RLI (RLI) 10-Q 21 Oct 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 12, 2022
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2022
Entity File Number	001-09463
Entity Registrant Name	RLI Corp
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	37-0889946
Entity Address, Address Line One	9025 North Lindbergh Drive,
Entity Address, City or Town	Peoria,
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	61615
City Area Code	309
Local Phone Number	692-1000
Title of 12(b) Security	Common Stock $0.01 par value
Trading Symbol	RLI
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		45,378,171
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000084246
Amendment Flag	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Net premiums earned	$ 291,468	$ 253,389	$ 843,430	$ 722,984
Net investment income	21,270	17,844	57,625	50,929
Net realized gains	573,170	1,829	591,562	52,442
Net unrealized gains (losses) on equity securities	(26,414)	(2,592)	(155,218)	29,526
Consolidated revenue	859,494	270,470	1,337,399	855,881
Losses and settlement expenses	165,089	143,656	388,527	355,574
Policy acquisition costs	96,977	80,449	271,879	232,674
Insurance operating expenses	20,606	15,560	58,794	54,504
Interest expense on debt	2,013	1,906	6,034	5,711
General corporate expenses	2,755	2,505	8,553	9,533
Total expenses	287,440	244,076	733,787	657,996
Equity in earnings (loss) of unconsolidated investees	(17,352)	9,043	3,061	29,407
Earnings (loss) before income taxes	554,702	35,437	606,673	227,292
Income tax expense	114,809	6,194	121,096	43,222
Net earnings (loss)	439,893	29,243	485,577	184,070
Other comprehensive earnings (loss), net of tax	(81,248)	(12,240)	(294,392)	(41,810)
Comprehensive earnings	$ 358,645	$ 17,003	$ 191,185	$ 142,260
Basic net earnings per share	$ 9.69	$ 0.65	$ 10.71	$ 4.07
Diluted net earnings per share	$ 9.61	$ 0.64	$ 10.61	$ 4.03
Weighted average number of common shares outstanding:
Basic	45,379	45,243	45,347	45,216
Diluted	45,775	45,689	45,775	45,714

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
ASSETS
Available-for-sale, at fair value (amortized cost of $2,753,631 and allowance for credit losses of $327 at 9/30/22) (amortized cost of $2,346,267 and allowance for credit losses of $441 at 12/31/21)	$ 2,452,039	$ 2,409,887
Equity securities, at fair value (cost - $327,964 at 9/30/22 and $324,501 at 12/31/21)	462,988	613,776
Other invested assets	48,837	50,501
Cash	723,511	88,804
Total investments and cash	3,687,375	3,162,968
Accrued investment income	19,355	17,505
Premiums and reinsurance balances receivable, net of allowances for uncollectible amounts of $18,478 at 9/30/22 and $18,067 at 12/31/21	201,781	167,279
Ceded unearned premium	137,346	130,916
Reinsurance balances recoverable on unpaid losses and settlement expenses, net of allowances for uncollectible amounts of $11,400 at 9/30/22 and $11,188 at 12/31/21	770,858	608,086
Deferred policy acquisition costs	128,979	103,553
Property and equipment, at cost, net of accumulated depreciation of $67,911 at 9/30/22 and $75,236 at 12/31/21	50,385	52,161
Investment in unconsolidated investees	58,105	171,311
Goodwill and intangibles	53,562	53,562
Income taxes-deferred	51,791
Other assets	52,128	40,961
TOTAL ASSETS	5,211,665	4,508,302
Liabilities
Unpaid losses and settlement expenses	2,322,737	2,043,555
Unearned premiums	786,485	680,444
Reinsurance balances payable	50,349	42,851
Funds held	100,547	89,773
Income taxes-current	132,446	3,092
Income taxes-deferred		83,509
Current portion of long-term debt	149,816
Long-term debt	50,000	199,676
Accrued expenses	81,066	98,274
Other liabilities	144,226	37,767
TOTAL LIABILITIES	3,817,672	3,278,941
Shareholders' Equity
Common stock ($0.01 par value) (Shares authorized - 200,000,000) (68,308,385 shares issued, 45,378,171 shares outstanding at 9/30/22) (68,219,551 shares issued, 45,289,337 shares outstanding at 12/31/21)	683	682
Paid-in capital	352,129	343,742
Accumulated other comprehensive earnings (loss)	(244,566)	49,826
Retained earnings	1,678,746	1,228,110
Deferred compensation	9,047	9,642
Less: Treasury shares, at cost (22,930,214 shares at 9/30/22 and 12/31/21)	(402,046)	(402,641)
TOTAL SHAREHOLDERS' EQUITY	1,393,993	1,229,361
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 5,211,665	$ 4,508,302

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Available-for-sale, amortized cost	$ 2,753,631	$ 2,346,267
Available-for-sale, allowance for credit losses	327	441
Equity securities, cost	327,964	324,501
Premiums and reinsurance balances receivable, allowances for uncollectible amounts	18,478	18,067
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	11,400	11,188
Property and equipment, accumulated depreciation	$ 67,911	$ 75,236
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	68,308,385	68,219,551
Common stock, shares outstanding (in shares)	45,378,171	45,289,337
Treasury stock, shares (in shares)	22,930,214	22,930,214

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Common stock	Paid-in Capital	Accumulated Other Comprehensive Earnings (Loss)	Retained Earnings	Deferred Compensation	Treasury Stock at Cost	Total
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2020	$ 681	$ 335,365	$ 108,714	$ 1,084,217	$ 8,292	$ (401,291)	$ 1,135,978
Shares, Outstanding, Beginning Balance at Dec. 31, 2020	45,142,580
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)				73,012			73,012
Other comprehensive earnings (loss), net of tax			(44,747)				(44,747)
Deferred compensation					(366)	366
Share-based compensation		1,392					1,392
Share-based compensation (in shares)	60,858
Dividends and dividend equivalents				(10,849)			(10,849)
Stockholders' Equity Attributable to Parent, Ending Balance at Mar. 31, 2021	$ 681	336,757	63,967	1,146,380	7,926	(400,925)	1,154,786
Shares, Outstanding, Ending Balance at Mar. 31, 2021	45,203,438
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2020	$ 681	335,365	108,714	1,084,217	8,292	(401,291)	1,135,978
Shares, Outstanding, Beginning Balance at Dec. 31, 2020	45,142,580
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)							184,070
Other comprehensive earnings (loss), net of tax							(41,810)
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2021	$ 682	340,868	66,904	1,234,801	8,330	(401,329)	1,250,256
Shares, Outstanding, Ending Balance at Sep. 30, 2021	45,244,505
Stockholders' Equity Attributable to Parent, Beginning Balance at Mar. 31, 2021	$ 681	336,757	63,967	1,146,380	7,926	(400,925)	1,154,786
Shares, Outstanding, Beginning Balance at Mar. 31, 2021	45,203,438
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)				81,815			81,815
Other comprehensive earnings (loss), net of tax			15,177				15,177
Deferred compensation					325	(325)
Share-based compensation	$ 1	1,342					1,343
Share-based compensation (in shares)	19,905
Dividends and dividend equivalents				(11,318)			(11,318)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2021	$ 682	338,099	79,144	1,216,877	8,251	(401,250)	1,241,803
Shares, Outstanding, Ending Balance at Jun. 30, 2021	45,223,343
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)				29,243			29,243
Other comprehensive earnings (loss), net of tax			(12,240)				(12,240)
Deferred compensation					79	(79)
Share-based compensation		2,769					2,769
Share-based compensation (in shares)	21,162
Dividends and dividend equivalents				(11,319)			(11,319)
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2021	$ 682	340,868	66,904	1,234,801	8,330	(401,329)	1,250,256
Shares, Outstanding, Ending Balance at Sep. 30, 2021	45,244,505
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2021	$ 682	343,742	49,826	1,228,110	9,642	(402,641)	1,229,361
Shares, Outstanding, Beginning Balance at Dec. 31, 2021	45,289,337
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)				47,923			47,923
Other comprehensive earnings (loss), net of tax			(115,581)				(115,581)
Deferred compensation					(973)	973
Share-based compensation		3,049					3,049
Share-based compensation (in shares)	26,605
Dividends and dividend equivalents				(11,330)			(11,330)
Stockholders' Equity Attributable to Parent, Ending Balance at Mar. 31, 2022	$ 682	346,791	(65,755)	1,264,703	8,669	(401,668)	1,153,422
Shares, Outstanding, Ending Balance at Mar. 31, 2022	45,315,942
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2021	$ 682	343,742	49,826	1,228,110	9,642	(402,641)	1,229,361
Shares, Outstanding, Beginning Balance at Dec. 31, 2021	45,289,337
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)							485,577
Other comprehensive earnings (loss), net of tax							(294,392)
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2022	$ 683	352,129	(244,566)	1,678,746	9,047	(402,046)	1,393,993
Shares, Outstanding, Ending Balance at Sep. 30, 2022	45,378,171
Stockholders' Equity Attributable to Parent, Beginning Balance at Mar. 31, 2022	$ 682	346,791	(65,755)	1,264,703	8,669	(401,668)	1,153,422
Shares, Outstanding, Beginning Balance at Mar. 31, 2022	45,315,942
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)				(2,239)			(2,239)
Other comprehensive earnings (loss), net of tax			(97,563)				(97,563)
Deferred compensation					276	(276)
Share-based compensation	$ 1	2,370					2,371
Share-based compensation (in shares)	52,862
Dividends and dividend equivalents				(11,803)			(11,803)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2022	$ 683	349,161	(163,318)	1,250,661	8,945	(401,944)	1,044,188
Shares, Outstanding, Ending Balance at Jun. 30, 2022	45,368,804
Increase Decrease In Stockholders Equity Roll Forward
Net earnings (loss)				439,893			439,893
Other comprehensive earnings (loss), net of tax			(81,248)				(81,248)
Deferred compensation					102	(102)
Share-based compensation		2,968					2,968
Share-based compensation (in shares)	9,367
Dividends and dividend equivalents				(11,808)			(11,808)
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2022	$ 683	$ 352,129	$ (244,566)	$ 1,678,746	$ 9,047	$ (402,046)	$ 1,393,993
Shares, Outstanding, Ending Balance at Sep. 30, 2022	45,378,171

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021
Statement Of Stockholders Equity [Abstract]
Cash dividends paid per common share	$ 0.26	$ 0.26	$ 0.25	$ 0.25	$ 0.25	$ 0.24

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Statement Of Cash Flows [Abstract]
Net cash provided by operating activities	$ 282,886	$ 280,441
Purchase of:
Fixed income securities, available-for-sale	(531,894)	(587,910)
Equity securities	(42,490)	(117,218)
Property and equipment	(4,432)	(5,005)
Other	(7,940)	(11,938)
Proceeds from sale of:
Fixed income securities - available-for-sale	46,448	42,776
Equity securities	59,264	157,973
Equity method investments	686,666
Other	2,298	4,496
Proceeds from call or maturity of:
Fixed income securities - available-for-sale	176,616	296,561
Net cash provided by (used in) investing activities	384,536	(220,265)
Cash Flows from Financing Activities
Cash dividends paid	(34,913)	(33,454)
Proceeds from stock option exercises	2,198	679
Net cash used in financing activities	(32,715)	(32,775)
Net increase in cash	634,707	27,401
Cash at the beginning of the period	88,804	62,217
Cash at the end of the period	$ 723,511	$ 89,618

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTES TO UNAUDITED CONDENSED CONSOLIDATED INTERIM FINANCIAL STATEMENTS ​ 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES ​ A. BASIS OF PRESENTATION ​ The unaudited condensed consolidated interim financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (GAAP) for interim financial reporting and with the instructions to Form 10-Q and Regulation S-X. Accordingly, they do not include all the disclosures required by GAAP for complete financial statements. As such, these unaudited condensed consolidated interim financial statements should be read in conjunction with our 2021 Annual Report on Form 10-K. Management believes that the disclosures are adequate to make the information presented not misleading, and all normal and recurring adjustments necessary to present fairly the financial position at September 30, 2022 and the results of operations of RLI Corp. (the Company) and subsidiaries for all periods presented have been made. The results of operations for any interim period are not necessarily indicative of the operating results for a full year. Certain reclassifications were made to 2021 to conform to the classifications used in the current year. ​ The preparation of the unaudited condensed consolidated interim financial statements requires management to make estimates and assumptions relating to the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated interim financial statements and the reported amounts of revenue and expenses during the period. These estimates are inherently subject to change and actual results could differ significantly from these estimates. ​ B. ADOPTED ACCOUNTING STANDARDS ​ No new accounting standards applicable in 2022 materially impact our financial statements. ​ C. PROSPECTIVE ACCOUNTING STANDARDS ​ There are no prospective accounting standards which would have a material impact on our financial statements as of September 30, 2022. ​ D. REINSURANCE ​ Ceded unearned premiums and reinsurance balances recoverable on unpaid losses and settlement expenses are reported separately as an asset, rather than being netted with the related liability, since reinsurance does not relieve the Company of our liability to policyholders. Such balances are subject to the credit risk associated with the individual reinsurer. We continually monitor the financial condition of our reinsurers and actively follow up on any past due or disputed amounts. As part of our monitoring efforts, we review reinsurers’ annual financial statements and Securities and Exchange Commission filings for those that are publicly traded. We also review insurance industry developments that may impact the financial condition of our reinsurers. We analyze the credit risk associated with our reinsurance balances recoverable by monitoring the AM Best and Standard & Poor’s (S&P) ratings of our reinsurers. In addition, we subject our reinsurance recoverables to detailed recoverability tests, including a segment-based analysis using the average default rating percentage by S&P rating, which assists the Company in assessing the sufficiency of its allowance. Additionally, we perform an in-depth reinsurer financial condition analysis prior to the renewal of each of our reinsurance placements. ​ Our policy is to charge to earnings, in the form of an allowance, an estimate of unrecoverable amounts from reinsurers. This allowance is reviewed on an ongoing basis to ensure that the amount makes a reasonable provision for reinsurance balances that we may be unable to recover. Once regulatory action (such as receivership, finding of insolvency, order of conservation or order of liquidation) is taken against a reinsurer, the paid and unpaid recoverable for the reinsurer are specifically identified and written off through use of our allowance for estimated unrecoverable amounts from reinsurers. When we write-off such a balance, it is done in full. We then re-evaluate the overall allowance and determine whether the balance is sufficient and, if needed, an additional allowance is recognized. ​ The allowances for uncollectible amounts on paid and unpaid reinsurance recoverables were $16.1 million and $11.4 million, respectively, at September 30, 2022. At December 31, 2021, the amounts were $16.1 million and $11.2 million, respectively. Changes in the allowances were due to changes in the amount of reinsurance balances outstanding, the composition of reinsurers from whom the balances were recoverable and their associated S&P default ratings. No write-offs were applied to the allowances in the first nine months of 2022 and less than $0.1 million was recovered. We have no receivables with a due date that extends beyond one year that are not included in our allowance for uncollectible amounts. ​ E. INTANGIBLE ASSETS ​ The composition of goodwill and intangible assets at September 30, 2022 and December 31, 2021 is detailed in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, (in thousands) 2022 2021 Goodwill ​ ​ ​ ​ ​ ​ Surety ​ $ 40,816 ​ $ 40,816 Casualty ​ ​ 5,246 ​ ​ 5,246 Total goodwill ​ $ 46,062 ​ $ 46,062 Intangibles ​ ​ ​ ​ ​ ​ Indefinite-lived intangibles - state insurance licenses ​ ​ 7,500 ​ ​ 7,500 Total goodwill and intangibles ​ $ 53,562 ​ $ 53,562 ​ Annual impairment assessments were performed on our goodwill and state insurance license indefinite-lived intangible asset during the second quarter of 2022. Based upon these reviews, none of the assets were impaired. In addition, there were no triggering events as of September 30, 2022 that would suggest an updated impairment test would be needed for our goodwill and intangible assets. ​ F. EARNINGS PER SHARE ​ Basic earnings per share (EPS) is computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the dilution that could occur if securities or other contracts to issue common stock or common stock equivalents were exercised or converted into common stock. When inclusion of these items increases the earnings per share or reduces the loss per share, the effect on earnings is anti-dilutive. Under these circumstances, the diluted net earnings or net loss per share is computed excluding these items. The following represents a reconciliation of the numerator and denominator of the basic and diluted EPS computations contained in the unaudited condensed consolidated interim financial statements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Three Months ​ ​ Ended September 30, 2022 ​ Ended September 30, 2021 ​ ​ Income ​ Shares ​ Per Share ​ Income ​ Shares ​ Per Share (in thousands, except per share data) (Numerator) (Denominator) Amount (Numerator) (Denominator) Amount Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 439,893 ​ 45,379 ​ $ 9.69 ​ $ 29,243 ​ 45,243 ​ $ 0.65 Effect of Dilutive Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options and restricted stock units ​ ​ — ​ 396 ​ ​ ​ ​ ​ — ​ 446 ​ ​ ​ Diluted EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 439,893 ​ 45,775 ​ $ 9.61 ​ $ 29,243 ​ 45,689 ​ $ 0.64 Anti-dilutive securities excluded from diluted EPS ​ ​ ​ ​ ​ 435 ​ ​ ​ ​ ​ ​ ​ ​ 191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months ​ For the Nine Months ​ ​ Ended September 30, 2022 ​ Ended September 30, 2021 ​ ​ Income ​ Shares ​ Per Share ​ Income ​ Shares ​ Per Share (in thousands, except per share data) (Numerator) (Denominator) Amount (Numerator) (Denominator) Amount Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 485,577 ​ 45,347 ​ $ 10.71 ​ $ 184,070 ​ 45,216 ​ $ 4.07 Effect of Dilutive Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options and restricted stock units ​ ​ — ​ 428 ​ ​ ​ ​ ​ — ​ 498 ​ ​ ​ Diluted EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 485,577 ​ 45,775 ​ $ 10.61 ​ $ 184,070 ​ 45,714 ​ $ 4.03 Anti-dilutive securities excluded from diluted EPS ​ ​ ​ ​ ​ 459 ​ ​ ​ ​ ​ ​ ​ ​ 191 ​ ​ ​ ​ G. COMPREHENSIVE EARNINGS ​ Our comprehensive earnings include net earnings plus after-tax unrealized gains and losses on our available-for-sale fixed income portfolio. In reporting the components of comprehensive earnings, we used the federal statutory tax rate of 21 percent. Other comprehensive earnings (loss), as shown in the consolidated statements of earnings and comprehensive earnings, is net of tax benefit of $21.6 million for the third quarter of 2022, compared to $3.2 million for the same period in 2021. For the nine-month period ended September 30, 2022, other comprehensive earnings (loss) is net of tax benefit of $78.3 million, compared to $11.1 million for the same period in 2021. ​ Unrealized losses, net of tax, recognized in other comprehensive earnings (loss) were $294.4 million for the first nine months of 2022, compared to $41.8 million during the same period last year. The unrealized losses were attributable to higher interest rates in both periods, which decreased the fair value of securities held in the fixed income portfolio. ​ The following table illustrates the changes in the balance of each component of accumulated other comprehensive earnings (loss) for each period presented in the unaudited condensed consolidated interim financial statements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ For the Three Months ​ For the Nine Months ​ ​ Ended September 30, ​ Ended September 30, Unrealized Gains/Losses on Available-for-Sale Securities 2022 2021 2022 2021 Beginning balance ​ $ (163,318) ​ $ 79,144 ​ $ 49,826 ​ $ 108,714 Other comprehensive earnings (loss) before reclassifications ​ ​ (82,785) ​ ​ (12,114) ​ ​ (296,422) ​ ​ (40,307) Amounts reclassified from accumulated other comprehensive earnings ​ ​ 1,537 ​ ​ (126) ​ ​ 2,030 ​ ​ (1,503) Net current-period other comprehensive earnings (loss) ​ $ (81,248) ​ $ (12,240) ​ $ (294,392) ​ $ (41,810) Ending balance ​ $ (244,566) ​ $ 66,904 ​ $ (244,566) ​ $ 66,904 Balance of securities for which an allowance for credit losses has been recognized in net earnings ​ ​ ​ ​ ​ ​ ​ $ 1,520 ​ $ 426 ​ Credit losses on or the sale of an available-for-sale security results in amounts being reclassified from accumulated other comprehensive earnings (loss) to current period net earnings. The effects of reclassifications out of accumulated other comprehensive earnings (loss) by the respective line items of net earnings are presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount Reclassified from Accumulated Other ​ ​ (in thousands) ​ Comprehensive Earnings (Loss) ​ ​ ​ ​ For the Three Months ​ For the Nine Months ​ ​ Component of Accumulated ​ Ended September 30, ​ Ended September 30, ​ Affected line item in the Other Comprehensive Earnings (Loss) 2022 2021 2022 2021 Statement of Earnings Unrealized gains and losses on available-for-sale securities ​ $ (1,912) ​ $ 182 ​ $ (2,684) ​ $ 1,731 ​ Net realized gains (losses) ​ ​ ​ (34) ​ ​ (22) ​ ​ 115 ​ ​ 171 ​ Credit gains presented within net realized gains ​ ​ $ (1,946) ​ $ 160 ​ $ (2,569) ​ $ 1,902 ​ Earnings (loss) before income taxes ​ ​ ​ 409 ​ ​ (34) ​ ​ 539 ​ ​ (399) ​ Income tax (expense) benefit ​ ​ $ (1,537) ​ $ 126 ​ $ (2,030) ​ $ 1,503 ​ Net earnings (loss) ​ H. FAIR VALUE MEASUREMENTS ​ Fair value is defined as the price in the principal market that would be received for an asset to facilitate an orderly transaction between market participants on the measurement date. We determined the fair value of certain financial instruments based on their underlying characteristics and relevant transactions in the marketplace. We maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ​ The following are the levels of the fair value hierarchy and a brief description of the type of valuation inputs that are used to establish each level. Financial assets are classified based upon the lowest level of significant input that is used to determine fair value. ​ Level 1 ​ Level 2 ​ Level 3 ​ As a part of management’s process to determine fair value, we utilize widely recognized, third-party pricing sources to determine our fair values. We have obtained an understanding of the third-party pricing sources’ valuation methodologies and inputs. The following is a description of the valuation techniques used for financial assets that are measured at fair value, including the general classification of such assets pursuant to the fair value hierarchy. ​ Corporate, Agencies, Government and Municipal Bonds: ​ Mortgage-backed Securities (MBS)/Commercial Mortgage-backed Securities (CMBS) and Asset-backed Securities (ABS): ​ Regulation D Private Placement Securities: ​ For all of our fixed income securities classified as Level 2, we periodically conduct a review to assess the reasonableness of the fair values provided by our pricing services. Our review consists of a two-pronged approach. First, we compare prices provided by our pricing services to those provided by an additional source. In some cases, we obtain prices from securities brokers and compare them to the prices provided by our pricing services. If discrepancies are found in our comparisons, we compare our prices to actual reported trade data for like securities. No changes to the fair values supplied by our pricing services have occurred as a result of our reviews. Based on these assessments, we have determined that the fair values of our Level 2 fixed income securities provided by our pricing services are reasonable. ​ Equity Securities: ​ Due to the relatively short-term nature of cash, short-term investments, accounts receivable and accounts payable, their carrying amounts are reasonable estimates of fair value. Our investments in private funds, classified as other invested assets, are measured using the investments’ net asset value per share and are not categorized within the fair value hierarchy. ​ I. RISKS AND UNCERTAINTIES ​ Certain risks and uncertainties are inherent in our day-to-day operations. Adverse changes in the economy, including inflation; rising interest rates; volatile equity markets; and ongoing supply chain disruptions, could lower demand for our insurance products, result in increased levels of loss costs that we could not anticipate at the time we priced our coverages, or negatively impact our investment results, all of which could have an adverse effect on the profitability of our operations. The COVID-19 pandemic may result in significant disruptions in economic activity and financial markets or exacerbate the impact of other economic trends. The cumulative effects of any public health outbreak could reduce demand for our insurance policies; result in increased level of losses, settlement expenses or other operating costs; reduce the market value of invested assets held by the Company or negatively impact the fair value of our goodwill. ​ Catastrophe Exposures ​ Our catastrophe reinsurance treaty renewed on January 1, 2022. We purchased limits of $600 million in excess of $25 million first-dollar retention for earthquakes in California, $625 million in excess of $25 million first-dollar retention for earthquakes outside of California and $475 million in excess of $25 million first-dollar retention for all other perils, including wind. These amounts are subject to certain co-participations by the Company on losses in excess of the $25 million retentions. On May 1, 2022, we purchased $150 million of additional catastrophe reinsurance protection on top of the previously described coverage, to support growth in our catastrophe-exposed business. This increases the limits to $750 million for earthquakes in California, $775 million for earthquakes outside of California and $625 million for all other perils, including wind, all of which are still subject to $25 million first-dollar retentions and certain co-participations in excess of the retentions.

Investments

Investments	9 Months Ended
	Sep. 30, 2022
Investments Debt And Equity Securities [Abstract]
Investments	2. INVESTMENTS ​ Our investments are primarily composed of fixed income debt securities and common stock equity securities. We carry our equity securities at fair value and categorize all of our debt securities as available-for-sale, which are carried at fair value. ​ Realized gains and losses on disposition of investments are based on specific identification of the investments sold on the settlement date. The following is a summary of the disposition of fixed income and equity securities for the nine-month periods ended September 30, 2022 and 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Sales ​ Proceeds ​ Gross Realized ​ Net Realized (in thousands) From Sales Gains Losses Gain (Loss) 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 48,559 ​ $ 286 ​ $ (2,481) ​ $ (2,195) Equity securities ​ ​ 59,264 ​ ​ 20,410 ​ ​ (609) ​ ​ 19,801 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 43,041 ​ $ 1,476 ​ $ (107) ​ $ 1,369 Equity securities ​ ​ 157,973 ​ ​ 52,409 ​ ​ (1,787) ​ ​ 50,622 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Calls/Maturities ​ ​ ​ ​ Gross Realized ​ Net Realized (in thousands) Proceeds Gains Losses Gain (Loss) 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 176,991 ​ $ 142 ​ $ (55) ​ $ 87 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 296,563 ​ $ 471 ​ $ (109) ​ $ 362 ​ FAIR VALUE MEASUREMENTS ​ Assets measured at fair value on a recurring basis as of September 30, 2022 and December 31, 2021 are summarized below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2022 ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ (in thousands) (Level 1) (Level 2) (Level 3) Total Fixed income securities - available-for-sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government ​ $ — ​ $ 340,442 ​ $ — ​ $ 340,442 U.S. agency ​ ​ — ​ ​ 56,935 ​ ​ — ​ ​ 56,935 Non-U.S. government & agency ​ ​ — ​ ​ 5,712 ​ ​ — ​ ​ 5,712 Agency MBS ​ ​ — ​ ​ 317,029 ​ ​ — ​ ​ 317,029 ABS/CMBS/MBS* ​ ​ — ​ ​ 241,512 ​ ​ — ​ ​ 241,512 Corporate ​ ​ — ​ ​ 910,979 ​ ​ 52,890 ​ ​ 963,869 Municipal ​ ​ — ​ ​ 526,540 ​ ​ — ​ ​ 526,540 Total fixed income securities - available-for-sale ​ $ — ​ $ 2,399,149 ​ $ 52,890 ​ $ 2,452,039 Equity securities ​ ​ 461,392 ​ ​ 49 ​ ​ 1,547 ​ ​ 462,988 Total ​ $ 461,392 ​ $ 2,399,198 ​ $ 54,437 ​ $ 2,915,027 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2021 ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ (in thousands) (Level 1) (Level 2) (Level 3) Total Fixed income securities - available-for-sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government ​ $ — ​ $ 134,554 ​ $ — ​ $ 134,554 U.S. agency ​ ​ — ​ ​ 32,760 ​ ​ — ​ ​ 32,760 Non-U.S. government & agency ​ ​ — ​ ​ 8,481 ​ ​ — ​ ​ 8,481 Agency MBS ​ ​ — ​ ​ 367,187 ​ ​ — ​ ​ 367,187 ABS/CMBS/MBS* ​ ​ — ​ ​ 264,054 ​ ​ — ​ ​ 264,054 Corporate ​ ​ — ​ ​ 913,577 ​ ​ 43,518 ​ ​ 957,095 Municipal ​ ​ — ​ ​ 645,756 ​ ​ — ​ ​ 645,756 Total fixed income securities - available-for-sale ​ $ — ​ $ 2,366,369 ​ $ 43,518 ​ $ 2,409,887 Equity securities ​ ​ 613,712 ​ ​ 64 ​ ​ — ​ ​ 613,776 Total ​ $ 613,712 ​ $ 2,366,433 ​ $ 43,518 ​ $ 3,023,663 * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities The following table summarizes changes in the balance of securities whose fair value was measured using significant unobservable inputs (Level 3). ​ ​ ​ ​ ​ (in thousands) Level 3 Securities Balance as of January 1, 2022 ​ $ 43,518 Net realized and unrealized gains (losses) ​ ​ ​ Included in net earnings as a part of: ​ ​ ​ Net investment income ​ ​ (662) Net realized gains ​ ​ (433) Included in other comprehensive earnings (loss) ​ ​ (8,350) Total net realized and unrealized gains (losses) ​ $ (9,445) Purchases ​ ​ 21,461 Transfers out of Level 3 ​ ​ (1,097) Balance as of September 30, 2022 ​ $ 54,437 Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in net realized gains ​ $ (433) Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in other comprehensive earnings (loss) ​ $ (8,350) ​ The amortized cost and fair value of available-for-sale fixed income securities by contractual maturity as of September 30, 2022 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 (in thousands) Amortized Cost Fair Value Due in one year or less ​ $ 206,921 ​ $ 206,327 Due after one year through five years ​ ​ 867,511 ​ ​ 818,569 Due after five years through 10 years ​ ​ 515,276 ​ ​ 457,011 Due after 10 years ​ ​ 526,093 ​ ​ 411,591 ABS/CMBS/MBS* ​ ​ 637,830 ​ ​ 558,541 Total available-for-sale ​ $ 2,753,631 ​ $ 2,452,039 * Asset-backed, commercial mortgage-backed and mortgage-backed securities ​ The amortized cost and fair value of available-for-sale securities at September 30, 2022 and December 31, 2021 are presented in the tables below. Amortized cost does not include the $18.4 million and $16.4 million of accrued interest receivable as of September 30, 2022 and December 31, 2021, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ ​ Cost or ​ Allowance ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ for Credit ​ Unrealized ​ Unrealized ​ Fair (in thousands) Cost Losses Gains Losses Value U.S. government ​ $ 349,419 ​ $ — ​ $ — ​ $ (8,977) ​ $ 340,442 U.S. agency ​ ​ 59,048 ​ ​ — ​ ​ 9 ​ ​ (2,122) ​ ​ 56,935 Non-U.S. government & agency ​ ​ 6,798 ​ ​ — ​ ​ — ​ ​ (1,086) ​ ​ 5,712 Agency MBS ​ ​ 360,429 ​ ​ — ​ ​ 172 ​ ​ (43,572) ​ ​ 317,029 ABS/CMBS/MBS* ​ ​ 277,401 ​ ​ (9) ​ ​ 21 ​ ​ (35,901) ​ ​ 241,512 Corporate ​ ​ 1,067,473 ​ ​ (318) ​ ​ 47 ​ ​ (103,333) ​ ​ 963,869 Municipal ​ ​ 633,063 ​ ​ — ​ ​ 194 ​ ​ (106,717) ​ ​ 526,540 Total Fixed Income ​ $ 2,753,631 ​ $ (327) ​ $ 443 ​ $ (301,708) ​ $ 2,452,039 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ Cost or ​ Allowance ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ for Credit ​ Unrealized ​ Unrealized ​ Fair (in thousands) Cost Losses Gains Losses Value U.S. government ​ $ 127,752 ​ $ — ​ $ 6,846 ​ $ (44) ​ $ 134,554 U.S. agency ​ ​ 30,403 ​ ​ — ​ ​ 2,374 ​ ​ (17) ​ ​ 32,760 Non-U.S. government & agency ​ ​ 8,297 ​ ​ — ​ ​ 338 ​ ​ (154) ​ ​ 8,481 Agency MBS ​ ​ 362,861 ​ ​ — ​ ​ 9,277 ​ ​ (4,951) ​ ​ 367,187 ABS/CMBS/MBS* ​ ​ 264,273 ​ ​ — ​ ​ 2,120 ​ ​ (2,339) ​ ​ 264,054 Corporate ​ ​ 925,394 ​ ​ (441) ​ ​ 37,247 ​ ​ (5,105) ​ ​ 957,095 Municipal ​ ​ 627,287 ​ ​ — ​ ​ 22,750 ​ ​ (4,281) ​ ​ 645,756 Total Fixed Income ​ $ 2,346,267 ​ $ (441) ​ $ 80,952 ​ $ (16,891) ​ $ 2,409,887 * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities ​ Allowance for Credit Losses and Unrealized Losses on Fixed Income Securities ​ A reversable allowance for credit losses is recognized on available-for-sale fixed income securities. Several criteria are reviewed to determine if securities in the fixed income portfolio should be included in the allowance for expected credit loss evaluation, including: ​ ● Changes in technology that may impair the earnings potential of the investment, ​ ● The discontinuance of a segment of business that may affect future earnings potential, ​ ● Reduction of or non-payment of interest and/or principal, ​ ● Specific concerns related to the issuer’s industry or geographic area of operation, ​ ● Significant or recurring operating losses, poor cash flows and/or deteriorating liquidity ratios and ​ ● Downgrades in credit quality by a major rating agency. ​ If changes in interest rates and credit spreads do not reasonably explain the unrealized loss for an available-for-sale security or if any of the criteria above indicate a potential credit loss, the security is subjected to a discounted cash flow analysis. Inputs into the discounted cash flow analysis include prepayment assumptions for structured securities, default rates and recoverability rates based on credit rating. The allowance for any security is limited to the amount that the security’s fair value is below amortized cost. As of September 30, 2022, the discounted cash flow analysis resulted in an allowance for credit losses on 18 securities. The following table presents changes in the allowance for expected credit losses on available-for-sale securities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, (in thousands) 2022 2021 2022 2021 Beginning balance ​ $ 292 ​ $ 204 ​ $ 441 ​ $ 397 Increase to allowance from securities for which credit losses were not previously recorded ​ ​ 168 ​ ​ — ​ ​ 292 ​ ​ — Reduction from securities sold during the period ​ ​ (166) ​ ​ — ​ ​ (619) ​ ​ ​ Reductions from intent to sell securities ​ ​ — ​ ​ — ​ ​ (17) ​ ​ — Net increase (decrease) from securities that had an allowance at the beginning of the period ​ ​ 33 ​ ​ 22 ​ ​ 230 ​ ​ (171) Balance as of September 30, ​ $ 327 ​ $ 226 ​ $ 327 ​ $ 226 ​ During 2022, net realized gains included $0.1 million of losses on fixed income securities for which we no longer had the intent to hold until recovery and the cost basis was written down to fair value. No such losses were recognized during the first nine months of 2021. ​ As of September 30, 2022, in addition to the securities included in the allowance for credit losses, the fixed income portfolio contained 1,543 securities with an unrealized loss position for which an allowance for credit losses had not been recorded. The $301.7 million in associated unrealized losses represents 10.8 percent of the fixed income portfolio’s cost basis and 8.2 percent of total invested assets. Isolated to these securities, unrealized losses increased through the first nine months of 2022, as interest rates increased during the period. Of the total 1,543 securities, 302 have been in an unrealized loss position for 12 consecutive months or longer. The following table illustrates the total value of fixed income securities that were in an unrealized loss position as of September 30, 2022 and December 31, 2021 after factoring in the allowance for credit losses. All fixed income securities continue to pay the expected coupon payments and we believe we will recover the amortized cost basis of available-for-sale securities that remain in an unrealized loss position. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ December 31, 2021 (in thousands) < 12 Mos. 12 Mos. & Greater Total < 12 Mos. 12 Mos. & Greater Total U.S. government ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 285,302 ​ $ 5,315 ​ $ 290,617 ​ $ 2,942 ​ $ — ​ $ 2,942 Amortized cost ​ ​ 293,829 ​ ​ 5,765 ​ ​ 299,594 ​ ​ 2,986 ​ ​ — ​ ​ 2,986 Unrealized loss ​ $ (8,527) ​ $ (450) ​ $ (8,977) ​ $ (44) ​ $ — ​ $ (44) U.S. agency ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 30,089 ​ $ — ​ $ 30,089 ​ $ 1,498 ​ $ — ​ $ 1,498 Amortized cost ​ ​ 32,211 ​ ​ — ​ ​ 32,211 ​ ​ 1,515 ​ ​ — ​ ​ 1,515 Unrealized loss ​ $ (2,122) ​ $ — ​ $ (2,122) ​ $ (17) ​ $ — ​ $ (17) Non-U.S. government ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 3,594 ​ $ 2,118 ​ $ 5,712 ​ $ 4,346 ​ $ — ​ $ 4,346 Amortized cost ​ ​ 3,798 ​ ​ 3,000 ​ ​ 6,798 ​ ​ 4,500 ​ ​ — ​ ​ 4,500 Unrealized Loss ​ $ (204) ​ $ (882) ​ $ (1,086) ​ $ (154) ​ $ — ​ $ (154) Agency MBS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 192,947 ​ $ 112,457 ​ $ 305,404 ​ $ 102,145 ​ $ 62,669 ​ $ 164,814 Amortized cost ​ ​ 210,448 ​ ​ 138,528 ​ ​ 348,976 ​ ​ 104,336 ​ ​ 65,429 ​ ​ 169,765 Unrealized loss ​ $ (17,501) ​ $ (26,071) ​ $ (43,572) ​ $ (2,191) ​ $ (2,760) ​ $ (4,951) ABS/CMBS/MBS* ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 148,272 ​ $ 89,792 ​ $ 238,064 ​ $ 150,997 ​ $ 3,935 ​ $ 154,932 Amortized cost ​ ​ 165,163 ​ ​ 108,802 ​ ​ 273,965 ​ ​ 153,235 ​ ​ 4,036 ​ ​ 157,271 Unrealized loss ​ $ (16,891) ​ $ (19,010) ​ $ (35,901) ​ $ (2,238) ​ $ (101) ​ $ (2,339) Corporate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 773,433 ​ $ 184,317 ​ $ 957,750 ​ $ 217,791 ​ $ 53,818 ​ $ 271,609 Amortized cost ​ ​ 844,169 ​ ​ 216,914 ​ ​ 1,061,083 ​ ​ 221,010 ​ ​ 55,704 ​ ​ 276,714 Unrealized loss ​ $ (70,736) ​ $ (32,597) ​ $ (103,333) ​ $ (3,219) ​ $ (1,886) ​ $ (5,105) Municipal ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 418,864 ​ $ 76,783 ​ $ 495,647 ​ $ 162,998 ​ $ 15,037 ​ $ 178,035 Amortized cost ​ ​ 493,485 ​ ​ 108,879 ​ ​ 602,364 ​ ​ 166,602 ​ ​ 15,714 ​ ​ 182,316 Unrealized loss ​ $ (74,621) ​ $ (32,096) ​ $ (106,717) ​ $ (3,604) ​ $ (677) ​ $ (4,281) Total fixed income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 1,852,501 ​ $ 470,782 ​ $ 2,323,283 ​ $ 642,717 ​ $ 135,459 ​ $ 778,176 Amortized cost ​ ​ 2,043,103 ​ ​ 581,888 ​ ​ 2,624,991 ​ ​ 654,184 ​ ​ 140,883 ​ ​ 795,067 Unrealized loss ​ $ (190,602) ​ $ (111,106) ​ $ (301,708) ​ $ (11,467) ​ $ (5,424) ​ $ (16,891) * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities ​ The following table shows the composition of the fixed income securities in unrealized loss positions, after factoring in the allowance for credit losses, at September 30, 2022 by the National Association of Insurance Commissioners (NAIC) rating and the generally equivalent Standard & Poor’s (S&P) and Moody’s ratings. The vast majority of the securities are rated by S&P and/or Moody’s. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equivalent ​ Equivalent ​ (dollars in thousands) ​ ​ ​ NAIC S&P Moody’s ​ Amortized ​ ​ ​ ​ Unrealized ​ Percent ​ Rating Rating Rating Cost Fair Value Loss to Total ​ 1 ​ AAA/AA/A ​ Aaa/Aa/A ​ $ 2,084,118 ​ $ 1,840,726 ​ $ (243,392) ​ 80.7 % 2 ​ BBB ​ Baa ​ ​ 399,832 ​ ​ 353,124 ​ ​ (46,708) ​ 15.5 % 3 ​ BB ​ Ba ​ ​ 75,146 ​ ​ 67,738 ​ ​ (7,408) ​ 2.5 % 4 ​ B ​ B ​ ​ 65,238 ​ ​ 61,152 ​ ​ (4,086) ​ 1.3 % 5 ​ CCC ​ Caa ​ ​ 657 ​ ​ 543 ​ ​ (114) ​ 0.0 % 6 ​ CC or lower ​ Ca or lower ​ ​ — ​ ​ — ​ ​ — ​ 0.0 % ​ ​ ​ ​ Total ​ $ 2,624,991 ​ $ 2,323,283 ​ $ (301,708) ​ 100.0 % ​ Other Invested Assets ​ We had $48.8 million of other invested assets at September 30, 2022, compared to $50.5 million at December 31, 2021. Other invested assets include investments in low income housing tax credit partnerships (LIHTC), membership in the Federal Home Loan Bank of Chicago (FHLBC), and investments in private funds. Our LIHTC investments are carried at amortized cost and our investment in FHLBC stock is carried at cost. Due to the nature of the LIHTC and our membership in the FHLBC, their carrying amounts approximate fair value. The private funds are carried at fair value, using each investment’s net asset value. ​ Our LIHTC interests had a balance of $14.2 million at September 30, 2022, compared to $16.6 million at December 31, 2021, and recognized a total tax benefit of $0.9 million during the third quarters of 2022 and 2021. For the nine-months ended ​ As of September 30, 2022, $60.2 million of investments were pledged as collateral with the FHLBC to ensure timely access to the secured lending facility that ownership of FHLBC stock provides. As of September 30, 2022, $50.0 million of borrowings were outstanding with the FHLBC. ​ Our investments in private funds totaled $28.9 million at September 30, 2022, compared to $28.6 million at December 31, 2021, and we had $5.7 million of associated unfunded commitments at September 30, 2022. Our interest in private funds is generally restricted from being transferred or otherwise redeemed without prior consent by the respective entities, and the timed dissolution of the partnerships would trigger redemption. ​ Investments in Unconsolidated Investees ​ We had $58.1 million of investments in unconsolidated investees at September 30, 2022, compared to $171.3 million at December 31, 2021. Our investments accounted for under the equity method are primarily related to Maui Jim, Inc. (Maui Jim) and Prime Holdings Insurance Services, Inc. (Prime). On September 30, 2022, we completed the sale of our investment in Maui Jim. See note 8 for more information on the sale. At September 30, 2022, our investment in Prime was $46.9 million. Other investments in unconsolidated investees totaled $11.2 million at September 30, 2022 and had unfunded commitments of $7.7 million. ​ Cash ​ Cash consists of uninvested balances in bank accounts. We had a cash balance of $723.5 million at September 30, 2022, compared to $88.8 million at December 31, 2021. Cash balances increased due to the sale of our investment in Maui Jim which was completed on September 30, 2022.

Historical Loss And LAE Develop

Historical Loss And LAE Development	9 Months Ended
	Sep. 30, 2022
Historical Loss And L A E Development Disclosure [Abstract]
Historical Loss And LAE Development	3. HISTORICAL LOSS AND LAE DEVELOPMENT ​ The following table is a reconciliation of our unpaid losses and settlement expenses (LAE) for the first nine months of 2022 and 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months ​ ​ Ended September 30, (in thousands) 2022 2021 Unpaid losses and LAE at beginning of year ​ ​ ​ ​ ​ ​ Gross ​ $ 2,043,555 ​ $ 1,750,049 Ceded ​ ​ (608,086) ​ ​ (443,729) Net ​ $ 1,435,469 ​ $ 1,306,320 ​ ​ ​ ​ ​ ​ ​ Increase (decrease) in incurred losses and LAE ​ ​ ​ ​ ​ ​ Current accident year ​ $ 491,559 ​ $ 452,542 Prior accident years ​ ​ (103,032) ​ ​ (96,968) Total incurred ​ $ 388,527 ​ $ 355,574 ​ ​ ​ ​ ​ ​ ​ Loss and LAE payments for claims incurred ​ ​ ​ ​ ​ ​ Current accident year ​ $ (52,435) ​ $ (58,411) Prior accident years ​ ​ (219,682) ​ ​ (172,120) Total paid ​ $ (272,117) ​ $ (230,531) ​ ​ ​ ​ ​ ​ ​ Net unpaid losses and LAE at September 30, ​ $ 1,551,879 ​ $ 1,431,363 ​ ​ ​ ​ ​ ​ ​ Unpaid losses and LAE at September 30, ​ ​ ​ ​ ​ ​ Gross ​ $ 2,322,737 ​ $ 2,033,517 Ceded ​ ​ (770,858) ​ ​ (602,154) Net ​ $ 1,551,879 ​ $ 1,431,363 ​ For the first nine months of 2022, incurred losses and LAE included $103.0 million of favorable development on prior years’ loss reserves. General liability, professional services, transportation, executive products, commercial excess, marine and surety were drivers of the favorable development. No products experienced significant adverse development. ​ For the first nine months of 2021, incurred losses and LAE included $97.0 million of favorable development on prior years’ loss reserves. General liability, transportation, professional services, small commercial, commercial excess, personal umbrella and marine were drivers of the favorable development. No products experienced significant adverse development. ​ Actuarial models base future loss emergence on historical experience, with adjustments for current trends, and the appropriateness of these assumptions involved more uncertainty as of September 30, 2022. We expect the timing of loss emergence and ultimate loss ratios for certain coverages we underwrite will be affected as a result of COVID-19 and the related economic impact. The industry is experiencing new issues, including the postponement of civil court cases, the extension of various statutes of limitations and changes in settlement trends. Our recorded reserves include consideration of these factors, but the duration and degree to which these issues persist, along with potential legislative, regulatory or judicial actions, could result in loss reserve deficiencies and reduce earnings in future periods.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Income Taxes	4. INCOME TAXES ​ Our effective tax rate for the three and nine months ended September 30, 2022 was 20.7 percent and 20.0 percent, respectively, compared to 17.5 percent and 19.0 percent, respectively, for the same period in 2021. Effective rates are dependent upon components of pretax earnings and the related tax effects. The effective tax rate was higher for the three and nine-month periods in 2022, as higher pretax income, resulting from the gain on our sale of Maui Jim, decreased the percentage impact of tax-favored adjustments. The sale of Maui Jim also resulted in a larger current income taxes payable balance as of September 30, 2022. ​ Income tax expense attributable to income from operations for the three and nine-month periods ended September 30, 2022 and 2021 differed from the amounts computed by applying the U.S. federal tax rate of 21 percent to pretax income by the items detailed in the below table. In interim periods, income taxes are adjusted to reflect the effective tax rate we anticipate for the year, with adjustments flowing through the other items, net line. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended September 30, 2022 ​ For the Nine Months Ended September 30, 2022 ​ ​ ​ 2022 ​ 2021 ​ 2022 ​ 2021 ​ (in thousands) Amount % Amount % Amount % Amount % ​ Provision for income taxes at the statutory rate of 21% ​ $ 116,487 ​ 21.0 % $ 7,442 ​ 21.0 % $ 127,401 ​ 21.0 % $ 47,731 ​ 21.0 % Increase (reduction) in taxes resulting from: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Excess tax benefit on share-based compensation ​ ​ (95) ​ (0.0) % ​ (225) ​ (0.6) % ​ (2,270) ​ (0.4) % ​ (2,419) ​ (1.1) % Tax exempt interest income ​ ​ (280) ​ (0.1) % ​ (298) ​ (0.8) % ​ (850) ​ (0.1) % ​ (927) ​ (0.4) % Dividends received deduction ​ ​ (240) ​ (0.0) % ​ (223) ​ (0.6) % ​ (673) ​ (0.1) % ​ (707) ​ (0.3) % Investment tax credit ​ ​ (1,181) ​ (0.2) % ​ (801) ​ (2.3) % ​ (3,545) ​ (0.6) % ​ (2,404) ​ (1.0) % ESOP dividends paid deduction ​ ​ (136) ​ (0.0) % ​ (132) ​ (0.4) % ​ (404) ​ (0.0) % ​ (399) ​ (0.2) % Nondeductible expenses ​ ​ 34 ​ 0.0 % ​ 642 ​ 1.8 % ​ 608 ​ 0.1 % ​ 1,879 ​ 0.8 % Other items, net ​ ​ 220 ​ 0.0 % ​ (211) ​ (0.6) % ​ 829 ​ 0.1 % ​ 468 ​ 0.2 % Total tax expense ​ $ 114,809 ​ 20.7 % $ 6,194 ​ 17.5 % $ 121,096 ​ 20.0 % $ 43,222 ​ 19.0 % ​ We have recorded our deferred tax assets and liabilities using the statutory federal tax rate of 21 percent. We believe it is more likely than not that all deferred tax assets will be recovered, given the carry back availability as well as the result of future operations, which will generate sufficient taxable income to realize the deferred tax asset. Unrealized losses on the investment portfolio during 2022 have moved us from a net deferred tax liability position as of December 31, 2021 to a net deferred tax asset position as of September 30, 2022.

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation	5. STOCK BASED COMPENSATION ​ Our RLI Corp. Long-Term Incentive Plan (2010 LTIP) was in place from 2010 to 2015. The 2010 LTIP provided for equity-based compensation, including stock options, up to a maximum of 4,000,000 shares of common stock (subject to adjustment for changes in our capitalization and other events). Between 2010 and 2015, we granted 2,878,000 stock options under the 2010 LTIP. The 2010 LTIP was replaced in 2015. ​ In 2015, our shareholders approved the 2015 RLI Corp. Long-Term Incentive Plan (2015 LTIP), which provides for equity-based compensation and replaced the 2010 LTIP. In conjunction with the adoption of the 2015 LTIP, effective May 7, 2015, options were no longer granted under the 2010 LTIP. Awards under the 2015 LTIP may be in the form of restricted stock, restricted stock units, stock options (non-qualified only), stock appreciation rights, performance units as well as other stock-based awards. Eligibility under the 2015 LTIP is limited to employees and directors of the Company or any affiliate. The granting of awards under the 2015 LTIP is solely at the discretion of the board of directors. The maximum number of shares of common stock available for distribution under the 2015 LTIP is 4,000,000 shares (subject to adjustment for changes in our capitalization and other events). Since the plan’s approval in 2015, we have granted 3,237,225 awards under the 2015 LTIP, including 336,805 thus far in 2022. ​ Compensation expense is based on the probable number of awards expected to vest. The total compensation expense related to equity awards was $2.4 million and $6.2 million in the three and nine-month periods ended September 30, 2022, respectively, compared to $1.6 million and $4.8 million, respectively, for the same period in 2021. The total income tax benefit was $0.4 million and $1.0 million for the three and nine-month periods ended September 30, 2022, compared to $0.2 million and $0.7 million, respectively, for the same period in 2021. Total unrecognized compensation expense relating to outstanding and unvested awards was $8.2 million, which will be recognized over the weighted average vesting period of 2.23 years. ​ Stock Options ​ Under the 2015 LTIP, as under the 2010 LTIP, we grant stock options for shares with an exercise price equal to the fair market value of the shares at the date of grant (subject to adjustments for changes in our capitalization, special dividends and other events as set forth in such plans). Options generally vest and become exercisable over a five-year period and expire eight years after grant. ​ For most participants, the requisite service period and vesting period will be the same. For participants who are retirement eligible, defined by the plan as those individuals whose age and years of service equals 75, the requisite service period is deemed to be met and options are immediately expensed on the date of grant. For participants who will become retirement eligible during the vesting period, the requisite service period over which expense is recognized is the period between the grant date and the attainment of retirement eligibility. Shares issued upon option exercise are newly issued shares. ​ The following tables summarize option activity for the nine-month period ended September 30, 2022: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Aggregate ​ ​ ​ ​ Weighted ​ Average ​ Intrinsic ​ ​ ​ ​ Average ​ Remaining ​ Value ​ Options Exercise Price Contractual Life (in 000’s) Outstanding options at January 1, 2022 ​ 1,669,325 ​ $ 78.63 ​ ​ ​ ​ ​ Options granted ​ 320,100 ​ ​ 115.27 ​ ​ ​ ​ ​ Options exercised ​ (98,967) ​ ​ 59.98 ​ ​ ​ ​ ​ Options canceled/forfeited ​ (9,485) ​ ​ 93.40 ​ ​ ​ ​ ​ Outstanding options at September 30, 2022 ​ 1,880,973 ​ $ 85.78 ​ 4.86 ​ $ 37,402 Exercisable options at September 30, 2022 ​ 960,605 ​ $ 71.37 ​ 3.48 ​ $ 30,181 ​ The intrinsic value, which is the difference between the fair value and the exercise price, of options exercised was $5.5 million and $8.4 million during the first nine months of 2022 and 2021, respectively. ​ The fair value of options was estimated using a Black-Scholes based option pricing model with the following weighted average grant-date assumptions and weighted average fair values as of September 30: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 ​ Weighted-average fair value of grants ​ $ 20.99 ​ $ 17.01 ​ Risk-free interest rates ​ ​ 2.86 % ​ 0.70 % Dividend yield ​ ​ 2.50 % ​ 2.06 % Expected volatility ​ ​ 22.89 % ​ 22.73 % Expected option life ​ ​ 5.06 years ​ 4.97 years ​ The risk-free rate was determined based on U.S. treasury yields that most closely approximated the option’s expected life. The dividend yield was determined based on the average annualized quarterly dividends paid during the most recent five-year period and incorporated a consideration for special dividends paid in recent history. The expected volatility was calculated based on the median of the rolling volatilities for the expected life of the options. The expected option life was determined based on historical exercise behavior and the assumption that all outstanding options will be exercised at the midpoint of the current date and remaining contractual term, adjusted for the demographics of the current year’s grant. ​ Restricted Stock Units ​ In addition to stock options, restricted stock units (RSUs) are granted with a value equal to the closing stock price of the Company’s stock on the dates the units are granted. For employees, these units generally have a three-year cliff vesting, but have an accelerated vesting feature for participants who are retirement eligible, defined by the plan as those individuals whose age and years of service equals 75. For directors, these units vest on the earlier of one year from the date of grant or the next annual shareholders meeting. In addition, the RSUs have dividend participation, which accrue as additional units and are settled with granted stock units at the end of the vesting period. The total fair value of restricted stock units that vested was $2.5 million and $2.2 million during the first nine months of 2022 and 2021, respectively. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date ​ RSUs Fair Value Nonvested at January 1, 2022 ​ 45,068 ​ $ 97.67 Granted ​ 16,705 ​ ​ 116.60 Reinvested ​ 291 ​ ​ 108.78 Vested ​ (21,380) ​ ​ 93.07 Forfeited ​ (1,291) ​ ​ 76.82 Nonvested at September 30, 2022 ​ 39,393 ​ $ 108.25 ​

Operating Segment Information

Operating Segment Information	9 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Operating Segment Information	6. OPERATING SEGMENT INFORMATION Selected information by operating segment is presented in the table below. Additionally, the table reconciles segment totals to total earnings and total revenues. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Nine Months Revenues ​ Ended September 30, ​ Ended September 30, (in thousands) 2022 2021 2022 2021 Casualty ​ $ 179,615 ​ $ 162,852 ​ $ 528,494 ​ $ 467,817 Property ​ ​ 80,844 ​ ​ 60,886 ​ ​ 222,974 ​ ​ 168,393 Surety ​ ​ 31,009 ​ ​ 29,651 ​ ​ 91,962 ​ ​ 86,774 Net premiums earned ​ $ 291,468 ​ $ 253,389 ​ $ 843,430 ​ $ 722,984 Net investment income ​ ​ 21,270 ​ ​ 17,844 ​ ​ 57,625 ​ ​ 50,929 Net realized gains ​ ​ 573,170 ​ ​ 1,829 ​ ​ 591,562 ​ ​ 52,442 Net unrealized gains (losses) on equity securities ​ ​ (26,414) ​ ​ (2,592) ​ ​ (155,218) ​ ​ 29,526 Total consolidated revenue ​ $ 859,494 ​ $ 270,470 ​ $ 1,337,399 ​ $ 855,881 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net Earnings ​ ​ ​ ​ ​ ​ (in thousands) 2022 2021 2022 2021 Casualty ​ $ 11,329 ​ $ 22,949 ​ $ 60,418 ​ $ 74,254 Property ​ ​ (8,308) ​ ​ (16,558) ​ ​ 40,273 ​ ​ (8,684) Surety ​ ​ 5,775 ​ ​ 7,333 ​ ​ 23,539 ​ ​ 14,662 Net underwriting income ​ $ 8,796 ​ $ 13,724 ​ $ 124,230 ​ $ 80,232 Net investment income ​ ​ 21,270 ​ ​ 17,844 ​ ​ 57,625 ​ ​ 50,929 Net realized gains ​ ​ 573,170 ​ ​ 1,829 ​ ​ 591,562 ​ ​ 52,442 Net unrealized gains (losses) on equity securities ​ ​ (26,414) ​ ​ (2,592) ​ ​ (155,218) ​ ​ 29,526 General corporate expense and interest on debt ​ ​ (4,768) ​ ​ (4,411) ​ ​ (14,587) ​ ​ (15,244) Equity in earnings (loss) of unconsolidated investees ​ ​ (17,352) ​ ​ 9,043 ​ ​ 3,061 ​ ​ 29,407 Earnings before income taxes ​ $ 554,702 ​ $ 35,437 ​ $ 606,673 ​ $ 227,292 Income tax expense ​ ​ 114,809 ​ ​ 6,194 ​ ​ 121,096 ​ ​ 43,222 Net earnings ​ $ 439,893 ​ $ 29,243 ​ $ 485,577 ​ $ 184,070 ​ The following table further summarizes revenues by major product type within each operating segment: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Nine Months Net Premiums Earned ​ Ended September 30, ​ Ended September 30, (in thousands) 2022 2021 2022 2021 Casualty ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial excess and personal umbrella ​ $ 65,131 ​ $ 56,285 ​ $ 187,666 ​ $ 161,287 General liability ​ ​ 25,284 ​ ​ 23,156 ​ ​ 74,130 ​ ​ 67,616 Commercial transportation ​ ​ 24,205 ​ ​ 22,571 ​ ​ 71,774 ​ ​ 60,926 Professional services ​ ​ 24,174 ​ ​ 22,401 ​ ​ 71,590 ​ ​ 66,095 Small commercial ​ ​ 17,005 ​ ​ 16,301 ​ ​ 50,463 ​ ​ 48,302 Executive products ​ ​ 6,556 ​ ​ 5,461 ​ ​ 20,208 ​ ​ 15,785 Other casualty ​ ​ 17,260 ​ ​ 16,677 ​ ​ 52,663 ​ ​ 47,806 Total ​ $ 179,615 ​ $ 162,852 ​ $ 528,494 ​ $ 467,817 Property ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial property ​ $ 43,201 ​ $ 28,683 ​ $ 115,419 ​ $ 76,488 Marine ​ ​ 29,592 ​ ​ 25,416 ​ ​ 84,499 ​ ​ 72,737 Specialty personal ​ ​ 6,409 ​ ​ 5,462 ​ ​ 18,405 ​ ​ 15,761 Other property ​ ​ 1,642 ​ ​ 1,325 ​ ​ 4,651 ​ ​ 3,407 Total ​ $ 80,844 ​ $ 60,886 ​ $ 222,974 ​ $ 168,393 Surety ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 12,057 ​ $ 11,541 ​ $ 35,423 ​ $ 33,594 Miscellaneous ​ ​ 10,751 ​ ​ 11,124 ​ ​ 33,691 ​ ​ 32,604 Contract ​ ​ 8,201 ​ ​ 6,986 ​ ​ 22,848 ​ ​ 20,576 Total ​ $ 31,009 ​ $ 29,651 ​ $ 91,962 ​ $ 86,774 Grand Total ​ $ 291,468 ​ $ 253,389 ​ $ 843,430 ​ $ 722,984 ​

Leases

Leases	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Leases	7. LEASES ​ Right-of-use (ROU) assets are included in the other assets line item and lease liabilities are included in the other liabilities line item of the consolidated balance sheet. We determine if a contract contains a lease at inception and recognize operating lease ROU assets and operating lease liabilities based on the present value of the future minimum lease payments at the commencement date. As our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of future payments. Lease agreements may include options to extend or terminate. The options are exercised at our discretion and are included in operating lease liabilities if it is reasonably certain the option will be exercised. Lease agreements have lease and non-lease components, which are accounted for as a single lease component. Operating lease cost for future minimum lease payments is recognized on a straight-line basis over the lease term. Variable lease cost is expensed in the period in which the obligation is incurred. Sublease income is recognized on a straight-line basis over the sublease term. ​ The Company’s operating lease obligations are for branch office facilities. The components of lease expense and other lease information as of and during the three and nine-month periods ended September 30, 2022 and 2021 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Nine Months ​ ​ Ended September 30, ​ Ended September 30, (in thousands) 2022 2021 2022 2021 Operating lease cost ​ $ 1,272 ​ $ 1,326 ​ $ 3,686 ​ $ 4,005 Variable lease cost ​ ​ 339 ​ ​ 348 ​ ​ 1,073 ​ ​ 1,090 Sublease income ​ ​ (139) ​ ​ (123) ​ ​ (416) ​ ​ (369) Total lease cost ​ $ 1,472 ​ $ 1,551 ​ $ 4,343 ​ $ 4,726 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in measurement of lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash outflows from operating leases ​ $ 1,387 ​ $ 1,490 ​ $ 3,987 ​ $ 4,455 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for new operating lease liabilities ​ $ 54 ​ $ 4,434 ​ $ 2,485 ​ $ 4,699 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reduction to ROU assets resulting from reduction to lease liabilities ​ $ — ​ $ — ​ $ — ​ $ 1,250 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other non-cash reductions to ROU assets ​ $ — ​ $ 48 ​ $ 73 ​ $ 48 ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) September 30, 2022 December 31, 2021 ​ Operating lease ROU assets ​ $ 13,749 ​ $ 14,765 ​ Operating lease liabilities ​ $ 15,658 ​ $ 16,905 ​ Weighted-average remaining lease term - operating leases ​ ​ 4.31 years ​ 4.52 years Weighted-average discount rate - operating leases ​ ​ 2.07 % ​ 2.02 % ​ Future minimum lease payments under non-cancellable leases as of September 30, 2022 were as follows: ​ ​ ​ ​ ​ (in thousands) September 30, 2022 2022 ​ $ 1,448 2023 ​ ​ 5,529 2024 ​ ​ 3,552 2025 ​ ​ 2,138 2026 ​ ​ 1,285 2027 ​ ​ 826 Thereafter ​ ​ 1,589 Total future minimum lease payments ​ $ 16,367 Less imputed interest ​ ​ (709) Total operating lease liability ​ $ 15,658 ​

Acquisitions and Dispositions

Acquisitions and Dispositions	9 Months Ended
	Sep. 30, 2022
Business Combination and Asset Acquisition [Abstract]
Acquisitions and Dispositions	8. ACQUISITONS AND DISPOSTIONS ​ On September 30, 2022, RLI Corp. completed the sale of its equity method investment in Maui Jim to Kering Eyewear for cash proceeds of $686.6 million. We recognized a net realized gain of $574.5 million as a result of the sale, which was recorded in the net realized gain line item of the statement of earnings. In addition, we have the right to receive additional consideration based on customary post-closing working capital and other adjustments. Any gain related to the additional consideration will be recognized when received.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Basis of Presentation	A. BASIS OF PRESENTATION ​ The unaudited condensed consolidated interim financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (GAAP) for interim financial reporting and with the instructions to Form 10-Q and Regulation S-X. Accordingly, they do not include all the disclosures required by GAAP for complete financial statements. As such, these unaudited condensed consolidated interim financial statements should be read in conjunction with our 2021 Annual Report on Form 10-K. Management believes that the disclosures are adequate to make the information presented not misleading, and all normal and recurring adjustments necessary to present fairly the financial position at September 30, 2022 and the results of operations of RLI Corp. (the Company) and subsidiaries for all periods presented have been made. The results of operations for any interim period are not necessarily indicative of the operating results for a full year. Certain reclassifications were made to 2021 to conform to the classifications used in the current year. ​ The preparation of the unaudited condensed consolidated interim financial statements requires management to make estimates and assumptions relating to the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the unaudited condensed consolidated interim financial statements and the reported amounts of revenue and expenses during the period. These estimates are inherently subject to change and actual results could differ significantly from these estimates.
Adopted Accounting Standards	​ B. ADOPTED ACCOUNTING STANDARDS ​ No new accounting standards applicable in 2022 materially impact our financial statements.
Prospective Accounting Standards	​ C. PROSPECTIVE ACCOUNTING STANDARDS ​ There are no prospective accounting standards which would have a material impact on our financial statements as of September 30, 2022.
Reinsurance	​ D. REINSURANCE ​ Ceded unearned premiums and reinsurance balances recoverable on unpaid losses and settlement expenses are reported separately as an asset, rather than being netted with the related liability, since reinsurance does not relieve the Company of our liability to policyholders. Such balances are subject to the credit risk associated with the individual reinsurer. We continually monitor the financial condition of our reinsurers and actively follow up on any past due or disputed amounts. As part of our monitoring efforts, we review reinsurers’ annual financial statements and Securities and Exchange Commission filings for those that are publicly traded. We also review insurance industry developments that may impact the financial condition of our reinsurers. We analyze the credit risk associated with our reinsurance balances recoverable by monitoring the AM Best and Standard & Poor’s (S&P) ratings of our reinsurers. In addition, we subject our reinsurance recoverables to detailed recoverability tests, including a segment-based analysis using the average default rating percentage by S&P rating, which assists the Company in assessing the sufficiency of its allowance. Additionally, we perform an in-depth reinsurer financial condition analysis prior to the renewal of each of our reinsurance placements. ​ Our policy is to charge to earnings, in the form of an allowance, an estimate of unrecoverable amounts from reinsurers. This allowance is reviewed on an ongoing basis to ensure that the amount makes a reasonable provision for reinsurance balances that we may be unable to recover. Once regulatory action (such as receivership, finding of insolvency, order of conservation or order of liquidation) is taken against a reinsurer, the paid and unpaid recoverable for the reinsurer are specifically identified and written off through use of our allowance for estimated unrecoverable amounts from reinsurers. When we write-off such a balance, it is done in full. We then re-evaluate the overall allowance and determine whether the balance is sufficient and, if needed, an additional allowance is recognized. ​ The allowances for uncollectible amounts on paid and unpaid reinsurance recoverables were $16.1 million and $11.4 million, respectively, at September 30, 2022. At December 31, 2021, the amounts were $16.1 million and $11.2 million, respectively. Changes in the allowances were due to changes in the amount of reinsurance balances outstanding, the composition of reinsurers from whom the balances were recoverable and their associated S&P default ratings. No write-offs were applied to the allowances in the first nine months of 2022 and less than $0.1 million was recovered. We have no receivables with a due date that extends beyond one year that are not included in our allowance for uncollectible amounts. ​
Intangible Assets	E. INTANGIBLE ASSETS ​ The composition of goodwill and intangible assets at September 30, 2022 and December 31, 2021 is detailed in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, (in thousands) 2022 2021 Goodwill ​ ​ ​ ​ ​ ​ Surety ​ $ 40,816 ​ $ 40,816 Casualty ​ ​ 5,246 ​ ​ 5,246 Total goodwill ​ $ 46,062 ​ $ 46,062 Intangibles ​ ​ ​ ​ ​ ​ Indefinite-lived intangibles - state insurance licenses ​ ​ 7,500 ​ ​ 7,500 Total goodwill and intangibles ​ $ 53,562 ​ $ 53,562 ​ Annual impairment assessments were performed on our goodwill and state insurance license indefinite-lived intangible asset during the second quarter of 2022. Based upon these reviews, none of the assets were impaired. In addition, there were no triggering events as of September 30, 2022 that would suggest an updated impairment test would be needed for our goodwill and intangible assets.
Earnings Per Share	F. EARNINGS PER SHARE ​ Basic earnings per share (EPS) is computed by dividing income available to common shareholders by the weighted-average number of common shares outstanding for the period. Diluted EPS reflects the dilution that could occur if securities or other contracts to issue common stock or common stock equivalents were exercised or converted into common stock. When inclusion of these items increases the earnings per share or reduces the loss per share, the effect on earnings is anti-dilutive. Under these circumstances, the diluted net earnings or net loss per share is computed excluding these items. The following represents a reconciliation of the numerator and denominator of the basic and diluted EPS computations contained in the unaudited condensed consolidated interim financial statements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Three Months ​ ​ Ended September 30, 2022 ​ Ended September 30, 2021 ​ ​ Income ​ Shares ​ Per Share ​ Income ​ Shares ​ Per Share (in thousands, except per share data) (Numerator) (Denominator) Amount (Numerator) (Denominator) Amount Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 439,893 ​ 45,379 ​ $ 9.69 ​ $ 29,243 ​ 45,243 ​ $ 0.65 Effect of Dilutive Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options and restricted stock units ​ ​ — ​ 396 ​ ​ ​ ​ ​ — ​ 446 ​ ​ ​ Diluted EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 439,893 ​ 45,775 ​ $ 9.61 ​ $ 29,243 ​ 45,689 ​ $ 0.64 Anti-dilutive securities excluded from diluted EPS ​ ​ ​ ​ ​ 435 ​ ​ ​ ​ ​ ​ ​ ​ 191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months ​ For the Nine Months ​ ​ Ended September 30, 2022 ​ Ended September 30, 2021 ​ ​ Income ​ Shares ​ Per Share ​ Income ​ Shares ​ Per Share (in thousands, except per share data) (Numerator) (Denominator) Amount (Numerator) (Denominator) Amount Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 485,577 ​ 45,347 ​ $ 10.71 ​ $ 184,070 ​ 45,216 ​ $ 4.07 Effect of Dilutive Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options and restricted stock units ​ ​ — ​ 428 ​ ​ ​ ​ ​ — ​ 498 ​ ​ ​ Diluted EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 485,577 ​ 45,775 ​ $ 10.61 ​ $ 184,070 ​ 45,714 ​ $ 4.03 Anti-dilutive securities excluded from diluted EPS ​ ​ ​ ​ ​ 459 ​ ​ ​ ​ ​ ​ ​ ​ 191 ​ ​ ​ ​
Comprehensive Earnings (Loss)	G. COMPREHENSIVE EARNINGS ​ Our comprehensive earnings include net earnings plus after-tax unrealized gains and losses on our available-for-sale fixed income portfolio. In reporting the components of comprehensive earnings, we used the federal statutory tax rate of 21 percent. Other comprehensive earnings (loss), as shown in the consolidated statements of earnings and comprehensive earnings, is net of tax benefit of $21.6 million for the third quarter of 2022, compared to $3.2 million for the same period in 2021. For the nine-month period ended September 30, 2022, other comprehensive earnings (loss) is net of tax benefit of $78.3 million, compared to $11.1 million for the same period in 2021. ​ Unrealized losses, net of tax, recognized in other comprehensive earnings (loss) were $294.4 million for the first nine months of 2022, compared to $41.8 million during the same period last year. The unrealized losses were attributable to higher interest rates in both periods, which decreased the fair value of securities held in the fixed income portfolio. ​ The following table illustrates the changes in the balance of each component of accumulated other comprehensive earnings (loss) for each period presented in the unaudited condensed consolidated interim financial statements: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ For the Three Months ​ For the Nine Months ​ ​ Ended September 30, ​ Ended September 30, Unrealized Gains/Losses on Available-for-Sale Securities 2022 2021 2022 2021 Beginning balance ​ $ (163,318) ​ $ 79,144 ​ $ 49,826 ​ $ 108,714 Other comprehensive earnings (loss) before reclassifications ​ ​ (82,785) ​ ​ (12,114) ​ ​ (296,422) ​ ​ (40,307) Amounts reclassified from accumulated other comprehensive earnings ​ ​ 1,537 ​ ​ (126) ​ ​ 2,030 ​ ​ (1,503) Net current-period other comprehensive earnings (loss) ​ $ (81,248) ​ $ (12,240) ​ $ (294,392) ​ $ (41,810) Ending balance ​ $ (244,566) ​ $ 66,904 ​ $ (244,566) ​ $ 66,904 Balance of securities for which an allowance for credit losses has been recognized in net earnings ​ ​ ​ ​ ​ ​ ​ $ 1,520 ​ $ 426 ​ Credit losses on or the sale of an available-for-sale security results in amounts being reclassified from accumulated other comprehensive earnings (loss) to current period net earnings. The effects of reclassifications out of accumulated other comprehensive earnings (loss) by the respective line items of net earnings are presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount Reclassified from Accumulated Other ​ ​ (in thousands) ​ Comprehensive Earnings (Loss) ​ ​ ​ ​ For the Three Months ​ For the Nine Months ​ ​ Component of Accumulated ​ Ended September 30, ​ Ended September 30, ​ Affected line item in the Other Comprehensive Earnings (Loss) 2022 2021 2022 2021 Statement of Earnings Unrealized gains and losses on available-for-sale securities ​ $ (1,912) ​ $ 182 ​ $ (2,684) ​ $ 1,731 ​ Net realized gains (losses) ​ ​ ​ (34) ​ ​ (22) ​ ​ 115 ​ ​ 171 ​ Credit gains presented within net realized gains ​ ​ $ (1,946) ​ $ 160 ​ $ (2,569) ​ $ 1,902 ​ Earnings (loss) before income taxes ​ ​ ​ 409 ​ ​ (34) ​ ​ 539 ​ ​ (399) ​ Income tax (expense) benefit ​ ​ $ (1,537) ​ $ 126 ​ $ (2,030) ​ $ 1,503 ​ Net earnings (loss)
Fair Value Measurements	H. FAIR VALUE MEASUREMENTS ​ Fair value is defined as the price in the principal market that would be received for an asset to facilitate an orderly transaction between market participants on the measurement date. We determined the fair value of certain financial instruments based on their underlying characteristics and relevant transactions in the marketplace. We maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. ​ The following are the levels of the fair value hierarchy and a brief description of the type of valuation inputs that are used to establish each level. Financial assets are classified based upon the lowest level of significant input that is used to determine fair value. ​ Level 1 ​ Level 2 ​ Level 3 ​ As a part of management’s process to determine fair value, we utilize widely recognized, third-party pricing sources to determine our fair values. We have obtained an understanding of the third-party pricing sources’ valuation methodologies and inputs. The following is a description of the valuation techniques used for financial assets that are measured at fair value, including the general classification of such assets pursuant to the fair value hierarchy. ​ Corporate, Agencies, Government and Municipal Bonds: ​ Mortgage-backed Securities (MBS)/Commercial Mortgage-backed Securities (CMBS) and Asset-backed Securities (ABS): ​ Regulation D Private Placement Securities: ​ For all of our fixed income securities classified as Level 2, we periodically conduct a review to assess the reasonableness of the fair values provided by our pricing services. Our review consists of a two-pronged approach. First, we compare prices provided by our pricing services to those provided by an additional source. In some cases, we obtain prices from securities brokers and compare them to the prices provided by our pricing services. If discrepancies are found in our comparisons, we compare our prices to actual reported trade data for like securities. No changes to the fair values supplied by our pricing services have occurred as a result of our reviews. Based on these assessments, we have determined that the fair values of our Level 2 fixed income securities provided by our pricing services are reasonable. ​ Equity Securities: ​ Due to the relatively short-term nature of cash, short-term investments, accounts receivable and accounts payable, their carrying amounts are reasonable estimates of fair value. Our investments in private funds, classified as other invested assets, are measured using the investments’ net asset value per share and are not categorized within the fair value hierarchy.
Risks and Uncertainties	I. RISKS AND UNCERTAINTIES ​ Certain risks and uncertainties are inherent in our day-to-day operations. Adverse changes in the economy, including inflation; rising interest rates; volatile equity markets; and ongoing supply chain disruptions, could lower demand for our insurance products, result in increased levels of loss costs that we could not anticipate at the time we priced our coverages, or negatively impact our investment results, all of which could have an adverse effect on the profitability of our operations. The COVID-19 pandemic may result in significant disruptions in economic activity and financial markets or exacerbate the impact of other economic trends. The cumulative effects of any public health outbreak could reduce demand for our insurance policies; result in increased level of losses, settlement expenses or other operating costs; reduce the market value of invested assets held by the Company or negatively impact the fair value of our goodwill. ​ Catastrophe Exposures ​ Our catastrophe reinsurance treaty renewed on January 1, 2022. We purchased limits of $600 million in excess of $25 million first-dollar retention for earthquakes in California, $625 million in excess of $25 million first-dollar retention for earthquakes outside of California and $475 million in excess of $25 million first-dollar retention for all other perils, including wind. These amounts are subject to certain co-participations by the Company on losses in excess of the $25 million retentions. On May 1, 2022, we purchased $150 million of additional catastrophe reinsurance protection on top of the previously described coverage, to support growth in our catastrophe-exposed business. This increases the limits to $750 million for earthquakes in California, $775 million for earthquakes outside of California and $625 million for all other perils, including wind, all of which are still subject to $25 million first-dollar retentions and certain co-participations in excess of the retentions.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Schedule of Goodwill and Intangible Assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, (in thousands) 2022 2021 Goodwill ​ ​ ​ ​ ​ ​ Surety ​ $ 40,816 ​ $ 40,816 Casualty ​ ​ 5,246 ​ ​ 5,246 Total goodwill ​ $ 46,062 ​ $ 46,062 Intangibles ​ ​ ​ ​ ​ ​ Indefinite-lived intangibles - state insurance licenses ​ ​ 7,500 ​ ​ 7,500 Total goodwill and intangibles ​ $ 53,562 ​ $ 53,562
Schedule of Reconciliation of Numerator and Denominator of the Basic and Diluted Earnings Per Share Computations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Three Months ​ ​ Ended September 30, 2022 ​ Ended September 30, 2021 ​ ​ Income ​ Shares ​ Per Share ​ Income ​ Shares ​ Per Share (in thousands, except per share data) (Numerator) (Denominator) Amount (Numerator) (Denominator) Amount Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 439,893 ​ 45,379 ​ $ 9.69 ​ $ 29,243 ​ 45,243 ​ $ 0.65 Effect of Dilutive Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options and restricted stock units ​ ​ — ​ 396 ​ ​ ​ ​ ​ — ​ 446 ​ ​ ​ Diluted EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 439,893 ​ 45,775 ​ $ 9.61 ​ $ 29,243 ​ 45,689 ​ $ 0.64 Anti-dilutive securities excluded from diluted EPS ​ ​ ​ ​ ​ 435 ​ ​ ​ ​ ​ ​ ​ ​ 191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months ​ For the Nine Months ​ ​ Ended September 30, 2022 ​ Ended September 30, 2021 ​ ​ Income ​ Shares ​ Per Share ​ Income ​ Shares ​ Per Share (in thousands, except per share data) (Numerator) (Denominator) Amount (Numerator) (Denominator) Amount Basic EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 485,577 ​ 45,347 ​ $ 10.71 ​ $ 184,070 ​ 45,216 ​ $ 4.07 Effect of Dilutive Securities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock options and restricted stock units ​ ​ — ​ 428 ​ ​ ​ ​ ​ — ​ 498 ​ ​ ​ Diluted EPS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earnings available to common shareholders ​ $ 485,577 ​ 45,775 ​ $ 10.61 ​ $ 184,070 ​ 45,714 ​ $ 4.03 Anti-dilutive securities excluded from diluted EPS ​ ​ ​ ​ ​ 459 ​ ​ ​ ​ ​ ​ ​ ​ 191 ​ ​ ​ ​
Schedule of Changes in the Balance of Each Component of Accumulated Other Comprehensive Earnings (Loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ For the Three Months ​ For the Nine Months ​ ​ Ended September 30, ​ Ended September 30, Unrealized Gains/Losses on Available-for-Sale Securities 2022 2021 2022 2021 Beginning balance ​ $ (163,318) ​ $ 79,144 ​ $ 49,826 ​ $ 108,714 Other comprehensive earnings (loss) before reclassifications ​ ​ (82,785) ​ ​ (12,114) ​ ​ (296,422) ​ ​ (40,307) Amounts reclassified from accumulated other comprehensive earnings ​ ​ 1,537 ​ ​ (126) ​ ​ 2,030 ​ ​ (1,503) Net current-period other comprehensive earnings (loss) ​ $ (81,248) ​ $ (12,240) ​ $ (294,392) ​ $ (41,810) Ending balance ​ $ (244,566) ​ $ 66,904 ​ $ (244,566) ​ $ 66,904 Balance of securities for which an allowance for credit losses has been recognized in net earnings ​ ​ ​ ​ ​ ​ ​ $ 1,520 ​ $ 426
Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Loss)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount Reclassified from Accumulated Other ​ ​ (in thousands) ​ Comprehensive Earnings (Loss) ​ ​ ​ ​ For the Three Months ​ For the Nine Months ​ ​ Component of Accumulated ​ Ended September 30, ​ Ended September 30, ​ Affected line item in the Other Comprehensive Earnings (Loss) 2022 2021 2022 2021 Statement of Earnings Unrealized gains and losses on available-for-sale securities ​ $ (1,912) ​ $ 182 ​ $ (2,684) ​ $ 1,731 ​ Net realized gains (losses) ​ ​ ​ (34) ​ ​ (22) ​ ​ 115 ​ ​ 171 ​ Credit gains presented within net realized gains ​ ​ $ (1,946) ​ $ 160 ​ $ (2,569) ​ $ 1,902 ​ Earnings (loss) before income taxes ​ ​ ​ 409 ​ ​ (34) ​ ​ 539 ​ ​ (399) ​ Income tax (expense) benefit ​ ​ $ (1,537) ​ $ 126 ​ $ (2,030) ​ $ 1,503 ​ Net earnings (loss)

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2022
Investments Debt And Equity Securities [Abstract]
Schedule of Disposition of Fixed Income and Equity Securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Sales ​ Proceeds ​ Gross Realized ​ Net Realized (in thousands) From Sales Gains Losses Gain (Loss) 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 48,559 ​ $ 286 ​ $ (2,481) ​ $ (2,195) Equity securities ​ ​ 59,264 ​ ​ 20,410 ​ ​ (609) ​ ​ 19,801 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 43,041 ​ $ 1,476 ​ $ (107) ​ $ 1,369 Equity securities ​ ​ 157,973 ​ ​ 52,409 ​ ​ (1,787) ​ ​ 50,622 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Calls/Maturities ​ ​ ​ ​ Gross Realized ​ Net Realized (in thousands) Proceeds Gains Losses Gain (Loss) 2022 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 176,991 ​ $ 142 ​ $ (55) ​ $ 87 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed income securities - available-for-sale ​ $ 296,563 ​ $ 471 ​ $ (109) ​ $ 362
Fair Value, Assets Measured on Recurring Basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of September 30, 2022 ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ (in thousands) (Level 1) (Level 2) (Level 3) Total Fixed income securities - available-for-sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government ​ $ — ​ $ 340,442 ​ $ — ​ $ 340,442 U.S. agency ​ ​ — ​ ​ 56,935 ​ ​ — ​ ​ 56,935 Non-U.S. government & agency ​ ​ — ​ ​ 5,712 ​ ​ — ​ ​ 5,712 Agency MBS ​ ​ — ​ ​ 317,029 ​ ​ — ​ ​ 317,029 ABS/CMBS/MBS* ​ ​ — ​ ​ 241,512 ​ ​ — ​ ​ 241,512 Corporate ​ ​ — ​ ​ 910,979 ​ ​ 52,890 ​ ​ 963,869 Municipal ​ ​ — ​ ​ 526,540 ​ ​ — ​ ​ 526,540 Total fixed income securities - available-for-sale ​ $ — ​ $ 2,399,149 ​ $ 52,890 ​ $ 2,452,039 Equity securities ​ ​ 461,392 ​ ​ 49 ​ ​ 1,547 ​ ​ 462,988 Total ​ $ 461,392 ​ $ 2,399,198 ​ $ 54,437 ​ $ 2,915,027 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, 2021 ​ ​ Quoted Prices in ​ Significant Other ​ Significant ​ ​ ​ ​ ​ Active Markets for ​ Observable ​ Unobservable ​ ​ ​ ​ ​ Identical Assets ​ Inputs ​ Inputs ​ ​ ​ (in thousands) (Level 1) (Level 2) (Level 3) Total Fixed income securities - available-for-sale ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. government ​ $ — ​ $ 134,554 ​ $ — ​ $ 134,554 U.S. agency ​ ​ — ​ ​ 32,760 ​ ​ — ​ ​ 32,760 Non-U.S. government & agency ​ ​ — ​ ​ 8,481 ​ ​ — ​ ​ 8,481 Agency MBS ​ ​ — ​ ​ 367,187 ​ ​ — ​ ​ 367,187 ABS/CMBS/MBS* ​ ​ — ​ ​ 264,054 ​ ​ — ​ ​ 264,054 Corporate ​ ​ — ​ ​ 913,577 ​ ​ 43,518 ​ ​ 957,095 Municipal ​ ​ — ​ ​ 645,756 ​ ​ — ​ ​ 645,756 Total fixed income securities - available-for-sale ​ $ — ​ $ 2,366,369 ​ $ 43,518 ​ $ 2,409,887 Equity securities ​ ​ 613,712 ​ ​ 64 ​ ​ — ​ ​ 613,776 Total ​ $ 613,712 ​ $ 2,366,433 ​ $ 43,518 ​ $ 3,023,663 * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities
Summary of Changes in Balance of Level 3 Securities	​ ​ ​ ​ ​ (in thousands) Level 3 Securities Balance as of January 1, 2022 ​ $ 43,518 Net realized and unrealized gains (losses) ​ ​ ​ Included in net earnings as a part of: ​ ​ ​ Net investment income ​ ​ (662) Net realized gains ​ ​ (433) Included in other comprehensive earnings (loss) ​ ​ (8,350) Total net realized and unrealized gains (losses) ​ $ (9,445) Purchases ​ ​ 21,461 Transfers out of Level 3 ​ ​ (1,097) Balance as of September 30, 2022 ​ $ 54,437 Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in net realized gains ​ $ (433) Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in other comprehensive earnings (loss) ​ $ (8,350)
Schedule of Contractual Maturity of Securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 (in thousands) Amortized Cost Fair Value Due in one year or less ​ $ 206,921 ​ $ 206,327 Due after one year through five years ​ ​ 867,511 ​ ​ 818,569 Due after five years through 10 years ​ ​ 515,276 ​ ​ 457,011 Due after 10 years ​ ​ 526,093 ​ ​ 411,591 ABS/CMBS/MBS* ​ ​ 637,830 ​ ​ 558,541 Total available-for-sale ​ $ 2,753,631 ​ $ 2,452,039 * Asset-backed, commercial mortgage-backed and mortgage-backed securities
Schedule of Amortized Cost and Fair Value of Available-for-sale Securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ ​ Cost or ​ Allowance ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ for Credit ​ Unrealized ​ Unrealized ​ Fair (in thousands) Cost Losses Gains Losses Value U.S. government ​ $ 349,419 ​ $ — ​ $ — ​ $ (8,977) ​ $ 340,442 U.S. agency ​ ​ 59,048 ​ ​ — ​ ​ 9 ​ ​ (2,122) ​ ​ 56,935 Non-U.S. government & agency ​ ​ 6,798 ​ ​ — ​ ​ — ​ ​ (1,086) ​ ​ 5,712 Agency MBS ​ ​ 360,429 ​ ​ — ​ ​ 172 ​ ​ (43,572) ​ ​ 317,029 ABS/CMBS/MBS* ​ ​ 277,401 ​ ​ (9) ​ ​ 21 ​ ​ (35,901) ​ ​ 241,512 Corporate ​ ​ 1,067,473 ​ ​ (318) ​ ​ 47 ​ ​ (103,333) ​ ​ 963,869 Municipal ​ ​ 633,063 ​ ​ — ​ ​ 194 ​ ​ (106,717) ​ ​ 526,540 Total Fixed Income ​ $ 2,753,631 ​ $ (327) ​ $ 443 ​ $ (301,708) ​ $ 2,452,039 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ ​ Cost or ​ Allowance ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ for Credit ​ Unrealized ​ Unrealized ​ Fair (in thousands) Cost Losses Gains Losses Value U.S. government ​ $ 127,752 ​ $ — ​ $ 6,846 ​ $ (44) ​ $ 134,554 U.S. agency ​ ​ 30,403 ​ ​ — ​ ​ 2,374 ​ ​ (17) ​ ​ 32,760 Non-U.S. government & agency ​ ​ 8,297 ​ ​ — ​ ​ 338 ​ ​ (154) ​ ​ 8,481 Agency MBS ​ ​ 362,861 ​ ​ — ​ ​ 9,277 ​ ​ (4,951) ​ ​ 367,187 ABS/CMBS/MBS* ​ ​ 264,273 ​ ​ — ​ ​ 2,120 ​ ​ (2,339) ​ ​ 264,054 Corporate ​ ​ 925,394 ​ ​ (441) ​ ​ 37,247 ​ ​ (5,105) ​ ​ 957,095 Municipal ​ ​ 627,287 ​ ​ — ​ ​ 22,750 ​ ​ (4,281) ​ ​ 645,756 Total Fixed Income ​ $ 2,346,267 ​ $ (441) ​ $ 80,952 ​ $ (16,891) ​ $ 2,409,887 * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities
Schedule of Debt Securities Available-for-sale Allowance for Credit Loss	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, (in thousands) 2022 2021 2022 2021 Beginning balance ​ $ 292 ​ $ 204 ​ $ 441 ​ $ 397 Increase to allowance from securities for which credit losses were not previously recorded ​ ​ 168 ​ ​ — ​ ​ 292 ​ ​ — Reduction from securities sold during the period ​ ​ (166) ​ ​ — ​ ​ (619) ​ ​ ​ Reductions from intent to sell securities ​ ​ — ​ ​ — ​ ​ (17) ​ ​ — Net increase (decrease) from securities that had an allowance at the beginning of the period ​ ​ 33 ​ ​ 22 ​ ​ 230 ​ ​ (171) Balance as of September 30, ​ $ 327 ​ $ 226 ​ $ 327 ​ $ 226
Schedule of Securities in an Unrealized Loss Position Segregated by Type and Length of Time in an Unrealized Loss Position	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2022 ​ December 31, 2021 (in thousands) < 12 Mos. 12 Mos. & Greater Total < 12 Mos. 12 Mos. & Greater Total U.S. government ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 285,302 ​ $ 5,315 ​ $ 290,617 ​ $ 2,942 ​ $ — ​ $ 2,942 Amortized cost ​ ​ 293,829 ​ ​ 5,765 ​ ​ 299,594 ​ ​ 2,986 ​ ​ — ​ ​ 2,986 Unrealized loss ​ $ (8,527) ​ $ (450) ​ $ (8,977) ​ $ (44) ​ $ — ​ $ (44) U.S. agency ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 30,089 ​ $ — ​ $ 30,089 ​ $ 1,498 ​ $ — ​ $ 1,498 Amortized cost ​ ​ 32,211 ​ ​ — ​ ​ 32,211 ​ ​ 1,515 ​ ​ — ​ ​ 1,515 Unrealized loss ​ $ (2,122) ​ $ — ​ $ (2,122) ​ $ (17) ​ $ — ​ $ (17) Non-U.S. government ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 3,594 ​ $ 2,118 ​ $ 5,712 ​ $ 4,346 ​ $ — ​ $ 4,346 Amortized cost ​ ​ 3,798 ​ ​ 3,000 ​ ​ 6,798 ​ ​ 4,500 ​ ​ — ​ ​ 4,500 Unrealized Loss ​ $ (204) ​ $ (882) ​ $ (1,086) ​ $ (154) ​ $ — ​ $ (154) Agency MBS ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 192,947 ​ $ 112,457 ​ $ 305,404 ​ $ 102,145 ​ $ 62,669 ​ $ 164,814 Amortized cost ​ ​ 210,448 ​ ​ 138,528 ​ ​ 348,976 ​ ​ 104,336 ​ ​ 65,429 ​ ​ 169,765 Unrealized loss ​ $ (17,501) ​ $ (26,071) ​ $ (43,572) ​ $ (2,191) ​ $ (2,760) ​ $ (4,951) ABS/CMBS/MBS* ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 148,272 ​ $ 89,792 ​ $ 238,064 ​ $ 150,997 ​ $ 3,935 ​ $ 154,932 Amortized cost ​ ​ 165,163 ​ ​ 108,802 ​ ​ 273,965 ​ ​ 153,235 ​ ​ 4,036 ​ ​ 157,271 Unrealized loss ​ $ (16,891) ​ $ (19,010) ​ $ (35,901) ​ $ (2,238) ​ $ (101) ​ $ (2,339) Corporate ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 773,433 ​ $ 184,317 ​ $ 957,750 ​ $ 217,791 ​ $ 53,818 ​ $ 271,609 Amortized cost ​ ​ 844,169 ​ ​ 216,914 ​ ​ 1,061,083 ​ ​ 221,010 ​ ​ 55,704 ​ ​ 276,714 Unrealized loss ​ $ (70,736) ​ $ (32,597) ​ $ (103,333) ​ $ (3,219) ​ $ (1,886) ​ $ (5,105) Municipal ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 418,864 ​ $ 76,783 ​ $ 495,647 ​ $ 162,998 ​ $ 15,037 ​ $ 178,035 Amortized cost ​ ​ 493,485 ​ ​ 108,879 ​ ​ 602,364 ​ ​ 166,602 ​ ​ 15,714 ​ ​ 182,316 Unrealized loss ​ $ (74,621) ​ $ (32,096) ​ $ (106,717) ​ $ (3,604) ​ $ (677) ​ $ (4,281) Total fixed income ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value ​ $ 1,852,501 ​ $ 470,782 ​ $ 2,323,283 ​ $ 642,717 ​ $ 135,459 ​ $ 778,176 Amortized cost ​ ​ 2,043,103 ​ ​ 581,888 ​ ​ 2,624,991 ​ ​ 654,184 ​ ​ 140,883 ​ ​ 795,067 Unrealized loss ​ $ (190,602) ​ $ (111,106) ​ $ (301,708) ​ $ (11,467) ​ $ (5,424) ​ $ (16,891) * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities
Schedule of Credit Quality Indicators for Investments in Unrealized Loss Positions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equivalent ​ Equivalent ​ (dollars in thousands) ​ ​ ​ NAIC S&P Moody’s ​ Amortized ​ ​ ​ ​ Unrealized ​ Percent ​ Rating Rating Rating Cost Fair Value Loss to Total ​ 1 ​ AAA/AA/A ​ Aaa/Aa/A ​ $ 2,084,118 ​ $ 1,840,726 ​ $ (243,392) ​ 80.7 % 2 ​ BBB ​ Baa ​ ​ 399,832 ​ ​ 353,124 ​ ​ (46,708) ​ 15.5 % 3 ​ BB ​ Ba ​ ​ 75,146 ​ ​ 67,738 ​ ​ (7,408) ​ 2.5 % 4 ​ B ​ B ​ ​ 65,238 ​ ​ 61,152 ​ ​ (4,086) ​ 1.3 % 5 ​ CCC ​ Caa ​ ​ 657 ​ ​ 543 ​ ​ (114) ​ 0.0 % 6 ​ CC or lower ​ Ca or lower ​ ​ — ​ ​ — ​ ​ — ​ 0.0 % ​ ​ ​ ​ Total ​ $ 2,624,991 ​ $ 2,323,283 ​ $ (301,708) ​ 100.0 %

Historical Loss And LAE Devel_2

Historical Loss And LAE Development (Tables)	9 Months Ended
	Sep. 30, 2022
Historical Loss And L A E Development Disclosure [Abstract]
Schedule of Reconciliation of Unpaid Losses and Settlement Expenses (LAE)	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Nine Months ​ ​ Ended September 30, (in thousands) 2022 2021 Unpaid losses and LAE at beginning of year ​ ​ ​ ​ ​ ​ Gross ​ $ 2,043,555 ​ $ 1,750,049 Ceded ​ ​ (608,086) ​ ​ (443,729) Net ​ $ 1,435,469 ​ $ 1,306,320 ​ ​ ​ ​ ​ ​ ​ Increase (decrease) in incurred losses and LAE ​ ​ ​ ​ ​ ​ Current accident year ​ $ 491,559 ​ $ 452,542 Prior accident years ​ ​ (103,032) ​ ​ (96,968) Total incurred ​ $ 388,527 ​ $ 355,574 ​ ​ ​ ​ ​ ​ ​ Loss and LAE payments for claims incurred ​ ​ ​ ​ ​ ​ Current accident year ​ $ (52,435) ​ $ (58,411) Prior accident years ​ ​ (219,682) ​ ​ (172,120) Total paid ​ $ (272,117) ​ $ (230,531) ​ ​ ​ ​ ​ ​ ​ Net unpaid losses and LAE at September 30, ​ $ 1,551,879 ​ $ 1,431,363 ​ ​ ​ ​ ​ ​ ​ Unpaid losses and LAE at September 30, ​ ​ ​ ​ ​ ​ Gross ​ $ 2,322,737 ​ $ 2,033,517 Ceded ​ ​ (770,858) ​ ​ (602,154) Net ​ $ 1,551,879 ​ $ 1,431,363

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Schedule of Reconciliation of Income Tax Expense Attributable to Income from Operations with Amounts Computed by Applying U.S. Federal Tax Rate to Pretax Income from Continuing Operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months Ended September 30, 2022 ​ For the Nine Months Ended September 30, 2022 ​ ​ ​ 2022 ​ 2021 ​ 2022 ​ 2021 ​ (in thousands) Amount % Amount % Amount % Amount % ​ Provision for income taxes at the statutory rate of 21% ​ $ 116,487 ​ 21.0 % $ 7,442 ​ 21.0 % $ 127,401 ​ 21.0 % $ 47,731 ​ 21.0 % Increase (reduction) in taxes resulting from: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Excess tax benefit on share-based compensation ​ ​ (95) ​ (0.0) % ​ (225) ​ (0.6) % ​ (2,270) ​ (0.4) % ​ (2,419) ​ (1.1) % Tax exempt interest income ​ ​ (280) ​ (0.1) % ​ (298) ​ (0.8) % ​ (850) ​ (0.1) % ​ (927) ​ (0.4) % Dividends received deduction ​ ​ (240) ​ (0.0) % ​ (223) ​ (0.6) % ​ (673) ​ (0.1) % ​ (707) ​ (0.3) % Investment tax credit ​ ​ (1,181) ​ (0.2) % ​ (801) ​ (2.3) % ​ (3,545) ​ (0.6) % ​ (2,404) ​ (1.0) % ESOP dividends paid deduction ​ ​ (136) ​ (0.0) % ​ (132) ​ (0.4) % ​ (404) ​ (0.0) % ​ (399) ​ (0.2) % Nondeductible expenses ​ ​ 34 ​ 0.0 % ​ 642 ​ 1.8 % ​ 608 ​ 0.1 % ​ 1,879 ​ 0.8 % Other items, net ​ ​ 220 ​ 0.0 % ​ (211) ​ (0.6) % ​ 829 ​ 0.1 % ​ 468 ​ 0.2 % Total tax expense ​ $ 114,809 ​ 20.7 % $ 6,194 ​ 17.5 % $ 121,096 ​ 20.0 % $ 43,222 ​ 19.0 %

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Option Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Aggregate ​ ​ ​ ​ Weighted ​ Average ​ Intrinsic ​ ​ ​ ​ Average ​ Remaining ​ Value ​ Options Exercise Price Contractual Life (in 000’s) Outstanding options at January 1, 2022 ​ 1,669,325 ​ $ 78.63 ​ ​ ​ ​ ​ Options granted ​ 320,100 ​ ​ 115.27 ​ ​ ​ ​ ​ Options exercised ​ (98,967) ​ ​ 59.98 ​ ​ ​ ​ ​ Options canceled/forfeited ​ (9,485) ​ ​ 93.40 ​ ​ ​ ​ ​ Outstanding options at September 30, 2022 ​ 1,880,973 ​ $ 85.78 ​ 4.86 ​ $ 37,402 Exercisable options at September 30, 2022 ​ 960,605 ​ $ 71.37 ​ 3.48 ​ $ 30,181
Summary of Weighted Average Grant-date Assumptions and Weighted Average Fair Values	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 ​ Weighted-average fair value of grants ​ $ 20.99 ​ $ 17.01 ​ Risk-free interest rates ​ ​ 2.86 % ​ 0.70 % Dividend yield ​ ​ 2.50 % ​ 2.06 % Expected volatility ​ ​ 22.89 % ​ 22.73 % Expected option life ​ ​ 5.06 years ​ 4.97 years
Schedule of Restricted Stock Units Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ ​ ​ Grant Date ​ RSUs Fair Value Nonvested at January 1, 2022 ​ 45,068 ​ $ 97.67 Granted ​ 16,705 ​ ​ 116.60 Reinvested ​ 291 ​ ​ 108.78 Vested ​ (21,380) ​ ​ 93.07 Forfeited ​ (1,291) ​ ​ 76.82 Nonvested at September 30, 2022 ​ 39,393 ​ $ 108.25

Operating Segment Information (

Operating Segment Information (Tables)	9 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Summary of Selected Information by Operating Segment	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Nine Months Revenues ​ Ended September 30, ​ Ended September 30, (in thousands) 2022 2021 2022 2021 Casualty ​ $ 179,615 ​ $ 162,852 ​ $ 528,494 ​ $ 467,817 Property ​ ​ 80,844 ​ ​ 60,886 ​ ​ 222,974 ​ ​ 168,393 Surety ​ ​ 31,009 ​ ​ 29,651 ​ ​ 91,962 ​ ​ 86,774 Net premiums earned ​ $ 291,468 ​ $ 253,389 ​ $ 843,430 ​ $ 722,984 Net investment income ​ ​ 21,270 ​ ​ 17,844 ​ ​ 57,625 ​ ​ 50,929 Net realized gains ​ ​ 573,170 ​ ​ 1,829 ​ ​ 591,562 ​ ​ 52,442 Net unrealized gains (losses) on equity securities ​ ​ (26,414) ​ ​ (2,592) ​ ​ (155,218) ​ ​ 29,526 Total consolidated revenue ​ $ 859,494 ​ $ 270,470 ​ $ 1,337,399 ​ $ 855,881 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net Earnings ​ ​ ​ ​ ​ ​ (in thousands) 2022 2021 2022 2021 Casualty ​ $ 11,329 ​ $ 22,949 ​ $ 60,418 ​ $ 74,254 Property ​ ​ (8,308) ​ ​ (16,558) ​ ​ 40,273 ​ ​ (8,684) Surety ​ ​ 5,775 ​ ​ 7,333 ​ ​ 23,539 ​ ​ 14,662 Net underwriting income ​ $ 8,796 ​ $ 13,724 ​ $ 124,230 ​ $ 80,232 Net investment income ​ ​ 21,270 ​ ​ 17,844 ​ ​ 57,625 ​ ​ 50,929 Net realized gains ​ ​ 573,170 ​ ​ 1,829 ​ ​ 591,562 ​ ​ 52,442 Net unrealized gains (losses) on equity securities ​ ​ (26,414) ​ ​ (2,592) ​ ​ (155,218) ​ ​ 29,526 General corporate expense and interest on debt ​ ​ (4,768) ​ ​ (4,411) ​ ​ (14,587) ​ ​ (15,244) Equity in earnings (loss) of unconsolidated investees ​ ​ (17,352) ​ ​ 9,043 ​ ​ 3,061 ​ ​ 29,407 Earnings before income taxes ​ $ 554,702 ​ $ 35,437 ​ $ 606,673 ​ $ 227,292 Income tax expense ​ ​ 114,809 ​ ​ 6,194 ​ ​ 121,096 ​ ​ 43,222 Net earnings ​ $ 439,893 ​ $ 29,243 ​ $ 485,577 ​ $ 184,070
Summary of Revenue by Major Product Type	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Nine Months Net Premiums Earned ​ Ended September 30, ​ Ended September 30, (in thousands) 2022 2021 2022 2021 Casualty ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial excess and personal umbrella ​ $ 65,131 ​ $ 56,285 ​ $ 187,666 ​ $ 161,287 General liability ​ ​ 25,284 ​ ​ 23,156 ​ ​ 74,130 ​ ​ 67,616 Commercial transportation ​ ​ 24,205 ​ ​ 22,571 ​ ​ 71,774 ​ ​ 60,926 Professional services ​ ​ 24,174 ​ ​ 22,401 ​ ​ 71,590 ​ ​ 66,095 Small commercial ​ ​ 17,005 ​ ​ 16,301 ​ ​ 50,463 ​ ​ 48,302 Executive products ​ ​ 6,556 ​ ​ 5,461 ​ ​ 20,208 ​ ​ 15,785 Other casualty ​ ​ 17,260 ​ ​ 16,677 ​ ​ 52,663 ​ ​ 47,806 Total ​ $ 179,615 ​ $ 162,852 ​ $ 528,494 ​ $ 467,817 Property ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial property ​ $ 43,201 ​ $ 28,683 ​ $ 115,419 ​ $ 76,488 Marine ​ ​ 29,592 ​ ​ 25,416 ​ ​ 84,499 ​ ​ 72,737 Specialty personal ​ ​ 6,409 ​ ​ 5,462 ​ ​ 18,405 ​ ​ 15,761 Other property ​ ​ 1,642 ​ ​ 1,325 ​ ​ 4,651 ​ ​ 3,407 Total ​ $ 80,844 ​ $ 60,886 ​ $ 222,974 ​ $ 168,393 Surety ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial ​ $ 12,057 ​ $ 11,541 ​ $ 35,423 ​ $ 33,594 Miscellaneous ​ ​ 10,751 ​ ​ 11,124 ​ ​ 33,691 ​ ​ 32,604 Contract ​ ​ 8,201 ​ ​ 6,986 ​ ​ 22,848 ​ ​ 20,576 Total ​ $ 31,009 ​ $ 29,651 ​ $ 91,962 ​ $ 86,774 Grand Total ​ $ 291,468 ​ $ 253,389 ​ $ 843,430 ​ $ 722,984

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Schedule of Components of Lease Expense and Other lease Information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Three Months ​ For the Nine Months ​ ​ Ended September 30, ​ Ended September 30, (in thousands) 2022 2021 2022 2021 Operating lease cost ​ $ 1,272 ​ $ 1,326 ​ $ 3,686 ​ $ 4,005 Variable lease cost ​ ​ 339 ​ ​ 348 ​ ​ 1,073 ​ ​ 1,090 Sublease income ​ ​ (139) ​ ​ (123) ​ ​ (416) ​ ​ (369) Total lease cost ​ $ 1,472 ​ $ 1,551 ​ $ 4,343 ​ $ 4,726 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in measurement of lease liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating cash outflows from operating leases ​ $ 1,387 ​ $ 1,490 ​ $ 3,987 ​ $ 4,455 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ROU assets obtained in exchange for new operating lease liabilities ​ $ 54 ​ $ 4,434 ​ $ 2,485 ​ $ 4,699 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reduction to ROU assets resulting from reduction to lease liabilities ​ $ — ​ $ — ​ $ — ​ $ 1,250 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other non-cash reductions to ROU assets ​ $ — ​ $ 48 ​ $ 73 ​ $ 48 ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) September 30, 2022 December 31, 2021 ​ Operating lease ROU assets ​ $ 13,749 ​ $ 14,765 ​ Operating lease liabilities ​ $ 15,658 ​ $ 16,905 ​ Weighted-average remaining lease term - operating leases ​ ​ 4.31 years ​ 4.52 years Weighted-average discount rate - operating leases ​ ​ 2.07 % ​ 2.02 % ​
Schedule of Future Minimum Lease Payments under Non-cancellable Leases	​ ​ ​ ​ ​ (in thousands) September 30, 2022 2022 ​ $ 1,448 2023 ​ ​ 5,529 2024 ​ ​ 3,552 2025 ​ ​ 2,138 2026 ​ ​ 1,285 2027 ​ ​ 826 Thereafter ​ ​ 1,589 Total future minimum lease payments ​ $ 16,367 Less imputed interest ​ ​ (709) Total operating lease liability ​ $ 15,658

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reinsurance - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
Ceded Credit Risk [Line Items]
Amount of allowance for uncollectible amounts on paid recoverables	$ 16,100,000	$ 16,100,000
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	11,400,000	$ 11,188,000
Financing receivable, allowance for credit Loss, write-off	0
Amount of allowance for uncollectible amounts due beyond one year	$ 0
Threshold period for including reinsurance receivables in the allowance for uncollectible amounts	1 year
Maximum
Ceded Credit Risk [Line Items]
Financing receivable, allowance for credit loss, recovery	$ 100,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Goodwill	$ 46,062	$ 46,062
Indefinite-lived intangibles - state insurance licenses	7,500	7,500
Total goodwill and intangibles	53,562	53,562
Surety
Business Acquisition [Line Items]
Goodwill	40,816	40,816
Casualty
Business Acquisition [Line Items]
Goodwill	$ 5,246	$ 5,246

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Intangible Assets - Additional Information (Details)	9 Months Ended
	Sep. 30, 2022 USD ($)
Accounting Policies [Abstract]
Goodwill and intangible asset impairment	$ 0

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Reconciliation of Numerator and Denominator of the Basic and Diluted Earnings Per Share Computations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Basic EPS, Income (Numerator)
Earnings available to common shareholders	$ 439,893	$ 29,243	$ 485,577	$ 184,070
Diluted EPS, Income (Numerator)
Earnings available to common shareholders	$ 439,893	$ 29,243	$ 485,577	$ 184,070
Basic EPS, Weighted Average Shares (Denominator)
Number of shares outstanding	45,379	45,243	45,347	45,216
Effect of Dilutive Securities, Shares (Denominator)
Stock options and restricted stock units	396	446	428	498
Diluted EPS, Weighted Average Shares (Denominator)
Number of shares outstanding	45,775	45,689	45,775	45,714
Earnings Per Share, Diluted, Other Disclosures
Anti-dilutive securities excluded from diluted EPS	435	191	459	191
Basic EPS, Per Share Amount
Basic net earnings per share (in dollars per share)	$ 9.69	$ 0.65	$ 10.71	$ 4.07
Diluted EPS, Per Share Amount
Diluted earnings per share (in dollars per share)	$ 9.61	$ 0.64	$ 10.61	$ 4.03

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Comprehensive Earnings (Loss) - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
COMPREHENSIVE EARNINGS (LOSS)
Tax rate used (as a percent)	21%			21%			21%	21%
Other comprehensive income (loss), tax	$ (21,600)			$ (3,200)			$ (78,300)	$ (11,100)
Changes in the balance of each component of accumulated other comprehensive earnings (loss)
Other comprehensive earnings (loss), net of tax	$ (81,248)	$ (97,563)	$ (115,581)	$ (12,240)	$ 15,177	$ (44,747)	$ (294,392)	$ (41,810)

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Schedule of Changes in the Balance of Each Component of Accumulated Other Comprehensive Earnings (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Changes in the balance of each component of accumulated other comprehensive earnings (loss)
Beginning balance			$ 49,826				$ 49,826
Net current-period other comprehensive earnings (loss)	$ (81,248)	$ (97,563)	(115,581)	$ (12,240)	$ 15,177	$ (44,747)	(294,392)	$ (41,810)
Ending balance	(244,566)						(244,566)
Unrealized Gains and Losses on Available-for-Sale Securities
Changes in the balance of each component of accumulated other comprehensive earnings (loss)
Beginning balance	(163,318)		$ 49,826	79,144		$ 108,714	49,826	108,714
Other comprehensive earnings (loss) before reclassifications	(82,785)			(12,114)			(296,422)	(40,307)
Amounts reclassified from accumulated other comprehensive earnings	1,537			(126)			2,030	(1,503)
Net current-period other comprehensive earnings (loss)	(81,248)			(12,240)			(294,392)	(41,810)
Ending balance	(244,566)	$ (163,318)		66,904	$ 79,144		(244,566)	66,904
Balance of securities for which an allowance for credit losses has not been recognized in net earnings	$ 1,520			$ 426			$ 1,520	$ 426

Summary of Significant Accou_10

Summary of Significant Accounting Policies - Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Net realized gains (losses)	$ 573,170			$ 1,829			$ 591,562	$ 52,442
Earnings (loss) before income taxes	554,702			35,437			606,673	227,292
Income tax (expense) benefit	(114,809)			(6,194)			(121,096)	(43,222)
Net earnings (loss)	439,893	$ (2,239)	$ 47,923	29,243	$ 81,815	$ 73,012	485,577	184,070
Unrealized Gains and Losses on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Net realized gains (losses)	(1,912)			182			(2,684)	1,731
Credit gains presented within net realized gains	(34)			(22)			115	171
Earnings (loss) before income taxes	(1,946)			160			(2,569)	1,902
Income tax (expense) benefit	409			(34)			539	(399)
Net earnings (loss)	$ (1,537)			$ 126			$ (2,030)	$ 1,503

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Catastrophe Exposures - Additional Information (Details) - USD ($) $ in Millions	May 01, 2022	Jan. 01, 2022
California Earthquake
Liability For Catastrophe Claims [Line Items]
Catastrophe reinsurance	$ 750	$ 600
First-dollar retention	25	25
Outside of California Earthquake
Liability For Catastrophe Claims [Line Items]
Catastrophe reinsurance	775	625
First-dollar retention	25	25
Other Perils including Wind
Liability For Catastrophe Claims [Line Items]
Catastrophe reinsurance	625	475
First-dollar retention	25	25
Catastrophe
Liability For Catastrophe Claims [Line Items]
First-dollar retention	25	$ 25
Additional catastrophe reinsurance	$ 150

Investments - Disposition of Fi

Investments - Disposition of Fixed Income and Equity Securities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Summary of the disposition of fixed income and equity securities
Fixed income securities - available-for-sale	$ 46,448	$ 42,776
Fixed income securities - available-for-sale	176,616	296,561
SALES
Summary of the disposition of fixed income and equity securities
Fixed income securities - available-for-sale	48,559	43,041
Gross Realized Gains - Fixed income securities - available-for-sale	286	1,476
Gross Realized Losses - Fixed income securities - available-for-sale	(2,481)	(107)
Net Realized Gain (Loss) - Fixed income securities - available-for-sale	(2,195)	1,369
Proceeds from Sales - Equity securities	59,264	157,973
Gross Realized Gains - Equity securities	20,410	52,409
Gross Realized Losses - Equity securities	(609)	(1,787)
Net Realized Gain (Loss) - Equity securities	19,801	50,622
Calls And Maturities Of Marketable Securities
Summary of the disposition of fixed income and equity securities
Fixed income securities - available-for-sale	176,991	296,563
Gross Realized Gains - Fixed income securities - available-for-sale	142	471
Gross Realized Losses - Fixed income securities - available-for-sale	(55)	(109)
Net Realized Gain (Loss) - Fixed income securities - available-for-sale	$ 87	$ 362

Investments - Assets Measured a

Investments - Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets measured at Fair Value
Available-for-sale fixed income	$ 2,452,039	$ 2,409,887
Equity securities	462,988	613,776
U.S. government
Assets measured at Fair Value
Available-for-sale fixed income	340,442	134,554
U.S. Agency
Assets measured at Fair Value
Available-for-sale fixed income	56,935	32,760
Non-U.S. government & agency
Assets measured at Fair Value
Available-for-sale fixed income	5,712	8,481
Agency MBS
Assets measured at Fair Value
Available-for-sale fixed income	317,029	367,187
ABS/CMBS/MBS
Assets measured at Fair Value
Available-for-sale fixed income	241,512	264,054
Corporate Debt
Assets measured at Fair Value
Available-for-sale fixed income	963,869	957,095
Municipal
Assets measured at Fair Value
Available-for-sale fixed income	526,540	645,756
Fair Value Measured on Recurring Basis
Assets measured at Fair Value
Available-for-sale fixed income	2,452,039	2,409,887
Equity securities	462,988	613,776
Total assets at fair value	2,915,027	3,023,663
Fair Value Measured on Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets measured at Fair Value
Equity securities	461,392	613,712
Total assets at fair value	461,392	613,712
Fair Value Measured on Recurring Basis | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	2,399,149	2,366,369
Equity securities	49	64
Total assets at fair value	2,399,198	2,366,433
Fair Value Measured on Recurring Basis | Significant Unobservable Inputs (Level 3)
Assets measured at Fair Value
Available-for-sale fixed income	52,890	43,518
Equity securities	1,547
Total assets at fair value	54,437	43,518
Fair Value Measured on Recurring Basis | U.S. government
Assets measured at Fair Value
Available-for-sale fixed income	340,442	134,554
Fair Value Measured on Recurring Basis | U.S. government | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	340,442	134,554
Fair Value Measured on Recurring Basis | U.S. Agency
Assets measured at Fair Value
Available-for-sale fixed income	56,935	32,760
Fair Value Measured on Recurring Basis | U.S. Agency | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	56,935	32,760
Fair Value Measured on Recurring Basis | Non-U.S. government & agency
Assets measured at Fair Value
Available-for-sale fixed income	5,712	8,481
Fair Value Measured on Recurring Basis | Non-U.S. government & agency | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	5,712	8,481
Fair Value Measured on Recurring Basis | Agency MBS
Assets measured at Fair Value
Available-for-sale fixed income	317,029	367,187
Fair Value Measured on Recurring Basis | Agency MBS | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	317,029	367,187
Fair Value Measured on Recurring Basis | ABS/CMBS/MBS
Assets measured at Fair Value
Available-for-sale fixed income	241,512	264,054
Fair Value Measured on Recurring Basis | ABS/CMBS/MBS | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	241,512	264,054
Fair Value Measured on Recurring Basis | Corporate Debt
Assets measured at Fair Value
Available-for-sale fixed income	963,869	957,095
Fair Value Measured on Recurring Basis | Corporate Debt | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	910,979	913,577
Fair Value Measured on Recurring Basis | Corporate Debt | Significant Unobservable Inputs (Level 3)
Assets measured at Fair Value
Available-for-sale fixed income	52,890	43,518
Fair Value Measured on Recurring Basis | Municipal
Assets measured at Fair Value
Available-for-sale fixed income	526,540	645,756
Fair Value Measured on Recurring Basis | Municipal | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	$ 526,540	$ 645,756

Investments - Summary of Change

Investments - Summary of Changes in Balance of Level 3 securities (Details) - Significant Unobservable Inputs (Level 3) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Summary of changes in Level 3 securities
Beginning balance	$ 43,518
Net investment income	(662)
Net realized gains	(433)
Included in other comprehensive earnings (loss)	(8,350)
Total net realized and unrealized gains (losses)	(9,445)
Purchases	21,461
Transfers out of Level 3	(1,097)
Ending balance	54,437
Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - Income	$ (433)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income	Net realized gains (losses)
Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - OCI	$ (8,350)
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Other Comprehensive Income	Other comprehensive earnings (loss), net of tax

Investments - Amortized Cost an

Investments - Amortized Cost and Fair Value of Available-for-sale Fixed Income Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized Cost
Due in one year or less	$ 206,921
Due after one year through five years	867,511
Due after five years through 10 years	515,276
Due after 10 years	526,093
ABS/CMBS/MBS	637,830
Total available-for-sale	2,753,631	$ 2,346,267
Fair Value
Due in one year or less	206,327
Due after one year through five years	818,569
Due after five years through 10 years	457,011
Due after 10 years	411,591
ABS/CMBS/MBS	558,541
Total available-for-sale	$ 2,452,039	$ 2,409,887

Investments - Additional Inform

Investments - Additional Information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($) security	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Investment Holdings [Line Items]
Accrued investment income	$ 19,355		$ 17,505
Unrealized loss	301,708		16,891
Fixed Income Securities
Investment Holdings [Line Items]
Accrued investment income	$ 18,400		$ 16,400
Number of debt securities for which there is an allowance for credit losses | security	18
Losses on fixed income securities	$ 100	$ 0
Number of debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded | security	1,543
Unrealized loss	$ 301,700
Unrealized losses as percentage of fixed income portfolio cost basis	10.80%
Unrealized losses relative to total invested assets (as a percent)	8.20%
Number of unrealized loss positions | security	1,543
Number of securities in unrealized loss positions for 12 months or longer | security	302

Investments - Amortized Cost _2

Investments - Amortized Cost and Fair Value of Available-for-sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	$ 2,753,631		$ 2,346,267
Allowance for Credit Losses	(327)	$ (292)	(441)	$ (226)	$ (204)	$ (397)
Gross Unrealized Gains	443		80,952
Gross Unrealized Losses	(301,708)		(16,891)
Fair Value	2,452,039		2,409,887
U.S. government
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	349,419		127,752
Gross Unrealized Gains			6,846
Gross Unrealized Losses	(8,977)		(44)
Fair Value	340,442		134,554
U.S. Agency
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	59,048		30,403
Gross Unrealized Gains	9		2,374
Gross Unrealized Losses	(2,122)		(17)
Fair Value	56,935		32,760
Non-U.S. government & agency
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	6,798		8,297
Gross Unrealized Gains			338
Gross Unrealized Losses	(1,086)		(154)
Fair Value	5,712		8,481
Agency MBS
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	360,429		362,861
Gross Unrealized Gains	172		9,277
Gross Unrealized Losses	(43,572)		(4,951)
Fair Value	317,029		367,187
ABS/CMBS/MBS
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	277,401		264,273
Allowance for Credit Losses	(9)
Gross Unrealized Gains	21		2,120
Gross Unrealized Losses	(35,901)		(2,339)
Fair Value	241,512		264,054
Corporate Debt
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	1,067,473		925,394
Allowance for Credit Losses	(318)		(441)
Gross Unrealized Gains	47		37,247
Gross Unrealized Losses	(103,333)		(5,105)
Fair Value	963,869		957,095
Municipal
Schedule Of Available For Sale Securities [Line Items]
Cost or Amortized Cost	633,063		627,287
Gross Unrealized Gains	194		22,750
Gross Unrealized Losses	(106,717)		(4,281)
Fair Value	$ 526,540		$ 645,756

Investments - Schedule of Debt

Investments - Schedule of Debt Securities Available-for-sale Allowance for Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Investments Debt And Equity Securities [Abstract]
Beginning balance	$ 292	$ 204	$ 441	$ 397
Increase to allowance from securities for which credit losses were not previously recorded	168		292
Reduction from securities sold during the period	(166)		(619)
Reductions from intent to sell securities			(17)
Net increase (decrease) from securities that had an allowance at the beginning of the period	33	22	230	(171)
Balance as of September 30,	$ 327	$ 226	$ 327	$ 226

Investments - Schedule of Secur

Investments - Schedule of Securities in an Unrealized Loss Position Segregated by Type and Length of Time in an Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair value
Less than 12 months	$ 1,852,501	$ 642,717
12 months and greater	470,782	135,459
Total Fair Value	2,323,283	778,176
Amortized Cost
Amortized cost, less than 12 months	2,043,103	654,184
12 months and greater	581,888	140,883
Total Cost or Amortized Cost	2,624,991	795,067
Unrealized Loss
Less than 12 months	(190,602)	(11,467)
12 months and greater	(111,106)	(5,424)
Total Unrealized Loss	(301,708)	(16,891)
U.S. government
Fair value
Less than 12 months	285,302	2,942
12 months and greater	5,315
Total Fair Value	290,617	2,942
Amortized Cost
Amortized cost, less than 12 months	293,829	2,986
12 months and greater	5,765
Total Cost or Amortized Cost	299,594	2,986
Unrealized Loss
Less than 12 months	(8,527)	(44)
12 months and greater	(450)
Total Unrealized Loss	(8,977)	(44)
U.S. Agency
Fair value
Less than 12 months	30,089	1,498
Total Fair Value	30,089	1,498
Amortized Cost
Amortized cost, less than 12 months	32,211	1,515
Total Cost or Amortized Cost	32,211	1,515
Unrealized Loss
Less than 12 months	(2,122)	(17)
Total Unrealized Loss	(2,122)	(17)
Non-U.S. government & agency
Fair value
Less than 12 months	3,594	4,346
12 months and greater	2,118
Total Fair Value	5,712	4,346
Amortized Cost
Amortized cost, less than 12 months	3,798	4,500
12 months and greater	3,000
Total Cost or Amortized Cost	6,798	4,500
Unrealized Loss
Less than 12 months	(204)	(154)
12 months and greater	(882)
Total Unrealized Loss	(1,086)	(154)
Agency MBS
Fair value
Less than 12 months	192,947	102,145
12 months and greater	112,457	62,669
Total Fair Value	305,404	164,814
Amortized Cost
Amortized cost, less than 12 months	210,448	104,336
12 months and greater	138,528	65,429
Total Cost or Amortized Cost	348,976	169,765
Unrealized Loss
Less than 12 months	(17,501)	(2,191)
12 months and greater	(26,071)	(2,760)
Total Unrealized Loss	(43,572)	(4,951)
ABS/CMBS/MBS
Fair value
Less than 12 months	148,272	150,997
12 months and greater	89,792	3,935
Total Fair Value	238,064	154,932
Amortized Cost
Amortized cost, less than 12 months	165,163	153,235
12 months and greater	108,802	4,036
Total Cost or Amortized Cost	273,965	157,271
Unrealized Loss
Less than 12 months	(16,891)	(2,238)
12 months and greater	(19,010)	(101)
Total Unrealized Loss	(35,901)	(2,339)
Corporate Debt
Fair value
Less than 12 months	773,433	217,791
12 months and greater	184,317	53,818
Total Fair Value	957,750	271,609
Amortized Cost
Amortized cost, less than 12 months	844,169	221,010
12 months and greater	216,914	55,704
Total Cost or Amortized Cost	1,061,083	276,714
Unrealized Loss
Less than 12 months	(70,736)	(3,219)
12 months and greater	(32,597)	(1,886)
Total Unrealized Loss	(103,333)	(5,105)
Municipal
Fair value
Less than 12 months	418,864	162,998
12 months and greater	76,783	15,037
Total Fair Value	495,647	178,035
Amortized Cost
Amortized cost, less than 12 months	493,485	166,602
12 months and greater	108,879	15,714
Total Cost or Amortized Cost	602,364	182,316
Unrealized Loss
Less than 12 months	(74,621)	(3,604)
12 months and greater	(32,096)	(677)
Total Unrealized Loss	$ (106,717)	$ (4,281)

Investments - Unrealized Losses

Investments - Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Cost or amortized Cost
Total Cost or Amortized Cost	$ 2,624,991	$ 795,067
Fair value
Total Fair Value	2,323,283	778,176
Unrealized Loss
Total Unrealized Loss	$ (301,708)	$ (16,891)
Percent to Total	100%
NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Cost or amortized Cost
Total Cost or Amortized Cost	$ 2,084,118
Fair value
Total Fair Value	1,840,726
Unrealized Loss
Total Unrealized Loss	$ (243,392)
Percent to Total	80.70%
NAIC Rating 2 | BBB | Baa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 399,832
Fair value
Total Fair Value	353,124
Unrealized Loss
Total Unrealized Loss	$ (46,708)
Percent to Total	15.50%
NAIC Rating 3 | BB | Ba
Cost or amortized Cost
Total Cost or Amortized Cost	$ 75,146
Fair value
Total Fair Value	67,738
Unrealized Loss
Total Unrealized Loss	$ (7,408)
Percent to Total	2.50%
NAIC Rating 4 | B | B
Cost or amortized Cost
Total Cost or Amortized Cost	$ 65,238
Fair value
Total Fair Value	61,152
Unrealized Loss
Total Unrealized Loss	$ (4,086)
Percent to Total	1.30%
NAIC Rating 5 | CCC | Caa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 657
Fair value
Total Fair Value	543
Unrealized Loss
Total Unrealized Loss	$ (114)
Percent to Total	0%
NAIC Six Rating Member | Standard Poors CC Or Lower Member | Ca
Unrealized Loss
Percent to Total	0%

Investments - Debt and Short-te

Investments - Debt and Short-term Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Investment Holdings [Line Items]
Other investments	$ 48,837		$ 48,837		$ 50,501
Investment in federal home loan bank stock	us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember
Cash and Short-term Investments
Investment in unconsolidated investees	$ 58,105		$ 58,105		$ 171,311
Cash	723,511		723,511		88,804
Prime Holdings Insurance Services, Inc. (Prime)
Cash and Short-term Investments
Investment in unconsolidated investees	46,900		46,900
Other Unconsolidated Investees
Cash and Short-term Investments
Investment in unconsolidated investees	11,200		11,200
Unfunded commitments	7,700		7,700
FHLBC
Investment Holdings [Line Items]
Investments pledged as collateral	60,200		60,200
Federal home loan bank borrowings fair value disclosure	50,000		50,000
Investment In Low Income Housing Tax Credit Partnership Net Of Amortization
Investment Holdings [Line Items]
Other investments	14,200		14,200		16,600
Total tax benefit on investments in housing tax credit partnership	900	$ 900	2,600	$ 2,700
Qualified affordable housing project investments, commitment	1,300		1,300
Investment in Private Funds
Investment Holdings [Line Items]
Other investments	28,900		28,900		$ 28,600
Fair value investments entities that calculate net asset value per share unfunded commitments	$ 5,700		$ 5,700

Historical Loss and LAE Devel_3

Historical Loss and LAE Development - Schedule of Reconciliation of Unpaid Losses and Settlement Expenses (LAE) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Unpaid losses and LAE at beginning of year
Gross	$ 2,043,555	$ 1,750,049
Ceded	(608,086)	(443,729)
Net	1,435,469	1,306,320
Increase (decrease) in incurred losses and LAE
Current accident year	491,559	452,542
Prior accident years	(103,032)	(96,968)
Total incurred	388,527	355,574
Loss and LAE payments for claims incurred
Current accident year	(52,435)	(58,411)
Prior accident years	(219,682)	(172,120)
Total paid	(272,117)	(230,531)
Net unpaid losses and LAE at September 30	1,551,879	1,431,363
Unpaid losses and LAE at September 30
Gross	2,322,737	2,033,517
Ceded	(770,858)	(602,154)
Net unpaid losses and LAE at September 30	$ 1,551,879	$ 1,431,363

Historical Loss and LAE Devel_4

Historical Loss and LAE Development - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Historical Loss And L A E Development Disclosure [Abstract]
Favorable development on prior years' loss reserves	$ 103,032	$ 96,968

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation, percent, total	20.70%	17.50%	20%	19%
U.S. federal tax rate	21%	21%	21%	21%

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliation of Income Tax Expense (Benefit) Attributable to Income from Operations with Amounts Computed by Applying U.S. Federal Tax Rate to Pretax Income from Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Reconciliation of income tax expense reported to amount computed by applying the U.S. federal tax rate
Provision for income taxes at the statutory rate	$ 116,487	$ 7,442	$ 127,401	$ 47,731
Increase (reduction) in taxes resulting from:
Excess tax benefit on share-based compensation	(95)	(225)	(2,270)	(2,419)
Tax exempt interest income	(280)	(298)	(850)	(927)
Dividends received deduction	(240)	(223)	(673)	(707)
Investment tax credit	(1,181)	(801)	(3,545)	(2,404)
ESOP dividends paid deduction	(136)	(132)	(404)	(399)
Nondeductible expenses	34	642	608	1,879
Other items, net	220	(211)	829	468
Total tax expense	$ 114,809	$ 6,194	$ 121,096	$ 43,222
Reconciliation of income tax expense rate to the U.S. federal tax rate
Tax rate used (as a percent)	21%	21%	21%	21%
Excess tax benefit on share-based compensation (as a percent)	0%	(0.60%)	(0.40%)	(1.10%)
Effective rate reduction due to tax exempt interest income (as a percent)	(0.10%)	(0.80%)	(0.10%)	(0.40%)
Effective rate reduction due to dividend received (as a percent)	(0.00%)	(0.60%)	(0.10%)	(0.30%)
Effective rate reduction due to investment tax credit (as a percent)	(0.20%)	(2.30%)	(0.60%)	(1.00%)
Effective rate reduction due to dividend paid to ESOP (as a percent)	(0.00%)	(0.40%)	(0.00%)	(0.20%)
Effective rate reduction due to nondeductible expenses (as a percent)	0%	1.80%	0.10%	0.80%
Effective rate reduction due to other items, net (as a percent)	0%	(0.60%)	0.10%	0.20%
Total tax expense	20.70%	17.50%	20%	19%

Stock Based Compensation - Stoc

Stock Based Compensation - Stock Plans - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		60 Months Ended	89 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	May 06, 2015	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted (in shares)			320,100
Intrinsic value of options			$ 5.5	$ 8.4
RLI Corp. Long-Term Incentive Plan (2010 LTIP)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorized for grant					4,000,000
Options granted (in shares)					2,878,000
RLI Corp. Long-Term Incentive Plan (2015 LTIP)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares authorized for grant	4,000,000		4,000,000			4,000,000
Options granted (in shares)			336,805			3,237,225
Stock-based compensation expenses	$ 2.4	$ 1.6	$ 6.2	4.8
Income tax benefit from stock-based compensation	0.4	$ 0.2	1	$ 0.7
Unrecognized stock-based compensation expense	$ 8.2		$ 8.2			$ 8.2
Stock-based compensation expenses, recognition period			2 years 2 months 23 days
RLI Corp. Long-Term Incentive Plan (LTIP 2010 and LTIP 2015) | Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period			5 years
Term of options			8 years
Age and period of service of the participant to be eligible for retirement			75 years

Stock Based Compensation - Summ

Stock Based Compensation - Summary of Option Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($) $ / shares shares	Sep. 30, 2021 USD ($)
Weighted Number of Options Outstanding
Outstanding options, Beginning Balance | shares	1,669,325
Options granted (in shares) | shares	320,100
Options exercised | shares	(98,967)
Options canceled/forfeited | shares	(9,485)
Outstanding options, Ending Balance | shares	1,880,973
Exercisable options, Ending Balance | shares	960,605
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding options, Beginning Balance | $ / shares	$ 78.63
Weighted Average Exercise Price, Options granted | $ / shares	115.27
Weighted Average Exercise Price, Options exercised | $ / shares	59.98
Weighted Average Exercise Price, Options canceled/forfeited | $ / shares	93.40
Weighted Average Exercise Price, Outstanding options, Ending Balance | $ / shares	85.78
Weighted Average Exercise Price, Exercisable options | $ / shares	$ 71.37
Weighted Average Remaining Contractual Life
Weighted Average Remaining Contractual Life, Outstanding options	4 years 10 months 9 days
Weighted Average Remaining Contractual Life, Exercisable options	3 years 5 months 23 days
Aggregate Intrinsic Value, Options exercised | $	$ 5,500	$ 8,400
Aggregate Intrinsic Value, Outstanding options | $	37,402
Aggregate Intrinsic Value, Exercisable options | $	$ 30,181

Stock Based Compensation - Su_2

Stock Based Compensation - Summary of Weighted Average Grant-date Assumptions and Weighted Average Fair Values (Details) - $ / shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Weighted average grant date assumptions and weighted average fair value
Weighted-average fair value of grants	$ 20.99	$ 17.01
Risk-free interest rates	2.86%	0.70%
Dividend yield	2.50%	2.06%
Expected volatility	22.89%	22.73%
Expected option life	5 years 21 days	4 years 11 months 19 days

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Stock Units - Additional Information (Details) - Restricted Stock Units (RSUs) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Age and period of service of the participant to be eligible for retirement	75 years
Fair value of restricted stock units vested	$ 2.5	$ 2.2
Employees
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	3 years
Directors
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period	1 year

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Restricted Stock Units Activity (Details)	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Number of RSUs
RSUs Nonvested, Beginning Balance | shares	45,068
RSUs Granted | shares	16,705
RSUs Reinvested | shares	291
RSUs Vested | shares	(21,380)
RSUs Forfeited | shares	(1,291)
RSUs Nonvested, Ending Balance | shares	39,393
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Nonvested, Beginning Balance | $ / shares	$ 97.67
Weighted Average Grant Date Fair Value, Granted | $ / shares	116.60
Weighted Average Grant Date Fair Value, Reinvested | $ / shares	108.78
Weighted Average Grant Date Fair Value, Vested | $ / shares	93.07
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	76.82
Weighted Average Grant Date Fair Value, Nonvested, Ending Balance | $ / shares	$ 108.25

Operating Segment Information -

Operating Segment Information - Summary of Selected Information by Operating Segment (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenues
Net premiums earned	$ 291,468			$ 253,389			$ 843,430	$ 722,984
Net investment income	21,270			17,844			57,625	50,929
Net realized gains	573,170			1,829			591,562	52,442
Net unrealized gains (losses) on equity securities	(26,414)			(2,592)			(155,218)	29,526
Consolidated revenue	859,494			270,470			1,337,399	855,881
Net Earnings
Net underwriting income	8,796			13,724			124,230	80,232
Net investment income	21,270			17,844			57,625	50,929
Net realized gains	573,170			1,829			591,562	52,442
Net unrealized gains (losses) on equity securities	(26,414)			(2,592)			(155,218)	29,526
General corporate expense and interest on debt	(4,768)			(4,411)			(14,587)	(15,244)
Equity in earnings (loss) of unconsolidated investees	(17,352)			9,043			3,061	29,407
Earnings (loss) before income taxes	554,702			35,437			606,673	227,292
Income tax expense	114,809			6,194			121,096	43,222
Net earnings (loss)	439,893	$ (2,239)	$ 47,923	29,243	$ 81,815	$ 73,012	485,577	184,070
Casualty Segment
Revenues
Net premiums earned	179,615			162,852			528,494	467,817
Net Earnings
Net underwriting income	11,329			22,949			60,418	74,254
Property Segment
Revenues
Net premiums earned	80,844			60,886			222,974	168,393
Net Earnings
Net underwriting income	(8,308)			(16,558)			40,273	(8,684)
Surety Segment
Revenues
Net premiums earned	31,009			29,651			91,962	86,774
Net Earnings
Net underwriting income	$ 5,775			$ 7,333			$ 23,539	$ 14,662

Operating Segment Information_2

Operating Segment Information - Summary of Revenue by Major Product Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Net premiums earned	$ 291,468	$ 253,389	$ 843,430	$ 722,984
Casualty Segment
Segment Reporting Information [Line Items]
Net premiums earned	179,615	162,852	528,494	467,817
Casualty Segment | Commercial excess and personal umbrella
Segment Reporting Information [Line Items]
Net premiums earned	65,131	56,285	187,666	161,287
Casualty Segment | General liability
Segment Reporting Information [Line Items]
Net premiums earned	25,284	23,156	74,130	67,616
Casualty Segment | Commercial transportation
Segment Reporting Information [Line Items]
Net premiums earned	24,205	22,571	71,774	60,926
Casualty Segment | Professional services
Segment Reporting Information [Line Items]
Net premiums earned	24,174	22,401	71,590	66,095
Casualty Segment | Small commercial
Segment Reporting Information [Line Items]
Net premiums earned	17,005	16,301	50,463	48,302
Casualty Segment | Executive products
Segment Reporting Information [Line Items]
Net premiums earned	6,556	5,461	20,208	15,785
Casualty Segment | Other casualty
Segment Reporting Information [Line Items]
Net premiums earned	17,260	16,677	52,663	47,806
Property Segment
Segment Reporting Information [Line Items]
Net premiums earned	80,844	60,886	222,974	168,393
Property Segment | Commercial property
Segment Reporting Information [Line Items]
Net premiums earned	43,201	28,683	115,419	76,488
Property Segment | Marine
Segment Reporting Information [Line Items]
Net premiums earned	29,592	25,416	84,499	72,737
Property Segment | Specialty personal
Segment Reporting Information [Line Items]
Net premiums earned	6,409	5,462	18,405	15,761
Property Segment | Other property
Segment Reporting Information [Line Items]
Net premiums earned	1,642	1,325	4,651	3,407
Surety Segment
Segment Reporting Information [Line Items]
Net premiums earned	31,009	29,651	91,962	86,774
Surety Segment | Commercial
Segment Reporting Information [Line Items]
Net premiums earned	12,057	11,541	35,423	33,594
Surety Segment | Miscellaneous
Segment Reporting Information [Line Items]
Net premiums earned	10,751	11,124	33,691	32,604
Surety Segment | Contract
Segment Reporting Information [Line Items]
Net premiums earned	$ 8,201	$ 6,986	$ 22,848	$ 20,576

Leases - Schedule of Components

Leases - Schedule of Components of Lease Expense and Other lease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Leases [Abstract]
Operating lease cost	$ 1,272	$ 1,326	$ 3,686	$ 4,005
Variable lease cost	339	348	1,073	1,090
Sublease income	(139)	(123)	(416)	(369)
Total lease cost	1,472	1,551	4,343	4,726
Cash paid for amounts included in measurement of lease liabilities
Operating cash outflows from operating leases	1,387	1,490	3,987	4,455
ROU assets obtained in exchange for new operating lease liabilities	54	4,434	2,485	4,699
Reduction to ROU assets resulting from reduction to lease liabilities				1,250
Other non-cash reductions to ROU assets		$ 48	73	$ 48
Operating lease ROU assets	$ 13,749		$ 13,749		$ 14,765
Operating Lease, Right-of-Use Asset, Statement of Financial Position	Other assets		Other assets		Other assets
Operating lease liabilities	$ 15,658		$ 15,658		$ 16,905
Operating Lease, Liability, Statement of Financial Position	Other liabilities		Other liabilities		Other liabilities
Weighted-average remaining lease term - operating leases	4 years 3 months 21 days		4 years 3 months 21 days		4 years 6 months 7 days
Weighted-average discount rate - operating leases	2.07%		2.07%		2.02%

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Lease Payments under Non-cancellable Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Future minimum lease payments under non-cancellable leases
2022	$ 1,448
2023	5,529
2024	3,552
2025	2,138
2026	1,285
2027	826
Thereafter	1,589
Total future minimum lease payments	16,367
Less imputed interest	(709)
Operating lease liabilities	$ 15,658	$ 16,905

Acquisitions and Dispositions (

Acquisitions and Dispositions (Details) - USD ($) $ in Thousands		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Dispositions
Cash proceeds from sale		$ 686,666
Maui Jim Inc.
Dispositions
Cash proceeds from sale	$ 686,600
Maui Jim Inc. | Net Realized Gain (Loss)
Dispositions
Recognized gain on sale	$ 574,500