RLI (RLI) 10-Q 22 Oct 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Oct. 14, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
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		45,244,505
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net premiums earned	$ 253,389	$ 216,630	$ 722,984	$ 640,946
Net investment income	17,844	16,543	50,929	51,238
Net realized gains	1,829	1,512	52,442	14,555
Net unrealized gains (losses) on equity securities	(2,592)	28,126	29,526	(27,564)
Consolidated revenue	270,470	262,811	855,881	679,175
Losses and settlement expenses	143,656	127,596	355,574	339,819
Policy acquisition costs	80,449	71,032	232,674	213,436
Insurance operating expenses	15,560	16,850	54,504	45,137
Interest expense on debt	1,906	1,901	5,711	5,701
General corporate expenses	2,505	2,668	9,533	6,417
Total expenses	244,076	220,047	657,996	610,510
Equity in earnings of unconsolidated investees	9,043	8,745	29,407	18,359
Earnings before income taxes	35,437	51,509	227,292	87,024
Income tax expense	6,194	9,122	43,222	13,738
Net earnings	29,243	42,387	184,070	73,286
Other comprehensive earnings (loss), net of tax	(12,240)	9,550	(41,810)	50,090
Comprehensive earnings	$ 17,003	$ 51,937	$ 142,260	$ 123,376
Basic net earnings per share	$ 0.65	$ 0.94	$ 4.07	$ 1.63
Diluted net earnings per share	$ 0.64	$ 0.93	$ 4.03	$ 1.62
Weighted average number of common shares outstanding:
Basic	45,243	45,014	45,216	44,962
Diluted	45,689	45,426	45,714	45,339

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
ASSETS
Available-for-sale, at fair value (amortized cost of $2,219,502 and allowance for credit losses of $204 at 9/30/21) (amortized cost of $2,061,467 and allowance for credit losses of $397 at 12/31/20)	$ 2,394,669	$ 2,196,626
Equity securities, at fair value (cost - $311,392 at 9/30/21 and $293,190 at 12/31/20)	565,238	524,006
Other invested assets	52,480	54,232
Cash	89,618	62,217
Total investments and cash	3,102,005	2,837,081
Accrued investment income	17,143	16,126
Premiums and reinsurance balances receivable, net of allowances for uncollectible amounts of $18,860 at 9/30/21 and $17,658 at 12/31/20	177,162	174,628
Ceded unearned premium	127,765	113,488
Reinsurance balances recoverable on unpaid losses and settlement expenses, net of allowances for uncollectible amounts of $10,067 at 9/30/21 and $8,634 at 12/31/20	602,154	443,729
Deferred policy acquisition costs	104,309	88,425
Property and equipment, at cost, net of accumulated depreciation of $73,746 at 9/30/21 and $68,682 at 12/31/20	50,860	51,406
Investment in unconsolidated investees	158,721	128,382
Goodwill and intangibles	53,562	53,719
Other assets	38,985	31,501
TOTAL ASSETS	4,432,666	3,938,485
Liabilities
Unpaid losses and settlement expenses	2,033,517	1,750,049
Unearned premiums	673,809	586,386
Reinsurance balances payable	38,093	42,265
Funds held	89,288	81,747
Income taxes-deferred	78,308	80,235
Bonds payable, long-term debt	149,629	149,489
Accrued expenses	74,155	75,925
Other liabilities	45,611	36,411
TOTAL LIABILITIES	3,182,410	2,802,507
Shareholders’ Equity
Common stock ($0.01 par value) (Shares authorized - 200,000,000 at 9/30/21 and 12/31/20) (68,153,557 shares issued, 45,223,343 shares outstanding at 9/30/21) (68,072,794 shares issued, 45,142,580 shares outstanding at 12/31/20)	682	681
Paid-in capital	340,868	335,365
Accumulated other comprehensive earnings	66,904	108,714
Retained earnings	1,234,801	1,084,217
Deferred compensation	8,330	8,292
Less: Treasury shares, at cost (22,930,214 shares at 9/30/21 and 12/31/20)	(401,329)	(401,291)
TOTAL SHAREHOLDERS’ EQUITY	1,250,256	1,135,978
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ 4,432,666	$ 3,938,485

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Available-for-sale, amortized cost	$ 2,310,314	$ 2,061,467
Available-for-sale, allowance for credit losses	226	397
Equity securities, cost	311,392	293,190
Premiums and reinsurance balances receivable, allowances for uncollectible amounts	18,860	17,658
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	10,067	8,634
Property and equipment, accumulated depreciation	$ 73,746	$ 68,682
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)	68,174,719	68,072,794
Common stock, shares outstanding (in shares)	45,244,505	45,142,580
Treasury stock, shares (in shares)	22,930,214	22,930,214

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common stock	Paid-in Capital	Accumulated Other Comprehensive Earnings (Loss)	Accumulated Other Comprehensive Earnings (Loss)Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Deferred Compensation	Treasury Stock at Cost
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2019	$ 995,388	$ 1,095	$ 678	$ 321,190	$ 52,473	$ 22	$ 1,014,046	$ 1,073	$ 7,980	$ (400,979)
Shares, Outstanding, Beginning Balance at Dec. 31, 2019			44,869,015
Accounting Standards Update [Extensible List]	ASU 2016-13
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	$ (61,267)						(61,267)
Other comprehensive earnings (loss), net of tax	(13,031)				(13,031)
Deferred compensation									(1,010)	1,010
Share-based compensation	3,863		$ 1	3,862
Share-based compensation (in shares)			53,641
Dividends and dividend equivalents	(10,343)						(10,343)
Stockholders' Equity Attributable to Parent, Ending Balance at Mar. 31, 2020	915,705		$ 679	325,052	39,464		943,509		6,970	(399,969)
Shares, Outstanding, Ending Balance at Mar. 31, 2020			44,922,656
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2019	995,388	$ 1,095	$ 678	321,190	52,473	$ 22	1,014,046	$ 1,073	7,980	(400,979)
Shares, Outstanding, Beginning Balance at Dec. 31, 2019			44,869,015
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	73,286
Other comprehensive earnings (loss), net of tax	50,090
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2020	1,099,340		$ 680	332,629	102,585		1,056,445		7,703	(400,702)
Shares, Outstanding, Ending Balance at Sep. 30, 2020			45,055,164
Stockholders' Equity Attributable to Parent, Beginning Balance at Mar. 31, 2020	915,705		$ 679	325,052	39,464		943,509		6,970	(399,969)
Shares, Outstanding, Beginning Balance at Mar. 31, 2020			44,922,656
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	92,166						92,166
Other comprehensive earnings (loss), net of tax	53,571				53,571
Deferred compensation									630	(630)
Share-based compensation	810			810
Share-based compensation (in shares)			29,946
Dividends and dividend equivalents	(10,794)						(10,794)
Stockholders' Equity Attributable to Parent, Ending Balance at Jun. 30, 2020	1,051,458		$ 679	325,862	93,035		1,024,881		7,600	(400,599)
Shares, Outstanding, Ending Balance at Jun. 30, 2020			44,952,602
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	42,387						42,387
Other comprehensive earnings (loss), net of tax	9,550				9,550
Deferred compensation									103	(103)
Share-based compensation	6,768		$ 1	6,767
Share-based compensation (in shares)			102,562
Dividends and dividend equivalents	(10,823)						(10,823)
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2020	1,099,340		$ 680	332,629	102,585		1,056,445		7,703	(400,702)
Shares, Outstanding, Ending Balance at Sep. 30, 2020			45,055,164
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2020	1,135,978		$ 681	335,365	108,714		1,084,217		8,292	(401,291)
Shares, Outstanding, Beginning Balance at Dec. 31, 2020			45,142,580
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	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	1,154,786		$ 681	336,757	63,967		1,146,380		7,926	(400,925)
Shares, Outstanding, Ending Balance at Mar. 31, 2021			45,203,438
Stockholders' Equity Attributable to Parent, Beginning Balance at Dec. 31, 2020	1,135,978		$ 681	335,365	108,714		1,084,217		8,292	(401,291)
Shares, Outstanding, Beginning Balance at Dec. 31, 2020			45,142,580
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	184,070
Other comprehensive earnings (loss), net of tax	(41,810)
Stockholders' Equity Attributable to Parent, Ending Balance at Sep. 30, 2021	1,250,256		$ 682	340,868	66,904		1,234,801		8,330	(401,329)
Shares, Outstanding, Ending Balance at Sep. 30, 2021			45,244,505
Stockholders' Equity Attributable to Parent, Beginning Balance at Mar. 31, 2021	1,154,786		$ 681	336,757	63,967		1,146,380		7,926	(400,925)
Shares, Outstanding, Beginning Balance at Mar. 31, 2021			45,203,438
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	81,815						81,815
Other comprehensive earnings (loss), net of tax	15,177				15,177
Deferred compensation									325	(325)
Share-based compensation	1,343		$ 1	1,342
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	1,241,803		$ 682	338,099	79,144		1,216,877		8,251	(401,250)
Shares, Outstanding, Ending Balance at Jun. 30, 2021			45,223,343
Increase Decrease In Stockholders Equity Roll Forward
Net earnings	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	$ 1,250,256		$ 682	$ 340,868	$ 66,904		$ 1,234,801		$ 8,330	$ (401,329)
Shares, Outstanding, Ending Balance at Sep. 30, 2021			45,244,505

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Statement Of Stockholders Equity [Abstract]
Cash dividends paid per common share	$ 0.25	$ 0.25	$ 0.24	$ 0.24	$ 0.24	$ 0.23

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Statement Of Cash Flows [Abstract]
Net cash provided by operating activities	$ 280,441	$ 163,244
Purchase of:
Fixed income securities, available-for-sale	(587,910)	(368,586)
Equity securities	(117,218)	(62,643)
Property and equipment	(5,005)	(4,969)
Other	(11,938)	(15,095)
Proceeds from sale of:
Fixed income securities, available-for-sale	42,776	68,229
Equity securities	157,973	66,185
Other	4,496	3,136
Proceeds from call or maturity of:
Fixed income securities, available-for-sale	296,561	199,036
Net cash used in investing activities	(220,265)	(114,707)
Cash Flows from Financing Activities
Cash dividends paid	(33,454)	(31,931)
Proceeds from stock option exercises	679	7,780
Net cash used in financing activities	(32,775)	(24,151)
Net increase in cash	27,401	24,386
Cash at the beginning of the period	62,217	46,203
Cash at the end of the period	$ 89,618	$ 70,589

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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 2020 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, 2021 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 2020 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 2021 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, 2021. 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 their annual financial statements and Securities and Exchange Commission (SEC) filings for those reinsurers 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 the existing 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, all paid and unpaid balances recoverable for the reinsurer are specifically identified and expensed into our allowance for estimated unrecoverable amounts from reinsurers. We then re-evaluate the remaining allowance and determine whether the balance is sufficient as detailed above and if needed, an additional allowance is recognized and income charged. The allowances for uncollectible amounts on paid and unpaid reinsurance recoverables were $16.1 million and $10.1 million, respectively, at September 30, 2021. At December 31, 2020, the amounts were $15.9 million and $8.6 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 2021 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, 2021 and December 31, 2020 is detailed in the following table: September 30, December 31, (in thousands) 2021 2020 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 Definite-lived intangibles, net of accumulated amortization of $4,035 at 9/30/21 and $3,878 at 12/31/20 - 157 Total intangibles $ 7,500 $ 7,657 Total goodwill and intangibles $ 53,562 $ 53,719 All definite-lived intangible assets are amortized based on their estimated useful lives. Amortization of intangible assets was less than $0.1 million for the third quarter of 2021 and $0.2 million for the nine-month period ended September 30, 2021. Amortization of intangible assets was $0.1 million for the third quarter of 2020 and $0.3 million for the nine-month period ended September 30, 2020. Annual impairment assessments were performed on our goodwill and state insurance license indefinite-lived intangible asset during the second quarter of 2021. Based upon these reviews, none of the assets were impaired. In addition, there were no triggering events as of September 30, 2021 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, 2021 Ended September 30, 2020 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 $ 29,243 45,243 $ 0.65 $ 42,387 45,014 $ 0.94 Effect of Dilutive Securities Stock options and restricted stock units — 446 — 412 Diluted EPS Earnings available to common shareholders $ 29,243 45,689 $ 0.64 $ 42,387 45,426 $ 0.93 Anti-dilutive options excluded from diluted EPS 191 339 For the Nine Months For the Nine Months Ended September 30, 2021 Ended September 30, 2020 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 $ 184,070 45,216 $ 4.07 $ 73,286 44,962 $ 1.63 Effect of Dilutive Securities Stock options and restricted stock units — 498 — 377 Diluted EPS Earnings available to common shareholders $ 184,070 45,714 $ 4.03 $ 73,286 45,339 $ 1.62 Anti-dilutive options excluded from diluted EPS 191 339 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 $3.2 million for the third quarter of 2021, compared to $2.5 million of net tax expense for the same period in 2020. For the nine-month period ended September 30, 2021, other comprehensive earnings is net of tax benefit of $11.1 million, compared to $13.3 million of net tax expense for the same period in 2020. Unrealized losses, net of tax, recognized in other comprehensive earnings (loss) were $41.8 million for the first nine months of 2021, compared to $50.1 million of unrealized gains, net of tax, during the same period last year. The unrealized losses were attributable to increased interest rates in 2021, which decreased the fair value of securities held in the fixed income portfolio, while interest rate declines resulted in unrealized gains in 2020. The following table illustrates the changes in the balance of each component of accumulated other comprehensive earnings 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 2021 2020 2021 2020 Beginning balance $ 79,144 $ 93,035 $ 108,714 $ 52,473 Cumulative-effect adjustment of ASU 2016-13 — — — 22 Adjusted beginning balance $ 79,144 $ 93,035 $ 108,714 $ 52,495 Other comprehensive earnings (loss) before reclassifications (12,114 ) 10,412 (40,307 ) 52,264 Amounts reclassified from accumulated other comprehensive earnings (126 ) (862 ) (1,503 ) (2,174 ) Net current-period other comprehensive earnings (loss) $ (12,240 ) $ 9,550 $ (41,810 ) $ 50,090 Ending balance $ 66,904 $ 102,585 $ 66,904 $ 102,585 Balance of securities for which an allowance for credit losses has been recognized in net earnings $ 426 $ 795 Credit losses on or the sale of an available-for-sale security results in amounts being reclassified from accumulated other comprehensive earnings to current period net earnings. The effects of reclassifications out of accumulated other comprehensive earnings by the respective line items of net earnings are presented in the following table: Amount Reclassified from Accumulated Other (in thousands) Comprehensive Earnings 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 2021 2020 2021 2020 Statement of Earnings Unrealized gains and losses on available-for-sale securities $ 182 $ 738 $ 1,731 $ 3,356 Net realized gains (22 ) 353 171 (604 ) Credit losses presented within net realized gains $ 160 $ 1,091 $ 1,902 $ 2,752 Earnings before income taxes (34 ) (229 ) (399 ) (578 ) Income tax expense $ 126 $ 862 $ 1,503 $ 2,174 Net earnings 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 is applied to valuations based on readily available, unadjusted quoted prices in active markets for identical assets. Level 2 is applied to valuations based upon quoted prices for similar assets in active markets, quoted prices for identical or similar assets in inactive markets; or valuations based on models where the significant inputs are observable (e.g. interest rates, yield curves, prepayment speeds, default rates, loss severities) or can be corroborated by observable market data. Level 3 is applied to valuations that are derived from techniques in which one or more of the significant inputs are unobservable. 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: The pricing vendor employs a multi-dimensional model which uses standard inputs including (listed in approximate order of priority for use) benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, market bids/offers and other reference data. The pricing vendor also monitors market indicators, as well as industry and economic events. All bonds valued using these techniques are classified as Level 2. All corporate, agency, government and municipal securities are deemed Level 2. Mortgage-backed Securities (MBS)/Commercial Mortgage-backed Securities (CMBS) and Asset-backed Securities (ABS): The pricing vendor evaluation methodology includes principally interest rate movements and new issue data. Evaluation of the tranches (non-volatile, volatile or credit sensitivity) is based on the pricing vendors’ interpretation of accepted modeling and pricing conventions. This information is then used to determine the cash flows for each tranche, benchmark yields, pre-payment assumptions and to incorporate collateral performance. To evaluate MBS and CMBS volatility, an option adjusted spread model is used in combination with models that simulate interest rate paths to determine market price information. This process allows the pricing vendor to obtain evaluations of a broad universe of securities in a way that reflects changes in yield curve, index rates, implied volatility, mortgage rates and recent trade activity. MBS/CMBS and ABS with corroborated, observable inputs are classified as Level 2. All of our MBS/CMBS and ABS are deemed Level 2. Regulation D Private Placement Securities: All Regulation D privately-placed bonds are classified as corporate securities and deemed Level 3. The pricing vendor evaluation methodology for these securities includes a combination of observable and unobservable inputs. Observable inputs include public corporate spread matrices classified by sector, rating and average life, as well as investment and non-investment grade matrices created from fixed income indices. Unobservable inputs include a liquidity spread premium calculated based on public corporate spread and private corporate spread matrices. The quantitative detail of the liquidity spread premium is neither provided nor reasonably available to the Company. An increase to the cred it spread assumptions would result in a lower fair value. 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. Common Stock: As of September 30, 2021, nearly all of our common stock holdings were traded on an exchange. Exchange traded equities have readily observable price levels and are classified as Level 1 (fair value based on quoted market prices). Pricing for the equity securities not traded on an exchange is provided by a third-party pricing source and are classified as Level 2. 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 to our day-to-day operations. Adverse changes in the economy could lower demand for our insurance products or negatively impact our investment results, both of which could have an adverse effect on the revenue and profitability of our operations. The COVID-19 pandemic may continue to result in significant disruptions in economic activity and financial markets. 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.

Investments

Investments	9 Months Ended
	Sep. 30, 2021
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, 2021 and 2020: Sales Proceeds Gross Realized Net Realized (in thousands) From Sales Gains Losses Gain (Loss) 2021 Available-for-sale $ 43,041 $ 1,476 $ (107 ) $ 1,369 Equities 157,973 52,409 (1,787 ) 50,622 2020 Available-for-sale $ 68,621 $ 4,959 $ (1,518 ) $ 3,441 Equities 66,185 22,172 (8,756 ) 13,416 Calls/Maturities Gross Realized Net Realized (in thousands) Proceeds Gains Losses Gain (Loss) 2021 Available-for-sale $ 296,563 $ 471 $ (109 ) $ 362 2020 Available-for-sale $ 199,036 $ 525 $ (10 ) $ 515 FAIR VALUE MEASUREMENTS Assets measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 are summarized below: As of September 30, 2021 Fair Value Measurements Using 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 $ — $ 147,193 $ — $ 147,193 U.S. agency — 31,625 — 31,625 Non-U.S. government & agency — 8,521 — 8,521 Agency MBS — 394,270 — 394,270 ABS/CMBS/MBS* — 250,558 — 250,558 Corporate — 906,734 31,536 938,270 Municipal — 624,232 — 624,232 Total fixed income securities - available-for-sale $ — $ 2,363,133 $ 31,536 $ 2,394,669 Equity securities 565,163 75 — 565,238 Other invested assets — — — — Total $ 565,163 $ 2,363,208 $ 31,536 $ 2,959,907 As of December 31, 2020 Fair Value Measurements Using 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 $ — $ 183,357 $ — $ 183,357 U.S. agency — 32,872 — 32,872 Non-U.S. government & agency — 10,965 — 10,965 Agency MBS — 402,071 — 402,071 ABS/CMBS/MBS* — 218,373 — 218,373 Corporate — 798,794 17,798 816,592 Municipal — 532,396 — 532,396 Total fixed income securities - available-for-sale $ — $ 2,178,828 $ 17,798 $ 2,196,626 Equity securities 523,923 83 — 524,006 Other invested assets 6,068 — — 6,068 Total $ 529,991 $ 2,178,911 $ 17,798 $ 2,726,700 * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities The following table summarizes changes in the balance of Regulation D private placement fixed income securities whose fair value was measured using significant unobservable inputs (Level 3). (in thousands) Level 3 Securities Balance as of January 1, 2021 $ 17,798 Net realized and unrealized gains (losses) Included in net earnings as a part of: Net investment income (39 ) Net realized gains (115 ) Included in other comprehensive earnings (loss) (88 ) Total net realized and unrealized gains (losses) $ (242 ) Purchases 13,980 Balance as of September 30, 2021 $ 31,536 Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in net realized gains $ (115 ) Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in other comprehensive earnings (loss) $ (88 ) The amortized cost and fair value of available-for-sale fixed income securities by contractual maturity as of September 30, 2021 were as follows: September 30, 2021 (in thousands) Amortized Cost Fair Value Due in one year or less $ 73,089 $ 73,903 Due after one year through five years 587,559 614,447 Due after five years through 10 years 551,943 581,761 Due after 10 years 464,725 479,730 ABS/CMBS/MBS* 632,998 644,828 Total available-for-sale $ 2,310,314 $ 2,394,669 * Asset-backed, commercial mortgage-backed and mortgage-backed securities The amortized cost and fair value of available-for-sale securities at September 30, 2021 and December 31, 2020 are presented in the tables below. Amortized cost does not include the $15.9 million and $14.9 million of accrued interest receivable as of September 30, 2021 and December 31, 2020, respectively. September 30, 2021 Cost or Allowance Gross Gross Amortized for Credit Unrealized Unrealized Fair (in thousands) Cost Losses Gains Losses Value U.S. government $ 139,441 $ — $ 8,549 $ (797 ) $ 147,193 U.S. agency 28,844 — 2,781 — 31,625 Non-U.S. government & agency 8,297 — 407 (183 ) 8,521 Agency MBS 385,400 — 12,179 (3,309 ) 394,270 ABS/CMBS/MBS* 247,598 — 3,915 (955 ) 250,558 Corporate 896,178 (226 ) 45,230 (2,912 ) 938,270 Municipal 604,556 — 23,593 (3,917 ) 624,232 Total Fixed Income $ 2,310,314 $ (226 ) $ 96,654 $ (12,073 ) $ 2,394,669 December 31, 2020 Cost or Allowance Gross Gross Amortized for Credit Unrealized Unrealized Fair (in thousands) Cost Losses Gains Losses Value U.S. government $ 170,110 $ — $ 13,504 $ (257 ) $ 183,357 U.S. agency 28,902 — 3,970 — 32,872 Non-U.S. government & agency 10,298 — 667 — 10,965 Agency MBS 384,015 — 18,789 (733 ) 402,071 ABS/CMBS/MBS* 213,223 (17 ) 5,580 (413 ) 218,373 Corporate 753,404 (380 ) 64,501 (933 ) 816,592 Municipal 501,515 — 31,099 (218 ) 532,396 Total Fixed Income $ 2,061,467 $ (397 ) $ 138,110 $ (2,554 ) $ 2,196,626 * Non-agency asset-backed, commercial mortgage-backed and mortgage-backed securities Allowance for Credit Losses and Unrealized Losses on Fixed Income Securities We adopted ASU 2016-13, Financial Instruments – Credit Losses, on January 1, 2020, which required the recognition of a reversable allowance for credit losses on available-for-sale fixed income securities. Available-for-sale securities in the fixed income portfolio are subjected to several criteria to determine if those securities 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 securities fair value is below amortized cost. As of September 30, 2021, the discounted cash flow analysis resulted in an allowance for credit losses on 11 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) 2021 2020 2021 2020 Beginning balance $ 204 $ 985 $ 397 $ — Adoption impact of ASU 2016-13 - - - 28 Increase to allowance from securities for which credit losses were not previously recorded - 17 - 751 Reduction from securities sold during the period - (6 ) - (116 ) Reductions from intent to sell securities - (186 ) - (186 ) Net increase (decrease) from securities that had an allowance at the beginning of the period 22 (178 ) (171 ) 155 Balance as of September 30, $ 226 $ 632 $ 226 $ 632 As of September 30, 2021, in addition to the securities included in the allowance for credit losses, the fixed income portfolio contained 327 securities with an unrealized loss position for which an allowance for credit losses had not been recorded. The $12.1 million in associated unrealized losses represents 0.5 percent of the fixed income portfolio’s cost basis and 0.4 nrealized losses increased through the first nine months of 2021, as interest rates increased during the period. The following table illustrates the total value of fixed income securities that were in an unrealized loss position as of September 30, 2021 and December 31, 2020 after factoring in the allowance for credit losses. September 30, 2021 December 31, 2020 (in thousands) < 12 Mos. 12 Mos. & Greater Total < 12 Mos. 12 Mos. & Greater Total U.S. government Fair value $ 2,976 $ 5,152 $ 8,128 $ 5,680 $ — $ 5,680 Amortized cost 2,986 5,939 8,925 5,937 — 5,937 Unrealized loss $ (10 ) $ (787 ) $ (797 ) $ (257 ) $ — $ (257 ) U.S. agency Fair value $ 1,003 $ — $ 1,003 $ — $ — $ — Amortized cost 1,003 — 1,003 — — — Unrealized loss $ — $ — $ — $ — $ — $ — Non-U.S. government Fair value $ 2,817 $ — $ 2,817 $ — $ — $ — Amortized cost 3,000 — 3,000 — — — Unrealized Loss $ (183 ) $ — $ (183 ) $ — $ — $ — Agency MBS Fair value $ 128,783 $ 15,940 $ 144,723 $ 43,999 $ — $ 43,999 Amortized cost 131,277 16,755 148,032 44,732 — 44,732 Unrealized loss $ (2,494 ) $ (815 ) $ (3,309 ) $ (733 ) $ — $ (733 ) ABS/CMBS/MBS* Fair value $ 92,083 $ 3,832 $ 95,915 $ 32,771 $ 16,161 $ 48,932 Amortized cost 93,020 3,850 96,870 33,094 16,251 49,345 Unrealized loss $ (937 ) $ (18 ) $ (955 ) $ (323 ) $ (90 ) $ (413 ) Corporate Fair value $ 173,508 $ 18,574 $ 192,082 $ 52,655 $ 6,235 $ 58,890 Amortized cost 175,695 19,299 194,994 53,440 6,383 59,823 Unrealized loss $ (2,187 ) $ (725 ) $ (2,912 ) $ (785 ) $ (148 ) $ (933 ) Municipal Fair value $ 154,883 $ 11,179 $ 166,062 $ 25,676 $ — $ 25,676 Amortized cost 158,310 11,669 169,979 25,894 — 25,894 Unrealized loss $ (3,427 ) $ (490 ) $ (3,917 ) $ (218 ) $ — $ (218 ) Total fixed income Fair value $ 556,053 $ 54,677 $ 610,730 $ 160,781 $ 22,396 $ 183,177 Amortized cost 565,291 57,512 622,803 163,097 22,634 185,731 Unrealized loss $ (9,238 ) $ (2,835 ) $ (12,073 ) $ (2,316 ) $ (238 ) $ (2,554 ) * 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, 2021 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 $ 491,071 $ 480,865 $ (10,206 ) 84.6 % 2 BBB Baa 91,432 90,332 (1,100 ) 9.1 % 3 BB Ba 15,455 15,211 (244 ) 2.0 % 4 B B 23,628 23,131 (497 ) 4.1 % 5 CCC Caa 1,217 1,191 (26 ) 0.2 % 6 CC or lower Ca or lower - - - 0.0 % Total $ 622,803 $ 610,730 $ (12,073 ) 100.0 % Net Unrealized Gains and Losses on Equity Securities Net unrealized losses recognized on equity securities still held as of September 30, 2021 were $0.8 million during the third quarter, while net unrealized gains were $80.1 million during the first nine months of 2021. Comparatively, net unrealized gain s recognized on equity securities still held as of September 30, 2020 were $ million during the third quarter , while net unrealized losses were $ million during the first nine months of 2020 . Other Invested Assets We had $52.5 million of other invested assets at September 30, 2021, compared to $54.2 million at December 31, 2020. 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 $17.4 million at September 30, 2021, compared to $20.3 million at December 31, 2020 and recognized a total tax benefit of $0.9 million during the third quarters of 2021 and 2020. For the nine-month period ended September 30, 2021, our LIHTC interests recognized a total benefit of $2.7 million, compared to $2.6 million during the same period of 2020. Our unfunded commitment for our LIHTC investments totaled $2.1 million at September 30, 2021 and will be paid out in installments through 2035. As of September 30, 2021, $9.1 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 and during the nine-month period ended September 30, 2021, there were no outstanding borrowings with the FHLBC. Our investments in private funds totaled $31.4 million at September 30, 2021, compared to $32.1 million at December 31, 2020, and we had $9.6 million of associated unfunded commitments at September 30, 2021. 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. At December 31, 2020, we had a publicly traded common stock with short-term restrictions that limited our ability to sell the security without prior approval. During the first quarter of 2021, our investment in this security became unrestricted and the investment was included in our equity portfolio as of September 30, 2021. Investments in Unconsolidated Investees We had $158.7 million of investments in unconsolidated investees at September 30, 2021, compared to $128.4 million at December 31, 2020. Our investments accounted for under the equity method are primarily related to Maui Jim, Inc. (Maui Jim) and Prime Holdings Insurance Services, Inc. (Prime). At September 30, 2021 our investment in Maui Jim was $110.6 million and our investment in Prime was $42.4 million. Other investments in unconsolidated investees totaled $5.7 million at September 30, 2021 and had unfunded commitments of $15.0 million. Cash Cash consists of uninvested balances in bank accounts. We had a cash balance of $89.6 million at September 30, 2021, compared to $62.2 million at December 31, 2020.

Historical Loss And LAE Develop

Historical Loss And LAE Development	9 Months Ended
	Sep. 30, 2021
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 2021 and 2020: For the Nine Months Ended September 30, (in thousands) 2021 2020 Unpaid losses and LAE at beginning of year Gross $ 1,750,049 $ 1,574,352 Ceded (443,729 ) (384,517 ) Net $ 1,306,320 $ 1,189,835 Adoption impact of ASU 2016-13 on reinsurance balances recoverable $ — $ (1,345 ) Increase (decrease) in incurred losses and LAE Current accident year $ 452,542 $ 409,867 Prior accident years (96,968 ) (70,048 ) Total incurred $ 355,574 $ 339,819 Loss and LAE payments for claims incurred Current accident year $ (58,411 ) $ (49,337 ) Prior accident years (172,120 ) (192,056 ) Total paid $ (230,531 ) $ (241,393 ) Net unpaid losses and LAE at September 30 $ 1,431,363 $ 1,286,916 Unpaid losses and LAE at September 30 Gross $ 2,033,517 $ 1,686,876 Ceded (602,154 ) (399,960 ) Net $ 1,431,363 $ 1,286,916 We adopted ASU 2016-13, Financial Instruments – Credit Losses, on January 1, 2020, which required financial assets, including reinsurance balances recoverable, to be presented at the net amount expected to be collected. We maintained an allowance for uncollectible reinsurance balances prior to the adoption of this update. However, in order to comply with the updated requirements, we released $1.3 million of the allowance on uncollectible reinsurance balances upon adoption. The implementation guidance required the cumulative-effect adjustment be made to the beginning balance of retained earnings, rather than through net earnings like historical changes have and ongoing modifications will continue to be recorded. 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. For the first nine months of 2020, incurred losses and LAE included $70.0 million of favorable development on prior years’ loss reserves. The majority of products experienced modest amounts of favorable development on prior accident years, with notable contributions from transportation, general liability, executive products, marine and surety. No products experienced significant adverse development. Actuarial models base future emergence on historic experience, with adjustments for current trends, and the appropriateness of these assumptions involved more uncertainty as of September 30, 2021. We expect the timing of loss emergence and ultimate loss ratios for certain coverages we underwrite will be affected as a result of the spread 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, 2021
Income Tax Disclosure [Abstract]
Income Taxes	4. INCOME TAXES Our effective tax rate for the three and nine months ended September 30, 2021 was 17.5 percent and 19.0 percent, respectively, compared to 17.7 percent and 15.8 percent, respectively, for the same period in 2020. Effective rates are dependent upon components of pretax earnings and the related tax effects. For the nine-month period ended September 30, the effective tax rate was higher for 2021 as lower pretax income was experienced in 2020, which increased the percentage impact of tax-favored adjustments. Income tax expense attributable to income from operations for the three and nine-month periods ended September 30, 2021 and 2020 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, For the Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Amount % Amount % Amount % Amount % Provision for income taxes at the statutory rate of 21% $ 7,442 21.0 % $ 10,817 21.0 % $ 47,731 21.0 % $ 18,275 21.0 % Increase (reduction) in taxes resulting from: Excess tax benefit on share-based compensation (225 ) (0.6 ) % (848 ) (1.6 ) % (2,419 ) (1.1 ) % (2,141 ) (2.4 ) % Tax exempt interest income (298 ) (0.8 ) % (324 ) (0.6 ) % (927 ) (0.4 ) % (960 ) (1.1 ) % Dividends received deduction (223 ) (0.6 ) % (221 ) (0.4 ) % (707 ) (0.3 ) % (705 ) (0.8 ) % Investment tax credit (801 ) (2.3 ) % (316 ) (0.6 ) % (2,404 ) (1.0 ) % (1,766 ) (2.0 ) % ESOP dividends paid deduction (132 ) (0.4 ) % (134 ) (0.3 ) % (399 ) (0.2 ) % (403 ) (0.5 ) % Nondeductible expenses 642 1.8 % 275 0.5 % 1,879 0.8 % 639 0.7 % Other items, net (211 ) (0.6 ) % (127 ) (0.3 ) % 468 0.2 % 799 0.9 % Total tax expense $ 6,194 17.5 % $ 9,122 17.7 % $ 43,222 19.0 % $ 13,738 15.8 %

Stock Based Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2021
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 2,876,920 awards under the 2015 LTIP, including 253,551 thus far in 2021. Compensation expense is based on the probable number of awards expected to vest. The total compensation expense related to equity awards was $1.6 million and $4.8 million in the three and nine-month periods ended September 30, 2021, respectively, compared to $1.6 million and $3.6 million, respectively, for the same periods in 2020. The total income tax benefit was $0.2 million and $0.7 million for the three and nine-month periods ended September 30, 2021, respectively, compared to $0.3 million and $0.6 million, respectively, for the same periods in 2020. Total unrecognized compensation expense relating to outstanding and unvested awards was $7.2 million, which will be recognized over the weighted average vesting period of 2.41 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 ratably 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, 2021: Weighted Aggregate Weighted Average Intrinsic Average Remaining Value Options Exercise Price Contractual Life (in 000’s) Outstanding options at January 1, 2021 1,632,334 $ 70.67 Options granted 236,771 109.64 Options exercised (148,247 ) 55.82 Options canceled/forfeited (8,215 ) 84.29 Outstanding options at September 30, 2021 1,712,643 $ 77.27 5.03 $ 41,702 Exercisable options at September 30, 2021 804,575 $ 65.36 3.74 $ 28,093 The intrinsic value, which is the difference between the fair value and the exercise price, of options exercised was $8.4 million and $7.6 million during the first nine months of 2021 and 2020, 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: 2021 2020 Weighted-average fair value of grants $ 17.01 $ 13.33 Risk-free interest rates 0.70 % 0.41 % Dividend yield 2.06 % 2.30 % Expected volatility 22.73 % 22.67 % Expected option life 4.97 years 4.96 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 Weighted Average Grant Date RSUs Fair Value Nonvested at January 1, 2021 47,658 $ 81.53 Granted 16,780 113.02 Reinvested 322 105.00 Vested (19,725 ) 72.53 Forfeited (789 ) 95.53 Nonvested at September 30, 2021 44,246 $ 97.41

Operating Segment Information

Operating Segment Information	9 Months Ended
	Sep. 30, 2021
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) 2021 2020 2021 2020 Casualty $ 162,852 $ 143,002 $ 467,817 $ 421,637 Property 60,886 45,380 168,393 135,115 Surety 29,651 28,248 86,774 84,194 Net premiums earned $ 253,389 $ 216,630 $ 722,984 $ 640,946 Net investment income 17,844 16,543 50,929 51,238 Net realized gains 1,829 1,512 52,442 14,555 Net unrealized gains (losses) on equity securities (2,592 ) 28,126 29,526 (27,564 ) Total consolidated revenue $ 270,470 $ 262,811 $ 855,881 $ 679,175 Net Earnings (in thousands) 2021 2020 2021 2020 Casualty $ 22,949 $ 13,993 $ 74,254 $ 22,403 Property (16,558 ) (19,951 ) (8,684 ) (3,876 ) Surety 7,333 7,110 14,662 24,027 Net underwriting income $ 13,724 $ 1,152 $ 80,232 $ 42,554 Net investment income 17,844 16,543 50,929 51,238 Net realized gains 1,829 1,512 52,442 14,555 Net unrealized gains (losses) on equity securities (2,592 ) 28,126 29,526 (27,564 ) General corporate expense and interest on debt (4,411 ) (4,569 ) (15,244 ) (12,118 ) Equity in earnings of unconsolidated investees 9,043 8,745 29,407 18,359 Earnings before income taxes $ 35,437 $ 51,509 $ 227,292 $ 87,024 Income tax expense 6,194 9,122 43,222 13,738 Net earnings $ 29,243 $ 42,387 $ 184,070 $ 73,286 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) 2021 2020 2021 2020 Casualty Commercial excess and personal umbrella $ 56,285 $ 46,404 $ 161,287 $ 128,813 General liability 23,156 22,747 67,616 69,396 Professional services 22,401 21,422 66,095 63,501 Commercial transportation 22,571 15,130 60,926 47,454 Small commercial 16,301 16,009 48,302 47,433 Executive products 5,461 6,387 15,785 20,693 Other casualty 16,677 14,903 47,806 44,347 Total $ 162,852 $ 143,002 $ 467,817 $ 421,637 Property Commercial property $ 28,683 $ 20,168 $ 76,488 $ 58,371 Marine 25,416 19,687 72,737 59,976 Specialty personal 5,462 4,794 15,761 14,730 Other property 1,325 731 3,407 2,038 Total $ 60,886 $ 45,380 $ 168,393 $ 135,115 Surety Commercial $ 11,541 $ 10,543 $ 33,594 $ 32,287 Miscellaneous 11,124 10,547 32,604 31,562 Contract 6,986 7,158 20,576 20,345 Total $ 29,651 $ 28,248 $ 86,774 $ 84,194 Grand Total $ 253,389 $ 216,630 $ 722,984 $ 640,946

Leases

Leases	9 Months Ended
	Sep. 30, 2021
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, 2021 and 2020 are as follows: For the Three Months For the Nine Months Ended September 30, Ended September 30, (in thousands) 2021 2020 2021 2020 Operating lease cost $ 1,326 $ 1,364 $ 4,005 $ 4,140 Variable lease cost 348 338 1,090 1,014 Sublease income (123 ) (96 ) (369 ) (139 ) Total lease cost $ 1,551 $ 1,606 $ 4,726 $ 5,015 Cash paid for amounts included in measurement of lease liabilities Operating cash outflows from operating leases $ 1,490 $ 1,480 $ 4,455 $ 4,470 ROU assets obtained in exchange for new operating lease liabilities $ 4,434 $ — $ 4,699 $ 15 Reduction to ROU assets resulting from reduction to lease liabilities $ — $ 18 $ 1,250 $ 18 Other non-cash reductions to ROU assets $ 48 $ — $ 48 $ 1,192 (in thousands) September 30, 2021 December 31, 2020 Operating lease ROU assets $ 15,882 $ 16,200 Operating lease liabilities $ 18,148 $ 19,072 Weighted-average remaining lease term - operating leases 4.58 years 3.87 years Weighted-average discount rate - operating leases 2.05 % 2.32 % Future minimum lease payments under non-cancellable leases as of September 30, 2021 were as follows: (in thousands) September 30, 2021 2021 $ 1,283 2022 5,475 2023 4,901 2024 2,871 2025 1,462 2026 884 Thereafter 2,176 Total future minimum lease payments $ 19,052 Less imputed interest (904 ) Total operating lease liability $ 18,148

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
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 2020 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, 2021 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 2020 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 2021 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, 2021.
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 their annual financial statements and Securities and Exchange Commission (SEC) filings for those reinsurers 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 the existing 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, all paid and unpaid balances recoverable for the reinsurer are specifically identified and expensed into our allowance for estimated unrecoverable amounts from reinsurers. We then re-evaluate the remaining allowance and determine whether the balance is sufficient as detailed above and if needed, an additional allowance is recognized and income charged. The allowances for uncollectible amounts on paid and unpaid reinsurance recoverables were $16.1 million and $10.1 million, respectively, at September 30, 2021. At December 31, 2020, the amounts were $15.9 million and $8.6 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 2021 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, 2021 and December 31, 2020 is detailed in the following table: September 30, December 31, (in thousands) 2021 2020 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 Definite-lived intangibles, net of accumulated amortization of $4,035 at 9/30/21 and $3,878 at 12/31/20 - 157 Total intangibles $ 7,500 $ 7,657 Total goodwill and intangibles $ 53,562 $ 53,719 All definite-lived intangible assets are amortized based on their estimated useful lives. Amortization of intangible assets was less than $0.1 million for the third quarter of 2021 and $0.2 million for the nine-month period ended September 30, 2021. Amortization of intangible assets was $0.1 million for the third quarter of 2020 and $0.3 million for the nine-month period ended September 30, 2020. Annual impairment assessments were performed on our goodwill and state insurance license indefinite-lived intangible asset during the second quarter of 2021. Based upon these reviews, none of the assets were impaired. In addition, there were no triggering events as of September 30, 2021 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, 2021 Ended September 30, 2020 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 $ 29,243 45,243 $ 0.65 $ 42,387 45,014 $ 0.94 Effect of Dilutive Securities Stock options and restricted stock units — 446 — 412 Diluted EPS Earnings available to common shareholders $ 29,243 45,689 $ 0.64 $ 42,387 45,426 $ 0.93 Anti-dilutive options excluded from diluted EPS 191 339 For the Nine Months For the Nine Months Ended September 30, 2021 Ended September 30, 2020 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 $ 184,070 45,216 $ 4.07 $ 73,286 44,962 $ 1.63 Effect of Dilutive Securities Stock options and restricted stock units — 498 — 377 Diluted EPS Earnings available to common shareholders $ 184,070 45,714 $ 4.03 $ 73,286 45,339 $ 1.62 Anti-dilutive options excluded from diluted EPS 191 339
Comprehensive Earnings	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 $3.2 million for the third quarter of 2021, compared to $2.5 million of net tax expense for the same period in 2020. For the nine-month period ended September 30, 2021, other comprehensive earnings is net of tax benefit of $11.1 million, compared to $13.3 million of net tax expense for the same period in 2020. Unrealized losses, net of tax, recognized in other comprehensive earnings (loss) were $41.8 million for the first nine months of 2021, compared to $50.1 million of unrealized gains, net of tax, during the same period last year. The unrealized losses were attributable to increased interest rates in 2021, which decreased the fair value of securities held in the fixed income portfolio, while interest rate declines resulted in unrealized gains in 2020. The following table illustrates the changes in the balance of each component of accumulated other comprehensive earnings 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 2021 2020 2021 2020 Beginning balance $ 79,144 $ 93,035 $ 108,714 $ 52,473 Cumulative-effect adjustment of ASU 2016-13 — — — 22 Adjusted beginning balance $ 79,144 $ 93,035 $ 108,714 $ 52,495 Other comprehensive earnings (loss) before reclassifications (12,114 ) 10,412 (40,307 ) 52,264 Amounts reclassified from accumulated other comprehensive earnings (126 ) (862 ) (1,503 ) (2,174 ) Net current-period other comprehensive earnings (loss) $ (12,240 ) $ 9,550 $ (41,810 ) $ 50,090 Ending balance $ 66,904 $ 102,585 $ 66,904 $ 102,585 Balance of securities for which an allowance for credit losses has been recognized in net earnings $ 426 $ 795 Credit losses on or the sale of an available-for-sale security results in amounts being reclassified from accumulated other comprehensive earnings to current period net earnings. The effects of reclassifications out of accumulated other comprehensive earnings by the respective line items of net earnings are presented in the following table: Amount Reclassified from Accumulated Other (in thousands) Comprehensive Earnings 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 2021 2020 2021 2020 Statement of Earnings Unrealized gains and losses on available-for-sale securities $ 182 $ 738 $ 1,731 $ 3,356 Net realized gains (22 ) 353 171 (604 ) Credit losses presented within net realized gains $ 160 $ 1,091 $ 1,902 $ 2,752 Earnings before income taxes (34 ) (229 ) (399 ) (578 ) Income tax expense $ 126 $ 862 $ 1,503 $ 2,174 Net earnings
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 is applied to valuations based on readily available, unadjusted quoted prices in active markets for identical assets. Level 2 is applied to valuations based upon quoted prices for similar assets in active markets, quoted prices for identical or similar assets in inactive markets; or valuations based on models where the significant inputs are observable (e.g. interest rates, yield curves, prepayment speeds, default rates, loss severities) or can be corroborated by observable market data. Level 3 is applied to valuations that are derived from techniques in which one or more of the significant inputs are unobservable. 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: The pricing vendor employs a multi-dimensional model which uses standard inputs including (listed in approximate order of priority for use) benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, market bids/offers and other reference data. The pricing vendor also monitors market indicators, as well as industry and economic events. All bonds valued using these techniques are classified as Level 2. All corporate, agency, government and municipal securities are deemed Level 2. Mortgage-backed Securities (MBS)/Commercial Mortgage-backed Securities (CMBS) and Asset-backed Securities (ABS): The pricing vendor evaluation methodology includes principally interest rate movements and new issue data. Evaluation of the tranches (non-volatile, volatile or credit sensitivity) is based on the pricing vendors’ interpretation of accepted modeling and pricing conventions. This information is then used to determine the cash flows for each tranche, benchmark yields, pre-payment assumptions and to incorporate collateral performance. To evaluate MBS and CMBS volatility, an option adjusted spread model is used in combination with models that simulate interest rate paths to determine market price information. This process allows the pricing vendor to obtain evaluations of a broad universe of securities in a way that reflects changes in yield curve, index rates, implied volatility, mortgage rates and recent trade activity. MBS/CMBS and ABS with corroborated, observable inputs are classified as Level 2. All of our MBS/CMBS and ABS are deemed Level 2. Regulation D Private Placement Securities: All Regulation D privately-placed bonds are classified as corporate securities and deemed Level 3. The pricing vendor evaluation methodology for these securities includes a combination of observable and unobservable inputs. Observable inputs include public corporate spread matrices classified by sector, rating and average life, as well as investment and non-investment grade matrices created from fixed income indices. Unobservable inputs include a liquidity spread premium calculated based on public corporate spread and private corporate spread matrices. The quantitative detail of the liquidity spread premium is neither provided nor reasonably available to the Company. An increase to the cred it spread assumptions would result in a lower fair value. 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. Common Stock: As of September 30, 2021, nearly all of our common stock holdings were traded on an exchange. Exchange traded equities have readily observable price levels and are classified as Level 1 (fair value based on quoted market prices). Pricing for the equity securities not traded on an exchange is provided by a third-party pricing source and are classified as Level 2. 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 to our day-to-day operations. Adverse changes in the economy could lower demand for our insurance products or negatively impact our investment results, both of which could have an adverse effect on the revenue and profitability of our operations. The COVID-19 pandemic may continue to result in significant disruptions in economic activity and financial markets. 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.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Schedule of Goodwill and Intangible Assets	September 30, December 31, (in thousands) 2021 2020 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 Definite-lived intangibles, net of accumulated amortization of $4,035 at 9/30/21 and $3,878 at 12/31/20 - 157 Total intangibles $ 7,500 $ 7,657 Total goodwill and intangibles $ 53,562 $ 53,719
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, 2021 Ended September 30, 2020 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 $ 29,243 45,243 $ 0.65 $ 42,387 45,014 $ 0.94 Effect of Dilutive Securities Stock options and restricted stock units — 446 — 412 Diluted EPS Earnings available to common shareholders $ 29,243 45,689 $ 0.64 $ 42,387 45,426 $ 0.93 Anti-dilutive options excluded from diluted EPS 191 339 For the Nine Months For the Nine Months Ended September 30, 2021 Ended September 30, 2020 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 $ 184,070 45,216 $ 4.07 $ 73,286 44,962 $ 1.63 Effect of Dilutive Securities Stock options and restricted stock units — 498 — 377 Diluted EPS Earnings available to common shareholders $ 184,070 45,714 $ 4.03 $ 73,286 45,339 $ 1.62 Anti-dilutive options excluded from diluted EPS 191 339
Schedule of Changes in the Balance of Each Component of Accumulated Other Comprehensive Earnings	(in thousands) For the Three Months For the Nine Months Ended September 30, Ended September 30, Unrealized Gains/Losses on Available-for-Sale Securities 2021 2020 2021 2020 Beginning balance $ 79,144 $ 93,035 $ 108,714 $ 52,473 Cumulative-effect adjustment of ASU 2016-13 — — — 22 Adjusted beginning balance $ 79,144 $ 93,035 $ 108,714 $ 52,495 Other comprehensive earnings (loss) before reclassifications (12,114 ) 10,412 (40,307 ) 52,264 Amounts reclassified from accumulated other comprehensive earnings (126 ) (862 ) (1,503 ) (2,174 ) Net current-period other comprehensive earnings (loss) $ (12,240 ) $ 9,550 $ (41,810 ) $ 50,090 Ending balance $ 66,904 $ 102,585 $ 66,904 $ 102,585 Balance of securities for which an allowance for credit losses has been recognized in net earnings $ 426 $ 795
Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings	Amount Reclassified from Accumulated Other (in thousands) Comprehensive Earnings 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 2021 2020 2021 2020 Statement of Earnings Unrealized gains and losses on available-for-sale securities $ 182 $ 738 $ 1,731 $ 3,356 Net realized gains (22 ) 353 171 (604 ) Credit losses presented within net realized gains $ 160 $ 1,091 $ 1,902 $ 2,752 Earnings before income taxes (34 ) (229 ) (399 ) (578 ) Income tax expense $ 126 $ 862 $ 1,503 $ 2,174 Net earnings

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2021
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) 2021 Available-for-sale $ 43,041 $ 1,476 $ (107 ) $ 1,369 Equities 157,973 52,409 (1,787 ) 50,622 2020 Available-for-sale $ 68,621 $ 4,959 $ (1,518 ) $ 3,441 Equities 66,185 22,172 (8,756 ) 13,416 Calls/Maturities Gross Realized Net Realized (in thousands) Proceeds Gains Losses Gain (Loss) 2021 Available-for-sale $ 296,563 $ 471 $ (109 ) $ 362 2020 Available-for-sale $ 199,036 $ 525 $ (10 ) $ 515
Fair Value, Assets Measured on Recurring Basis	Assets measured at fair value on a recurring basis as of September 30, 2021 and December 31, 2020 are summarized below: As of September 30, 2021 Fair Value Measurements Using 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 $ — $ 147,193 $ — $ 147,193 U.S. agency — 31,625 — 31,625 Non-U.S. government & agency — 8,521 — 8,521 Agency MBS — 394,270 — 394,270 ABS/CMBS/MBS* — 250,558 — 250,558 Corporate — 906,734 31,536 938,270 Municipal — 624,232 — 624,232 Total fixed income securities - available-for-sale $ — $ 2,363,133 $ 31,536 $ 2,394,669 Equity securities 565,163 75 — 565,238 Other invested assets — — — — Total $ 565,163 $ 2,363,208 $ 31,536 $ 2,959,907 As of December 31, 2020 Fair Value Measurements Using 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 $ — $ 183,357 $ — $ 183,357 U.S. agency — 32,872 — 32,872 Non-U.S. government & agency — 10,965 — 10,965 Agency MBS — 402,071 — 402,071 ABS/CMBS/MBS* — 218,373 — 218,373 Corporate — 798,794 17,798 816,592 Municipal — 532,396 — 532,396 Total fixed income securities - available-for-sale $ — $ 2,178,828 $ 17,798 $ 2,196,626 Equity securities 523,923 83 — 524,006 Other invested assets 6,068 — — 6,068 Total $ 529,991 $ 2,178,911 $ 17,798 $ 2,726,700 * 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, 2021 $ 17,798 Net realized and unrealized gains (losses) Included in net earnings as a part of: Net investment income (39 ) Net realized gains (115 ) Included in other comprehensive earnings (loss) (88 ) Total net realized and unrealized gains (losses) $ (242 ) Purchases 13,980 Balance as of September 30, 2021 $ 31,536 Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in net realized gains $ (115 ) Change in unrealized gains (losses) during the period for Level 3 assets held at period-end - included in other comprehensive earnings (loss) $ (88 )
Schedule of Contractual Maturity of Securities	September 30, 2021 (in thousands) Amortized Cost Fair Value Due in one year or less $ 73,089 $ 73,903 Due after one year through five years 587,559 614,447 Due after five years through 10 years 551,943 581,761 Due after 10 years 464,725 479,730 ABS/CMBS/MBS* 632,998 644,828 Total available-for-sale $ 2,310,314 $ 2,394,669 * Asset-backed, commercial mortgage-backed and mortgage-backed securities
Schedule of Amortized Cost and Fair Value of Available-for-sale Securities	The amortized cost and fair value of available-for-sale securities at September 30, 2021 and December 31, 2020 are presented in the tables below. Amortized cost does not include the $15.9 million and $14.9 million of accrued interest receivable as of September 30, 2021 and December 31, 2020, respectively. September 30, 2021 Cost or Allowance Gross Gross Amortized for Credit Unrealized Unrealized Fair (in thousands) Cost Losses Gains Losses Value U.S. government $ 139,441 $ — $ 8,549 $ (797 ) $ 147,193 U.S. agency 28,844 — 2,781 — 31,625 Non-U.S. government & agency 8,297 — 407 (183 ) 8,521 Agency MBS 385,400 — 12,179 (3,309 ) 394,270 ABS/CMBS/MBS* 247,598 — 3,915 (955 ) 250,558 Corporate 896,178 (226 ) 45,230 (2,912 ) 938,270 Municipal 604,556 — 23,593 (3,917 ) 624,232 Total Fixed Income $ 2,310,314 $ (226 ) $ 96,654 $ (12,073 ) $ 2,394,669 December 31, 2020 Cost or Allowance Gross Gross Amortized for Credit Unrealized Unrealized Fair (in thousands) Cost Losses Gains Losses Value U.S. government $ 170,110 $ — $ 13,504 $ (257 ) $ 183,357 U.S. agency 28,902 — 3,970 — 32,872 Non-U.S. government & agency 10,298 — 667 — 10,965 Agency MBS 384,015 — 18,789 (733 ) 402,071 ABS/CMBS/MBS* 213,223 (17 ) 5,580 (413 ) 218,373 Corporate 753,404 (380 ) 64,501 (933 ) 816,592 Municipal 501,515 — 31,099 (218 ) 532,396 Total Fixed Income $ 2,061,467 $ (397 ) $ 138,110 $ (2,554 ) $ 2,196,626 * 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) 2021 2020 2021 2020 Beginning balance $ 204 $ 985 $ 397 $ — Adoption impact of ASU 2016-13 - - - 28 Increase to allowance from securities for which credit losses were not previously recorded - 17 - 751 Reduction from securities sold during the period - (6 ) - (116 ) Reductions from intent to sell securities - (186 ) - (186 ) Net increase (decrease) from securities that had an allowance at the beginning of the period 22 (178 ) (171 ) 155 Balance as of September 30, $ 226 $ 632 $ 226 $ 632
Schedule of Securities in an Unrealized Loss Position Segregated by Type and Length of Time in an Unrealized Loss Position	September 30, 2021 December 31, 2020 (in thousands) < 12 Mos. 12 Mos. & Greater Total < 12 Mos. 12 Mos. & Greater Total U.S. government Fair value $ 2,976 $ 5,152 $ 8,128 $ 5,680 $ — $ 5,680 Amortized cost 2,986 5,939 8,925 5,937 — 5,937 Unrealized loss $ (10 ) $ (787 ) $ (797 ) $ (257 ) $ — $ (257 ) U.S. agency Fair value $ 1,003 $ — $ 1,003 $ — $ — $ — Amortized cost 1,003 — 1,003 — — — Unrealized loss $ — $ — $ — $ — $ — $ — Non-U.S. government Fair value $ 2,817 $ — $ 2,817 $ — $ — $ — Amortized cost 3,000 — 3,000 — — — Unrealized Loss $ (183 ) $ — $ (183 ) $ — $ — $ — Agency MBS Fair value $ 128,783 $ 15,940 $ 144,723 $ 43,999 $ — $ 43,999 Amortized cost 131,277 16,755 148,032 44,732 — 44,732 Unrealized loss $ (2,494 ) $ (815 ) $ (3,309 ) $ (733 ) $ — $ (733 ) ABS/CMBS/MBS* Fair value $ 92,083 $ 3,832 $ 95,915 $ 32,771 $ 16,161 $ 48,932 Amortized cost 93,020 3,850 96,870 33,094 16,251 49,345 Unrealized loss $ (937 ) $ (18 ) $ (955 ) $ (323 ) $ (90 ) $ (413 ) Corporate Fair value $ 173,508 $ 18,574 $ 192,082 $ 52,655 $ 6,235 $ 58,890 Amortized cost 175,695 19,299 194,994 53,440 6,383 59,823 Unrealized loss $ (2,187 ) $ (725 ) $ (2,912 ) $ (785 ) $ (148 ) $ (933 ) Municipal Fair value $ 154,883 $ 11,179 $ 166,062 $ 25,676 $ — $ 25,676 Amortized cost 158,310 11,669 169,979 25,894 — 25,894 Unrealized loss $ (3,427 ) $ (490 ) $ (3,917 ) $ (218 ) $ — $ (218 ) Total fixed income Fair value $ 556,053 $ 54,677 $ 610,730 $ 160,781 $ 22,396 $ 183,177 Amortized cost 565,291 57,512 622,803 163,097 22,634 185,731 Unrealized loss $ (9,238 ) $ (2,835 ) $ (12,073 ) $ (2,316 ) $ (238 ) $ (2,554 ) * 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 $ 491,071 $ 480,865 $ (10,206 ) 84.6 % 2 BBB Baa 91,432 90,332 (1,100 ) 9.1 % 3 BB Ba 15,455 15,211 (244 ) 2.0 % 4 B B 23,628 23,131 (497 ) 4.1 % 5 CCC Caa 1,217 1,191 (26 ) 0.2 % 6 CC or lower Ca or lower - - - 0.0 % Total $ 622,803 $ 610,730 $ (12,073 ) 100.0 %

Historical Loss And LAE Devel_2

Historical Loss And LAE Development (Tables)	9 Months Ended
	Sep. 30, 2021
Historical Loss And L A E Development Disclosure [Abstract]
Schedule of Reconciliation of Unpaid Losses and Settlement Expenses (LAE)	The following table is a reconciliation of our unpaid losses and settlement expenses (LAE) for the first nine months of 2021 and 2020: For the Nine Months Ended September 30, (in thousands) 2021 2020 Unpaid losses and LAE at beginning of year Gross $ 1,750,049 $ 1,574,352 Ceded (443,729 ) (384,517 ) Net $ 1,306,320 $ 1,189,835 Adoption impact of ASU 2016-13 on reinsurance balances recoverable $ — $ (1,345 ) Increase (decrease) in incurred losses and LAE Current accident year $ 452,542 $ 409,867 Prior accident years (96,968 ) (70,048 ) Total incurred $ 355,574 $ 339,819 Loss and LAE payments for claims incurred Current accident year $ (58,411 ) $ (49,337 ) Prior accident years (172,120 ) (192,056 ) Total paid $ (230,531 ) $ (241,393 ) Net unpaid losses and LAE at September 30 $ 1,431,363 $ 1,286,916 Unpaid losses and LAE at September 30 Gross $ 2,033,517 $ 1,686,876 Ceded (602,154 ) (399,960 ) Net $ 1,431,363 $ 1,286,916

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2021
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, For the Nine Months Ended September 30, 2021 2020 2021 2020 (in thousands) Amount % Amount % Amount % Amount % Provision for income taxes at the statutory rate of 21% $ 7,442 21.0 % $ 10,817 21.0 % $ 47,731 21.0 % $ 18,275 21.0 % Increase (reduction) in taxes resulting from: Excess tax benefit on share-based compensation (225 ) (0.6 ) % (848 ) (1.6 ) % (2,419 ) (1.1 ) % (2,141 ) (2.4 ) % Tax exempt interest income (298 ) (0.8 ) % (324 ) (0.6 ) % (927 ) (0.4 ) % (960 ) (1.1 ) % Dividends received deduction (223 ) (0.6 ) % (221 ) (0.4 ) % (707 ) (0.3 ) % (705 ) (0.8 ) % Investment tax credit (801 ) (2.3 ) % (316 ) (0.6 ) % (2,404 ) (1.0 ) % (1,766 ) (2.0 ) % ESOP dividends paid deduction (132 ) (0.4 ) % (134 ) (0.3 ) % (399 ) (0.2 ) % (403 ) (0.5 ) % Nondeductible expenses 642 1.8 % 275 0.5 % 1,879 0.8 % 639 0.7 % Other items, net (211 ) (0.6 ) % (127 ) (0.3 ) % 468 0.2 % 799 0.9 % Total tax expense $ 6,194 17.5 % $ 9,122 17.7 % $ 43,222 19.0 % $ 13,738 15.8 %

Stock Based Compensation (Table

Stock Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Option Activity	The following tables summarize option activity for the nine-month period ended September 30, 2021: Weighted Aggregate Weighted Average Intrinsic Average Remaining Value Options Exercise Price Contractual Life (in 000’s) Outstanding options at January 1, 2021 1,632,334 $ 70.67 Options granted 236,771 109.64 Options exercised (148,247 ) 55.82 Options canceled/forfeited (8,215 ) 84.29 Outstanding options at September 30, 2021 1,712,643 $ 77.27 5.03 $ 41,702 Exercisable options at September 30, 2021 804,575 $ 65.36 3.74 $ 28,093
Summary of Weighted Average Grant-date Assumptions and Weighted Average Fair Values	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: 2021 2020 Weighted-average fair value of grants $ 17.01 $ 13.33 Risk-free interest rates 0.70 % 0.41 % Dividend yield 2.06 % 2.30 % Expected volatility 22.73 % 22.67 % Expected option life 4.97 years 4.96 years
Schedule of Restricted Stock Units Activity	Weighted Average Grant Date RSUs Fair Value Nonvested at January 1, 2021 47,658 $ 81.53 Granted 16,780 113.02 Reinvested 322 105.00 Vested (19,725 ) 72.53 Forfeited (789 ) 95.53 Nonvested at September 30, 2021 44,246 $ 97.41

Operating Segment Information (

Operating Segment Information (Tables)	9 Months Ended
	Sep. 30, 2021
Segment Reporting [Abstract]
Summary of Selected Information by Operating Segment	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) 2021 2020 2021 2020 Casualty $ 162,852 $ 143,002 $ 467,817 $ 421,637 Property 60,886 45,380 168,393 135,115 Surety 29,651 28,248 86,774 84,194 Net premiums earned $ 253,389 $ 216,630 $ 722,984 $ 640,946 Net investment income 17,844 16,543 50,929 51,238 Net realized gains 1,829 1,512 52,442 14,555 Net unrealized gains (losses) on equity securities (2,592 ) 28,126 29,526 (27,564 ) Total consolidated revenue $ 270,470 $ 262,811 $ 855,881 $ 679,175 Net Earnings (in thousands) 2021 2020 2021 2020 Casualty $ 22,949 $ 13,993 $ 74,254 $ 22,403 Property (16,558 ) (19,951 ) (8,684 ) (3,876 ) Surety 7,333 7,110 14,662 24,027 Net underwriting income $ 13,724 $ 1,152 $ 80,232 $ 42,554 Net investment income 17,844 16,543 50,929 51,238 Net realized gains 1,829 1,512 52,442 14,555 Net unrealized gains (losses) on equity securities (2,592 ) 28,126 29,526 (27,564 ) General corporate expense and interest on debt (4,411 ) (4,569 ) (15,244 ) (12,118 ) Equity in earnings of unconsolidated investees 9,043 8,745 29,407 18,359 Earnings before income taxes $ 35,437 $ 51,509 $ 227,292 $ 87,024 Income tax expense 6,194 9,122 43,222 13,738 Net earnings $ 29,243 $ 42,387 $ 184,070 $ 73,286
Summary of Revenue by Major Product Type	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) 2021 2020 2021 2020 Casualty Commercial excess and personal umbrella $ 56,285 $ 46,404 $ 161,287 $ 128,813 General liability 23,156 22,747 67,616 69,396 Professional services 22,401 21,422 66,095 63,501 Commercial transportation 22,571 15,130 60,926 47,454 Small commercial 16,301 16,009 48,302 47,433 Executive products 5,461 6,387 15,785 20,693 Other casualty 16,677 14,903 47,806 44,347 Total $ 162,852 $ 143,002 $ 467,817 $ 421,637 Property Commercial property $ 28,683 $ 20,168 $ 76,488 $ 58,371 Marine 25,416 19,687 72,737 59,976 Specialty personal 5,462 4,794 15,761 14,730 Other property 1,325 731 3,407 2,038 Total $ 60,886 $ 45,380 $ 168,393 $ 135,115 Surety Commercial $ 11,541 $ 10,543 $ 33,594 $ 32,287 Miscellaneous 11,124 10,547 32,604 31,562 Contract 6,986 7,158 20,576 20,345 Total $ 29,651 $ 28,248 $ 86,774 $ 84,194 Grand Total $ 253,389 $ 216,630 $ 722,984 $ 640,946

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Schedule of Components of Lease Expense and Other lease Information	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, 2021 and 2020 are as follows: For the Three Months For the Nine Months Ended September 30, Ended September 30, (in thousands) 2021 2020 2021 2020 Operating lease cost $ 1,326 $ 1,364 $ 4,005 $ 4,140 Variable lease cost 348 338 1,090 1,014 Sublease income (123 ) (96 ) (369 ) (139 ) Total lease cost $ 1,551 $ 1,606 $ 4,726 $ 5,015 Cash paid for amounts included in measurement of lease liabilities Operating cash outflows from operating leases $ 1,490 $ 1,480 $ 4,455 $ 4,470 ROU assets obtained in exchange for new operating lease liabilities $ 4,434 $ — $ 4,699 $ 15 Reduction to ROU assets resulting from reduction to lease liabilities $ — $ 18 $ 1,250 $ 18 Other non-cash reductions to ROU assets $ 48 $ — $ 48 $ 1,192 (in thousands) September 30, 2021 December 31, 2020 Operating lease ROU assets $ 15,882 $ 16,200 Operating lease liabilities $ 18,148 $ 19,072 Weighted-average remaining lease term - operating leases 4.58 years 3.87 years Weighted-average discount rate - operating leases 2.05 % 2.32 %
Schedule of Future Minimum Lease Payments under Non-cancellable Leases	Future minimum lease payments under non-cancellable leases as of September 30, 2021 were as follows: (in thousands) September 30, 2021 2021 $ 1,283 2022 5,475 2023 4,901 2024 2,871 2025 1,462 2026 884 Thereafter 2,176 Total future minimum lease payments $ 19,052 Less imputed interest (904 ) Total operating lease liability $ 18,148

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Reinsurance - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Ceded Credit Risk [Line Items]
Amount of allowance for uncollectible amounts on paid recoverables	$ 16,100,000	$ 15,900,000
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	10,067,000	$ 8,634,000
Financing Receivable, Allowance for Credit Loss, Writeoff	0
Financing receivable with due date extend 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, 2021	Dec. 31, 2020
Business Acquisition [Line Items]
Goodwill	$ 46,062	$ 46,062
Indefinite-lived intangibles - state insurance licenses	7,500	7,500
Definite-lived intangibles, net of accumulated amortization of $4,035 at 9/30/21 and $3,878 at 12/31/20		157
Total intangibles	7,500	7,657
Total goodwill and intangibles	53,562	53,719
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 - Schedule of Goodwill and Intangible Assets (Parenthetical) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Accumulated amortization of definite-lived intangibles	$ 4,035	$ 3,878

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Intangible Assets - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Amortization of intangible assets		$ 100,000	$ 200,000	$ 300,000
Goodwill and intangible asset impairment			$ 0
Maximum
Business Acquisition [Line Items]
Amortization of intangible assets	$ 100,000

Summary of Significant Accoun_8

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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Basic EPS, Income (Numerator)
Earnings available to common shareholders	$ 29,243	$ 42,387	$ 184,070	$ 73,286
Diluted EPS, Income (Numerator)
Earnings available to common shareholders	$ 29,243	$ 42,387	$ 184,070	$ 73,286
Basic EPS, Weighted Average Shares (Denominator)
Number of shares outstanding	45,243	45,014	45,216	44,962
Effect of Dilutive Securities, Shares (Denominator)
Stock options and restricted stock units	446	412	498	377
Diluted EPS, Weighted Average Shares (Denominator)
Number of shares outstanding	45,689	45,426	45,714	45,339
Earnings Per Share, Diluted, Other Disclosures
Anti-dilutive options excluded from diluted EPS	191	339	191	339
Basic EPS, Per Share Amount
Basic net earnings per share (in dollars per share)	$ 0.65	$ 0.94	$ 4.07	$ 1.63
Diluted EPS, Per Share Amount
Diluted earnings per share (in dollars per share)	$ 0.64	$ 0.93	$ 4.03	$ 1.62

Summary of Significant Accoun_9

Summary of Significant Accounting Policies - Comprehensive Earnings - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
COMPREHENSIVE EARNINGS
Tax rate used (as a percent)	21.00%			21.00%			21.00%	21.00%
Other comprehensive income (loss), tax expense (benefit)	$ (3,200)			$ 2,500			$ (11,100)	$ 13,300
Changes in the balance of each component of accumulated other comprehensive earnings
Other comprehensive earnings (loss), net of tax	$ (12,240)	$ 15,177	$ (44,747)	$ 9,550	$ 53,571	$ (13,031)	$ (41,810)	$ 50,090

Summary of Significant Accou_10

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, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Changes in the balance of each component of accumulated other comprehensive earnings
Beginning balance			$ 108,714				$ 108,714
Accounting Standards Update [Extensible List]						ASU 2016-13
Net current-period other comprehensive earnings (loss)	$ (12,240)	$ 15,177	(44,747)	$ 9,550	$ 53,571	$ (13,031)	(41,810)	$ 50,090
Ending balance	66,904						66,904
Balance of securities for which an allowance for credit losses has been recognized in net earnings	426			795			426	795
Unrealized Gains and Losses on Available-for-Sale Securities
Changes in the balance of each component of accumulated other comprehensive earnings
Beginning balance	79,144		108,714	93,035		52,473	108,714	52,473
Other comprehensive earnings (loss) before reclassifications	(12,114)			10,412			(40,307)	52,264
Amounts reclassified from accumulated other comprehensive earnings	(126)			(862)			(1,503)	(2,174)
Ending balance	$ 66,904	79,144		$ 102,585	93,035		$ 66,904	102,585
Unrealized Gains and Losses on Available-for-Sale Securities | Cumulative Effect, Period of Adoption, Adjustment
Changes in the balance of each component of accumulated other comprehensive earnings
Beginning balance						22		$ 22
Accounting Standards Update [Extensible List]	ASU 2016-13			ASU 2016-13			ASU 2016-13	ASU 2016-13
Unrealized Gains and Losses on Available-for-Sale Securities | Cumulative Effect, Period of Adoption, Adjusted Balance
Changes in the balance of each component of accumulated other comprehensive earnings
Beginning balance	$ 79,144		$ 108,714	$ 93,035		$ 52,495	$ 108,714	$ 52,495
Ending balance		$ 79,144			$ 93,035

Summary of Significant Accou_11

Summary of Significant Accounting Policies - Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment Out of Accumulated Other Comprehensive Income
Net realized gains	$ 1,829			$ 1,512			$ 52,442	$ 14,555
Earnings before income taxes	35,437			51,509			227,292	87,024
Income tax expense	(6,194)			(9,122)			(43,222)	(13,738)
Net earnings	29,243	$ 81,815	$ 73,012	42,387	$ 92,166	$ (61,267)	184,070	73,286
Unrealized Gains and Losses on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out of Accumulated Other Comprehensive Income
Net realized gains	182			738			1,731	3,356
Credit losses on available-for-sale securities	(22)			353			171	(604)
Earnings before income taxes	160			1,091			1,902	2,752
Income tax expense	(34)			(229)			(399)	(578)
Net earnings	$ 126			$ 862			$ 1,503	$ 2,174

Investments - Disposition of Fi

Investments - Disposition of Fixed Income and Equity Securities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Sales | Debt Securities | Available for sale securities
Summary of the disposition of fixed income and equity securities
Proceeds From Sales	$ 43,041	$ 68,621
Gross Realized Gains	1,476	4,959
Gross Realized Losses	(107)	(1,518)
Net Realized Gain (Loss)	1,369	3,441
Sales | Equity Securities
Summary of the disposition of fixed income and equity securities
Proceeds From Sales	157,973	66,185
Gross Realized Gains	52,409	22,172
Gross Realized Losses	(1,787)	(8,756)
Net Realized Gain (Loss)	50,622	13,416
Calls/Maturities | Debt Securities | Available for sale securities
Summary of the disposition of fixed income and equity securities
Proceeds From Sales	296,563	199,036
Gross Realized Gains	471	525
Gross Realized Losses	(109)	(10)
Net Realized Gain (Loss)	$ 362	$ 515

Investments - Assets Measured a

Investments - Assets Measured at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets measured at Fair Value
Available-for-sale fixed income	$ 2,394,669	$ 2,196,626
Equity securities	565,238	524,006
Municipal
Assets measured at Fair Value
Available-for-sale fixed income	624,232	532,396
Fair Value Measured on Recurring Basis
Assets measured at Fair Value
Available-for-sale fixed income	2,394,669	2,196,626
Equity securities	565,238	524,006
Other invested assets		6,068
Total assets at fair value	2,959,907	2,726,700
Fair Value Measured on Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets measured at Fair Value
Equity securities	565,163	523,923
Other invested assets		6,068
Total assets at fair value	565,163	529,991
Fair Value Measured on Recurring Basis | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	2,363,133	2,178,828
Equity securities	75	83
Total assets at fair value	2,363,208	2,178,911
Fair Value Measured on Recurring Basis | Significant Unobservable Inputs (Level 3)
Assets measured at Fair Value
Available-for-sale fixed income	31,536	17,798
Total assets at fair value	31,536	17,798
Fair Value Measured on Recurring Basis | U.S. government
Assets measured at Fair Value
Available-for-sale fixed income	147,193	183,357
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	147,193	183,357
Fair Value Measured on Recurring Basis | U.S. Agency
Assets measured at Fair Value
Available-for-sale fixed income	31,625	32,872
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	31,625	32,872
Fair Value Measured on Recurring Basis | Non-U.S. government & agency
Assets measured at Fair Value
Available-for-sale fixed income	8,521	10,965
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	8,521	10,965
Fair Value Measured on Recurring Basis | Agency MBS
Assets measured at Fair Value
Available-for-sale fixed income	394,270	402,071
Fair Value Measured on Recurring Basis | Agency MBS | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	394,270	402,071
Fair Value Measured on Recurring Basis | ABS/CMBS/MBS
Assets measured at Fair Value
Available-for-sale fixed income	250,558	218,373
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	250,558	218,373
Fair Value Measured on Recurring Basis | Corporate Debt
Assets measured at Fair Value
Available-for-sale fixed income	938,270	816,592
Fair Value Measured on Recurring Basis | Corporate Debt | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	906,734	798,794
Fair Value Measured on Recurring Basis | Corporate Debt | Significant Unobservable Inputs (Level 3)
Assets measured at Fair Value
Available-for-sale fixed income	31,536	17,798
Fair Value Measured on Recurring Basis | Municipal
Assets measured at Fair Value
Available-for-sale fixed income	624,232	532,396
Fair Value Measured on Recurring Basis | Municipal | Significant Other Observable Inputs (Level 2)
Assets measured at Fair Value
Available-for-sale fixed income	$ 624,232	$ 532,396

Investments - Summary of Change

Investments - Summary of Changes in Balance of Level 3 securities (Details) - Regulation D Private Placement Fixed Income Securities $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Summary of changes in Level 3 securities
Beginning balance	$ 17,798
Net investment income	(39)
Net realized gains	(115)
Included in other comprehensive earnings (loss)	(88)
Total net realized and unrealized gains (losses)	(242)
Purchases	13,980
Ending balance	31,536
Net Realized Gains (Losses)
Summary of changes in Level 3 securities
Change in unrealized gains (losses) during the period for Level 3 assets held at period-end	(115)
Other Comprehensive Earnings (Loss)
Summary of changes in Level 3 securities
Change in unrealized gains (losses) during the period for Level 3 assets held at period-end	$ (88)

Investments - Amortized Cost an

Investments - Amortized Cost and Fair Value of Available-for-sale Fixed Income Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Amortized Cost
Due in one year or less	$ 73,089
Due after one year through five years	587,559
Due after five years through 10 years	551,943
Due after 10 years	464,725
ABS/CMBS/MBS	632,998
Total available-for-sale	2,310,314	$ 2,061,467
Fair Value
Due in one year or less	73,903
Due after one year through five years	614,447
Due after five years through 10 years	581,761
Due after 10 years	479,730
ABS/CMBS/MBS	644,828
Total available-for-sale	$ 2,394,669	$ 2,196,626

Investments - Additional Inform

Investments - Additional Information (Details) $ in Thousands	Sep. 30, 2021USD ($)security	Dec. 31, 2020USD ($)
Investment Holdings [Line Items]
Accrued investment income | $	$ 17,143	$ 16,126
ASU 2016-13
Investment Holdings [Line Items]
Change in accounting principle accounting standards update adopted	true
Change in accounting principle accounting standards update adoption date	Jan. 1, 2020
Debt Securities
Investment Holdings [Line Items]
Accrued investment income | $	$ 15,900	14,900
Number of debt securities for which there is an allowance for credit losses	11
Number of debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded	327
Unrealized loss | $	$ 12,073	$ 2,554
Unrealized losses as percentage of fixed income portfolio cost basis	0.50%
Unrealized losses relative to total invested assets (as a percent)	0.40%
Number of unrealized loss positions	327
Number of securities in unrealized loss positions for 12 months or longer	39

Investments - Amortized Cost _2

Investments - Amortized Cost and Fair Value of Available-for-sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	$ 2,310,314		$ 2,061,467
Allowance for Credit Losses	(226)	$ (204)	(397)	$ (632)	$ (985)	$ 0
Gross Unrealized Gains	96,654		138,110
Gross Unrealized Losses	(12,073)		(2,554)
Fair Value	2,394,669		2,196,626
U.S. government
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	139,441		170,110
Gross Unrealized Gains	8,549		13,504
Gross Unrealized Losses	(797)		(257)
Fair Value	147,193		183,357
U.S. Agency
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	28,844		28,902
Gross Unrealized Gains	2,781		3,970
Fair Value	31,625		32,872
Non-U.S. government & agency
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	8,297		10,298
Gross Unrealized Gains	407		667
Gross Unrealized Losses	(183)
Fair Value	8,521		10,965
Agency MBS
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	385,400		384,015
Gross Unrealized Gains	12,179		18,789
Gross Unrealized Losses	(3,309)		(733)
Fair Value	394,270		402,071
ABS/CMBS/MBS
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	247,598		213,223
Allowance for Credit Losses			(17)
Gross Unrealized Gains	3,915		5,580
Gross Unrealized Losses	(955)		(413)
Fair Value	250,558		218,373
Corporate Debt
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	896,178		753,404
Allowance for Credit Losses	(226)		(380)
Gross Unrealized Gains	45,230		64,501
Gross Unrealized Losses	(2,912)		(933)
Fair Value	938,270		816,592
Municipal
Schedule Of Available For Sale Securities [Line Items]
Total available-for-sale	604,556		501,515
Gross Unrealized Gains	23,593		31,099
Gross Unrealized Losses	(3,917)		(218)
Fair Value	$ 624,232		$ 532,396

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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Investment Holdings [Line Items]
Beginning balance	$ 204	$ 985	$ 397	$ 0
Increase to allowance from securities for which credit losses were not previously recorded		17		751
Reduction from securities sold during the period		(6)		(116)
Reductions from intent to sell securities		(186)		(186)
Net increase (decrease) from securities that had an allowance at the beginning of the period	22	(178)	(171)	155
Balance as of September 30,	$ 226	$ 632	$ 226	632
ASU 2016-13
Investment Holdings [Line Items]
Beginning balance				$ 28

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, 2021	Dec. 31, 2020
U.S. government
Fair Value
Less than 12 months	$ 2,976	$ 5,680
12 months and greater	5,152
Total Fair Value	8,128	5,680
Amortized Cost
Amortized cost, less than 12 months	2,986	5,937
12 months and greater	5,939
Total Cost or Amortized Cost	8,925	5,937
Unrealized Loss
Less than 12 months	(10)	(257)
12 months and greater	(787)
Total Unrealized Loss	(797)	(257)
U.S. Agency
Fair Value
Less than 12 months	1,003
Total Fair Value	1,003
Amortized Cost
Amortized cost, less than 12 months	1,003
Total Cost or Amortized Cost	1,003
Non-U.S. government & agency
Fair Value
Less than 12 months	2,817
Total Fair Value	2,817
Amortized Cost
Amortized cost, less than 12 months	3,000
Total Cost or Amortized Cost	3,000
Unrealized Loss
Less than 12 months	(183)
Total Unrealized Loss	(183)
Agency MBS
Fair Value
Less than 12 months	128,783	43,999
12 months and greater	15,940
Total Fair Value	144,723	43,999
Amortized Cost
Amortized cost, less than 12 months	131,277	44,732
12 months and greater	16,755
Total Cost or Amortized Cost	148,032	44,732
Unrealized Loss
Less than 12 months	(2,494)	(733)
12 months and greater	(815)
Total Unrealized Loss	(3,309)	(733)
ABS/CMBS/MBS
Fair Value
Less than 12 months	92,083	32,771
12 months and greater	3,832	16,161
Total Fair Value	95,915	48,932
Amortized Cost
Amortized cost, less than 12 months	93,020	33,094
12 months and greater	3,850	16,251
Total Cost or Amortized Cost	96,870	49,345
Unrealized Loss
Less than 12 months	(937)	(323)
12 months and greater	(18)	(90)
Total Unrealized Loss	(955)	(413)
Corporate Debt
Fair Value
Less than 12 months	173,508	52,655
12 months and greater	18,574	6,235
Total Fair Value	192,082	58,890
Amortized Cost
Amortized cost, less than 12 months	175,695	53,440
12 months and greater	19,299	6,383
Total Cost or Amortized Cost	194,994	59,823
Unrealized Loss
Less than 12 months	(2,187)	(785)
12 months and greater	(725)	(148)
Total Unrealized Loss	(2,912)	(933)
Municipal
Fair Value
Less than 12 months	154,883	25,676
12 months and greater	11,179
Total Fair Value	166,062	25,676
Amortized Cost
Amortized cost, less than 12 months	158,310	25,894
12 months and greater	11,669
Total Cost or Amortized Cost	169,979	25,894
Unrealized Loss
Less than 12 months	(3,427)	(218)
12 months and greater	(490)
Total Unrealized Loss	(3,917)	(218)
Debt Securities
Fair Value
Less than 12 months	556,053	160,781
12 months and greater	54,677	22,396
Total Fair Value	610,730	183,177
Amortized Cost
Amortized cost, less than 12 months	565,291	163,097
12 months and greater	57,512	22,634
Total Cost or Amortized Cost	622,803	185,731
Unrealized Loss
Less than 12 months	(9,238)	(2,316)
12 months and greater	(2,835)	(238)
Total Unrealized Loss	$ (12,073)	$ (2,554)

Investments - Unrealized Losses

Investments - Unrealized Losses (Details) - Debt Securities - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cost or amortized Cost
Total Cost or Amortized Cost	$ 622,803	$ 185,731
Fair value
Total Fair Value	610,730	183,177
Unrealized Loss
Total Unrealized Loss	$ (12,073)	$ (2,554)
Percent to Total	100.00%
NAIC Rating 1 | AAA/AA/A | Aaa/Aa/A
Cost or amortized Cost
Total Cost or Amortized Cost	$ 491,071
Fair value
Total Fair Value	480,865
Unrealized Loss
Total Unrealized Loss	$ (10,206)
Percent to Total	84.60%
NAIC Rating 2 | BBB | Baa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 91,432
Fair value
Total Fair Value	90,332
Unrealized Loss
Total Unrealized Loss	$ (1,100)
Percent to Total	9.10%
NAIC Rating 3 | BB | Ba
Cost or amortized Cost
Total Cost or Amortized Cost	$ 15,455
Fair value
Total Fair Value	15,211
Unrealized Loss
Total Unrealized Loss	$ (244)
Percent to Total	2.00%
NAIC Rating 4 | B | B
Cost or amortized Cost
Total Cost or Amortized Cost	$ 23,628
Fair value
Total Fair Value	23,131
Unrealized Loss
Total Unrealized Loss	$ (497)
Percent to Total	4.10%
NAIC Rating 5 | CCC | Caa
Cost or amortized Cost
Total Cost or Amortized Cost	$ 1,217
Fair value
Total Fair Value	1,191
Unrealized Loss
Total Unrealized Loss	$ (26)
Percent to Total	0.20%
NAIC Six Rating Member | Standard Poors CC Or Lower Member | Ca
Unrealized Loss
Percent to Total	0.00%

Investments - Allowance for Cre

Investments - Allowance for Credit Losses, Unrealized Losses on Securities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Equity Securities
Investment Holdings [Line Items]
Net unrealized gains (losses) on equity securities still held	$ (0.8)	$ 28.7	$ 80.1	$ (14.1)

Investments - Debt and Short-te

Investments - Debt and Short-term Investments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Investment Holdings [Line Items]
Other investments	$ 52,480,000		$ 52,480,000		$ 54,232,000
Investment in federal home loan bank stock	us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember
Cash and Short-term Investments
Investment amount	$ 158,721,000		$ 158,721,000		$ 128,382,000
Cash	89,618,000		89,618,000		62,217,000
Other Investments in Unconsolidated Investees
Cash and Short-term Investments
Investment amount	5,700,000		5,700,000
Unfunded commitments	15,000,000		15,000,000
Maui Jim Inc.
Cash and Short-term Investments
Investment amount	110,600,000		110,600,000
Prime Holdings Insurance Services, Inc. (Prime)
Cash and Short-term Investments
Investment amount	42,400,000		42,400,000
FHLBC
Investment Holdings [Line Items]
Investments pledged as collateral	9,100,000		9,100,000
Federal home loan bank borrowings fair value disclosure	0		0
Investment In Low Income Housing Tax Credit Partnership Net Of Amortization
Investment Holdings [Line Items]
Other investments	17,400,000		17,400,000		20,300,000
Total tax benefit on investments in housing tax credit partnership	900,000	$ 900,000	2,700,000	$ 2,600,000
Qualified affordable housing project investments, commitment	2,100,000		2,100,000
Investment in Private Funds
Investment Holdings [Line Items]
Other investments	31,400,000		31,400,000		$ 32,100,000
Fair value investments entities that calculate net asset value per share unfunded commitments	$ 9,600,000		$ 9,600,000

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, 2021	Sep. 30, 2020
Unpaid losses and LAE at beginning of year
Gross	$ 1,750,049	$ 1,574,352
Ceded	(443,729)	(384,517)
Net	1,306,320	1,189,835
Increase (decrease) in incurred losses and LAE
Current accident year	452,542	409,867
Prior accident years	(96,968)	(70,048)
Total incurred	355,574	339,819
Loss and LAE payments for claims incurred
Current accident year	(58,411)	(49,337)
Prior accident years	(172,120)	(192,056)
Total paid	(230,531)	(241,393)
Net unpaid losses and LAE at September 30	1,431,363	1,286,916
Unpaid losses and LAE at September 30
Gross	2,033,517	1,686,876
Ceded	(602,154)	(399,960)
Net unpaid losses and LAE at September 30	$ 1,431,363	1,286,916
ASU 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
Unpaid losses and LAE at beginning of year
Ceded		$ (1,345)

Historical Loss and LAE Devel_4

Historical Loss and LAE Development - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
(Favorable)/Unfavorable Reserve Development
Unpaid losses and LAE, Ceded	$ 602,154	$ 399,960	$ 443,729	$ 384,517
Favorable development on prior years' loss reserves	$ 96,968	$ 70,048
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
(Favorable)/Unfavorable Reserve Development
Unpaid losses and LAE, Ceded				$ 1,345

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation, percent, total	17.50%	17.70%	19.00%	15.80%
U.S. federal tax rate	21.00%	21.00%	21.00%	21.00%

Income Taxes - Schedule of Reco

Income Taxes - 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 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
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	$ 7,442	$ 10,817	$ 47,731	$ 18,275
Increase (reduction) in taxes resulting from:
Excess tax benefit on share-based compensation	(225)	(848)	(2,419)	(2,141)
Tax exempt interest income	(298)	(324)	(927)	(960)
Dividends received deduction	(223)	(221)	(707)	(705)
Investment tax credit	(801)	(316)	(2,404)	(1,766)
ESOP dividends paid deduction	(132)	(134)	(399)	(403)
Nondeductible expenses	642	275	1,879	639
Other items, net	(211)	(127)	468	799
Total tax expense	$ 6,194	$ 9,122	$ 43,222	$ 13,738
Reconciliation of income tax expense rate to the U.S. federal tax rate
Tax rate used (as a percent)	21.00%	21.00%	21.00%	21.00%
Excess tax benefit on share-based compensation (as a percent)	(0.60%)	(1.60%)	(1.10%)	(2.40%)
Effective rate reduction due to tax exempt interest income (as a percent)	(0.80%)	(0.60%)	(0.40%)	(1.10%)
Effective rate reduction due to dividend received (as a percent)	(0.60%)	(0.40%)	(0.30%)	(0.80%)
Effective rate reduction due to investment tax credit (as a percent)	(2.30%)	(0.60%)	(1.00%)	(2.00%)
Effective rate reduction due to dividend paid to ESOP (as a percent)	(0.40%)	(0.30%)	(0.20%)	(0.50%)
Effective rate reduction due to nondeductible expenses (as a percent)	1.80%	0.50%	0.80%	0.70%
Effective rate reduction due to other items, net (as a percent)	(0.60%)	(0.30%)	0.20%	0.90%
Total tax expense	17.50%	17.70%	19.00%	15.80%

Stock Based Compensation - Stoc

Stock Based Compensation - Stock Plans - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		60 Months Ended	77 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	May 06, 2015	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options granted (in shares)			236,771
Aggregate Intrinsic Value, Options exercised			$ 8.4	$ 7.6
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)			253,551			2,876,920
Stock-based compensation expenses	$ 1.6	$ 1.6	$ 4.8	3.6
Income tax benefit from stock-based compensation	0.2	$ 0.3	0.7	$ 0.6
Unrecognized stock-based compensation expense	$ 7.2		$ 7.2			$ 7.2
Stock-based compensation expenses, recognition period			2 years 4 months 28 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, 2021USD ($)$ / sharesshares	Sep. 30, 2020USD ($)
Weighted Number of Options Outstanding
Outstanding options, Beginning Balance | shares	1,632,334
Options granted (in shares) | shares	236,771
Options exercised | shares	(148,247)
Options canceled/forfeited | shares	(8,215)
Outstanding options, Ending Balance | shares	1,712,643
Exercisable options, Ending Balance | shares	804,575
Weighted Average Exercise Price
Weighted Average Exercise Price, Outstanding options, Beginning Balance | $ / shares	$ 70.67
Weighted Average Exercise Price, Options granted | $ / shares	109.64
Weighted Average Exercise Price, Options exercised | $ / shares	55.82
Weighted Average Exercise Price, Options canceled/forfeited | $ / shares	84.29
Weighted Average Exercise Price, Outstanding options, Ending Balance | $ / shares	77.27
Weighted Average Exercise Price, Exercisable options | $ / shares	$ 65.36
Weighted Average Remaining Contractual Life
Weighted Average Remaining Contractual Life, Outstanding options	5 years 10 days
Weighted Average Remaining Contractual Life, Exercisable options	3 years 8 months 26 days
Aggregate Intrinsic Value, Options exercised | $	$ 8,400	$ 7,600
Aggregate Intrinsic Value, Outstanding options | $	41,702
Aggregate Intrinsic Value, Exercisable options | $	$ 28,093

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, 2021	Sep. 30, 2020
Weighted average grant date assumptions and weighted average fair value
Weighted-average fair value of grants	$ 17.01	$ 13.33
Risk-free interest rates	0.70%	0.41%
Dividend yield	2.06%	2.30%
Expected volatility	22.73%	22.67%
Expected option life	4 years 11 months 19 days	4 years 11 months 15 days

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Stock Units - Additional Information (Details) - Restricted Stock Units (RSUs) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
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	$ 2.2	$ 1.5
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) shares in Thousands	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Number of RSUs
RSUs Nonvested, Beginning Balance | shares	47,658
RSUs Granted | shares	16,780
RSUs Reinvested | shares	322
RSUs Vested | shares	(19,725)
RSUs Forfeited | shares	(789)
RSUs Nonvested, Ending Balance | shares	44,246
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Nonvested, Beginning Balance | $ / shares	$ 81.53
Weighted Average Grant Date Fair Value, Granted | $ / shares	113.02
Weighted Average Grant Date Fair Value, Reinvested | $ / shares	105
Weighted Average Grant Date Fair Value, Vested | $ / shares	72.53
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	95.53
Weighted Average Grant Date Fair Value, Nonvested, Ending Balance | $ / shares	$ 97.41

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, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues
Net premiums earned	$ 253,389			$ 216,630			$ 722,984	$ 640,946
Net investment income	17,844			16,543			50,929	51,238
Net realized gains	1,829			1,512			52,442	14,555
Net unrealized gains (losses) on equity securities	(2,592)			28,126			29,526	(27,564)
Consolidated revenue	270,470			262,811			855,881	679,175
Net Earnings
Net underwriting income	13,724			1,152			80,232	42,554
Net investment income	17,844			16,543			50,929	51,238
Net realized gains	1,829			1,512			52,442	14,555
Net unrealized gains (losses) on equity securities	(2,592)			28,126			29,526	(27,564)
General corporate expense and interest on debt	(4,411)			(4,569)			(15,244)	(12,118)
Equity in earnings of unconsolidated investees	9,043			8,745			29,407	18,359
Earnings before income taxes	35,437			51,509			227,292	87,024
Income tax expense	6,194			9,122			43,222	13,738
Net earnings	29,243	$ 81,815	$ 73,012	42,387	$ 92,166	$ (61,267)	184,070	73,286
Casualty Segment
Revenues
Net premiums earned	162,852			143,002			467,817	421,637
Net Earnings
Net underwriting income	22,949			13,993			74,254	22,403
Property Segment
Revenues
Net premiums earned	60,886			45,380			168,393	135,115
Net Earnings
Net underwriting income	(16,558)			(19,951)			(8,684)	(3,876)
Surety Segment
Revenues
Net premiums earned	29,651			28,248			86,774	84,194
Net Earnings
Net underwriting income	$ 7,333			$ 7,110			$ 14,662	$ 24,027

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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Net premiums earned	$ 253,389	$ 216,630	$ 722,984	$ 640,946
Casualty Segment
Segment Reporting Information [Line Items]
Net premiums earned	162,852	143,002	467,817	421,637
Casualty Segment | Commercial excess and personal umbrella
Segment Reporting Information [Line Items]
Net premiums earned	56,285	46,404	161,287	128,813
Casualty Segment | General liability
Segment Reporting Information [Line Items]
Net premiums earned	23,156	22,747	67,616	69,396
Casualty Segment | Professional services
Segment Reporting Information [Line Items]
Net premiums earned	22,401	21,422	66,095	63,501
Casualty Segment | Commercial transportation
Segment Reporting Information [Line Items]
Net premiums earned	22,571	15,130	60,926	47,454
Casualty Segment | Small commercial
Segment Reporting Information [Line Items]
Net premiums earned	16,301	16,009	48,302	47,433
Casualty Segment | Executive products
Segment Reporting Information [Line Items]
Net premiums earned	5,461	6,387	15,785	20,693
Casualty Segment | Other casualty
Segment Reporting Information [Line Items]
Net premiums earned	16,677	14,903	47,806	44,347
Property Segment
Segment Reporting Information [Line Items]
Net premiums earned	60,886	45,380	168,393	135,115
Property Segment | Marine
Segment Reporting Information [Line Items]
Net premiums earned	25,416	19,687	72,737	59,976
Property Segment | Commercial property
Segment Reporting Information [Line Items]
Net premiums earned	28,683	20,168	76,488	58,371
Property Segment | Specialty personal
Segment Reporting Information [Line Items]
Net premiums earned	5,462	4,794	15,761	14,730
Property Segment | Other property
Segment Reporting Information [Line Items]
Net premiums earned	1,325	731	3,407	2,038
Surety Segment
Segment Reporting Information [Line Items]
Net premiums earned	29,651	28,248	86,774	84,194
Surety Segment | Commercial
Segment Reporting Information [Line Items]
Net premiums earned	11,541	10,543	33,594	32,287
Surety Segment | Miscellaneous
Segment Reporting Information [Line Items]
Net premiums earned	11,124	10,547	32,604	31,562
Surety Segment | Contract
Segment Reporting Information [Line Items]
Net premiums earned	$ 6,986	$ 7,158	$ 20,576	$ 20,345

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, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Leases [Abstract]
Operating lease cost	$ 1,326	$ 1,364	$ 4,005	$ 4,140
Variable lease cost	348	338	1,090	1,014
Sublease income	(123)	(96)	(369)	(139)
Total lease cost	1,551	1,606	4,726	5,015
Cash paid for amounts included in measurement of lease liabilities
Operating cash outflows from operating leases	1,490	1,480	4,455	4,470
ROU assets obtained in exchange for new operating lease liabilities	4,434		4,699	15
Reduction to ROU assets resulting from reduction to lease liabilities		$ 18	1,250	18
Other non-cash reductions to ROU assets	48		48	$ 1,192
Operating lease ROU assets	$ 15,882		$ 15,882		$ 16,200
Operating Lease, Right-of-Use Asset, Statement of Financial Position	Other assets		Other assets		Other assets
Operating lease liabilities	$ 18,148		$ 18,148		$ 19,072
Operating Lease, Liability, Statement of Financial Position	Other liabilities		Other liabilities		Other liabilities
Weighted-average remaining lease term - operating leases	4 years 6 months 29 days		4 years 6 months 29 days		3 years 10 months 13 days
Weighted-average discount rate - operating leases	2.05%		2.05%		2.32%

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Lease Payments under Non-cancellable Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Future minimum lease payments under non-cancellable leases
2021	$ 1,283
2022	5,475
2023	4,901
2024	2,871
2025	1,462
2026	884
Thereafter	2,176
Total future minimum lease payments	19,052
Less imputed interest	(904)
Operating lease liabilities	$ 18,148	$ 19,072