1,831 1 Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses .
Schedule of List Of Direct, Assumed, And Ceded Reinsurance Amounts	Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Premiums written: Direct $ 932,752 839,275 $ 2,796,296 2,420,350 Assumed 7,136 5,450 17,541 17,902 Ceded (126,982) (125,217) (369,548) (346,665) Net $ 812,906 719,508 $ 2,444,289 2,091,587 Premiums earned: Direct $ 877,620 803,957 $ 2,568,445 2,292,495 Assumed 6,304 6,147 16,391 18,375 Ceded (116,677) (115,563) (352,111) (333,955) Net $ 767,247 694,541 $ 2,232,725 1,976,915 Loss and loss expenses incurred: Direct $ 655,483 530,192 $ 1,557,063 1,407,000 Assumed 4,143 4,232 10,807 13,430 Ceded (154,357) (86,622) (227,577) (168,355) Net $ 505,269 447,802 $ 1,340,293 1,252,075
Schedule of Ceded Premiums and Losses Related to Flood Operations	Ceded to NFIP Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Ceded premiums written $ (77,697) (77,318) $ (218,520) (213,592) Ceded premiums earned (69,197) (68,427) (203,549) (202,656) Ceded loss and loss expenses incurred (153,713) (48,132) (174,861) (66,219)

Reserve for Loss and Loss Exp_2

Reserve for Loss and Loss Expense (Tables)	9 Months Ended
	Sep. 30, 2021
Insurance Loss Reserves [Abstract]
Schedule of Liability for Unpaid Claims and Claims Adjustment Expense	Nine Months ended September 30, ($ in thousands) 2021 2020 Gross reserve for loss and loss expense, at beginning of year $ 4,260,355 4,067,163 Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year 1 554,269 547,066 Net reserve for loss and loss expense, at beginning of year 3,706,086 3,520,097 Incurred loss and loss expense for claims occurring in the: Current year 1,408,240 1,295,285 Prior years (67,947) (43,210) Total incurred loss and loss expense 1,340,293 1,252,075 Paid loss and loss expense for claims occurring in the: Current year 430,288 421,981 Prior years 675,782 646,974 Total paid loss and loss expense 1,106,070 1,068,955 Net reserve for loss and loss expense, at end of period 3,940,309 3,703,217 Add: Reinsurance recoverable on unpaid loss and loss expense, at end of period 670,031 590,059 Gross reserve for loss and loss expense at end of period $ 4,610,340 4,293,276 1 Nine Months 2020 includes an adjustment of $2.9 million related to our adoption of ASU 2016-13, Financial Instruments - Credit Losses

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Schedule of Revenue By Segment	Revenue by Segment Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Standard Commercial Lines: Net premiums earned: Commercial property $ 111,981 97,997 $ 320,904 287,279 Workers compensation 78,318 75,595 230,845 204,207 General liability 205,904 181,459 596,717 509,312 Commercial automobile 185,610 160,937 535,519 449,162 Businessowners' policies 23,025 27,605 80,963 82,157 Bonds 8,850 9,226 26,436 28,075 Other 5,883 5,266 17,082 15,477 Miscellaneous income 4,168 5,521 13,670 11,107 Total Standard Commercial Lines revenue 623,739 563,606 1,822,136 1,586,776 Standard Personal Lines: Net premiums earned: Personal automobile 40,575 42,458 122,977 123,134 Homeowners 30,633 31,395 91,801 94,537 Other 2,154 2,123 5,698 6,066 Miscellaneous income 420 598 1,242 1,520 Total Standard Personal Lines revenue 73,782 76,574 221,718 225,257 E&S Lines: Net premiums earned: Casualty lines 52,983 43,650 144,458 130,444 Property lines 21,331 16,830 59,325 47,065 Total E&S Lines revenue 74,314 60,480 203,783 177,509 Investments: Net investment income 93,032 68,185 246,479 158,596 Net realized and unrealized investment gains (losses) 177 7,721 15,353 (24,296) Total Investments revenue 93,209 75,906 261,832 134,300 Total revenues $ 865,044 776,566 $ 2,509,469 2,123,842
Schedule of Income Before and After Federal Income Tax	Income Before and After Federal Income Tax Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Standard Commercial Lines: Underwriting gain, before federal income tax $ 17,413 42,718 $ 154,850 76,574 Underwriting gain, after federal income tax 13,756 33,746 122,332 60,493 Combined ratio 97.2 % 92.3 91.4 95.1 ROE contribution 2.1 5.7 6.2 3.5 Standard Personal Lines: Underwriting gain (loss), before federal income tax $ (11,146) (14,404) $ 2,193 (20,342) Underwriting gain (loss), after federal income tax (8,805) (11,379) 1,732 (16,070) Combined ratio 115.2 % 119.0 99.0 109.1 ROE contribution (1.3) (1.9) 0.1 (0.9) E&S Lines: Underwriting gain (loss), before federal income tax $ 4,672 (7,277) $ 7,494 (3,965) Underwriting gain (loss), after federal income tax 3,691 (5,748) 5,920 (3,132) Combined ratio 93.7 % 112.0 96.3 102.2 ROE contribution 0.5 (1.0) 0.3 (0.2) Investments: Net investment income $ 93,032 68,185 $ 246,479 158,596 Net realized and unrealized investment gains (losses) 177 7,721 15,353 (24,296) Total investments segment income, before federal income tax 93,209 75,906 261,832 134,300 Tax on investments segment income 18,379 14,676 51,229 24,338 Total investments segment income, after federal income tax $ 74,830 61,230 $ 210,603 109,962 ROE contribution of after-tax net investment income 11.0 9.4 10.1 7.5
Schedule of Reconciliation of Segment Results to Income Before Federal Income Tax	Reconciliation of Segment Results to Income Before Federal Income Tax Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Underwriting gain Standard Commercial Lines $ 17,413 42,718 $ 154,850 76,574 Standard Personal Lines (11,146) (14,404) 2,193 (20,342) E&S Lines 4,672 (7,277) 7,494 (3,965) Investment income 93,209 75,906 261,832 134,300 Total all segments 104,148 96,943 426,369 186,567 Interest expense (7,242) (7,781) (21,967) (23,310) Corporate expenses (4,270) (3,905) (22,936) (19,310) Income, before federal income tax $ 92,636 85,257 $ 381,466 143,947 Preferred stock dividends (2,300) — (7,053) — Income available to common stockholders, before federal income tax $ 90,336 85,257 $ 374,413 143,947

Retirement Plans (Table)

Retirement Plans (Table)	9 Months Ended
	Sep. 30, 2021
Retirement Benefits [Abstract]
Schedule of Components of Net Periodic Benefit Cost	Pension Plan Pension Plan Quarter ended September 30, Nine Months ended September 30, ($ in thousands) 2021 2020 2021 2020 Net Periodic Pension Cost (Benefit): Interest cost $ 2,148 2,828 $ 6,445 8,484 Expected return on plan assets (5,744) (5,477) (17,232) (16,430) Amortization of unrecognized net actuarial loss 626 704 1,876 2,112 Total net periodic pension benefit 1 $ (2,970) (1,945) $ (8,911) (5,834) 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.
Schedule of Weighted-Average Expense Assumptions	Pension Plan Nine Months ended September 30, 2021 2020 Weighted-Average Expense Assumptions: Discount rate 2.68 % 3.33 % Effective interest rate for calculation of interest cost 2.06 2.95 Expected return on plan assets 5.40 5.80

Comprehensive Income (Tables)

Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2021
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Schedule of Components of Comprehensive Income-Gross and Net of Tax	Third Quarter 2021 ($ in thousands) Gross Tax Net Net income $ 92,636 18,931 73,705 Components of OCI: Unrealized losses on investment securities : Unrealized holding losses during the period (35,285) (7,410) (27,875) Unrealized losses on securities with credit loss recognized in earnings (2,343) (492) (1,851) Amounts reclassified into net income: HTM securities 1 — 1 Net realized gains on disposals and losses on intent-to-sell AFS securities (1,296) (272) (1,024) Credit loss expense 1,334 280 1,054 Total unrealized losses on investment securities (37,589) (7,894) (29,695) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 693 145 548 Total defined benefit pension and post-retirement plans 693 145 548 Other comprehensive loss (36,896) (7,749) (29,147) Comprehensive income $ 55,740 11,182 44,558 Third Quarter 2020 ($ in thousands) Gross Tax Net Net income $ 85,257 15,382 69,875 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during the period 37,836 7,947 29,889 Unrealized gains on securities with credit loss recognized in earnings 9,239 1,940 7,299 Amounts reclassified into net income: HTM securities (1) (1) — Net realized gains on disposals and losses on intent-to-sell AFS securities (515) (109) (406) Credit loss benefit (2,853) (599) (2,254) Total unrealized gains on investment securities 43,706 9,178 34,528 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 754 158 596 Total defined benefit pension and post-retirement plans 754 158 596 Other comprehensive income 44,460 9,336 35,124 Comprehensive income $ 129,717 24,718 104,999 Nine Months 2021 ($ in thousands) Gross Tax Net Net income $ 381,466 76,608 304,858 Components of OCI: Unrealized losses on investment securities : Unrealized holding losses during the period (103,040) (21,638) (81,402) Unrealized losses on securities with credit loss recognized in earnings (3,678) (772) (2,906) Amounts reclassified into net income: HTM securities (4) (1) (3) Net realized gains on disposals and losses on intent-to-sell AFS securities (634) (133) (501) Credit loss expense 4,059 852 3,207 Total unrealized losses on investment securities (103,297) (21,692) (81,605) Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 2,079 436 1,643 Total defined benefit pension and post-retirement plans 2,079 436 1,643 Other comprehensive loss (101,218) (21,256) (79,962) Comprehensive income $ 280,248 55,352 224,896 Nine Months 2020 ($ in thousands) Gross Tax Net Net income $ 143,947 24,653 119,294 Components of OCI: Unrealized gains on investment securities : Unrealized holding gains during the period 132,623 27,852 104,771 Unrealized losses on securities with credit loss recognized in earnings (18,672) (3,921) (14,751) Amounts reclassified into net income: HTM securities (7) (2) (5) Net realized losses on disposals and losses on intent-to-sell AFS securities 9,126 1,916 7,210 Credit loss expense 8,010 1,682 6,328 Total unrealized gains on investment securities 131,080 27,527 103,553 Defined benefit pension and post-retirement plans: Amounts reclassified into net income: Net actuarial loss 2,261 474 1,787 Total defined benefit pension and post-retirement plans 2,261 474 1,787 Other comprehensive income 133,341 28,001 105,340 Comprehensive income $ 277,288 52,654 224,634
Schedule of Components of Accumulated Other Comprehensive Income Net of Tax	September 30, 2021 Defined Benefit Net Unrealized (Losses) Gains on Investment Securities Total AOCI ($ in thousands) Credit Loss Related 1 HTM All Investments Balance, December 31, 2020 $ (2,546) 6 307,790 305,250 (85,064) 220,186 OCI before reclassifications (2,906) — (81,402) (84,308) — (84,308) Amounts reclassified from AOCI 3,207 (3) (501) 2,703 1,643 4,346 Net current period OCI 301 (3) (81,903) (81,605) 1,643 (79,962) Balance, September 30, 2021 $ (2,245) 3 225,887 223,645 (83,421) 140,224
Schedule of Reclassifications Out Of Accumulated Other Comprehensive Income	Quarter ended September 30, Nine Months ended September 30, Affected Line Item in the Unaudited Consolidated Statements of Income ($ in thousands) 2021 2020 2021 2020 HTM related Unrealized (gains) losses on HTM disposals $ (1) 4 $ (1) 5 Net realized and unrealized investment gains (losses) Amortization of net unrealized losses (gains) on HTM securities 2 (5) (3) (12) Net investment income earned 1 (1) (4) (7) Income before federal income tax — 1 1 2 Total federal income tax expense 1 — (3) (5) Net income Net realized (gains) losses on disposals and intent-to-sell AFS securities Net realized (gains) losses on disposals and intent-to-sell AFS securities (1,296) (515) (634) 9,126 Net realized and unrealized investment gains (losses) (1,296) (515) (634) 9,126 Income before federal income tax 272 109 133 (1,916) Total federal income tax expense (1,024) (406) (501) 7,210 Net income Credit loss related Credit loss expense (benefit) 1,334 (2,853) 4,059 8,010 Net realized and unrealized investment gains (losses) 1,334 (2,853) 4,059 8,010 Income before federal income tax (280) 599 (852) (1,682) Total federal income tax expense 1,054 (2,254) 3,207 6,328 Net income Defined benefit pension and post-retirement life plans Net actuarial loss 159 162 478 486 Loss and loss expense incurred 534 592 1,601 1,775 Other insurance expenses Total defined benefit pension and post-retirement life 693 754 2,079 2,261 Income before federal income tax (145) (158) (436) (474) Total federal income tax expense 548 596 1,643 1,787 Net income Total reclassifications for the period $ 579 (2,064) $ 4,346 15,320 Net income

Statements of Cash Flows (Cash

Statements of Cash Flows (Cash Flow Supplemental Disclosures) (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020
Interest		$ 23,278	$ 24,449
Federal income tax		93,000	34,000
Operating cash flows from operating leases		6,480	7,077
Operating cash flows from financing leases		5	13
Financing cash flows from finance leases		298	429
Assets acquired under finance lease arrangements		183	119
Assets acquired under operating lease arrangements		273	22,104
Non-cash purchase of property and equipment		0	9
Available-for-sale Securities
Corporate actions related to securities	[1]	50,501	32,580
Equity Securities [Member]
Corporate actions related to securities	[1]	527	890
Held-to-maturity Securities [Member]
Corporate actions related to securities	[1]	$ 0	$ 2,596
[1]	Examples of corporate actions include exchanges, non-cash acquisitions, and stock splits.

Statements of Cash Flows (Sched

Statements of Cash Flows (Schedule of Cash and Restricted Cash) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Schedule of Cash and Restricted Cash [Line Items]
Cash	$ 477	$ 394
Restricted cash	34,312	14,837
Total cash and restricted cash shown in the Statements of Cash Flows	$ 34,789	$ 15,231	$ 15,895	$ 7,975

Investments (Available-For-Sale

Investments (Available-For-Sale Securities Disclosure) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	$ 6,011	$ 10,395	$ 3,969	$ 0
Allowance for credit losses, Period ending balance	7,169	7,180	7,169	7,180
Interest and dividends due or accrued	46,082		46,082		$ 45,004
Current provision for securities without prior allowance	1,666	1,025	5,139	8,100
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(333)	(3,856)	(1,087)	0
Reductions for securities sold	(95)	(362)	(711)	(830)
Reductions for securities identified as intent (or requirement) to sell during the period	(80)	(22)	(141)	(90)
Debt Securities, Available-for-sale, Fair Value	6,677,070		6,677,070		6,455,928
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	293,966		293,966		397,922
Fixed income securities, available-for-sale, amortized cost	6,401,167		6,401,167		6,073,517
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	10,894		10,894		11,542
Available-for-sale Securities | U.S. Government and Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance			0
Allowance for credit losses, Period ending balance	0		0
Debt Securities, Available-for-sale, Fair Value	131,058		131,058		116,140
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3,600		3,600		6,239
Fixed income securities, available-for-sale, amortized cost	128,415		128,415		110,038
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	957		957		137
Available-for-sale Securities | Foreign Government [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	49	28	1	0
Allowance for credit losses, Period ending balance	47	7	47	7
Current provision for securities without prior allowance	0	0	47	26
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(2)	(2)	(1)	0
Reductions for securities sold	0	(19)	0	(19)
Reductions for securities identified as intent (or requirement) to sell during the period	0	0	0	0
Debt Securities, Available-for-sale, Fair Value	15,140		15,140		18,366
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	695		695		1,569
Fixed income securities, available-for-sale, amortized cost	14,567		14,567		16,801
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	75		75		3
Available-for-sale Securities | Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	38	17	4	0
Allowance for credit losses, Period ending balance	99	15	99	15
Current provision for securities without prior allowance	61	9	84	15
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	0	(11)	11	0
Reductions for securities sold	0	0	0	0
Reductions for securities identified as intent (or requirement) to sell during the period	0	0	0	0
Debt Securities, Available-for-sale, Fair Value	1,165,924		1,165,924		1,247,137
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	71,507		71,507		87,564
Fixed income securities, available-for-sale, amortized cost	1,094,619		1,094,619		1,159,588
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	103		103		11
Available-for-sale Securities | Corporate Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	3,477	8,077	2,782	0
Allowance for credit losses, Period ending balance	4,719	5,358	4,719	5,358
Current provision for securities without prior allowance	1,307	1,016	3,413	6,100
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	64	(3,455)	(765)	0
Reductions for securities sold	(49)	(265)	(570)	(659)
Reductions for securities identified as intent (or requirement) to sell during the period	(80)	(15)	(141)	(83)
Debt Securities, Available-for-sale, Fair Value	2,544,526		2,544,526		2,328,052
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	131,442		131,442		180,971
Fixed income securities, available-for-sale, amortized cost	2,420,904		2,420,904		2,152,203
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,101		3,101		2,340
Available-for-sale Securities | Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	1,399	1,389	592	0
Allowance for credit losses, Period ending balance	926	1,121	926	1,121
Current provision for securities without prior allowance	46	0	573	1,237
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(517)	(210)	(219)	0
Reductions for securities sold	(2)	(51)	(20)	(109)
Reductions for securities identified as intent (or requirement) to sell during the period	0	(7)	0	(7)
Debt Securities, Available-for-sale, Fair Value	1,339,801		1,339,801		1,026,551
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	18,896		18,896		20,166
Fixed income securities, available-for-sale, amortized cost	1,326,348		1,326,348		1,014,820
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	4,517		4,517		7,843
Available-for-sale Securities | Residential Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	1,034	831	561	0
Allowance for credit losses, Period ending balance	1,363	647	1,363	647
Current provision for securities without prior allowance	248	0	1,018	690
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	125	(157)	(95)	0
Reductions for securities sold	(44)	(27)	(121)	(43)
Reductions for securities identified as intent (or requirement) to sell during the period	0	0	0	0
Debt Securities, Available-for-sale, Fair Value	816,782		816,782		1,051,788
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	33,361		33,361		53,065
Fixed income securities, available-for-sale, amortized cost	785,840		785,840		999,485
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,056		1,056		201
Available-for-sale Securities | Commercial Mortgage Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Allowance for credit losses, Period beginning balance	14	53	29	0
Allowance for credit losses, Period ending balance	15	32	15	32
Current provision for securities without prior allowance	4	0	4	32
Increase or (Decrease) on securities with prior allowance, excluding intent (or Requirements) to sell securities	(3)	(21)	(18)	0
Reductions for securities sold	0	0	0	0
Reductions for securities identified as intent (or requirement) to sell during the period	0	$ 0	0	$ 0
Debt Securities, Available-for-sale, Fair Value	663,839		663,839		667,894
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	34,465		34,465		48,348
Fixed income securities, available-for-sale, amortized cost	630,474		630,474		620,582
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,085		1,085		1,007
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Interest and dividends due or accrued	$ 44,900		$ 44,900		$ 43,800

Investments (Fair Value and Gro

Investments (Fair Value and Gross Pre-Tax Net Unrealized Loss of Securities By Length of Time) (Details) - Available-for-sale Securities - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
AFS Fair Value, Less than 12 Months	$ 984,751	$ 415,506
AFS Unrealized Losses, Less than 12 months	(9,904)	(6,108)
AFS Fair Value, 12 months or longer	68,027	185,335
AFS Unrealized Losses, 12 months or longer	(990)	(5,434)
AFS Fair Value	1,052,778	600,841
AFS Unrealized Losses	(10,894)	(11,542)
U.S. Government and Government Agencies [Member]
AFS Fair Value, Less than 12 Months	34,717	11,519
AFS Unrealized Losses, Less than 12 months	(940)	(137)
AFS Fair Value, 12 months or longer	156	0
AFS Unrealized Losses, 12 months or longer	(17)	0
AFS Fair Value	34,873	11,519
AFS Unrealized Losses	(957)	(137)
Foreign Government [Member]
AFS Fair Value, Less than 12 Months	3,114	1,122
AFS Unrealized Losses, Less than 12 months	(75)	(3)
AFS Fair Value, 12 months or longer	0	0
AFS Unrealized Losses, 12 months or longer	0	0
AFS Fair Value	3,114	1,122
AFS Unrealized Losses	(75)	(3)
Obligations of States and Political Subdivisions [Member]
AFS Fair Value, Less than 12 Months	7,936	2,223
AFS Unrealized Losses, Less than 12 months	(103)	(11)
AFS Fair Value, 12 months or longer	0	0
AFS Unrealized Losses, 12 months or longer	0	0
AFS Fair Value	7,936	2,223
AFS Unrealized Losses	(103)	(11)
Corporate Securities [Member]
AFS Fair Value, Less than 12 Months	236,164	65,187
AFS Unrealized Losses, Less than 12 months	(3,067)	(2,152)
AFS Fair Value, 12 months or longer	2,412	2,400
AFS Unrealized Losses, 12 months or longer	(34)	(188)
AFS Fair Value	238,576	67,587
AFS Unrealized Losses	(3,101)	(2,340)
Collateralized Loan Obligations and Other Asset Backed Securities [Member]
AFS Fair Value, Less than 12 Months	515,458	261,746
AFS Unrealized Losses, Less than 12 months	(3,723)	(2,995)
AFS Fair Value, 12 months or longer	57,153	165,661
AFS Unrealized Losses, 12 months or longer	(794)	(4,848)
AFS Fair Value	572,611	427,407
AFS Unrealized Losses	(4,517)	(7,843)
Residential Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 Months	111,648	18,227
AFS Unrealized Losses, Less than 12 months	(1,055)	(194)
AFS Fair Value, 12 months or longer	20	1,181
AFS Unrealized Losses, 12 months or longer	(1)	(7)
AFS Fair Value	111,668	19,408
AFS Unrealized Losses	(1,056)	(201)
Commercial Mortgage Backed Securities [Member]
AFS Fair Value, Less than 12 Months	75,714	55,482
AFS Unrealized Losses, Less than 12 months	(941)	(616)
AFS Fair Value, 12 months or longer	8,286	16,093
AFS Unrealized Losses, 12 months or longer	(144)	(391)
AFS Fair Value	84,000	71,575
AFS Unrealized Losses	$ (1,085)	$ (1,007)

Investments (Fixed Income Secur

Investments (Fixed Income Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule of Fixed Income Securities [Line Items]
Due in one year or less fair value, AFS	$ 511,751
Due after one year through five years fair value, AFS	3,389,351
Due after five years through 10 years fair value, AFS	2,101,275
Due after 10 years fair value, AFS	674,693
Total AFS fixed income securities, Fair Value	6,677,070	$ 6,455,928
Due in one year or less carrying value, HTM	32
Due after one year through five years carrying value, HTM	14,548
Due after five years through 10 years carrying value, HTM	10,672
Due after 10 years carrying value, HTM	0
Total HTM fixed income securities carrying value	25,252	16,824
Due in one year or less fair value, HTM	33
Due after one year through five years fair value, HTM	15,340
Due after five years through 10 years fair value, HTM	10,664
Due after 10 years fair value, HTM	0
Total HTM fixed income securities, Fair Value	$ 26,037	$ 18,001

Investments (Other Investment P

Investments (Other Investment Portfolio by Strategy and the Remaining Commitment Amount and Maximum Exposure to Loss Associated With Each Strategy) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Net investment income earned		$ 93,032	$ 68,185	$ 246,479	$ 158,596
Carrying Value		392,788		392,788		$ 266,322
Alternative Investments [Member]
Net investment income earned		42,800	$ 18,700	92,900	$ 8,900
Other Securities [Member]
Carrying Value		50,296		50,296		35,370
Remaining Commitment		0		0		0
Maximum Exposure to Loss	[1]	50,296		50,296		35,370
Alternative Investments [Member]
Carrying Value		342,492		342,492		230,952
Remaining Commitment		219,249		219,249		215,728
Maximum Exposure to Loss	[1]	561,741		561,741		446,680
Alternative Investments [Member] | Private Equity Funds [Member]
Carrying Value		257,160		257,160		157,276
Remaining Commitment		103,792		103,792		100,905
Maximum Exposure to Loss	[1]	360,952		360,952		258,181
Alternative Investments [Member] | Private Credit Funds [Member]
Carrying Value		62,462		62,462		54,017
Remaining Commitment		91,991		91,991		98,330
Maximum Exposure to Loss	[1]	154,453		154,453		152,347
Alternative Investments [Member] | Real Assets [Member]
Carrying Value		22,870		22,870		19,659
Remaining Commitment		23,466		23,466		16,493
Maximum Exposure to Loss	[1]	46,336		46,336		36,152
Other Investments [Member]
Carrying Value		392,788		392,788		266,322
Remaining Commitment		219,249		219,249		215,728
Maximum Exposure to Loss	[1]	$ 612,037		$ 612,037		$ 482,050
[1]	The maximum exposure to loss includes both the carry value of these investments and the related remaining commitments. In addition, tax credits that have been previously recognized in Other securities are subject to the risk of recapture, which we do not consider significant.

Investments (Aggregated Income

Investments (Aggregated Income Statement Summarized Financial Information for Partnerhips in our Alternative Investment Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Net investment income earned	$ 93,032	$ 68,185	$ 246,479	$ 158,596
Carrying Value	392,788		392,788		$ 266,322
Alternative Investments [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income earned	42,800	18,700	92,900	8,900
Investments accounted for under the equity method [Member]
Schedule of Equity Method Investments [Line Items]
Net investment income	60,400	83,400	550,300	92,900
Realized gains	1,857,600	731,300	4,026,200	1,075,000
Net change in unrealized appreciation	11,188,200	2,230,400	20,767,900	571,600
Insurance Subsidiaries' alternative investments income	$ 13,106,200	$ 3,045,100	$ 25,344,400	$ 1,739,500

Investments (Investments Pledge

Investments (Investments Pledged as Collateral) (Details) $ in Millions	Sep. 30, 2021USD ($)
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral On Deposit With Various State And Regulatory Agencies	$ 26.1
Securities Pledged As Collateral	159.9
Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	74.4
Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	59.4
U.S. Government and Government Agencies [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral On Deposit With Various State And Regulatory Agencies	22.1
Securities Pledged As Collateral	22.1
U.S. Government and Government Agencies [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	0
U.S. Government and Government Agencies [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	0
Obligations of States and Political Subdivisions [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral On Deposit With Various State And Regulatory Agencies	4
Securities Pledged As Collateral	4
Obligations of States and Political Subdivisions [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	0
Obligations of States and Political Subdivisions [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	0
Residential Mortgage Backed Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	112.6
Residential Mortgage Backed Securities [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	67.8
Residential Mortgage Backed Securities [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	44.8
Commercial Mortgage Backed Securities [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral On Deposit With Various State And Regulatory Agencies	0
Securities Pledged As Collateral	21.2
Commercial Mortgage Backed Securities [Member] | Federal Home Loan Bank of Indianapolis [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	6.6
Commercial Mortgage Backed Securities [Member] | Federal Home Loan Bank of New York [Member]
Financial Instruments Owned and Pledged as Collateral [Line Items]
Securities Pledged as Collateral on FHLB	$ 14.6

Investments (Credit Concentrati

Investments (Credit Concentration Risk) (Details)	Sep. 30, 2021	Dec. 31, 2020
Investments [Abstract]
Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government-backed investments	10.00%	10.00%

Investments (Net Investment Inc

Investments (Net Investment Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net Investment Income [Line Items]
Net investment income earned	$ 93,032	$ 68,185	$ 246,479	$ 158,596
Investment Expense	(5,218)	(4,208)	(14,314)	(11,004)
Fixed Income Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	51,683	51,285	157,114	152,617
Commercial Mortgage Loans [Member]
Net Investment Income [Line Items]
Net investment income earned	683	245	1,892	463
Equity Securities [Member]
Net Investment Income [Line Items]
Net investment income earned	2,955	1,948	8,425	5,523
Short-Term Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	64	244	204	1,830
Other Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	42,865	18,671	93,158	9,167
Alternative Investments [Member]
Net Investment Income [Line Items]
Net investment income earned	$ 42,800	$ 18,700	$ 92,900	$ 8,900

Investments (Net Realized and U

Investments (Net Realized and Unrealized Investment Gains and (Losses)) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Gain (Loss) on Securities [Line Items]
Gross gains on sales	$ 7,151	$ 2,975	$ 12,906	$ 15,129
Gross losses on sales	(2,505)	(2,402)	(8,787)	(7,841)
Debt and Equity Securities, Realized Gain (Loss)	4,646	573	4,119	7,288
Net unrealized gains (losses) on equity securities	(3,111)	4,338	15,830	(7,098)
Losses on securities for which we have the intent to sell	(30)	(44)	(483)	(16,259)
Net realized and unrealized investment gains (losses)	177	7,721	15,353	(24,296)
Available-for-sale Securities [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss benefit (expense) on fixed maturities	(1,334)	2,853	(4,059)	(8,011)
Held-to-maturity Securities [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss benefit (expense) on fixed maturities	6	3	(54)	4
Commercial Mortgage Loans [Member]
Gain (Loss) on Securities [Line Items]
Net credit loss benefit (expense) on fixed maturities	$ 0	$ (2)	$ 0	$ (220)

Investments (Unrealized Gains (

Investments (Unrealized Gains (Losses) on Equity Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Gain (Loss) on Securities [Line Items]
Unrealized gains (losses) recognized in income on equity securities on securities remaining in our portfolio at June 30, 2021	$ 269	$ 4,338	$ 14,767	$ (7,101)
Unrealized (losses) gains recognized in income on equity securities on securities sold during period	(3,380)	0	1,063	3
Total unrealized (losses) gains recognized in income on equity securities	$ (3,111)	$ 4,338	$ 15,830	$ (7,098)

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Values and Estimated Fair Values of Financial Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance lease liabilities	$ 394	$ 508
Long-term debt, carrying amount	500,904	550,743
Long-term debt, fair value	640,304	695,596
Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	64,955	66,148
Seven Point Twenty Five Percent Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	49,917	49,914
Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	127,279	127,886
Six Point Seventy Percent Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	99,514	99,499
Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	382,961	383,669
Five Point Three Hundred Seventy Five Senior Notes [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	294,307	294,241
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	25,182
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	0	25,000
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	25,198
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	0	25,000
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	65,109	67,513
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	60,000	60,000
Long Term Debt Excluding Issuance Costs and Finance Lease Obligations [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying amount	503,738	553,654
Unamortized Debt Issuance Costs [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unamortized debt issuance costs	$ (3,228)	$ (3,419)

Fair Value Measurements (Quanti

Fair Value Measurements (Quantitative Disclosures of Fair Value Assets) (Details) - USD ($) $ in Thousands		Sep. 30, 2021	Dec. 31, 2020
AFS Fixed Income Securities		$ 6,677,070	$ 6,455,928
Equity Securities		324,186	310,367
Short-term investments		355,937	409,852
Net Asset Value	[1]	96,200	46,800
Fair Value, Recurring [Member]
AFS Fixed Income Securities		6,677,070	6,455,928
Equity Securities		324,186	310,367
Short-term investments		355,937	409,852
Total assets measured at fair value		7,357,193	7,176,147
U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		131,058	116,140
Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		15,140	18,366
Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,165,924	1,247,137
Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		2,544,526	2,328,052
Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,339,801	1,026,551
Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		816,782	1,051,788
Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		663,839	667,894
Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	322,074	308,632
Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		2,112	1,735
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		59,264	40,960
Equity Securities		228,023	263,581
Short-term investments		355,937	405,400
Total assets measured at fair value		643,224	709,941
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		59,264	40,960
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		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]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		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]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	225,911	261,846
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		2,112	1,735
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		6,437,087	6,284,999
Equity Securities		0	0
Short-term investments		0	4,452
Total assets measured at fair value		6,437,087	6,289,451
Significant Other Observable Inputs (Level 2) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		71,794	75,180
Significant Other Observable Inputs (Level 2) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		15,140	18,366
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,157,920	1,244,243
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		2,434,240	2,257,352
Significant Other Observable Inputs (Level 2) [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		1,277,372	970,176
Significant Other Observable Inputs (Level 2) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		816,782	1,051,788
Significant Other Observable Inputs (Level 2) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		663,839	667,894
Significant Other Observable Inputs (Level 2) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	0	0
Significant Other Observable Inputs (Level 2) [Member] | Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		180,719	129,969
Equity Securities		0	0
Short-term investments		0	0
Total assets measured at fair value		180,719	129,969
Significant Unobservable Inputs (Level 3) [Member] | U.S. Government and Government Agencies [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Foreign Government [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		8,004	2,894
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		110,286	70,700
Significant Unobservable Inputs (Level 3) [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		62,429	56,375
Significant Unobservable Inputs (Level 3) [Member] | Residential Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Commercial Mortgage Backed Securities [Member] | Fair Value, Recurring [Member]
AFS Fixed Income Securities		0	0
Significant Unobservable Inputs (Level 3) [Member] | Common Stock [Member] | Fair Value, Recurring [Member]
Equity Securities	[1]	0	0
Significant Unobservable Inputs (Level 3) [Member] | Preferred Stock [Member] | Fair Value, Recurring [Member]
Equity Securities		$ 0	$ 0
[1]	Investments amounting to $96.2 million at September 30, 2021, and $46.8 million at December 31, 2020, were measured at fair value using net asset value per share (or its practical expedient) and are not 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 in this table enables reconciliation of the fair value hierarchy to total assets measured at fair value.

Fair Value Measurements (Change

Fair Value Measurements (Change in Fair Value of Securities Using Level 3 Inputs) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31	$ 2,894	$ 0
Total net (losses) gains for the period included in OCI	9	(36)
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	5,101	2,890
Transfers out of Level 3	0	0
Fair value, September 30	8,004	2,854
Period change unrealized losses in earnings for assets held at period end	0	0
Period change unrealized gains in OCI for assets held at period end	9	(36)
Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31	70,700	17,051
Total net (losses) gains for the period included in OCI	2,607	(2,415)
Purchases	43,833	19,002
Sales	0	0
Issuances	0	0
Settlements	(210)	(138)
Transfers into Level 3	981	4,592
Transfers out of Level 3	(7,454)	0
Fair value, September 30	110,286	37,636
Period change unrealized losses in earnings for assets held at period end	(185)	(456)
Period change unrealized gains in OCI for assets held at period end	2,607	(2,415)
Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31	56,375	17,034
Total net (losses) gains for the period included in OCI	206	732
Purchases	19,041	11,751
Sales	0	0
Issuances	0	0
Settlements	(1,750)	(1,030)
Transfers into Level 3	3,226	26,401
Transfers out of Level 3	(14,643)	(9,924)
Fair value, September 30	62,429	44,720
Period change unrealized losses in earnings for assets held at period end	(35)	(247)
Period change unrealized gains in OCI for assets held at period end	206	732
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value, December 31	129,969	34,085
Total net (losses) gains for the period included in OCI	2,822	(1,719)
Purchases	62,874	30,753
Sales	0	0
Issuances	0	0
Settlements	(1,960)	(1,168)
Transfers into Level 3	9,308	33,883
Transfers out of Level 3	(22,097)	(9,924)
Fair value, September 30	180,719	85,210
Period change unrealized losses in earnings for assets held at period end	(220)	(703)
Period change unrealized gains in OCI for assets held at period end	2,822	(1,719)
Gain (Loss) on Investments [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	0	0
Gain (Loss) on Investments [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	(185)	(456)
Gain (Loss) on Investments [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	(35)	(247)
Gain (Loss) on Investments [Member] | Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	(220)	(703)
Net Investment Income Earned [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	0	0
Net Investment Income Earned [Member] | Corporate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	14	0
Net Investment Income Earned [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	9	3
Net Investment Income Earned [Member] | Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total net (losses) gains for the period included in net income	$ 23	$ 3

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	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	$ 26,037	$ 18,001
Long-term debt, fair value	640,304	695,596
Commercial mortgage loan, fair value	86,001	47,289
Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	64,955	66,148
Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	127,279	127,886
Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	382,961	383,669
One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	25,182
One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	25,198
Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	65,109	67,513
Long-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	640,304	695,596
Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	3,619	4,795
Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	22,418	13,206
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	0	0
Long-term debt, fair value	0	0
Commercial mortgage loan, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, 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, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	0	0
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1) [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	26,037	18,001
Long-term debt, fair value	640,304	695,596
Commercial mortgage loan, fair value	0	0
Significant Other Observable Inputs (Level 2) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	64,955	66,148
Significant Other Observable Inputs (Level 2) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	127,279	127,886
Significant Other Observable Inputs (Level 2) [Member] | Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	382,961	383,669
Significant Other Observable Inputs (Level 2) [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		25,182
Significant Other Observable Inputs (Level 2) [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		25,198
Significant Other Observable Inputs (Level 2) [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	65,109	67,513
Significant Other Observable Inputs (Level 2) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	3,619	4,795
Significant Other Observable Inputs (Level 2) [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	22,418	13,206
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	0	0
Long-term debt, fair value	0	0
Commercial mortgage loan, fair value	86,001	47,289
Significant Unobservable Inputs (Level 3) [Member] | Seven Point Twenty Five Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Six Point Seventy Percent Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Five Point Three Hundred Seventy Five Senior Notes [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		0
Significant Unobservable Inputs (Level 3) [Member] | One Point Fifty Six Percent Borrowing From Federal Home Loan Bank Due August 16, 2021 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value		0
Significant Unobservable Inputs (Level 3) [Member] | Three Point Zero Three Percent Borrowing From Federal Home Loan Bank Due December 16, 2026 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Obligations of States and Political Subdivisions [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	0	0
Significant Unobservable Inputs (Level 3) [Member] | Corporate Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fixed income securities, held-to-maturity - fair value	$ 0	$ 0

Allowance for Uncollectible P_3

Allowance for Uncollectible Premiums Receivable (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss	$ 16,500		$ 16,500		$ 18,300	$ 21,000	$ 21,000	$ 6,400
Allowance for credit losses, net of write-offs				$ 13,500
Premiums Receivable [Member]
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss	16,500	$ 21,000	16,500	21,000	18,300	21,000	21,000	7,458
Current period provision for expected credit losses	180	802	1,721	16,369
Write-offs charged against the allowance for credit losses	(2,154)	(996)	(6,554)	(3,272)
Recoveries	$ 174	$ 194	$ 333	$ 445
Premiums Receivable [Member] | Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member]
Premiums Receiveable, Allowance for Credit Loss [Line Items]
Premium Receivable, Allowance for Credit Loss					$ 0	$ 0	$ 0	$ 1,058	[1]
[1]	Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses .

Reinsurance Recoverable Credit

Reinsurance Recoverable Credit Ratings (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance recoverable	$ 687,812		$ 589,269
Reinsurance Recoverable, Allowance for Credit Loss	(1,595)	$ (1,777)	(1,777)	$ (1,831)	$ (2,396)	$ (4,400)
Reinsurance recoverable, net of allowance for credit losses	686,217		587,492
Change in Total Reinsurance Recoverables, net	98,700
AM Best, A++ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	39,338		37,566
AM Best, A++ Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	13		102
AM Best, A++ Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	39,325		37,464
AM Best, A+ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	339,799		357,298
AM Best, A+ Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	887		2,452
AM Best, A+ Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	338,912		354,846
AM Best, A Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	96,510		106,067
AM Best, A Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	439		415
AM Best, A Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	96,071		105,652
AM Best, A- Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	3,437		2,139
AM Best, A- Rating [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	271		0
AM Best, A- Rating [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	3,166		2,139
AM Best, B++ Rating [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0		380
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] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0		56
AM Best, B+ Rating [Member]
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, B+ Rating [Member] | Financial Asset, Not 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	479,084		503,450
AM Best Rated Reinsurer [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	1,610		3,293
AM Best Rated Reinsurer [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	477,474		500,157
Total federal and state pools [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	204,001		82,575
Total federal and state pools [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	0		0
Total federal and state pools [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	204,001		82,575
Other than Federal And State Pools [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	4,727		3,244
Other than Federal And State Pools [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	29		568
Other than Federal And State Pools [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	4,698		2,676
Total Non Rated Reinsurer [Member]
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	208,728		85,819
Total Non Rated Reinsurer [Member] | Financial Asset, Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	29		568
Total Non Rated Reinsurer [Member] | Financial Asset, Not Past Due
Reinsurance Recoverable, Credit Quality Indicator [Line Items]
Reinsurance Recoverables, Gross	208,699		85,251
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	1,639		3,861
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	$ 686,173		$ 585,408

Reinsurance Allowance for Credi

Reinsurance Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	$ 1,777	$ 2,396	$ 1,777	$ 4,400
Current period provision for expected credit losses	(182)	(565)	(182)	334
Write-offs charged against the allowance for credit losses	0	0	0	0
Recoveries	0	0	0	0
Allowance for credit losses, end of period	1,595	1,831	1,595	1,831
Reinsurance Recoverable [Domain]
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	1,777	2,396	1,777	1,497
Retained Earnings [Member] | Reinsurance Recoverable [Domain] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses, beginning of period	$ 0	$ 0	$ 0	$ (2,903)	[1]
[1]	Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses .

Reinsurance (List of Direct, As

Reinsurance (List of Direct, Assumed, and Ceded Reinsurance Amounts) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Premiums written:
Change in Direct Premiums Written					$ 375,900
Change in Direct Premiums Written Percentage					16.00%
Premiums earned:
Net	$ 767,247	$ 694,541			$ 2,232,725	$ 1,976,915
Loss and loss expenses incurred:
Net	$ 505,269	447,802			1,340,293	1,252,075
COVID-19 [Member] | Commercial & Personal Automobile [Member] | Premium Credit [Member]
Premiums written:
Direct			$ 19,700
Return audit and midterm endorsement premium [Member] | COVID-19 [Member]
Premiums written:
Direct				$ 75,000
Change in Direct Premiums Written Percentage	4.00%
Direct Assumed and Ceded Reinsurance Amounts [Member]
Premiums written:
Direct	$ 932,752	839,275			2,796,296	2,420,350
Assumed	7,136	5,450			17,541	17,902
Ceded	(126,982)	(125,217)			(369,548)	(346,665)
Net	812,906	719,508			2,444,289	2,091,587
Premiums earned:
Direct	877,620	803,957			2,568,445	2,292,495
Assumed	6,304	6,147			16,391	18,375
Ceded	(116,677)	(115,563)			(352,111)	(333,955)
Net	767,247	694,541			2,232,725	1,976,915
Loss and loss expenses incurred:
Direct	655,483	530,192			1,557,063	1,407,000
Assumed	4,143	4,232			10,807	13,430
Ceded	(154,357)	(86,622)			(227,577)	(168,355)
Net	$ 505,269	$ 447,802			$ 1,340,293	$ 1,252,075

Reinsurance (Ceded Premiums and

Reinsurance (Ceded Premiums and Losses Related to Flood Operations) (Details) - National Flood Insurance Program [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Percentage of NFIP claims ceded by federal government			100.00%
Ceded premiums written	$ (77,697)	$ (77,318)	$ (218,520)	$ (213,592)
Ceded premiums earned	(69,197)	(68,427)	(203,549)	(202,656)
Ceded loss and loss expenses incurred	$ (153,713)	$ (48,132)	$ (174,861)	$ (66,219)

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	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Liability for Claims and Claims Adjustment Expense [Line Items]
Gross reserve for loss and loss expense, at beginning of year	$ 4,260,355	$ 4,067,163
Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year	554,269	547,066
Net reserve for loss and loss expense, at beginning of year	3,706,086	3,520,097
Incurred loss and loss expense for claims occurring in the current year	1,408,240	1,295,285
Total incurred loss and loss expense	1,340,293	1,252,075
Paid loss and loss expense for claims occurring in the current year	430,288	421,981
Paid loss and loss expense for claims occurring in the prior years	675,782	646,974
Total paid loss and loss expense	1,106,070	1,068,955
Net reserve for loss and loss expense, at end of period	3,940,309	3,703,217
Add: reinsurance recoverable on unpaid loss and loss expense, at end of period	670,031	590,059
Gross reserve for loss and loss expense, at end of period	4,610,340	4,293,276
Allowance for credit losses	(1,595)	(1,831)	$ (1,777)	$ (1,777)	$ (2,396)	$ (4,400)
Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development	(67,947)	(43,210)
Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development	(66,000)	(50,000)
Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member] | Workers' Compensation Insurance [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development	(28,000)	(40,000)
Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member] | General Liability [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development	(29,000)	(20,000)
Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member] | Commercial Automobile [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development		10,000
Property Insurance [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development		$ 6,800
E&S Lines | Casualty Insurance Product Line [Member] | Change in Historical Claim Rate Experience [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Prior year development	$ (7,000)
Reinsurance Recoverable [Domain]
Liability for Claims and Claims Adjustment Expense [Line Items]
Allowance for credit losses			(1,777)	(1,777)	(2,396)	(1,497)
Reinsurance Recoverable [Domain] | Retained Earnings [Member] | Accounting Standards Update 2016-13 [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Allowance for credit losses			$ 0	$ 0	$ 0	$ 2,903	[1]
[1]	Represents the impact of our adoption of ASU 2016-13, Financial Instruments - Credit Losses .

Segment Information Narrative (

Segment Information Narrative (Details)	9 Months Ended
	Sep. 30, 2021
Number of Operating Segments	4

Segment Information (Revenue by

Segment Information (Revenue by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Total net premiums earned	$ 767,247	$ 694,541	$ 2,232,725	$ 1,976,915
Miscellaneous income	4,588	6,119	14,912	12,627
Net investment income	93,032	68,185	246,479	158,596
Net realized and unrealized investment gains (losses)	177	7,721	15,353	(24,296)
Total Investments revenue	93,209	75,906	261,832	134,300
Total revenues	865,044	776,566	2,509,469	2,123,842
Standard Commercial Lines
Segment Reporting Information [Line Items]
Miscellaneous income	4,168	5,521	13,670	11,107
Total revenues	623,739	563,606	1,822,136	1,586,776
Standard Commercial Lines | Commercial Property [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	111,981	97,997	320,904	287,279
Standard Commercial Lines | Workers Compensation [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	78,318	75,595	230,845	204,207
Standard Commercial Lines | General Liability [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	205,904	181,459	596,717	509,312
Standard Commercial Lines | Commercial Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	185,610	160,937	535,519	449,162
Standard Commercial Lines | Business Owners Policies [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	23,025	27,605	80,963	82,157
Standard Commercial Lines | Bonds Segment [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	8,850	9,226	26,436	28,075
Standard Commercial Lines | Other Commercial [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	5,883	5,266	17,082	15,477
Standard Personal Lines
Segment Reporting Information [Line Items]
Miscellaneous income	420	598	1,242	1,520
Total revenues	73,782	76,574	221,718	225,257
Standard Personal Lines | Personal Automobile [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	40,575	42,458	122,977	123,134
Standard Personal Lines | Homeowners [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	30,633	31,395	91,801	94,537
Standard Personal Lines | Other Personal [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	2,154	2,123	5,698	6,066
E&S Lines
Segment Reporting Information [Line Items]
Total revenues	74,314	60,480	203,783	177,509
E&S Lines | Casualty Insurance Product Line [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	52,983	43,650	144,458	130,444
E&S Lines | Property Insurance [Member]
Segment Reporting Information [Line Items]
Total net premiums earned	$ 21,331	$ 16,830	$ 59,325	$ 47,065

Segment Information (Income Bef

Segment Information (Income Before and After Federal Income Tax) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Net investment income	$ 93,032	$ 68,185	$ 246,479	$ 158,596
Net realized and unrealized investment gains (losses)	177	7,721	15,353	(24,296)
Total investment segment income, before federal income tax	93,209	75,906	261,832	134,300
Tax on investment income	18,379	14,676	51,229	24,338
Total investment segment income, after federal income tax	74,830	61,230	210,603	109,962
Standard Commercial Lines
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	17,413	42,718	154,850	76,574
Underwriting gain (loss), after federal income tax	$ 13,756	$ 33,746	$ 122,332	$ 60,493
Combined ratio	97.20%	92.30%	91.40%	95.10%
ROE Contribution	2.10%	5.70%	6.20%	3.50%
Standard Personal Lines
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ (11,146)	$ (14,404)	$ 2,193	$ (20,342)
Underwriting gain (loss), after federal income tax	$ (8,805)	$ (11,379)	$ 1,732	$ (16,070)
Combined ratio	115.20%	119.00%	99.00%	109.10%
ROE Contribution	(1.30%)	(1.90%)	0.10%	(0.90%)
E&S Lines
Segment Reporting Information [Line Items]
Underwriting gain (loss), before federal income tax	$ 4,672	$ (7,277)	$ 7,494	$ (3,965)
Underwriting gain (loss), after federal income tax	$ 3,691	$ (5,748)	$ 5,920	$ (3,132)
Combined ratio	93.70%	112.00%	96.30%	102.20%
ROE Contribution	0.50%	(1.00%)	0.30%	(0.20%)
Investments
Segment Reporting Information [Line Items]
ROE Contribution	11.00%	9.40%	10.10%	7.50%

Segment Information (Reconcilia

Segment Information (Reconciliation of Segment Results to Income Before Federal Income Tax (Details)) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Investment income	$ 93,209	$ 75,906	$ 261,832	$ 134,300
Interest expense	(7,242)	(7,781)	(21,967)	(23,310)
Corporate expenses	(4,270)	(3,905)	(22,936)	(19,310)
Income before federal income tax	92,636	85,257	381,466	143,947
Preferred stock dividends	(2,300)	0	(7,053)	0
Income available to common stockholders, before tax	90,336	85,257	374,413	143,947
Standard Commercial Lines
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	$ 17,413	$ 42,718	$ 154,850	$ 76,574
ROE Contribution	2.10%	5.70%	6.20%	3.50%
Standard Personal Lines
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	$ (11,146)	$ (14,404)	$ 2,193	$ (20,342)
ROE Contribution	(1.30%)	(1.90%)	0.10%	(0.90%)
E&S Lines
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Underwriting gain (loss), before federal income tax	$ 4,672	$ (7,277)	$ 7,494	$ (3,965)
ROE Contribution	0.50%	(1.00%)	0.30%	(0.20%)
Investments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
ROE Contribution	11.00%	9.40%	10.10%	7.50%
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total income, before federal income tax all segments	$ 104,148	$ 96,943	$ 426,369	$ 186,567

Retirement Plans (Components of

Retirement Plans (Components of Net Periodic Benefit Cost) (Details) - Pension Plan [Member] - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost		$ 2,148	$ 2,828	$ 6,445	$ 8,484
Expected return on plan assets		(5,744)	(5,477)	(17,232)	(16,430)
Amortization of unrecognized net actuarial loss		626	704	1,876	2,112
Total net periodic pension benefit	[1]	$ (2,970)	$ (1,945)	$ (8,911)	$ (5,834)
[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) - Pension Plan [Member]	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.68%	3.33%
Effective interest rate for calculation of interest cost	2.06%	2.95%
Expected return on plan assets	5.40%	5.80%

Comprehensive Income (Component

Comprehensive Income (Components of Comprehensive Income-Gross and Net of Tax) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net income, Gross	$ 92,636	$ 85,257	$ 381,466	$ 143,947
Unrealized holding gains (losses) during the period, Gross	(35,285)	37,836	(103,040)	132,623
Unrealized gains (losses) on securities with credit loss recognized in earnings; Gross	(2,343)	9,239	(3,678)	(18,672)
Amounts reclassified into net income: HTM securities, Gross	1	(1)	(4)	(7)
Amounts reclassified into net income: Net realized losses (gains) on disposals and losses on intent-to-sell AFS securities, Gross	(1,296)	(515)	(634)	9,126
Amounts reclassified into net income: Credit loss (benefit) expense, Gross	1,334	(2,853)	4,059	8,010
Total unrealized gains (losses) on investment securities, Gross	(37,589)	43,706	(103,297)	131,080
Amount reclassified into net income: Net actuarial loss, Gross	693	754	2,079	2,261
Total defined benefit pension and post-retirement benefit plans, Gross	693	754	2,079	2,261
Other comprehensive income (loss), Gross	(36,896)	44,460	(101,218)	133,341
Comprehensive income before tax	55,740	129,717	280,248	277,288
Net income, Tax	18,931	15,382	76,608	24,653
Unrealized holding gains (losses) during the period, Tax	(7,410)	7,947	(21,638)	27,852
Unrealized gains (losses) on securities with credit loss recognized in earnings; Tax	(492)	1,940	(772)	(3,921)
Amounts reclassified into net income: HTM securities, Tax	0	(1)	(1)	(2)
Amounts reclassified into net income: Net realized losses (gains) on disposals and losses on intent-to-sell AFS securities, Tax	(272)	(109)	(133)	1,916
Amounts reclassified into net income: Credit loss (benefit) expense, Tax	280	(599)	852	1,682
Total unrealized losses (gains) on investment securities, Tax	(7,894)	9,178	(21,692)	27,527
Amount reclassified into net income: Net actuarial loss, Tax	145	158	436	474
Total defined benefit pension and post-retirement benefit plans, Tax	145	158	436	474
Other comprehensive income (loss), Tax	(7,749)	9,336	(21,256)	28,001
Comprehensive income, Tax	11,182	24,718	55,352	52,654
Net income	73,705	69,875	304,858	119,294
Unrealized holding gains (losses) arising during period, Net	(27,875)	29,889	(81,402)	104,771
Unrealized (losses) gains on securities with credit loss recognized in earnings, Net	(1,851)	7,299	(2,906)	(14,751)
Amounts reclassified into net income: HTM Securities, Net	1	0	(3)	(5)
Amounts reclassified into net income: Net realized (gains) losses on disposals and losses on intent-to-sell AFS Securities, Net	(1,024)	(406)	(501)	7,210
Amounts reclassified into net income: Credit loss (benefit) expense, Net	1,054	(2,254)	3,207	6,328
Total Unrealized (Losses) Gains on Investment Securities, Net	(29,695)	34,528	(81,605)	103,553
Amount reclassified into net income: Net actuarial loss, Net	548	596	1,643	1,787
Total defined benefit pension and post-retirement plans, Net	548	596	1,643	1,787
Other Comprehensive (loss) income	(29,147)	35,124	(79,962)	105,340
Comprehensive Income	$ 44,558	$ 104,999	$ 224,896	$ 224,634

Comprehensive Income (Compone_2

Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			$ 220,186
Amounts reclassified from AOCI, HTM related	$ 1	$ 0	(3)	$ (5)
Amount reclassified into net income: Net actuarial loss	548	596	1,643	1,787
Other comprehensive income (loss)	(29,147)	35,124	(79,962)	105,340
Other comprehensive income, defined pension and post retirement plans	548	596	1,643	1,787
Ending Balance, September 30, 2021	140,224		140,224
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			307,790
OCI before reclassifications			(81,402)
Amounts reclassified from AOCI, All Other			(501)
Other comprehensive income (loss)			(81,903)
Ending Balance, September 30, 2021	225,887		225,887
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			305,250
OCI before reclassifications			(84,308)
Amounts reclassified from AOCI			2,703
Other comprehensive income (loss)			(81,605)
Ending Balance, September 30, 2021	223,645		223,645
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			(2,546)
OCI before reclassifications			(2,906)
Amounts reclassified from AOCI, Credit loss related			3,207
Other comprehensive income (loss)			301
Ending Balance, September 30, 2021	(2,245)		(2,245)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			6
OCI before reclassifications			0
Amounts reclassified from AOCI, HTM related			(3)
Other comprehensive income (loss)			(3)
Ending Balance, September 30, 2021	3		3
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			(85,064)
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans			0
Amount reclassified into net income: Net actuarial loss			1,643
Ending Balance, September 30, 2021	(83,421)		(83,421)
Accumulated other comprehensive income (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance, December 31, 2020			220,186
OCI before reclassifications			(84,308)
Amounts reclassified from AOCI			4,346
Other comprehensive income (loss)	(29,147)	$ 35,124	(79,962)	$ 105,340
Ending Balance, September 30, 2021	$ 140,224		$ 140,224

Comprehensive Income (Reclassif

Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Net realized and unrealized investment gains (losses)	$ 177	$ 7,721	$ 15,353	$ (24,296)
Net investment income earned	93,032	68,185	246,479	158,596
Loss and loss expense incurred	505,269	447,802	1,340,293	1,252,075
Other insurance expenses	94,759	89,530	278,531	269,477
Income before federal income tax	92,636	85,257	381,466	143,947
Total federal income tax expense	(18,931)	(15,382)	(76,608)	(24,653)
Net income	73,705	69,875	304,858	119,294
Reclassification out of AOCI
Net income	579	(2,064)	4,346	15,320
Pension Plan [Member] | Reclassification out of AOCI
Loss and loss expense incurred	159	162	478	486
Other insurance expenses	534	592	1,601	1,775
Income before federal income tax	693	754	2,079	2,261
Total federal income tax expense	(145)	(158)	(436)	(474)
Net income	548	596	1,643	1,787
Held-to-maturity Securities [Member] | Reclassification out of AOCI
Net realized and unrealized investment gains (losses)	(1)	4	(1)	5
Net investment income earned	2	(5)	(3)	(12)
Income before federal income tax	1	(1)	(4)	(7)
Total federal income tax expense	0	1	1	2
Net income	1	0	(3)	(5)
Available for sale securities, excluding credit losses [Member] | Reclassification out of AOCI
Net realized and unrealized investment gains (losses)	(1,296)	(515)	(634)	9,126
Income before federal income tax	(1,296)	(515)	(634)	9,126
Total federal income tax expense	272	109	133	(1,916)
Net income	(1,024)	(406)	(501)	7,210
Available for sale securities, including credit losses | Reclassification out of AOCI
Net realized and unrealized investment gains (losses)	1,334	(2,853)	4,059	8,010
Income before federal income tax	1,334	(2,853)	4,059	8,010
Total federal income tax expense	(280)	599	(852)	(1,682)
Net income	$ 1,054	$ (2,254)	$ 3,207	$ 6,328

Equity (Details)

Equity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 02, 2020
Equity [Abstract]
Authorized amount for share repurchase program					$ 100,000
Shares repurchased	0	0	52,781	0
Treasury stock, share repurchase authorization, cost			$ 3,400
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 96,600		$ 96,600