Kinsale Capital (KNSL) 10-K 21 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2024	Feb. 14, 2025	Jun. 30, 2024
Document and Entity Information [Abstract]
Entity Registrant Name	KINSALE CAPITAL GROUP, INC.
Trading Symbol	KNSL
Entity Listing, Description	Common Stock, par value $0.01 per share
Entity Address, Address Line One	2035 Maywill Street
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Richmond
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	23230
City Area Code	804
Local Phone Number	289-1300
Entity Incorporation, State or Country Code	DE
Entity Central Index Key	0001669162
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-37848
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		23,277,395
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Public Float			$ 7,793,514,938
Security Exchange Name	NYSE
Entity Tax Identification Number	98-0664337
ICFR Auditor Attestation Flag	true
Auditor Name	KPMG LLP
Auditor Location	Richmond, VA
Auditor Firm ID	185
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement relating to its 2025 annual meeting of stockholders (the "2025 Proxy Statement") are incorporated by reference into Part III of this Annual Report on Form 10-K. The 2025 Proxy Statement will be filed with the Securities and Exchange Commission within 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K.
Document Financial Statement Error Correction [Flag]	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Investments:
Fixed-maturity securities available-for-sale, at fair value (amortized cost: $3,663,031 allowance for credit loss: $27 – 2024; $2,834,463 and $553 – 2023)	$ 3,537,563	$ 2,711,759
Equity securities, at fair value (cost: $313,722 – 2024; $193,543 – 2023)	398,359	234,813
Real Estate Investments, Net	15,045	14,791
Short-Term Investments	3,714	5,589
Total investments	3,954,681	2,966,952
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents	113,213	126,694
Investment income due and accrued	27,366	21,689
Premiums and fees receivable, net of allowance for credit losses of $26,926 in 2024 and $13,383 in 2023	140,027	143,212
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	337,891	247,836
Ceded unearned premiums	52,736	52,516
Deferred policy acquisition costs, net of ceding commissions	109,263	88,395
Intangible assets	3,538	3,538
Deferred income tax asset, net	60,215	55,699
Other assets	87,774	66,443
Total assets	4,886,704	3,772,974
Liabilities:
Gross reserves for unpaid losses and loss adjustment expenses, beginning of year	2,285,668	1,692,875
Unearned premiums	828,449	701,351
Payable to reinsurers	43,959	47,582
Accounts payable and accrued expenses	55,159	44,922
Long-Term Debt	184,122	183,846
Other liabilities	5,786	15,566
Total liabilities	3,403,143	2,686,142
Contingencies
Common stock, shares issued (in shares)	23,294,783	23,181,919
Stockholders' equity:
Common stock, $0.01 par value, 400,000,000 shares authorized, 23,294,783 shares issued and 23,272,157 shares outstanding at December 31, 2024; 23,181,919 shares issued and outstanding at December 31, 2023	$ 233	$ 232
Additional paid-in capital	361,398	352,970
Retained earnings	1,229,136	828,247
Accumulated other comprehensive loss	$ (97,206)	$ (94,617)
Treasury Stock, Common, Shares	22,626	0
Treasury Stock, Value	$ (10,000)	$ 0
Stockholders' equity	1,483,561	1,086,832
Total liabilities and stockholders' equity	$ 4,886,704	$ 3,772,974
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares outstanding (in shares)	23,272,157	23,181,919
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	$ 27	$ 553

Consolidated Balance Sheets - (

Consolidated Balance Sheets - (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Investments:
Amortized cost	$ 3,663,031	$ 2,834,463
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	27	553
Equity securities - cost	313,722	193,543
Allowance for credit losses	26,926	13,383
Reinsurance Recoverable, Allowance for Credit Loss	$ 932	$ 744
Stockholders' equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, shares issued (in shares)	23,294,783	23,181,919
Common stock, shares outstanding (in shares)	23,272,157	23,181,919

Consolidated Statements of Inco

Consolidated Statements of Income and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues:
Gross written premiums	$ 1,870,341	$ 1,568,815	$ 1,102,092
Ceded written premiums	(392,993)	(304,185)	(165,282)
Net written premiums	1,477,348	1,264,630	936,810
Change in unearned premiums	(126,878)	(192,093)	(142,691)
Net earned premiums	1,350,470	1,072,537	794,119
Insurance Fee Income	34,118	27,026	19,604
Net investment income	150,287	102,335	51,282
Change in the fair value of equity securities	43,367	15,277	(27,723)
Net realized investment gains	6,831	6,040	1,191
Change in allowance for credit losses on investments	526	(187)	(366)
Other income	1,926	1,421	697
Total revenues	1,587,525	1,224,449	838,804
Expenses:
Losses and loss adjustment expenses	772,899	600,219	457,913
Underwriting, acquisition and insurance expenses	285,808	228,970	180,322
Interest expense	10,134	10,301	4,284
Other expenses	3,968	942	721
Total expenses	1,072,809	840,432	643,240
Income before income taxes	514,716	384,017	195,564
Income tax expense	99,873	75,924	36,450
Net income	414,843	308,093	159,114
Other comprehensive income (loss):
Change in unrealized (losses) gains on available-for-sale investments, net of taxes	(2,589)	40,301	(153,043)
Total comprehensive income	$ 412,254	$ 348,394	$ 6,071
Earnings per share:
Basic	$ 17.92	$ 13.37	$ 6.97
Diluted	$ 17.78	$ 13.22	$ 6.88
Weighted-average common shares outstanding:
Basic	23,153	23,045	22,815
Diluted	23,332	23,307	23,125

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock, Common
Balance, shares at Dec. 31, 2021		22,834,377
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued, shares		155,000
Stock-based compensation, shares		116,140
Restricted shares withheld for taxes, shares		(14,991)
Balance, shares at Dec. 31, 2022		23,090,526
Balance at Dec. 31, 2021	$ 699,335	$ 228	$ 295,040	$ 385,942	$ 18,125
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, net of issuance costs	47,498	2	47,496
Issuance of stock under stock-based compensation plan	1,090	1	1,089
Stock-based compensation expense	6,678		6,678
Restricted shares withheld for taxes	$ (3,288)		(3,288)
Dividends declared, per share	$ 0.52
Dividends declared	$ (11,935)			(11,935)
Other comprehensive income (loss), net of income tax	(153,043)				(153,043)
Net income	159,114			159,114
Balance at Dec. 31, 2022	$ 745,449	$ 231	347,015	533,121	(134,918)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, shares		104,949
Restricted shares withheld for taxes, shares		(13,556)
Balance, shares at Dec. 31, 2023	23,181,919	23,181,919
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under stock-based compensation plan	$ 877	$ 1	876
Stock-based compensation expense	9,361		9,361
Restricted shares withheld for taxes	$ (4,282)		(4,282)
Dividends declared, per share	$ 0.56
Dividends declared	$ (12,967)			(12,967)
Other comprehensive income (loss), net of income tax	40,301				40,301
Net income	308,093			308,093
Balance at Dec. 31, 2023	$ 1,086,832	$ 232	352,970	828,247	(94,617)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation, shares		127,265
Restricted shares withheld for taxes, shares		(14,401)
Treasury Stock, Shares, Acquired		(22,626)
Balance, shares at Dec. 31, 2024	23,272,157	23,272,157
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock under stock-based compensation plan	$ 1,330	$ 1	1,329
Stock-based compensation expense	14,146		14,146
Restricted shares withheld for taxes	$ (7,047)		(7,047)
Dividends declared, per share	$ 0.60
Dividends declared	$ (13,954)			(13,954)
Other comprehensive income (loss), net of income tax	(2,589)				(2,589)
Net income	414,843			414,843
Treasury Stock, Value, Acquired, Cost Method	(10,000)					$ (10,000)
Balance at Dec. 31, 2024	$ 1,483,561	$ 233	$ 361,398	$ 1,229,136	$ (97,206)	$ 10,000

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Stockholders' Equity [Abstract]
Dividends declared, per share	$ 0.60	$ 0.56	$ 0.52

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net income	$ 414,843	$ 308,093	$ 159,114
Adjustments to reconcile net income to net cash provided by operating activities:
Change in fair value of equity securities	(43,367)	(15,277)	27,723
Net investment gains	(6,831)	(6,040)	(1,191)
Change in allowance for credit losses on investments	526	(187)	(366)
Deferred tax (benefit) expense	(3,828)	(9,429)	(14,191)
Depreciation and amortization	5,802	3,274	2,721
Stock compensation expense	14,146	9,361	6,678
Change in operating assets and liabilities:
Investment income due and accrued	(5,677)	(7,238)	(6,793)
Premiums receivable, net	3,185	(37,458)	(34,750)
Reserves for unpaid loss and loss adjustment expenses	592,793	454,473	357,058
Unearned premiums	127,098	201,674	151,947
Reinsurance balances, net	(93,898)	(21,405)	(90,828)
Deferred policy acquisition costs	(20,868)	(26,801)	(19,626)
Income taxes (recoverable) payable	(359)	742	7,518
Accounts payable and accrued expenses	8,936	12,519	8,111
Other	(15,148)	(6,840)	3,958
Net cash provided by operating activities	976,301	859,835	557,815
Investing Activities:
Purchase of property and equipment	(23,943)	(6,607)	(6,901)
Purchase of real estate investment	(312)	(2,116)	(76,623)
Sale of property and equipment	0	62,036	0
Payments for (Proceeds from) Short-Term Investments	2,056	36,706	(40,638)
Purchases - fixed-maturity securities	(1,557,541)	(1,317,048)	(751,402)
Purchases - equity securities	(156,477)	(86,605)	(11,506)
Sales - fixed-maturity securities	289,360	245,618	63,092
Sales - equity securities	34,380	30,623	4,990
Maturities and calls - fixed-maturity securities	452,352	176,501	110,415
Net cash provided by (used in) investing activities	(960,125)	(860,892)	(708,573)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	0	0	47,498
Proceeds from Lines of Credit	0	0	73,000
Repayments of Long-Term Lines of Credit	0	(62,000)	(43,000)
Debt issuance costs	0	(164)	(2,381)
Proceeds from Issuance of Long-Term Debt	0	50,000	125,000
Payroll taxes withheld and remitted on share-based payments	(7,047)	(4,282)	(3,288)
Common stock issued, stock options exercised	1,330	877	1,090
Dividends paid	(13,940)	(12,954)	(11,927)
Payments for Repurchase of Common Stock	(10,000)	0	0
Net cash provided by (used in) financing activities	(29,657)	(28,523)	185,992
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Beginning Balance	126,694	156,274	121,040
Net change in cash and cash equivalents	(13,481)	(29,580)	35,234
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents	$ 113,213	$ 126,694	$ 156,274

Description of business

Description of business	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of business	Description of business

Summary of significant accounti

Summary of significant accounting policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Summary of significant accounting policies	Summary of significant accounting policies Principles of consolidation The accompanying consolidated financial statements include the accounts of Kinsale Capital Group, Inc. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Certain prior year amounts have been reclassified to conform to the current year's presentation. Use of estimates The preparation of consolidated financial statements in conformity with U.S. generally accepted accounting principles ("U.S. GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, if any, at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Management periodically reviews its estimates and assumptions. These reviews include evaluating the adequacy of reserves for unpaid losses and loss adjustment expenses, allowance for credit losses and uncollectible reinsurance, fair value of investments, as well as evaluating the investment portfolio for credit impairments. Cash and cash equivalents The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents. Short-term investments Short-term investments are carried at amortized cost, which approximates fair value. Short-term investments have maturities greater than three months but less than one year at the date of purchase. Fixed-maturity and equity securities Fixed-maturity securities are classified as available-for-sale and reported at fair value. Unrealized gains and losses on these securities are excluded from earnings but are recorded as a separate component of other comprehensive income and stockholders' equity, net of deferred income taxes. Equity securities are reported at fair value. Changes in unrealized gains and losses in fair value of these investments are recognized in net income. The Company regularly reviews all its available-for-sale investments with unrealized losses to assess whether the decline in the fair value is deemed to be a credit loss. See Note 2 for further discussion regarding the determination of credit losses. Interest on fixed-maturity securities is credited to earnings as it accrues. Premiums and discounts are amortized or accreted using the effective interest method over the lives of the related fixed maturities, or to the earliest call date for securities purchased at a premium. This method includes an adjustment for estimated principal prepayments, if any, on asset- and mortgage-backed securities. To the extent that the estimated lives of such securities change as a result of changes in estimated prepayment rates, the adjustments are included in net investment income using the retrospective method. Dividends on equity securities are included in earnings on the ex-dividend date. Realized gains and losses on disposition of investments are based on specific identification of the investments sold on the trade date. Real estate investments Real estate investments include real estate and the related assets purchased for investment purposes. Real estate and the related depreciable assets are carried at cost, net of accumulated depreciation. Depreciation is calculated on a straight-line basis over the estimated useful life of the assets and is included in net investment income. Rental income is recognized on a straight-line basis over the term of the respective lease and is included in net investment income. Land is not depreciated. Real estate is evaluated for impairment when events or circumstances indicate the carrying value of the real estate may not be recoverable. Reinsurance Reinsurance premiums, commissions, and ceded unearned premiums on reinsured business are accounted for on a basis consistent with that used in accounting for the original policies issued and the terms of the reinsurance contracts. The Company receives ceding commissions in accordance with certain reinsurance treaties. The ceding commissions are capitalized and amortized as a reduction of underwriting, acquisition and insurance expenses. Reinsurance recoverables represent paid losses and loss adjustment expenses and reserves for unpaid losses and loss adjustment expenses ceded to reinsurers that are subject to reimbursement under reinsurance treaties. The method for determining reinsurance recoverables for unpaid losses and loss adjustment expenses involves reviewing actuarial estimates of gross unpaid losses and loss adjustment expenses to determine the Company's ability to cede unpaid losses and loss adjustment expenses under the Company's existing reinsurance contracts. This method is continually reviewed and updated and any resulting adjustments are reflected in earnings in the period identified. See Note 8 for a further discussion of the Company's reinsurance program. Premiums receivable, net Premiums receivable balances are carried at face value, net of any allowance for credit losses. The allowance for credit losses represents an estimate of amounts considered uncollectible based on the Company’s assessment of the collectability of receivables that are past due. The estimate considers historical loss data, current and future economic conditions and specific identification of collectability concerns where applicable. The following table presents the rollforward of the allowance for credit losses for premiums receivable for the years ended December 31, 2024 and 2023: Year Ended December 31, 2024 2023 (in thousands) Beginning balance $ 13,383 $ 8,067 Current period change for estimated uncollectible premiums 17,397 9,790 Write-offs of uncollectible premiums receivable (3,854) (4,474) Ending balance $ 26,926 $ 13,383 Deferred policy acquisition costs, net of ceding commissions The Company defers commissions, net of ceding commissions, and certain other costs that are directly related to the successful acquisition of insurance contracts. All eligible costs are capitalized and charged to expense in proportion to premium earned over the estimated policy life. To the extent that unearned premiums on existing policies are not adequate to cover the related costs and expenses, referred to as a premium deficiency, deferred policy acquisition costs are charged to earnings. The Company considers anticipated investment income in determining whether a premium deficiency exists. Property and equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation of property and equipment is calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives range from 39 years for the building and parking deck, 15 to 20 years for land improvements, 7 to 10 years for furniture and equipment, and 3 to 7 years for electronic data processing hardware and software. Property and equipment are included in other assets in the accompanying consolidated balance sheets and consists of the following: December 31, 2024 2023 (in thousands) Building $ 37,190 $ 37,181 Parking deck 5,072 5,072 Land 3,068 3,068 Equipment 4,401 3,958 Software 20,203 15,375 Furniture and fixtures 3,200 3,065 Leasehold improvements 153 153 Land improvements 474 474 Construction in progress - building 26,530 6,623 100,291 74,969 Accumulated depreciation (17,367) (11,565) Total property and equipment, net $ 82,924 $ 63,404 Construction in progress includes capitalized expenses related to the development of the new corporate headquarters' building. Construction is expected to be completed in the fourth quarter of 2025. Indefinite-lived intangible assets Indefinite-lived intangible assets are recorded at fair value at the date of acquisition. The Company's indefinite-lived intangible assets are comprised solely of regulatory approvals granted by the various state insurance departments to write insurance business in the respective states on a non-admitted basis. In accordance with U.S. GAAP, amortization of indefinite-lived intangible assets is not permitted. Indefinite-lived intangible assets are tested for impairment during the fourth quarter on an annual basis, or earlier if there is reason to suspect that their values may have been diminished or impaired. There were no impairments recognized in December 31, 2024, 2023, or 2022. In addition, as of December 31, 2024, no triggering events occurred that suggested an updated review was necessary. Reserves for unpaid losses and loss adjustment expenses Reserves for unpaid losses and loss adjustment expenses represent management's best estimate of ultimate unpaid cost of all reported and unreported losses and loss adjustment expenses incurred prior to the financial statement date. The estimates are based on several actuarial methods that use a variety of inputs including initial expected loss ratios, loss development patterns, paid losses, reported losses, claim counts and price indices. All estimates are regularly reviewed and, as experience develops and new information becomes known, the reserves for unpaid losses and loss adjustment expenses are adjusted as necessary. Such adjustments are reflected in the results of operations in the period in which they are determined. Although management believes that the reserves for losses and loss adjustment expenses are reasonable, due to the inherent uncertainty in estimating reserves for unpaid losses and loss adjustment expenses, it is possible that the Company’s actual incurred losses and loss adjustment expenses will not develop in a manner consistent with the assumptions inherent in the determination of these reserves. If actual liabilities exceed recorded amounts, there will be an increase to the Company’s reserves resulting in a reduction in net income and stockholders’ equity in the period in which the deficiency is identified. Furthermore, management may determine that recorded reserves are more than adequate to cover expected losses which will result in a reduction to the reserves. The Company believes that the reserves for unpaid losses and loss adjustment expenses at December 31, 2024 and 2023 are adequate and represent a reasonable estimate of the Company's future obligations. See Note 7 for a further discussion of reserves for unpaid losses and loss adjustment expenses. Revenue recognition Premiums are recognized as revenue ratably over the term of the insurance contracts, net of ceded reinsurance. Unearned premiums are calculated on a daily pro rata basis. Fee income is recognized as revenue when the related premium is written. Income taxes Deferred income tax assets and liabilities are determined based on the differences between the recorded amounts and the tax bases of assets and liabilities, using enacted tax rates expected to be in effect during the year in which the basis differences reverse. The effect on deferred taxes of a change in tax rates is recognized in income in the period in which such change was enacted. Valuation allowances on deferred tax assets are estimated based on the Company's assessment of the realizability of such amounts. Valuation allowances are recorded when it is more likely than not that some portion, or all, of the deferred tax assets will not be realizable. The Company provides for uncertain tax positions, and the related interest and penalties, based upon management’s assessment of whether a tax benefit is more likely than not to be sustained upon examination by tax authorities. To the extent that the anticipated tax outcome of these uncertain tax positions changes, such changes in estimate will impact the income tax provision in the period in which such determination is made. The Company recognizes accrued interest and penalties related to uncertain tax positions as a component of income tax expense. The Company uses the portfolio approach to release stranded tax effects in accumulated other comprehensive income ("AOCI") related to its available-for-sale fixed-maturity securities. Under this approach, stranded tax effects remaining in AOCI are released only when the entire portfolio of the available-for-sale fixed-maturity securities are liquidated, sold or extinguished. Contingencies Liabilities for loss contingencies, arising from noninsurance policy claims, assessments, litigation, fines, and penalties and other sources, are recorded when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred. Fair value of financial instruments Fair value is estimated for each class of financial instrument based on the framework established in the fair value accounting guidance. This guidance requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Fair value hierarchy disclosures are based on the quality of inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). See Note 3 for further details regarding fair value disclosures. Stock-based compensation Stock-based compensation is expensed based upon the estimated fair value of employee stock awards. Compensation cost for awards of equity instruments to employees is measured based on the grant-date fair value of those awards and compensation expense is recognized over the service period that the awards vest. Forfeitures of stock-based compensation awards are recognized as they occur. See Note 9 for further discussion and related disclosures regarding stock-based compensation. Recently adopted accounting pronouncements Accounting Standards Update ("ASU") 2023-07, Segment Reporting - Improvements to Reportable Segment Disclosures In November 2023, the Financial Accounting Standards Board ("FASB") issued ASU 2023-07, "Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures," which expands reportable segment disclosure requirements by requiring disclosures of significant reportable segment expenses that are regularly provided to the Chief Operating Decision Maker ("CODM") and included within each reported measure of a segment's profit or loss. The ASU also requires disclosure of the title and position of the individual identified as the CODM and an explanation of how the CODM uses the reported measures of a segment's profit or loss in assessing segment performance and deciding how to allocate resources. Additionally, ASU 2023-07 requires all segment profit or loss and assets disclosures to be provided on an annual and interim basis. ASU 2023-07 became effective for the Company for the year ended December 31, 2024 and will be effective for interim periods beginning in 2025. Refer to Note 15 for the Company's segment reporting disclosures. Prospective accounting pronouncements ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures In November 2024, the FASB issued ASU 2024-03, "Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses," requiring public entities to disclose additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the effect the guidance will have on its disclosures.

Investments

Investments	12 Months Ended
	Dec. 31, 2024
Investments [Abstract]
Investments	Investments Available-for-sale investments The following tables summarize the Company’s available-for-sale investments at December 31, 2024 and 2023: December 31, 2024 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Allowance for Credit Losses Estimated Fair Value (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 15,465 $ — $ (417) $ — $ 15,048 Obligations of states, municipalities and political subdivisions 168,894 46 (22,633) (3) 146,304 Corporate and other securities 2,037,372 5,779 (53,638) (23) 1,989,490 Asset-backed securities 729,658 4,606 (1,522) — 732,742 Residential mortgage-backed securities 502,121 747 (53,994) — 448,874 Commercial mortgage-backed securities 209,521 423 (4,838) (1) 205,105 Total fixed-maturity investments $ 3,663,031 $ 11,601 $ (137,042) $ (27) $ 3,537,563 December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Allowance for Credit Losses Estimated Fair Value (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 28,003 $ 57 $ (806) $ — $ 27,254 Obligations of states, municipalities and political subdivisions 191,080 212 (20,248) — 171,044 Corporate and other securities 1,437,468 5,532 (54,755) (552) 1,387,693 Asset-backed securities 641,700 2,833 (2,773) — 641,760 Residential mortgage-backed securities 463,904 1,732 (48,530) — 417,106 Commercial mortgage-backed securities 72,308 11 (5,416) (1) 66,902 Total fixed-maturity investments $ 2,834,463 $ 10,377 $ (132,528) $ (553) $ 2,711,759 Available-for-sale investments in a loss position The Company regularly reviews all its available-for-sale investments with unrealized losses to assess whether the decline in the fair value is deemed to be a credit loss. The Company considers a number of factors in completing its review of credit losses, including the extent to which a security's fair value has been below cost and the financial condition of an issuer. In addition to specific issuer information, the Company also evaluates the current market and interest rate environment. Generally, a change in a security’s value caused by a change in the market or interest rate environment does not constitute a credit loss. For fixed-maturity securities, the Company also considers whether it intends to sell the security or if it is more likely than not that it will be required to sell the security before recovery and the ability to recover all amounts outstanding when contractually due. When assessing whether it intends to sell a fixed-maturity security or if it is likely to be required to sell a fixed-maturity security before recovery of its amortized cost, the Company evaluates facts and circumstances including, but not limited to, decisions to reposition the investment portfolio, potential sales of investments to meet cash flow needs and potential sales of investments to capitalize on favorable pricing. For fixed-maturity securities where a decline in fair value is below the amortized cost basis and the Company intends to sell the security, or it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost, an impairment is recognized in net income based on the fair value of the security at the time of assessment. For fixed-maturity securities that the Company does not intend to sell or for which it is more likely than not that the Company would not be required to sell before recovery of its amortized cost, the Company compares the estimated present value of the cash flows expected to be collected to the amortized cost of the security. Inputs into the present value cash flow analysis include default rates and recoverability rates based on credit rating. The extent to which the estimated present value of the cash flows expected to be collected is less than the amortized cost of the security represents the credit-related portion of the impairment, which is recognized in net income through an allowance for credit losses. Any remaining decline in fair value represents the noncredit portion of the impairment, which is recognized in other comprehensive income. The Company reports investment income due and accrued separately from fixed-maturity securities, available for sale, and has elected not to measure an allowance for credit losses for investment income due and accrued. Investment income due and accrued is written off through earnings at the time the issuer of the bond defaults or is expected to default on payments. As of December 31, 2024, the Company's credit loss review resulted in an allowance for credit losses on four securities. The following table presents changes in the allowance for expected credit losses on available-for-sale securities: Years Ended December 31, 2024 2023 (in thousands) Beginning balance $ 553 $ 366 Increase to allowance from securities for which credit losses were not previously recorded 3 1 Reduction from securities sold during the period (479) (12) Net (decrease) increase from securities that had an allowance at the beginning of the period (50) 198 Ending balance $ 27 $ 553 The following tables summarize gross unrealized losses and estimated fair value for available-for-sale investments by length of time that the securities have continuously been in an unrealized loss position: December 31, 2024 Less than 12 Months 12 Months or Longer Total Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 838 $ (13) $ 14,210 $ (404) $ 15,048 $ (417) Obligations of states, municipalities and political subdivisions 27,049 (417) 114,620 (22,216) 141,669 (22,633) Corporate and other securities 667,645 (9,139) 493,598 (44,499) 1,161,243 (53,638) Asset-backed securities 121,371 (943) 24,656 (579) 146,027 (1,522) Residential mortgage-backed securities 144,955 (1,934) 237,514 (52,060) 382,469 (53,994) Commercial mortgage-backed securities 92,024 (960) 53,812 (3,878) 145,836 (4,838) Total fixed-maturity investments $ 1,053,882 $ (13,406) $ 938,410 $ (123,636) $ 1,992,292 $ (137,042) At December 31, 2024, in addition to the securities included in the allowance for credit losses, the Company held 1,031 fixed-maturity securities with a total estimated fair value of $2.0 billion and gross unrealized losses of $137.0 million. Of those securities, 616 were in a continuous unrealized loss position for greater than one year. As discussed above, the Company regularly reviews all fixed-maturity securities within its investment portfolio to determine whether a credit loss has occurred. Based on the Company's review as of December 31, 2024, except for securities previously discussed, the securities in unrealized loss positions were caused by interest rate changes or other market factors and were not credit-specific issues, nor did the Company intend to sell these securities. At December 31, 2024, 79.8% of the Company’s fixed-maturity securities were rated "A-" or better and all of Company's fixed-maturity securities made expected coupon payments under the contractual terms of the securities. December 31, 2023 Less than 12 Months 12 Months or Longer Total Estimated Fair Value Gross Unrealized Holding Losses Estimated Fair Value Gross Unrealized Holding Losses Estimated Fair Value Gross Unrealized Holding Losses (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ — $ — $ 15,484 $ (806) $ 15,484 $ (806) Obligations of states, municipalities and political subdivisions 20,886 (221) 121,911 (20,027) 142,797 (20,248) Corporate and other securities 246,355 (1,444) 651,525 (53,311) 897,880 (54,755) Asset-backed securities 142,287 (872) 217,401 (1,901) 359,688 (2,773) Residential mortgage-backed securities 26,158 (49) 268,891 (48,481) 295,049 (48,530) Commercial mortgage-backed securities 8,775 (55) 56,731 (5,361) 65,506 (5,416) Total fixed-maturity investments $ 444,461 $ (2,641) $ 1,331,943 $ (129,887) $ 1,776,404 $ (132,528) Contractual maturities of available-for-sale fixed-maturity securities The amortized cost and estimated fair value of available-for-sale fixed-maturity securities at December 31, 2024 are summarized, by contractual maturity, as follows: Amortized Estimated Cost Fair Value (in thousands) Due in one year or less $ 415,494 $ 415,674 Due after one year through five years 1,070,687 1,058,729 Due after five years through ten years 513,549 496,044 Due after ten years 222,001 180,395 Asset-backed securities 729,658 732,742 Residential mortgage-backed securities 502,121 448,874 Commercial mortgage-backed securities 209,521 205,105 Total fixed maturities $ 3,663,031 $ 3,537,563 Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties, and the lenders may have the right to put the securities back to the borrower. Real estate investments Real estate investments represents directly owned property held for investment purposes and consisted of land with a carrying value of $15.0 million and $14.8 million at December 31, 2024 and 2023, respectively. There was no accumulated depreciation on real estate investments at December 31, 2024 and 2023. During the third quarter of 2023, the Company sold the parking deck, one of the office buildings and the related in-place leases of its real estate investment property for approximately $62.0 million in cash, net of seller’s costs. The Company recognized a gain on the sale of $4.3 million, which is included in net realized investment gains on the consolidated statement of income. The Company used the net sale proceeds to pay down a portion of its Credit Facility. Concurrent with the sale of the investment property, the Company refined its plans for the remainder of the property and determined the predominant use of the remaining office building would be for future office space expansion. Upon this determination, the Company reclassified the carrying value of the building to construction in progress within property and equipment. Net investment income The following table presents the components of net investment income: Year Ended December 31, 2024 2023 2022 (in thousands) Interest: Taxable bonds $ 143,242 $ 92,227 $ 44,806 Municipal bonds (tax exempt) 1,592 2,217 3,380 Cash equivalents and short-term investments 3,012 3,004 1,251 Dividends on equity securities 6,442 5,097 4,406 Real estate investment income 153 3,716 234 Gross investment income 154,441 106,261 54,077 Investment expenses (4,154) (3,926) (2,795) Net investment income $ 150,287 $ 102,335 $ 51,282 There was no depreciation expense related to real estate investments for the year ended December 31, 2024 as the Company sold the related assets during 2023. Investment expenses included depreciation expense related to real estate investments of $0.5 million and $0.2 million for the years ended December 31, 2023 and 2022, respectively. Realized investment gains and losses The following table presents realized investment gains and losses: Year Ended December 31, 2024 2023 2022 (in thousands) Fixed-maturity securities: Realized gains $ 1,151 $ 1,852 $ 1,078 Realized losses (1,131) (2,374) (904) Net realized gains (losses) from fixed-maturity securities 20 (522) 174 Equity securities: Realized gains 7,271 7,678 1,363 Realized losses (455) (5,329) (297) Net realized gains from equity securities 6,816 2,349 1,066 Realized losses from the sales of short-term investments — (37) (49) Realized (losses) gains on sale of real estate investments (5) 4,250 — Net realized investment gains $ 6,831 $ 6,040 $ 1,191 The net realized gains or losses on sales of equity securities represent the total gains or losses from the purchase dates of the equity securities. The change in unrealized gains (losses) in the consolidated statement of income consists of two components: (1) the reversal of the gain or loss recognized in previous periods on equity securities sold and (2) the change in unrealized gain or loss resulting from mark-to-market adjustments on equity securities still held. Change in net unrealized gains (losses) on fixed-maturity securities The change in net unrealized gains (losses) for fixed-maturity securities was $(3.3) million, $51.0 million, and $(193.7) million for the years ended December 31, 2024, 2023, and 2022, respectively. Insurance – statutory deposits The Company had invested assets with a carrying value of $3.7 million and $5.8 million on deposit with state regulatory authorities at December 31, 2024 and 2023, respectively. Payable for investments purchased The Company did not have a payable for investments purchased at December 31, 2024. The Company recorded a payable for investments purchased, not yet settled, of $12.3 million at December 31, 2023. The payable balance was included in the other liabilities line item of the consolidated balance sheet.

Fair value measurements

Fair value measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements Fair value is estimated for each class of financial instrument based on the framework established in the fair value accounting guidance. Fair value is defined as the price in the principal market that would be received for an asset or paid to transfer a liability to facilitate an orderly transaction between market participants on the measurement date. Market participants are assumed to be independent, knowledgeable, able and willing to transact an exchange and not acting under duress. Fair value hierarchy disclosures are based on the quality of inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). Adjustments to transaction prices or quoted market prices may be required in illiquid or disorderly markets in order to estimate fair value. The three levels of the fair value hierarchy are defined as follows: Level 1 - Inputs to the valuation methodology are quoted prices (unadjusted) for identical assets or liabilities traded in active markets. Level 2 - Inputs to the valuation methodology include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability and market-corroborated inputs. Level 3 - Inputs to the valuation methodology are unobservable for the asset or liability and are significant to the fair value measurement. Fair values of the Company's investment portfolio are estimated using unadjusted prices obtained by its investment accounting vendor from nationally recognized third-party pricing services, where available. Values for U.S. Treasuries, exchange traded funds and common stocks are generally based on Level 1 inputs which use quoted prices in active markets for identical assets. For other fixed-maturity securities and non-redeemable preferred stock, the pricing vendors use a pricing methodology involving the market approach, including pricing models which use prices and relevant market information regarding a particular security or securities with similar characteristics to establish a valuation. The estimates of fair value of these investments are included in the amounts disclosed as Level 2. For those investments where significant inputs are unobservable, the Company's investment accounting vendor obtains valuations from pricing vendors or brokers using the market approach and income approach valuation techniques and are disclosed as Level 3. Management performs several procedures to ascertain the reasonableness of investment values included in the consolidated financial statements at December 31, 2024 and 2023, including 1) obtaining and reviewing internal control reports from the Company's investment accounting vendor that assess fair values from third party pricing services, 2) discussing with the Company's investment accounting vendor its process for reviewing and validating pricing obtained from third party pricing services and 3) reviewing the security pricing received from the Company's investment accounting vendor and monitoring changes in unrealized gains and losses at the individual security level. The Company has evaluated the various types of securities in its investment portfolio to determine an appropriate fair value hierarchy level based upon trading activity and the observability of market inputs. The following tables present the balances of assets measured at fair value on a recurring basis as of December 31, 2024 and 2023, by level within the fair value hierarchy: December 31, 2024 Level 1 Level 2 Level 3 Total (in thousands) Assets Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 15,048 $ — $ — $ 15,048 Obligations of states, municipalities and political subdivisions — 146,304 — 146,304 Corporate and other securities — 1,989,490 — 1,989,490 Asset-backed securities — 732,742 — 732,742 Residential mortgage-backed securities — 448,874 — 448,874 Commercial mortgage-backed securities — 205,105 — 205,105 Total fixed maturities 15,048 3,522,515 — 3,537,563 Equity securities: Exchange traded funds 129,731 — — 129,731 Non-redeemable preferred stock — 26,433 — 26,433 Common stocks 242,195 — — 242,195 Total equity securities 371,926 26,433 — 398,359 Short-term investments 3,714 — — 3,714 Total $ 390,688 $ 3,548,948 $ — $ 3,939,636 December 31, 2023 Level 1 Level 2 Level 3 Total (in thousands) Assets Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 22,235 $ 5,019 $ — $ 27,254 Obligations of states, municipalities and political subdivisions — 171,044 — 171,044 Corporate and other securities — 1,387,693 — 1,387,693 Asset-backed securities — 641,760 — 641,760 Residential mortgage-backed securities — 417,106 — 417,106 Commercial mortgage-backed securities — 66,902 — 66,902 Total fixed maturities 22,235 2,689,524 — 2,711,759 Equity securities: Exchange traded funds 106,300 — — 106,300 Non-redeemable preferred stock — 33,173 — 33,173 Common stocks 95,340 — — 95,340 Total equity securities 201,640 33,173 — 234,813 Short-term investments 1,862 3,727 — 5,589 Total $ 225,737 $ 2,726,424 $ — $ 2,952,161 There were no assets or liabilities measured at fair value on a nonrecurring basis as of December 31, 2024 or 2023. The carrying amount of the Company's fixed-rate senior notes was $175.0 million, less debt issuance cost, and the corresponding estimated fair value was $168.6 million and $171.6 million at December 31, 2024 and 2023, respectively. The fair value measurement was determined using a discounted cash flow analysis that factors in current market yields for comparable borrowing arrangements under the Company's credit profile. Since this methodology is based upon market yields for comparable arrangements, the measurement is categorized as Level 2. The estimated fair value of outstanding borrowings under the Company's revolving Credit Facility approximated its carrying value at December 31, 2024 and 2023. See Note 11 for further information regarding the Company's debt arrangements.

Deferred policy acquisition cos

Deferred policy acquisition costs	12 Months Ended
	Dec. 31, 2024
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred policy acquisition costs	Deferred policy acquisition costs The following table presents the amounts of policy acquisition costs deferred and amortized for the years ended: Year Ended December 31, 2024 2023 2022 (in thousands) Balance, beginning of year $ 88,395 $ 61,594 $ 41,968 Policy acquisition costs deferred: Direct commissions 274,124 227,755 160,523 Ceding commissions (120,459) (88,449) (48,022) Other underwriting and policy acquisition costs 14,215 10,982 8,155 Policy acquisition costs deferred 167,880 150,288 120,656 Amortization of net policy acquisition costs (147,012) (123,487) (101,030) Balance, end of year $ 109,263 $ 88,395 $ 61,594 Amortization of net policy acquisition costs is included in underwriting, acquisition and insurance expense in the accompanying consolidated statements of income and comprehensive income.

Underwriting, acquisition and i

Underwriting, acquisition and insurance expenses	12 Months Ended
	Dec. 31, 2024
Underwriting, Acquisition and Insurance Expenses [Abstract]
Underwriting, acquisition and insurance expenses	Underwriting, acquisition and insurance expenses Underwriting, acquisition and insurance expenses consist of the following: Year Ended December 31, 2024 2023 2022 (in thousands) Underwriting, acquisition and insurance expenses incurred: Direct commissions $ 254,523 $ 198,715 $ 138,451 Ceding commissions (120,339) (84,998) (44,695) Other underwriting expenses 151,624 115,253 86,566 Total $ 285,808 $ 228,970 $ 180,322 Other underwriting expenses within underwriting, acquisition and insurance expenses included salaries, employee benefits and bonus expense of $109.3 million, $85.7 million and $64.8 million, for the years ended December 31, 2024, 2023 and 2022, respectively.

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income taxes	Income taxes The Company’s subsidiaries file a consolidated U.S. federal income tax return. Under a tax sharing agreement, Kinsale collects from or refunds to its subsidiaries the amount of taxes determined as if Kinsale and the subsidiaries filed separate returns. The Company is no longer subject to income tax examination by tax authorities for the years ended before January 1, 2021. Income tax expense includes the following components for the years ending December 31, 2024, 2023 and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Current federal income tax expense $ 103,701 $ 85,353 $ 50,641 Deferred federal income tax benefit (3,828) (9,429) (14,191) Income tax expense $ 99,873 $ 75,924 $ 36,450 The Company paid $104.1 million, $84.6 million and $43.1 million in federal income taxes during the years ended December 31, 2024, 2023 and 2022, respectively. Current income taxes payable were $2.8 million and $3.2 million at December 31, 2024 and 2023, respectively, and included in other liabilities in the accompanying consolidated balance sheets. The prevailing federal income tax rate was 21% in December 31, 2024, 2023 and 2022. The Company’s effective income tax rate on income before income taxes differs from the prevailing federal income tax rate and is summarized as follows: Year ended December 31, 2024 2023 2022 (in thousands) Income tax expense at federal income tax rate $ 108,090 $ 80,644 $ 41,068 Stock options exercised (7,972) (3,676) (3,240) Restricted stock award vesting (2,147) (1,256) (1,048) Tax-exempt investment income (249) (347) (527) Other 2,151 559 197 Total $ 99,873 $ 75,924 $ 36,450 The significant components of the net deferred tax asset are summarized as follows: December 31, 2024 2023 (in thousands) Deferred tax assets: Unrealized losses on fixed-maturity securities $ 26,343 $ 25,655 Unpaid losses and loss adjustment expenses 36,491 27,422 Unearned premiums 32,580 27,251 State operating loss carryforwards 8,859 6,012 Stock compensation 3,276 2,155 Allowance for credit losses 5,210 2,810 Other 1,939 2,394 Deferred tax assets before allowance 114,698 93,699 Less: valuation allowance (9,066) (6,182) Total deferred tax assets 105,632 87,517 Deferred tax liabilities: Unrealized gains on equity securities 17,774 8,667 Deferred policy acquisition costs, net of ceding commissions 22,945 18,563 Property and equipment 3,263 3,005 Other 1,435 1,583 Total deferred tax liabilities 45,417 31,818 Net deferred tax asset $ 60,215 $ 55,699 At December 31, 2024 and 2023, the Company had state net operating losses ("NOLs") of $186.9 million and $126.8 million, respectively. The state NOLs are available to offset future taxable income or reduce taxes payable and begin expiring in 2029. Management evaluates the need for a valuation allowance related to its deferred tax assets. At December 31, 2024 and 2023, the Company recorded a tax valuation allowance equal to the state NOLs and the deferred tax assets, net of existing deferred tax liabilities that were expected to reverse in future periods, related to certain state jurisdictions. No other valuation allowances were established against the Company’s deferred tax assets at December 31, 2024 and 2023, as the Company believes that it is more likely than not that the remaining deferred tax assets will be realized given the carry back availability, reversal of existing temporary differences and future taxable income. With respect to deferred tax assets associated with unrealized losses on fixed-maturity securities, management has the ability and intent to execute a tax planning strategy to hold those securities to recovery or maturity to the extent not matched with realized capital gains or available carry back to ensure recognition of the deferred tax asset. After consideration of all available evidence, we concluded that it is more likely than not that these deferred tax assets will be realized. The Company did not have any material uncertain tax positions in 2024 or 2023. Management is not aware of any events that would give rise to any material uncertain tax positions.

Reserves for unpaid losses and

Reserves for unpaid losses and loss adjustment expenses	12 Months Ended
	Dec. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense, Activity in Liability [Abstract]
Reserves for unpaid losses and loss adjustment expenses	Reserves for unpaid losses and loss adjustment expenses The reserves for unpaid losses and loss adjustment expenses represent the Company's estimated ultimate cost of all unreported and reported but unpaid insured claims and the cost to adjust these claims. Reserves are estimated using individual case-basis valuations of reported claims and statistical analyses. Case reserves are established for individual claims that have been reported to the Company, typically by the Company's insureds or their brokers. Based on the information provided, case reserves are established by estimating the ultimate losses from the claim, including defense costs associated with the ultimate settlement of the claim. Incurred-but-not-reported ("IBNR") reserves are determined using actuarial methods to estimate losses that have occurred but have not yet been reported to the Company. Various actuarial methods are used to arrive at the Company's loss reserve estimates for each line of business. These methods utilize numerous inputs including initial expected loss ratios, loss development patterns, paid losses, reported losses, claim counts and price indices. The Company also uses industry and peer-group data, in addition to its own data, to assist in analyzing loss development patterns by line of business. As part of the reserving process, the Company reviews historical data and considers the effect of various factors on claims development patterns including polices written on a "claims made" versus "occurrence" basis. Policies written on a claims made basis provide coverage to the insured only for losses incurred during the coverage period, and only if the claim was reported during a specified reporting period. Policies written on an occurrence basis provide coverage to the insured for liabilities arising from events occurring during the term of the policy, regardless of when a claim is actually made. Accordingly, claims related to policies written on an occurrence basis may arise many years after a policy has lapsed. Property losses, while written on an occurrence basis, are generally reported within a short time from the date of loss, and in most instances, property claims are settled and paid within a relatively short period of time. The following table presents a reconciliation of consolidated beginning and ending reserves for unpaid losses and loss adjustment expenses: December 31, 2024 2023 2022 (in thousands) Gross reserves for unpaid losses and loss adjustment expenses, beginning of year $ 1,692,875 $ 1,238,402 $ 881,344 Less: reinsurance recoverable on unpaid losses 241,357 177,039 117,561 Net reserves for unpaid losses and loss adjustment expenses, beginning of year 1,451,518 1,061,363 763,783 Incurred losses and loss adjustment expenses: Current year 810,554 635,993 493,800 Prior years (37,655) (35,774) (35,887) Total net losses and loss adjustment expenses incurred 772,899 600,219 457,913 Payments: Current year 49,747 38,565 49,205 Prior years 212,062 171,499 111,128 Total payments 261,809 210,064 160,333 Net reserves for unpaid losses and loss adjustment expenses, end of year 1,962,608 1,451,518 1,061,363 Reinsurance recoverable on unpaid losses, net of allowance 323,060 241,357 177,039 Gross reserves for unpaid losses and loss adjustment expenses, end of year $ 2,285,668 $ 1,692,875 $ 1,238,402 During the year ended December 31, 2024, prior accident years developed favorably by $37.7 million, of which $57.6 million was attributable to the 2021 through 2023 accident years due to lower emergence of reported losses than expected across most lines of business. This favorable development was offset in part by adverse development primarily from the 2017 through 2019 accident years due to construction defect claims that are more exposed to inflation, from the 2020 accident year due to a large property claim and more conservative actuarial assumptions in the 2021 through 2023 accident years for lines of business exposed to construction liability. Current accident year incurred losses and loss adjustment expenses for the year ended December 31, 2024 included $25.5 million of net catastrophe losses primarily related to Hurricanes Milton, Helene and Francine and tornadoes in the Midwest. During the year ended December 31, 2023, prior accident years developed favorably by $35.8 million, of which $49.0 million was attributable to the 2021 and 2022 accident years due to lower emergence of reported losses than expected across most lines of business. This favorable development was offset in part by adverse development largely from the 2017 through 2019 accident years due to construction defect claims that are more exposed to inflation. During the year ended December 31, 2022, prior accident years developed favorably by $35.9 million, of which $41.8 million was attributable to the 2020 and 2021 accident years due to lower emergence of reported losses than expected across most lines of business. This favorable development was offset in part by adverse development largely from the 2016 and 2018 accident years due to routine variability in reported losses and modest adjustments in actuarial assumptions. Current accident year incurred losses and loss adjustment expenses for the year ended December 31, 2022 included $26.6 million of catastrophe losses primarily related to Hurricane Ian. Incurred and Paid Claims Development The following is information about incurred and paid claims development as of December 31, 2024, net of reinsurance, as well as cumulative claim frequency and the total of IBNR liabilities plus expected development on reported claims included within the net incurred claims amounts. The development and claims duration tables below exclude commuted multi-line quota-share reinsurance treaty ("MLQS") contracts, which would distort development patterns related to those transactions. Cumulative number of reported claims is reported on a per claim basis. The information about incurred and paid claims development for the years ended December 31, 2015 to December 31, 2023, is presented as unaudited supplementary information. Property Incurred Claims and Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2024 Accident Year 2020 2021 2022 2023 2024 Total of IBNR Liabilities Plus Expected Development on Reported Claims Cumulative Number of Reported Claims ($ in thousands) 2020 $ 40,612 $ 37,939 $ 36,807 $ 37,078 $ 42,287 $ — 2,309 2021 36,531 33,518 29,750 31,392 1,087 1,146 2022 67,127 53,676 53,527 4,131 2,346 2023 75,517 54,503 24,306 979 2024 112,051 61,791 1,376 Total $ 293,760 Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2020 2021 2022 2023 2024 ($ in thousands) 2020 $ 19,897 $ 30,321 $ 31,765 $ 35,023 $ 41,696 2021 14,268 21,257 27,324 30,200 2022 33,004 46,965 48,030 2023 20,267 26,434 2024 31,303 Total 177,663 All outstanding liabilities before 2020, net of reinsurance 15 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 116,112 Historical Claims Duration The following is supplementary information about average historical claims duration as of December 31, 2024: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (Unaudited) Years 1 2 3 4 5 Property 43.9 % 21.1 % 8.2 % 8.4 % 15.8 % Casualty - Claims Made Incurred Claims and Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2024 Accident Year 2015 Unaudited 2016 Unaudited 2017 Unaudited 2018 Unaudited 2019 Unaudited 2020 Unaudited 2021 Unaudited 2022 Unaudited 2023 Unaudited 2024 Total of IBNR Liabilities Plus Expected Development on Reported Claims Cumulative Number of Reported Claims ($ in thousands) 2015 $ 18,883 $ 16,777 $ 14,896 $ 13,583 $ 13,942 $ 13,548 $ 13,414 $ 13,066 $ 12,759 $ 12,679 $ 20 260 2016 19,170 14,693 14,675 14,322 13,583 13,602 13,228 12,707 12,703 12 312 2017 18,116 17,097 16,120 15,794 14,989 13,698 13,471 12,840 39 372 2018 22,429 20,234 18,612 17,057 14,411 14,272 14,186 840 466 2019 34,693 29,056 26,426 24,489 21,788 22,839 2,583 565 2020 55,630 44,641 38,287 33,667 28,877 5,467 787 2021 84,018 66,191 52,935 36,710 18,461 1,081 2022 101,064 81,394 60,873 32,026 1,234 2023 115,858 91,516 61,696 1,467 2024 123,511 103,838 1,461 Total $ 416,734 Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2015 Unaudited 2016 Unaudited 2017 Unaudited 2018 Unaudited 2019 Unaudited 2020 Unaudited 2021 Unaudited 2022 Unaudited 2023 Unaudited 2024 ($ in thousands) 2015 $ 217 $ 4,496 $ 7,563 $ 9,238 $ 11,372 $ 11,522 $ 12,142 $ 12,463 $ 12,474 $ 12,659 2016 1,158 3,015 6,907 9,839 11,381 12,105 12,299 12,691 12,691 2017 340 4,897 8,252 10,484 11,357 12,235 12,335 12,779 2018 507 5,030 8,931 10,330 11,205 12,623 13,247 2019 2,487 6,005 10,123 14,476 15,406 16,598 2020 1,002 7,446 12,551 18,589 22,445 2021 1,146 8,437 12,895 16,294 2022 3,052 12,381 24,033 2023 4,830 16,895 2024 6,755 Total 154,396 All outstanding liabilities before 2015, net of reinsurance 132 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 262,470 Casualty - Occurrence Incurred Claims and Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2024 Accident Year 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 Total of IBNR Liabilities Plus Expected Development on Reported Claims Cumulative Number of Reported Claims ($ in thousands) 2015 $ 59,717 $ 51,739 $ 49,122 $ 52,100 $ 54,697 $ 54,090 $ 54,090 $ 54,637 $ 55,259 $ 56,101 $ 3,740 1,947 2016 61,440 55,680 53,549 55,534 57,401 60,861 64,612 65,323 65,025 5,511 1,694 2017 71,126 67,151 68,985 70,641 71,117 69,911 76,715 79,203 9,117 2,288 2018 86,157 78,331 78,386 83,952 93,215 97,005 101,939 13,824 2,585 2019 112,266 109,994 108,138 107,480 115,681 120,003 26,442 2,535 2020 154,619 136,212 131,082 135,045 140,203 69,005 3,072 2021 200,598 190,879 193,722 204,787 127,633 3,228 2022 272,692 271,399 287,977 199,307 3,832 2023 372,245 372,413 322,319 3,813 2024 490,719 471,397 2,513 Total $ 1,918,370 Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 ($ in thousands) 2015 $ 941 $ 3,161 $ 12,685 $ 28,385 $ 37,690 $ 41,724 $ 44,161 $ 47,106 $ 49,147 $ 51,010 2016 1,099 6,015 17,225 28,924 34,437 43,311 51,533 55,595 57,421 2017 1,581 9,352 22,407 37,736 46,025 52,069 61,108 66,435 2018 2,638 10,995 22,860 35,138 54,441 72,174 82,927 2019 3,944 16,687 30,518 46,478 69,384 84,496 2020 2,400 8,673 17,805 32,606 55,548 2021 3,205 12,944 31,494 57,465 2022 4,658 23,084 56,201 2023 4,329 21,930 2024 6,032 Total 539,465 All outstanding liabilities before 2015, net of reinsurance 6,942 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,385,847 Historical Claims Duration The following is supplementary information about average historical claims duration as of December 31, 2024: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (Unaudited) Years 1 2 3 4 5 6 7 8 9 10 Casualty - claims made 5.0 % 22.4 % 21.9 % 16.1 % 9.9 % 5.8 % 2.9 % 3.0 % — % 1.5 % Casualty - occurrence 1.9 % 6.7 % 12.6 % 16.3 % 15.0 % 11.7 % 9.7 % 6.1 % 3.2 % 3.3 % Reconciliation of Incurred and Paid Claims Development to the Liability for Unpaid Claims and Claim Adjustment Expenses The reconciliation of the net incurred and paid claims development tables to the liability for unpaid claims and claim adjustment expenses in the consolidated statement of financial position is as follows: (in thousands) December 31, 2024 Net outstanding liabilities Property $ 116,112 Casualty - claims made 262,470 Casualty - occurrence 1,385,847 Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance 1,764,429 Reinsurance recoverable on unpaid claims Property 99,478 Casualty - claims made 21,051 Casualty - occurrence 203,463 Allowance for credit losses (932) Total reinsurance recoverable on unpaid claims 323,060 Unallocated claims adjustment expenses 197,247 Allowance for credit losses 932 Gross liability for unpaid claims and claim adjustment expense $ 2,285,668

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2024
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance The Company purchases reinsurance from other insurance companies ("reinsurers") in order to limit its exposure to large losses and enable it to underwrite policies with sufficient limits to meet policyholder needs. In a reinsurance transaction, an insurance company transfers, or cedes, part or all of its exposure to the reinsurer that receives a portion of the premium. The ceding of insurance does not legally discharge the Company from its primary liability for the full amount of the policy coverage, and therefore the Company will be required to pay the loss and bear collection risk if the reinsurer fails to meet its obligations under the reinsurance agreement. The following table summarizes the effect of reinsurance on premiums written and earned: Year Ended December 31, 2024 2023 2022 (in thousands) Written: Direct $ 1,870,341 $ 1,568,815 $ 1,102,092 Ceded (392,993) (304,185) (165,282) Net written $ 1,477,348 $ 1,264,630 $ 936,810 Earned: Direct $ 1,743,243 $ 1,367,141 $ 950,145 Ceded (392,773) (294,604) (156,026) Net earned $ 1,350,470 $ 1,072,537 $ 794,119 Incurred losses and loss adjustment expenses were net of reinsurance recoverables (ceded incurred losses and loss adjustment expenses) of $125.4 million, $115.9 million and $117.9 million for the years ended December 31, 2024, 2023 and 2022, respectively. Reinsurance balances The following table presents reinsurance recoverables on paid and unpaid losses as of December 31, 2024 and 2023: December 31, 2024 December 31, 2023 (in thousands) Reinsurance recoverables on paid losses $ 14,831 $ 6,479 Reinsurance recoverables on unpaid losses 323,060 241,357 Reinsurance recoverables $ 337,891 $ 247,836 Credit risk exists with reinsurance ceded to the extent that any reinsurer is unable to meet the obligations assumed under the reinsurance agreements. Allowances are established for amounts deemed uncollectible. The Company evaluates the financial condition of its reinsurers and monitors concentration of credit risk arising from its exposure to individual reinsurers. All reinsurance recoverables are from companies with A.M. Best ratings of "A-" (Excellent) or better. To further reduce credit exposure to reinsurance recoverable balances, the Company has received letters of credit from certain reinsurers that are not authorized as reinsurers under U.S. state insurance regulations. The Company recorded an allowance for credit losses of $0.9 million and $0.7 million related to its reinsurance balances at December 31, 2024 and 2023, respectively; however, the deterioration in the credit quality of existing reinsurers or disputes over reinsurance agreements could result in future charges. At December 31, 2024, reinsurance recoverables on paid and unpaid losses from the Company’s five largest reinsurers were $83.8 million, $37.6 million, $34.3 million, $30.0 million and $20.5 million, representing 61.0% of the total balance. At December 31, 2024, unearned premiums ceded to five reinsurers were $11.5 million, $6.3 million, $5.5 million, $4.8 million and $4.7 million representing 62.2% of the total balance.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2024
Equity, Attributable to Parent [Abstract]
Stockholders' equity	Stockholders’ equity Capital Stock The Company’s authorized capital stock consists of 400,000,000 shares of common stock, par value $0.01 per share, and 100,000,000 shares of preferred stock, par value $0.01 per share. There were no shares of preferred stock issued or outstanding at December 31, 2024 or 2023. Treasury Stock In October 2024, the Company's Board of Directors authorized a share repurchase program authorizing the repurchase of up to $100.0 million of the Company's common stock. The shares may be repurchased from time to time in open market purchases, privately-negotiated transactions, block purchases, accelerated share repurchase agreements or a combination of methods and pursuant to safe harbors provided by Rule 10b-18 and Rule 10b5-1 under the Securities Exchange Act of 1934. The timing, manner, price and amount of any repurchases under the share repurchase program will be determined by the Company in its discretion. The stock repurchase program does not require the Company to repurchase any specific number of shares, and may be modified, suspended or terminated at any time. Public Offerings In November 2022, the Company completed an underwritten public offering and sold and issued 155,000 shares of its common stock at a price of $308.30 per share, to the underwriter. The Company received net proceeds from the offering of $47.5 million. Equity-based Compensation On July 27, 2016, the Kinsale Capital Group, Inc. 2016 Omnibus Incentive Plan (the "2016 Incentive Plan") became effective. The 2016 Incentive Plan, which is administered by the Compensation, Nominating and Corporate Governance Committee of the Company's Board of Directors, provides for grants of stock options, restricted stock, restricted stock units and other stock-based awards to officers, employees, directors, independent contractors and consultants. The number of shares of common stock available for issuance under the 2016 Incentive Plan may not exceed 2,073,832. The Company recognized total equity-based compensation expense of $14.1 million, $9.4 million and $6.7 million for the years ended December 31, 2024, 2023 and 2022, respectively. Stock Options On July 27, 2016, the Board of Directors approved, and the Company granted, 1,036,916 stock options with an exercise price equal to the initial public offering price of $16.00 per share. The options have a maximum contractual term of 10 years and vested in 4 equal annual installments following the date of the grant. The weighted average grant date fair value of options granted during 2016 was $2.71 per share. The value of the options granted was estimated at the date of grant using the Black-Scholes pricing model. A summary of option activity as of December 31, 2024 and changes during the year then ended is presented below: Number of Shares Weighted-average exercise price Weighted-average remaining years of contractual life Aggregate intrinsic value (in thousands) Outstanding at December 31, 2023 201,560 $ 16.00 Granted — — Forfeited — — Exercised (83,092) 16.00 Outstanding at December 31, 2024 118,468 $ 16.00 1.6 $ 53,208 Exercisable at December 31, 2024 118,468 $ 16.00 1.6 $ 53,208 The total intrinsic value of options exercised was $38.2 million during the year ended December 31, 2024 and $17.7 million during the year ended December 31, 2023. Restricted Stock Awards During 2024, the Board of Directors approved, and the Company granted, restricted stock awards under the 2016 Incentive Plan. The restricted stock awards were valued on the date of grant and will vest over a period of 1 to 4 years corresponding to the anniversary date of the grants. The fair value of restricted stock awards was determined based on the closing trading price of the Company’s common stock on the grant date or, if no common stock was traded on the grant date, the last preceding date for which there was a sale of common stock. Except for restrictions placed on the transferability of restricted stock, holders of unvested restricted stock have full stockholder’s rights, including voting rights and the right to receive cash dividends. Unvested restricted stock awards and accrued dividends, if any, are forfeited upon the termination of service to or employment with the Company. A summary of restricted stock activity under the equity compensation plans for the year ended is as follows: December 31, 2024 Number of Shares Weighted Average Grant Date Fair Value per Share Nonvested outstanding at the beginning of the period 107,822 $ 250.86 Granted 47,689 $ 502.43 Vested (41,872) $ 230.81 Forfeited (3,516) $ 308.84 Nonvested outstanding at the end of the period 110,123 $ 366.73 Employees surrender restricted stock awards to pay for withholding tax obligations resulting from any vesting of those awards. During the year ended December 31, 2024, restricted stock awards withheld for taxes in connection with the vesting of those awards totaled 14,401. The per share weighted average grant-date fair value of the Company's restricted stock awards granted during the years ended December 31, 2024, 2023 and 2022 was $502.43, $313.35 and $211.86, respectively. The fair value of restricted stock awards that vested during the year ended December 31, 2024, 2023 and 2022 was $20.0 million, $12.8 million and $10.0 million, respectively. As of December 31, 2024, the Company had $28.3 million of total unrecognized stock-based compensation expense expected to be charged to earnings over a weighted-average period of 2.2 years. Subsequent Events The Board of Directors granted 3,186 restricted stock awards on January 1, 2025 under the 2016 Incentive Plan to the Company’s non-employee directors. The restricted stock awards had a fair value on the date of grant of $465.13 per share and will vest on the first anniversary date of the grant. On February 10, 2025, the Company’s Board of Directors declared a cash dividend of $0.17 per share of common stock. This dividend is payable on March 13, 2025 to all stockholders of record on February 27, 2025.

Earnings per share

Earnings per share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings per share	Earnings per share The following table represents a reconciliation of the numerator and denominator of the basic and diluted earnings per share computations contained in the consolidated financial statements: Year ended December 31, 2024 2023 2022 (in thousands, except per share data) Net income $ 414,843 $ 308,093 $ 159,114 Weighted average common shares outstanding - basic 23,153 23,045 22,815 Dilutive effect of shares issued under stock compensation arrangements: Stock options 136 214 269 Restricted stock awards 43 48 41 Total dilutive effect of shares issued under stock compensation arrangements 179 262 310 Weighted average common shares outstanding - diluted 23,332 23,307 23,125 Earnings per common share: Basic $ 17.92 $ 13.37 $ 6.97 Diluted $ 17.78 $ 13.22 $ 6.88 There were 43,000, 1,000 and zero anti-dilutive stock awards for the years ended December 31, 2024, 2023 and 2022.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies Contingencies arise in the normal conduct of the Company’s operations and are not expected to have a material effect on the Company’s financial condition or results of operations. However, adverse outcomes are possible and could negatively affect the Company’s financial condition and results of operations. In June 2019, Marie Hughes, as authorized administrator for the estate of George Hughes, filed a wrongful death claim against Venetian Hills Apartments, LLC ("Venetian Hills") in DeKalb County in Georgia state court. On December 20, 2023, the jury awarded a verdict to the plaintiff of $140 million. Venetian Hills was a policyholder of a $1 million general liability policy issued by Kinsale Insurance. The Company believes exclusions in the policy apply to the claim and intends to defend any action related to this proceeding vigorously. The Company has begun the appeal process and does not expect a resolution as to the Company’s liability, if any, with respect to this matter in the foreseeable future, and potentially for multiple years. The Company does not believe this legal proceeding will have a material adverse effect on its results of operations or business. The Company believes adequate provision has been made in its consolidated financial statements and its existing reserves account for liabilities to the Company relating to claims such as this legal proceeding.
Legal Matters and Contingencies	In June 2019, Marie Hughes, as authorized administrator for the estate of George Hughes, filed a wrongful death claim against Venetian Hills Apartments, LLC ("Venetian Hills") in DeKalb County in Georgia state court. On December 20, 2023, the jury awarded a verdict to the plaintiff of $140 million. Venetian Hills was a policyholder of a $1 million general liability policy issued by Kinsale Insurance. The Company believes exclusions in the policy apply to the claim and intends to defend any action related to this proceeding vigorously. The Company has begun the appeal process and does not expect a resolution as to the Company’s liability, if any, with respect to this matter in the foreseeable future, and potentially for multiple years. The Company does not believe this legal proceeding will have a material adverse effect on its results of operations or business. The Company believes adequate provision has been made in its consolidated financial statements and its existing reserves account for liabilities to the Company relating to claims such as this legal proceeding.

Employee benefit plan

Employee benefit plan	12 Months Ended
	Dec. 31, 2024
Retirement Benefits [Abstract]
Employee benefit plan	Employee benefit plan The Company has established a defined contribution employee retirement plan ("Plan") in accordance with Section 401(k) of the Internal Revenue Code. Expenses related to the Plan were $5.0 million, $3.8 million and $3.1 million in 2024, 2023 and 2022, respectively.

Other comprehensive income (los

Other comprehensive income (loss)	12 Months Ended
	Dec. 31, 2024
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income (loss)	Other comprehensive (loss) income The following table summarizes the components of other comprehensive (loss) income: Year Ending December 31, 2024 2023 2022 (in thousands) Unrealized (losses) gains on fixed-maturity securities arising during the period, before income taxes: $ (2,921) $ 49,384 $ (193,970) Income tax benefit (expense) 613 (10,371) 40,734 Unrealized (losses) gains arising during the period, net of income taxes (2,308) 39,013 (153,236) Less reclassification adjustment: Net realized investment (losses) gains on available-for-sale investments (170) (1,443) 121 Income tax benefit (expense) 36 303 (25) Reclassification adjustment included in net income (134) (1,140) 96 Change in allowance for credit losses on investments, before income taxes 526 (187) (366) Income tax (expense) benefit (111) 39 77 Reclassification adjustment included in net income 415 (148) (289) Other comprehensive (loss) income $ (2,589) $ 40,301 $ (153,043) The sale of or credit loss on an available-for-sale security results in amounts being reclassified from accumulated other comprehensive income to realized gains or losses in current period earnings. The related tax effect of the reclassification adjustment is recorded in income tax expense in current period earnings. See Note 2 for additional information.

Underwriting information

Underwriting information	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Underwriting information	Segment and underwriting information The Company has one reportable segment, the Excess and Surplus Lines Insurance segment, which primarily offers commercial excess and surplus lines liability and property insurance products through its underwriting divisions in the United States. The Company reports operating and financial results in a single segment based on the Company's exclusive focus on property and casualty insurance in the excess and surplus lines market and the consolidated information used by the chief operating decision maker ("CODM") in evaluating the financial performance of its business and allocating resources. Additionally, while the Company's individual underwriting divisions are evaluated on premium volume, the CODM does not use discrete financial information for measures of profit or loss in making resource allocation decisions. The Company's CODM is the Chief Executive Officer. The CODM uses consolidated net income to allocate resources primarily during the annual budgeting process and uses that measure to assess performance by considering budget-to-actual variances and evaluating financial results. The measure of segment assets is reported on the consolidated balance sheets as total assets. The accounting policies used to prepare the segment reporting data are the same as those described in Note 1. Year Ended December 31, 2024 2023 2022 (in thousands) Revenues: Net earned premiums $ 1,350,470 $ 1,072,537 $ 794,119 Fee income 34,118 27,026 19,604 Net investment income 150,287 102,335 51,282 Change in fair value of equity securities 43,367 15,277 (27,723) Net realized investment gains 6,831 6,040 1,191 Change in allowance for credit losses on investments 526 (187) (366) Other income (1) 1,926 1,421 697 Total revenues 1,587,525 1,224,449 838,804 Expenses: Losses and loss adjustment expenses - current year 785,036 631,407 467,182 Losses and loss adjustment expenses - catastrophes 25,518 4,586 26,618 Losses and loss adjustment expenses - prior year development (37,655) (35,774) (35,887) Net commissions incurred 134,184 113,717 93,756 Salaries, employee benefits and bonus expense 109,319 85,689 64,765 Credit loss expense - premiums receivable 17,397 9,790 5,988 Depreciation (2) 4,686 2,655 2,267 Interest expense 10,134 10,301 4,284 Other segment items (3) 24,190 18,061 14,267 Income tax expense 99,873 75,924 36,450 Segment net income 414,843 308,093 159,114 Reconciliation of profit or loss: Adjustments and reconciling items — — — Consolidated net income $ 414,843 $ 308,093 $ 159,114 (1) Other income primarily includes income generated from the Company's real estate operations. (2) Excludes depreciation expense allocated to loss adjustment expenses and investment expenses (3) Other segment items primarily includes other general and administrative expenses such as technology costs, facility expenses and audit and inspection costs. Gross written premiums by underwriting division are presented below: Year Ended December 31, 2024 2023 2022 (in thousands) Commercial: Commercial Property $ 456,170 $ 411,956 $ 181,505 Excess Casualty 245,137 194,049 147,485 Small Business Casualty 195,593 174,080 149,366 General Casualty 169,162 118,745 69,784 Construction 148,333 137,887 122,524 Allied Health 83,058 67,808 58,839 Small Business Property 76,800 43,893 21,002 Products Liability 67,035 61,786 60,374 Entertainment 58,506 39,218 22,268 Energy 42,710 38,637 32,217 Life Sciences 36,252 41,379 41,346 Commercial Auto 35,047 19,050 5,950 Professional Liability 34,841 35,743 30,313 Excess Professional 32,633 24,033 22,826 Environmental 30,372 25,938 19,455 Inland Marine 27,184 18,669 14,396 Health Care 23,179 20,378 16,916 Management Liability 21,705 26,617 28,856 Public Entity 20,047 20,028 15,512 Aviation 8,591 6,453 4,424 Ocean Marine 3,655 2,339 765 Agribusiness 2,775 — — Product Recall 2,397 1,637 1,419 Railroad 225 15 — Total commercial 1,821,407 1,530,338 1,067,542 Personal: High Value Homeowners 26,844 14,295 3,261 Personal Insurance 22,090 24,182 31,289 Total personal 48,934 38,477 34,550 Total $ 1,870,341 $ 1,568,815 $ 1,102,092 Certain prior year amounts are reclassified to conform to current year's divisions and the business underwritten within them. Commercial Property underwrites first-party coverage on manufacturing facilities, government and municipal buildings, professional buildings, offices and general commercial properties, vacant properties, as well as entertainment and retail facilities. Excess Casualty underwrites excess liability over risks that would fit within the general casualty, construction, products liability and small business casualty divisions. Coverage is written over the Company's primary liability policies as well as those of other insurers. This division also writes excess liability over primary commercial auto liability policies written by other carriers. Small Business Casualty underwrites commercial general liability on smaller risks, generally businesses with revenues not exceeding $2.5 million, with an emphasis on artisan contractors and premises related exposures. General Casualty underwrites general liability and liquor liability on hospitality, habitational and retail risks, among others, with similar premises liability loss exposures. Construction underwrites commercial general liability coverage on contractors focusing on new residential construction, residential remodeling and renovation and commercial construction. Allied Health underwrites commercial general liability, professional liability and excess liability on allied health and social service risks including assisted living facilities, home health care agencies and outpatient medical facilities. Small Business Property underwrites Commercial Property coverage for smaller properties, generally with total insured values not exceeding $3.5 million, including banks, daycare centers, strip malls, and greenhouses, among others. Products Liability underwrites commercial general liability on manufacturers, distributors and importers of a wide array of consumer, commercial and industrial products. Entertainment underwrites commercial general liability for small-to-medium sized entertainment classes, including such classes as bowling alleys, campgrounds, escape rooms, fitness centers, museums and paintball facilities, among others. Energy underwrites commercial general liability, pollution liability, professional liability and excess liability on enterprises engaged in the business of energy production or distribution or mining including drillers, lease operators, contractors, product manufacturers and alternative energy. Life Sciences underwrites general liability, products liability and professional liability coverage for manufacturers, distributors and developers of dietary supplements, medical devices, pharmaceuticals, biologics, health and beauty products, durable medical equipment and clinical trials. Commercial Auto underwrites garage liability and excess auto coverages. Professional Liability underwrites small-to-medium sized non-medical professional liability risks. The classes of risks include accountants, architects and engineers, financial planners, insurance agents, lawyers, realtors and certain other professions. Excess Professional underwrites excess coverage over an array of insurance products in Allied Health, Management Liability, Health Care and Professional Liability. Environmental underwrites commercial general liability, pollution liability and professional liability on a wide range of commercial risks where environmental exposures exist that are operational in nature or related to the premises. Inland Marine underwrites a variety of inland marine coverages including builders risk, contractors' equipment, transportation risks and mobile equipment. Health Care underwrites medical professional liability for physicians, surgeons, dentists, chiropractors and podiatrists. Policies cover both individuals and small practice groups. Management Liability underwrites directors and officers liability, employment practices liability and fiduciary liability coverage on a variety of commercial and government risks. Public Entity underwrites law enforcement professional liability and school board liability. Aviation underwrites general liability coverage for small-to-medium sized aviation-related businesses. Ocean Marine underwrites marine cargo coverage for small-to-medium sized risks that transport goods and products in domestic inland waterways and certain U.S. coastal waters. Agribusiness underwrites general liability coverage for operations, manufacturers and land related to the agriculture industry. Product Recall underwrites recall expense and liability coverage for life sciences and general products sector consumable, commercial and consumer goods. Railroad underwrites excess liability for Class III short line railroads, railroad support activities and contractors and other miscellaneous railroad-related risks. High Value Homeowners underwrites first party homeowners' coverage on homes valued above $1.0 million on a primary and excess basis. Personal Insurance writes homeowners' coverage on manufactured homes with catastrophe exposure due to coastal location. The Company does business with three unaffiliated insurance brokers that generated $366.4 million, $325.5 million and $213.9 million of gross written premiums for the year ended December 31, 2024, representing 19.6%, 17.4% and 11.4% of gross written premiums, respectively. No other broker generated 10.0% or more of the gross written premiums for the year ended December 31, 2024.

Statutory financial information

Statutory financial information	12 Months Ended
	Dec. 31, 2024
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments [Abstract]
Statutory financial information	Statutory financial information Kinsale Insurance maintains its accounts in conformity with accounting practices prescribed or permitted by state regulatory authorities that vary in certain respects from U.S. GAAP. In converting from statutory accounting principles to U.S. GAAP, typical adjustments include deferral of policy acquisition costs, the inclusion of statutory non-admitted assets and the inclusion of net unrealized gains or losses relating to fixed maturities in stockholders’ equity. The Company does not use any permitted practices that are different from prescribed statutory accounting practices. Statutory net income and statutory capital and surplus for Kinsale Insurance as of December 31, 2024, 2023, and 2022 and for the years then ended are summarized as follows: Year ended December 31, 2024 2023 2022 (in thousands) Statutory net income $ 357,896 $ 259,042 $ 151,105 Statutory capital and surplus $ 1,525,851 $ 1,167,382 $ 835,664 Kinsale Insurance is subject to risk-based capital ("RBC") requirements. RBC is a method developed by the National Association of Insurance Commissioners ("NAIC") to determine the minimum amount of statutory capital appropriate for an insurance company to support its overall business operations in consideration of its size and risk profile. The formula for determining the amount of RBC is calculated using various factors, weighted based on the perceived degree of risk, which are applied to certain financial balances and financial activity. The adequacy of a company’s actual capital is evaluated by a comparison to the RBC results, as determined by the formula. Companies that do not maintain statutory capital and surplus at a level in excess of the company action level RBC are required to take specified actions. At December 31, 2024 and 2023, actual statutory capital and surplus for Kinsale Insurance substantially exceeded the regulatory requirements. Dividend payments to Kinsale from Kinsale Insurance are restricted by state insurance laws as to the amount that may be paid without prior approval of the regulatory authorities of Arkansas. The maximum dividend distribution is limited by Arkansas law to the greater of 10% of policyholder surplus as of December 31 of the previous year or statutory net income, not including realized capital gains, for the previous calendar year. Dividend payments are further limited to that part of available policyholder surplus which is derived from net profits on its business. The maximum dividend distribution that can be paid by Kinsale Insurance during 2025 without prior approval is $351.9 million.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	Subsequent event In January 2025, a series of wildfires began in Southern California. The Company is evaluating the impact of such wildfires and currently estimates pre-tax catastrophe losses of approximately $25.0 million, net of reinsurance, to be reflected in the first quarter of 2025. These estimates are subject to change due to the ongoing nature of these events and the complexity of the claims.

SEC Schedule, Article 12-15, Su

SEC Schedule, Article 12-15, Summary of Investments - Other than Investments in Related Parties	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties	Schedule I KINSALE CAPITAL GROUP, INC. AND SUBSIDIARIES Summary of Investments—Other than Investments in Related Parties Type of Investment Cost or Amortized Cost Fair Value Amount at which shown on Balance Sheet (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 15,465 $ 15,048 $ 15,048 Obligations of states, municipalities and political subdivisions 168,894 146,304 146,304 Corporate and other securities 2,037,372 1,989,490 1,989,490 Asset-backed securities 729,658 732,742 732,742 Residential mortgage-backed securities 502,121 448,874 448,874 Commercial mortgage-backed securities 209,521 205,105 205,105 Total fixed maturities 3,663,031 3,537,563 3,537,563 Equity securities: Common stocks: ETFs (industrial, miscellaneous and all other) 72,773 129,731 129,731 Banks, trust and insurance companies 47,994 58,777 58,777 Industrial, miscellaneous and all other 165,017 183,418 183,418 Non-redeemable preferred stock 27,938 26,433 26,433 Total equity securities 313,722 398,359 398,359 Short-term investments 3,714 3,714 3,714 Real estate investments (none acquired in satisfaction of debt) 15,045 15,045 Total investments $ 3,995,512 $ 3,954,681

Schedule II - Condensed Financi

Schedule II - Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure	KINSALE CAPITAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information of Registrant Balance Sheets (Parent Company Only) December 31, 2024 2023 (in thousands) Assets Cash and cash equivalents $ 12,336 $ 17,082 Due from subsidiaries 52,296 26,479 Investment in subsidiaries 1,604,811 1,230,371 Deferred income tax asset, net 2,527 1,673 Other assets 664 410 Total assets $ 1,672,634 $ 1,276,015 Liabilities and Stockholders' Equity Liabilities: Accounts payable and accrued expenses $ 2,001 $ 2,042 Income taxes payable 2,842 3,201 Debt 184,122 183,846 Other liabilities 108 94 Total liabilities 189,073 189,183 Stockholders’ equity: Common stock 233 232 Additional paid-in capital 361,398 352,970 Retained earnings 1,229,136 828,247 Accumulated other comprehensive loss (97,206) (94,617) Treasury stock, at cost (10,000) — Stockholders’ equity 1,483,561 1,086,832 Total liabilities and stockholders’ equity $ 1,672,634 $ 1,276,015 See accompanying notes to condensed financial information. See accompanying Report of Independent Registered Public Accounting Firm. Schedule II KINSALE CAPITAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information of Registrant Statements of Income and Comprehensive Income (Parent Company Only) Years Ended December 31, 2024 2023 2022 (in thousands) Revenues: Management fees from subsidiaries $ 16,769 $ 11,918 $ 8,686 Net investment income 641 — 121 Net realized investment gains — — 8 Total revenues 17,410 11,918 8,815 Expenses: Operating expenses 17,193 13,007 9,765 Interest expense 10,134 10,301 4,284 Other expenses 615 — — Total expenses 27,942 23,308 14,049 Loss before income taxes (10,532) (11,390) (5,234) Income tax benefit (12,346) (7,324) (5,387) Income (loss) before equity in net income of subsidiaries 1,814 (4,066) 153 Equity in undistributed earnings of subsidiaries 413,029 312,159 158,961 Net income 414,843 308,093 159,114 Other comprehensive income (loss): Equity in other comprehensive (losses) income of subsidiaries (2,589) 40,301 (153,043) Total comprehensive income $ 412,254 $ 348,394 $ 6,071 See accompanying notes to condensed financial information. See accompanying Report of Independent Registered Public Accounting Firm. Schedule II KINSALE CAPITAL GROUP, INC. AND SUBSIDIARIES Condensed Financial Information of Registrant Statements of Cash Flows (Parent Company Only) Years Ended December 31, 2024 2023 2022 (in thousands) Operating activities Net income $ 414,843 $ 308,093 $ 159,114 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Deferred tax benefit (854) (372) (367) Stock compensation expense 14,146 9,361 6,678 Equity in undistributed earnings of subsidiaries (413,029) (312,159) (158,961) Changes in operating assets and liabilities (25,795) 55,893 (71,639) Current taxes payable (359) — — Change in accounts payable and accrued expenses (41) — — Dividends received from subsidiary 47,000 — — Net cash provided by (used in) operating activities 35,911 60,816 (65,175) Investing activities Contributions to subsidiary (11,000) (50,000) (100,624) Net cash used in investing activities (11,000) (50,000) (100,624) Financing activities Common stock issued, net of transaction costs — — 47,498 Proceeds from credit facility — — 73,000 Proceeds from notes payable — 50,000 125,000 Repayment of credit facility — (62,000) (43,000) Debt issuance costs — (164) (2,381) Payroll taxes withheld and remitted on share-based payments (7,047) (4,282) (3,288) Common stock issued, stock options exercised 1,330 877 1,090 Dividends paid (13,940) (12,954) (11,927) Treasury stock acquired — share repurchases (10,000) — — Net cash (used in) provided by financing activities (29,657) (28,523) 185,992 Net change in cash and cash equivalents (4,746) (17,707) 20,193 Cash and cash equivalents at beginning of year 17,082 34,789 14,596 Cash and cash equivalents at end of year $ 12,336 $ 17,082 $ 34,789 See accompanying notes to condensed financial information. See accompanying Report of Independent Registered Public Accounting Firm. KINSALE CAPITAL GROUP, INC. Condensed Financial Information of Registrant Notes to Condensed Financial Information (Parent Company Only) 1. Accounting policies Organization Kinsale Capital Group, Inc. (the "Company"), a Delaware domiciled insurance holding company, was formed on June 3, 2009 for the purpose of acquiring and managing insurance entities. Basis of presentation The accompanying condensed financial statements have been prepared using the equity method. Under the equity method, the investment in consolidated subsidiaries is stated at cost plus equity in undistributed earnings of consolidated subsidiaries since the date of acquisition. These condensed financial statements should be read in conjunction with the Company’s consolidated financial statements. Estimates and assumptions Preparation of the condensed financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed financial statements and accompanying disclosures. Those estimates are inherently subject to change, and actual results may ultimately differ from those estimates. Debt Note Purchase and Private Shelf Agreement On July 22, 2022, the Company entered into a Note Purchase and Private Shelf Agreement (as subsequently amended, the "Note Purchase Agreement") with PGIM, Inc. ("Prudential") and the purchasers of the Series A and Series B Senior Notes (as defined below). The Note Purchase Agreement provides for issuance of senior promissory notes with an aggregate principal amount of up to $200.0 million through September 18, 2026. Pursuant to the Note Purchase Agreement, on July 22, 2022, the Company issued $125.0 million aggregate principal amount of 5.15% Series A Senior Notes Due July 22, 2034 (collectively, the "Series A Notes”), and on September 18, 2023, the Company issued a $50.0 million aggregate principal amount 6.21% Series B Senior Note ("Series B Note") due July 22, 2034. The Series A and B Notes are senior unsecured obligations of the Company and rank pari passu with the Company’s Amended and Restated Credit Agreement. Principal payments on the Series A Notes are required annually beginning on July 22, 2030 in equal installments of $25.0 million through July 22, 2034. Principal payments on the Series B Note are required annually beginning on July 22, 2030 in equal installments of $10.0 million through July 22, 2034. Credit Agreement On July 22, 2022, the Company entered into an Amended and Restated Credit Agreement, with JPMorgan Chase Bank, N.A., as administrative agent and as issuing bank, Truist Bank, as syndication agent, and the lenders party thereto (collectively, the "Lenders"). The Amended and Restated Credit Agreement provides the Company with a $100.0 million senior unsecured revolving credit facility (the "Credit Facility"), with the option to increase the aggregate commitment by $30.0 million. The Company is required to pay a Commitment Fee Rate (as defined therein) of 0.25% on the average daily amount of the Available Revolving Commitment (as defined therein). Borrowings under the Amended and Restated Credit Agreement may be used for general corporate purposes (which may include, without limitation, to fund future growth, to finance working capital needs, to fund capital expenditures, and to refinance, redeem or repay indebtedness). In September 2023, the Company used proceeds from the sale of its real estate investment property to pay down $62.0 million from the Credit Facility. The loans under the Amended and Restated Credit Agreement bear interest, at the Company's option, at a rate equal to the Adjusted Term SOFR Rate (as defined therein) plus 1.625% or the Alternate Base Rate (as defined therein) plus 0.625%. For the year ended December 31, 2024, the annual weighted-average interest rate of borrowings under the Credit Facility was 6.91%. The following table presents the Company's outstanding debt as of December 31, 2024 and December 31, 2023: Issuance Maturities December 31, 2024 December 31, 2023 (in thousands) Credit Facility Various 7/22/2027 $ 11,000 $ 11,000 5.15% Series A Notes 7/22/2022 7/22/2034 125,000 125,000 6.21% Series B Note 9/18/2023 7/22/2034 50,000 50,000 Less: Unamortized debt issuance costs (1,878) (2,154) Total debt $ 184,122 $ 183,846 Interest paid under both agreements totaled $10.3 million, $10.5 million and $2.4 million for the years ended December 31, 2024, 2023 and 2022, respectively. Both the Note Purchase Agreement and the Amended and Restated Credit Agreement contain representations and affirmative and negative covenants, including financial covenants customary for agreements of this type, as well as customary events of default provisions. In October 2024, the covenants limiting restricted payments under the Note Purchase Agreement and Amended and Restated Credit Agreement were amended. The amendments allow the Company to make restricted payments so long as the aggregate amount of all such restricted payments does not exceed the greater of $300.0 million and 6.5% of the total assets of the Company and its subsidiaries at the end of the most recently completed fiscal quarter. As of December 31, 2024, the Company was in compliance with all of its financial covenants under both the Note Purchase Agreement and the Credit Facility. Dividends from subsidiary Cash dividends paid to Kinsale Capital Group, Inc. by its wholly-owned subsidiary, Kinsale Insurance Company, were $47.0 million for year ended December 31, 2024. There were no cash dividends paid by the insurance subsidiary for the years ended December 31, 2023 and 2022. Contingencies Liabilities for loss contingencies, arising from non-insurance policy claims, assessments, litigation, fines, and penalties and other sources, are recorded when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred.

Schedule V - Valuation and Qual

Schedule V - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule V - Valuation and Qualifying Accounts	Schedule V KINSALE CAPITAL GROUP, INC. AND SUBSIDIARIES Valuation and Qualifying Accounts Additions Deductions (in thousands) Balance Amounts Amounts Balance Year Ended December 31, 2024: Allowance for premiums receivable $ 13,383 $ 17,397 $ 3,854 $ 26,926 Valuation allowance for deferred tax assets 6,182 2,884 — 9,066 Allowance for reinsurance recoverables 744 188 — 932 Allowance for credit losses on fixed-maturity investments 553 (47) 479 27 Year Ended December 31, 2023: Allowance for premiums receivable 8,067 9,790 4,474 13,383 Valuation allowance for deferred tax assets 5,188 994 — 6,182 Allowance for reinsurance recoverables 459 285 — 744 Allowance for credit losses on fixed-maturity investments 366 199 12 553 Year Ended December 31, 2022: Allowance for premiums receivable 3,391 5,988 1,312 8,067 Valuation allowance for deferred tax assets 4,159 1,029 — 5,188 Allowance for reinsurance recoverables 400 59 — 459 Allowance for credit losses on fixed-maturity investments — 366 — 366

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net income	$ 414,843	$ 308,093	$ 159,114

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement	Securities Trading Plans of Directors and Executive Officers Transactions in our securities by our non-employee directors and executive officers are required to be made in accordance with our insider trading policy, which, among other things, requires that the transactions be in accordance with applicable U.S. federal securities laws that prohibit trading while in possession of material nonpublic information. Rule 10b5-1 under the Exchange Act provides an affirmative defense that enables prearranged transactions in securities in a manner that avoids concerns about initiating transactions at a future date while possibly in possession of material nonpublic information. Our insider trading policy permits our non-employee directors and executive officers to enter into trading plans designed to comply with Rule 10b5-1. The following table describes any contracts, instructions or written plans adopted for the sale or purchase of our securities by our non-employee directors and executive officers during the fourth quarter of 2024, which is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c), referred to as Rule 10b5-1 trading plans. Name Title Date of Adoption of Rule 10b5-1 Trading Plan Scheduled Expiration Date of Rule 10b5-1 Trading Plan (1) Aggregate Number of Securities to Be Purchased or Sold Gregory M. Share Director December 11, 2024 January 30, 2026 Sale of up to 1,578 shares beginning on the commencement date of the trading period (1) A trading plan may also expire on such earlier date as all transactions under the trading plan are completed. During the fourth quarter of 2024, none of our non-employee directors or executive officers modified or terminated a Rule 10b5-1 trading plan or adopted, modified or terminated a non-Rule 10b5-1 trading arrangement (as defined in Item 408(c) of Regulation S-K).
Name	Gregory M. Share
Title	Director
Rule 10b5-1 Arrangement Adopted	true
Non-Rule 10b5-1 Arrangement Adopted	false
Adoption Date	December 11, 2024
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Expiration Date	January 30, 2026
Aggregate Available	1,578

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Risk management and strategy The Company’s risk management process includes assessing, identifying and managing material risks from various sources, including those related to cybersecurity. The Company uses information from incident history, industry publications and analysis centers, public news, government information sharing and recognized information security frameworks to inform its risk management program. Management employs a suite of detective and preventative cybersecurity measures including, but not limited to • Maintaining a vulnerability management program, • implementing and operating controls over logical access provisioning, • maintaining an enterprise-wide security awareness program and • administering periodic trainings. The Company engages multiple vendors with subject matter and technological expertise in various aspects of cybersecurity management, including continuous threat detection and response coverage, endpoint detection, anti-malware, penetration testing and suspicious activity alerting, among others. When the Company engages third parties, management retains responsibility for the security and resiliency of its information assets. The Company maintains an incident response plan that includes escalation criteria and preliminary materiality assessments to guide business continuity and disclosure objectives.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Text Block]	We describe risks related to cybersecurity threats that could materially impact our business strategy, results of operations or financial condition under the heading “Risk Factors.” Material impacts could include loss of access to systems and data, financial costs and reputational harm, among others.
Cybersecurity Risk Board of Directors Oversight [Text Block]	The Audit Committee of the Board of Directors (the "Audit Committee") is responsible for receiving periodic updates on cybersecurity and information security risks, reviewing and discussing with management the quality and effectiveness of the Company’s efforts to mitigate such risks and reporting such findings to the Board of Directors. Management informs the Audit Committee about prevention, detection, mitigation and remediation of cybersecurity incidents at least semi-annually and monitors such matters continuously. In 2025, the oversight over the Company's cybersecurity risk will transition from the Audit Committee to the Board of Directors ("the Board") to align with the Board's oversight of operational risks.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee of the Board of Directors (the "Audit Committee") is responsible for receiving periodic updates on cybersecurity and information security risks, reviewing and discussing with management the quality and effectiveness of the Company’s efforts to mitigate such risks and reporting such findings to the Board of Directors. Management informs the Audit Committee about prevention, detection, mitigation and remediation of cybersecurity incidents at least semi-annually and monitors such matters continuously.
Cybersecurity Risk Role of Management [Text Block]	Our Chief Executive Officer ("CEO") is responsible for assessing and managing overall material risks to the Company. With respect to cybersecurity risks, our CEO leverages the collective expertise of the Company’s information security function which reports to our CEO through the Company’s Chief Information Officer. The information security function is staffed with individuals with extensive information security employment experience, including in the financial services sector, educational experience and relevant credentials.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	With respect to cybersecurity risks, our CEO leverages the collective expertise of the Company’s information security function which reports to our CEO through the Company’s Chief Information Officer. The information security function is staffed with individuals with extensive information security employment experience, including in the financial services sector, educational experience and relevant credentials.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	Management informs the Audit Committee about prevention, detection, mitigation and remediation of cybersecurity incidents at least semi-annually and monitors such matters continuously.

Summary of significant accoun_2

Summary of significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Principles of consolidation	Principles of consolidation The accompanying consolidated financial statements include the accounts of Kinsale Capital Group, Inc. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. Certain prior year amounts have been reclassified to conform to the current year's presentation.
Use of estimates	Use of estimates
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investments with an original maturity of three months or less to be cash equivalents.
Short-term investments	Short-term investments
Fixed maturity and equity securities	Fixed-maturity and equity securities Fixed-maturity securities are classified as available-for-sale and reported at fair value. Unrealized gains and losses on these securities are excluded from earnings but are recorded as a separate component of other comprehensive income and stockholders' equity, net of deferred income taxes. Equity securities are reported at fair value. Changes in unrealized gains and losses in fair value of these investments are recognized in net income. The Company regularly reviews all its available-for-sale investments with unrealized losses to assess whether the decline in the fair value is deemed to be a credit loss. See Note 2 for further discussion regarding the determination of credit losses. Interest on fixed-maturity securities is credited to earnings as it accrues. Premiums and discounts are amortized or accreted using the effective interest method over the lives of the related fixed maturities, or to the earliest call date for securities purchased at a premium. This method includes an adjustment for estimated principal prepayments, if any, on asset- and mortgage-backed securities. To the extent that the estimated lives of such securities change as a result of changes in estimated prepayment rates, the adjustments are included in net investment income using the retrospective method. Dividends on equity securities are included in earnings on the ex-dividend date. Realized gains and losses on disposition of investments are based on specific identification of the investments sold on the trade date.
Investment Real Estate	Real estate investments Real estate investments include real estate and the related assets purchased for investment purposes. Real estate and the related depreciable assets are carried at cost, net of accumulated depreciation. Depreciation is calculated on a straight-line basis over the estimated useful life of the assets and is included in net investment income. Rental income is recognized on a straight-line basis over the term of the respective lease and is included in net investment income. Land is not depreciated. Real estate is evaluated for impairment when events or circumstances indicate the carrying value of the real estate may not be recoverable.
Reinsurance	Reinsurance Reinsurance premiums, commissions, and ceded unearned premiums on reinsured business are accounted for on a basis consistent with that used in accounting for the original policies issued and the terms of the reinsurance contracts. The Company receives ceding commissions in accordance with certain reinsurance treaties. The ceding commissions are capitalized and amortized as a reduction of underwriting, acquisition and insurance expenses. Reinsurance recoverables represent paid losses and loss adjustment expenses and reserves for unpaid losses and loss adjustment expenses ceded to reinsurers that are subject to reimbursement under reinsurance treaties. The method for determining reinsurance recoverables for unpaid losses and loss adjustment expenses involves reviewing actuarial estimates of gross unpaid losses and loss adjustment expenses to determine the Company's ability to cede unpaid losses and loss adjustment expenses under the Company's existing reinsurance contracts. This method is continually reviewed and updated and any resulting adjustments are reflected in earnings in the period identified. See Note 8 for a further discussion of the Company's reinsurance program.
Premiums receivable, net	Premiums receivable, net Premiums receivable balances are carried at face value, net of any allowance for credit losses. The allowance for credit losses represents an estimate of amounts considered uncollectible based on the Company’s assessment of the collectability of receivables that are past due. The estimate considers historical loss data, current and future economic conditions and specific identification of collectability concerns where applicable. The following table presents the rollforward of the allowance for credit losses for premiums receivable for the years ended December 31, 2024 and 2023: Year Ended December 31, 2024 2023 (in thousands) Beginning balance $ 13,383 $ 8,067 Current period change for estimated uncollectible premiums 17,397 9,790 Write-offs of uncollectible premiums receivable (3,854) (4,474) Ending balance $ 26,926 $ 13,383
Deferred policy acquisition costs, net of ceding commissions	Deferred policy acquisition costs, net of ceding commissions The Company defers commissions, net of ceding commissions, and certain other costs that are directly related to the successful acquisition of insurance contracts. All eligible costs are capitalized and charged to expense in proportion to premium earned over the estimated policy life. To the extent that unearned premiums on existing policies are not adequate to cover the related costs and expenses, referred to as a premium deficiency, deferred policy acquisition costs are charged to earnings. The Company considers anticipated investment income in determining whether a premium deficiency exists.
Property and equipment, net	Property and equipment, net Property and equipment are stated at cost less accumulated depreciation. Depreciation of property and equipment is calculated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives range from 39 years for the building and parking deck, 15 to 20 years for land improvements, 7 to 10 years for furniture and equipment, and 3 to 7 years for electronic data processing hardware and software. Property and equipment are included in other assets in the accompanying consolidated balance sheets and consists of the following: December 31, 2024 2023 (in thousands) Building $ 37,190 $ 37,181 Parking deck 5,072 5,072 Land 3,068 3,068 Equipment 4,401 3,958 Software 20,203 15,375 Furniture and fixtures 3,200 3,065 Leasehold improvements 153 153 Land improvements 474 474 Construction in progress - building 26,530 6,623 100,291 74,969 Accumulated depreciation (17,367) (11,565) Total property and equipment, net $ 82,924 $ 63,404 Construction in progress includes capitalized expenses related to the development of the new corporate headquarters' building. Construction is expected to be completed in the fourth quarter of 2025.
Indefinite-Lived intangible assets	Indefinite-lived intangible assets Indefinite-lived intangible assets are recorded at fair value at the date of acquisition. The Company's indefinite-lived intangible assets are comprised solely of regulatory approvals granted by the various state insurance departments to write insurance business in the respective states on a non-admitted basis. In accordance with U.S. GAAP, amortization of indefinite-lived intangible assets is not permitted. Indefinite-lived intangible assets are tested for impairment during the fourth quarter on an annual basis, or earlier if there is reason to suspect that their values may have been diminished or impaired. There were no impairments recognized in December 31, 2024, 2023, or 2022. In addition, as of December 31, 2024, no triggering events occurred that suggested an updated review was necessary.
Reserves for unpaid losses and loss adjustment expenses	Reserves for unpaid losses and loss adjustment expenses Reserves for unpaid losses and loss adjustment expenses represent management's best estimate of ultimate unpaid cost of all reported and unreported losses and loss adjustment expenses incurred prior to the financial statement date. The estimates are based on several actuarial methods that use a variety of inputs including initial expected loss ratios, loss development patterns, paid losses, reported losses, claim counts and price indices. All estimates are regularly reviewed and, as experience develops and new information becomes known, the reserves for unpaid losses and loss adjustment expenses are adjusted as necessary. Such adjustments are reflected in the results of operations in the period in which they
Revenue recognition	Revenue recognition Premiums are recognized as revenue ratably over the term of the insurance contracts, net of ceded reinsurance. Unearned premiums are calculated on a daily pro rata basis. Fee income is recognized as revenue when the related premium is written.
Income taxes	Income taxes Deferred income tax assets and liabilities are determined based on the differences between the recorded amounts and the tax bases of assets and liabilities, using enacted tax rates expected to be in effect during the year in which the basis differences reverse. The effect on deferred taxes of a change in tax rates is recognized in income in the period in which such change was enacted. Valuation allowances on deferred tax assets are estimated based on the Company's assessment of the realizability of such amounts. Valuation allowances are recorded when it is more likely than not that some portion, or all, of the deferred tax assets will not be realizable. The Company provides for uncertain tax positions, and the related interest and penalties, based upon management’s assessment of whether a tax benefit is more likely than not to be sustained upon examination by tax authorities. To the extent that the anticipated tax outcome of these uncertain tax positions changes, such changes in estimate will impact the income tax provision in the period in which such determination is made. The Company recognizes accrued interest and penalties related to uncertain tax positions as a component of income tax expense. The Company uses the portfolio approach to release stranded tax effects in accumulated other comprehensive income ("AOCI") related to its available-for-sale fixed-maturity securities. Under this approach, stranded tax effects remaining in AOCI are released only when the entire portfolio of the available-for-sale fixed-maturity securities are liquidated, sold or extinguished.
Commitments and contingencies	Contingencies Liabilities for loss contingencies, arising from noninsurance policy claims, assessments, litigation, fines, and penalties and other sources, are recorded when it is probable that a liability has been incurred and the amount of the assessment and/or remediation can be reasonably estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred.
Fair value of financial instruments	Fair value of financial instruments Fair value is estimated for each class of financial instrument based on the framework established in the fair value accounting guidance. This guidance requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Fair value hierarchy disclosures are based on the quality of inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). See Note 3 for further details regarding fair value disclosures.
Stock-based compensation	Stock-based compensation Stock-based compensation is expensed based upon the estimated fair value of employee stock awards. Compensation cost for awards of equity instruments to employees is measured based on the grant-date fair value of those awards and compensation expense is recognized over the service period that the awards vest. Forfeitures of stock-based compensation awards are recognized as they occur. See Note 9 for further discussion and related disclosures regarding stock-based compensation.
Prospective accounting pronouncements	Recently adopted accounting pronouncements Accounting Standards Update ("ASU") 2023-07, Segment Reporting - Improvements to Reportable Segment Disclosures In November 2023, the Financial Accounting Standards Board ("FASB") issued ASU 2023-07, "Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures," which expands reportable segment disclosure requirements by requiring disclosures of significant reportable segment expenses that are regularly provided to the Chief Operating Decision Maker ("CODM") and included within each reported measure of a segment's profit or loss. The ASU also requires disclosure of the title and position of the individual identified as the CODM and an explanation of how the CODM uses the reported measures of a segment's profit or loss in assessing segment performance and deciding how to allocate resources. Additionally, ASU 2023-07 requires all segment profit or loss and assets disclosures to be provided on an annual and interim basis. ASU 2023-07 became effective for the Company for the year ended December 31, 2024 and will be effective for interim periods beginning in 2025. Refer to Note 15 for the Company's segment reporting disclosures. Prospective accounting pronouncements ASU 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures In November 2024, the FASB issued ASU 2024-03, "Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses," requiring public entities to disclose additional information about specific expense categories in the notes to the financial statements on an interim and annual basis. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and for interim periods beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the effect the guidance will have on its disclosures.

Accounting Policies (Tables)

Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Property, Plant and Equipment	Property and equipment are included in other assets in the accompanying consolidated balance sheets and consists of the following: December 31, 2024 2023 (in thousands) Building $ 37,190 $ 37,181 Parking deck 5,072 5,072 Land 3,068 3,068 Equipment 4,401 3,958 Software 20,203 15,375 Furniture and fixtures 3,200 3,065 Leasehold improvements 153 153 Land improvements 474 474 Construction in progress - building 26,530 6,623 100,291 74,969 Accumulated depreciation (17,367) (11,565) Total property and equipment, net $ 82,924 $ 63,404 Construction in progress includes capitalized expenses related to the development of the new corporate headquarters' building. Construction is expected to be completed in the fourth quarter of 2025.
Premium Receivable, Allowance for Credit Loss	The following table presents the rollforward of the allowance for credit losses for premiums receivable for the years ended December 31, 2024 and 2023: Year Ended December 31, 2024 2023 (in thousands) Beginning balance $ 13,383 $ 8,067 Current period change for estimated uncollectible premiums 17,397 9,790 Write-offs of uncollectible premiums receivable (3,854) (4,474) Ending balance $ 26,926 $ 13,383

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2024
Investments [Abstract]
Available-for-sale Investments	The following tables summarize the Company’s available-for-sale investments at December 31, 2024 and 2023: December 31, 2024 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Allowance for Credit Losses Estimated Fair Value (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 15,465 $ — $ (417) $ — $ 15,048 Obligations of states, municipalities and political subdivisions 168,894 46 (22,633) (3) 146,304 Corporate and other securities 2,037,372 5,779 (53,638) (23) 1,989,490 Asset-backed securities 729,658 4,606 (1,522) — 732,742 Residential mortgage-backed securities 502,121 747 (53,994) — 448,874 Commercial mortgage-backed securities 209,521 423 (4,838) (1) 205,105 Total fixed-maturity investments $ 3,663,031 $ 11,601 $ (137,042) $ (27) $ 3,537,563 December 31, 2023 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Allowance for Credit Losses Estimated Fair Value (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 28,003 $ 57 $ (806) $ — $ 27,254 Obligations of states, municipalities and political subdivisions 191,080 212 (20,248) — 171,044 Corporate and other securities 1,437,468 5,532 (54,755) (552) 1,387,693 Asset-backed securities 641,700 2,833 (2,773) — 641,760 Residential mortgage-backed securities 463,904 1,732 (48,530) — 417,106 Commercial mortgage-backed securities 72,308 11 (5,416) (1) 66,902 Total fixed-maturity investments $ 2,834,463 $ 10,377 $ (132,528) $ (553) $ 2,711,759
Debt Securities, Available-for-Sale, Allowance for Credit Loss	The following table presents changes in the allowance for expected credit losses on available-for-sale securities: Years Ended December 31, 2024 2023 (in thousands) Beginning balance $ 553 $ 366 Increase to allowance from securities for which credit losses were not previously recorded 3 1 Reduction from securities sold during the period (479) (12) Net (decrease) increase from securities that had an allowance at the beginning of the period (50) 198 Ending balance $ 27 $ 553
Available-for-sale Securities in a Unrealized Loss Position	The following tables summarize gross unrealized losses and estimated fair value for available-for-sale investments by length of time that the securities have continuously been in an unrealized loss position: December 31, 2024 Less than 12 Months 12 Months or Longer Total Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 838 $ (13) $ 14,210 $ (404) $ 15,048 $ (417) Obligations of states, municipalities and political subdivisions 27,049 (417) 114,620 (22,216) 141,669 (22,633) Corporate and other securities 667,645 (9,139) 493,598 (44,499) 1,161,243 (53,638) Asset-backed securities 121,371 (943) 24,656 (579) 146,027 (1,522) Residential mortgage-backed securities 144,955 (1,934) 237,514 (52,060) 382,469 (53,994) Commercial mortgage-backed securities 92,024 (960) 53,812 (3,878) 145,836 (4,838) Total fixed-maturity investments $ 1,053,882 $ (13,406) $ 938,410 $ (123,636) $ 1,992,292 $ (137,042) December 31, 2023 Less than 12 Months 12 Months or Longer Total Estimated Fair Value Gross Unrealized Holding Losses Estimated Fair Value Gross Unrealized Holding Losses Estimated Fair Value Gross Unrealized Holding Losses (in thousands) Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ — $ — $ 15,484 $ (806) $ 15,484 $ (806) Obligations of states, municipalities and political subdivisions 20,886 (221) 121,911 (20,027) 142,797 (20,248) Corporate and other securities 246,355 (1,444) 651,525 (53,311) 897,880 (54,755) Asset-backed securities 142,287 (872) 217,401 (1,901) 359,688 (2,773) Residential mortgage-backed securities 26,158 (49) 268,891 (48,481) 295,049 (48,530) Commercial mortgage-backed securities 8,775 (55) 56,731 (5,361) 65,506 (5,416) Total fixed-maturity investments $ 444,461 $ (2,641) $ 1,331,943 $ (129,887) $ 1,776,404 $ (132,528)
Contractual Maturities of Available-for-sale Fixed Maturity Securities	The amortized cost and estimated fair value of available-for-sale fixed-maturity securities at December 31, 2024 are summarized, by contractual maturity, as follows: Amortized Estimated Cost Fair Value (in thousands) Due in one year or less $ 415,494 $ 415,674 Due after one year through five years 1,070,687 1,058,729 Due after five years through ten years 513,549 496,044 Due after ten years 222,001 180,395 Asset-backed securities 729,658 732,742 Residential mortgage-backed securities 502,121 448,874 Commercial mortgage-backed securities 209,521 205,105 Total fixed maturities $ 3,663,031 $ 3,537,563
Net Investment Income	The following table presents the components of net investment income: Year Ended December 31, 2024 2023 2022 (in thousands) Interest: Taxable bonds $ 143,242 $ 92,227 $ 44,806 Municipal bonds (tax exempt) 1,592 2,217 3,380 Cash equivalents and short-term investments 3,012 3,004 1,251 Dividends on equity securities 6,442 5,097 4,406 Real estate investment income 153 3,716 234 Gross investment income 154,441 106,261 54,077 Investment expenses (4,154) (3,926) (2,795) Net investment income $ 150,287 $ 102,335 $ 51,282
Schedule of Realized Gain (Loss)	The following table presents realized investment gains and losses: Year Ended December 31, 2024 2023 2022 (in thousands) Fixed-maturity securities: Realized gains $ 1,151 $ 1,852 $ 1,078 Realized losses (1,131) (2,374) (904) Net realized gains (losses) from fixed-maturity securities 20 (522) 174 Equity securities: Realized gains 7,271 7,678 1,363 Realized losses (455) (5,329) (297) Net realized gains from equity securities 6,816 2,349 1,066 Realized losses from the sales of short-term investments — (37) (49) Realized (losses) gains on sale of real estate investments (5) 4,250 — Net realized investment gains $ 6,831 $ 6,040 $ 1,191 The net realized gains or losses on sales of equity securities represent the total gains or losses from the purchase dates of the equity securities. The change in unrealized gains (losses) in the consolidated statement of income consists of two components: (1) the reversal of the gain or loss recognized in previous periods on equity securities sold and (2) the change in unrealized gain or loss resulting from mark-to-market adjustments on equity securities still held.
Schedule of Real Estate Properties	During the third quarter of 2023, the Company sold the parking deck, one of the office buildings and the related in-place leases of its real estate investment property for approximately $62.0 million in cash, net of seller’s costs. The Company recognized a gain on the sale of $4.3 million, which is included in net realized investment gains on the consolidated statement of income. The Company used the net sale proceeds to pay down a portion of its Credit Facility. Concurrent with the sale of the investment property, the Company refined its plans for the remainder of the property and determined the predominant use of the remaining office building would be for future office space expansion. Upon this determination, the Company reclassified the carrying value of the building to construction in progress within property and equipment.

Fair value measurements (Tables

Fair value measurements (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value on a Recurring Basis	The following tables present the balances of assets measured at fair value on a recurring basis as of December 31, 2024 and 2023, by level within the fair value hierarchy: December 31, 2024 Level 1 Level 2 Level 3 Total (in thousands) Assets Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 15,048 $ — $ — $ 15,048 Obligations of states, municipalities and political subdivisions — 146,304 — 146,304 Corporate and other securities — 1,989,490 — 1,989,490 Asset-backed securities — 732,742 — 732,742 Residential mortgage-backed securities — 448,874 — 448,874 Commercial mortgage-backed securities — 205,105 — 205,105 Total fixed maturities 15,048 3,522,515 — 3,537,563 Equity securities: Exchange traded funds 129,731 — — 129,731 Non-redeemable preferred stock — 26,433 — 26,433 Common stocks 242,195 — — 242,195 Total equity securities 371,926 26,433 — 398,359 Short-term investments 3,714 — — 3,714 Total $ 390,688 $ 3,548,948 $ — $ 3,939,636 December 31, 2023 Level 1 Level 2 Level 3 Total (in thousands) Assets Fixed maturities: U.S. Treasury securities and obligations of U.S. government agencies $ 22,235 $ 5,019 $ — $ 27,254 Obligations of states, municipalities and political subdivisions — 171,044 — 171,044 Corporate and other securities — 1,387,693 — 1,387,693 Asset-backed securities — 641,760 — 641,760 Residential mortgage-backed securities — 417,106 — 417,106 Commercial mortgage-backed securities — 66,902 — 66,902 Total fixed maturities 22,235 2,689,524 — 2,711,759 Equity securities: Exchange traded funds 106,300 — — 106,300 Non-redeemable preferred stock — 33,173 — 33,173 Common stocks 95,340 — — 95,340 Total equity securities 201,640 33,173 — 234,813 Short-term investments 1,862 3,727 — 5,589 Total $ 225,737 $ 2,726,424 $ — $ 2,952,161

Deferred policy acquisition c_2

Deferred policy acquisition costs (Tables)	12 Months Ended
	Dec. 31, 2024
Deferred Policy Acquisition Costs Disclosures [Abstract]
Deferred Policy Acquisition Costs	The following table presents the amounts of policy acquisition costs deferred and amortized for the years ended: Year Ended December 31, 2024 2023 2022 (in thousands) Balance, beginning of year $ 88,395 $ 61,594 $ 41,968 Policy acquisition costs deferred: Direct commissions 274,124 227,755 160,523 Ceding commissions (120,459) (88,449) (48,022) Other underwriting and policy acquisition costs 14,215 10,982 8,155 Policy acquisition costs deferred 167,880 150,288 120,656 Amortization of net policy acquisition costs (147,012) (123,487) (101,030) Balance, end of year $ 109,263 $ 88,395 $ 61,594

Underwriting, acquisition and_2

Underwriting, acquisition and insurance expenses (Tables)	12 Months Ended
	Dec. 31, 2024
Underwriting, Acquisition and Insurance Expenses [Abstract]
Underwriting, Acquisition and Insurance Expenses	Underwriting, acquisition and insurance expenses consist of the following: Year Ended December 31, 2024 2023 2022 (in thousands) Underwriting, acquisition and insurance expenses incurred: Direct commissions $ 254,523 $ 198,715 $ 138,451 Ceding commissions (120,339) (84,998) (44,695) Other underwriting expenses 151,624 115,253 86,566 Total $ 285,808 $ 228,970 $ 180,322

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Components of Income Tax Expense (Benefit)	Income tax expense includes the following components for the years ending December 31, 2024, 2023 and 2022: Year Ended December 31, 2024 2023 2022 (in thousands) Current federal income tax expense $ 103,701 $ 85,353 $ 50,641 Deferred federal income tax benefit (3,828) (9,429) (14,191) Income tax expense $ 99,873 $ 75,924 $ 36,450
Effective Income Tax Rate Reconciliation	The Company’s effective income tax rate on income before income taxes differs from the prevailing federal income tax rate and is summarized as follows: Year ended December 31, 2024 2023 2022 (in thousands) Income tax expense at federal income tax rate $ 108,090 $ 80,644 $ 41,068 Stock options exercised (7,972) (3,676) (3,240) Restricted stock award vesting (2,147) (1,256) (1,048) Tax-exempt investment income (249) (347) (527) Other 2,151 559 197 Total $ 99,873 $ 75,924 $ 36,450
Deferred Tax Assets and Liabilities	The significant components of the net deferred tax asset are summarized as follows: December 31, 2024 2023 (in thousands) Deferred tax assets: Unrealized losses on fixed-maturity securities $ 26,343 $ 25,655 Unpaid losses and loss adjustment expenses 36,491 27,422 Unearned premiums 32,580 27,251 State operating loss carryforwards 8,859 6,012 Stock compensation 3,276 2,155 Allowance for credit losses 5,210 2,810 Other 1,939 2,394 Deferred tax assets before allowance 114,698 93,699 Less: valuation allowance (9,066) (6,182) Total deferred tax assets 105,632 87,517 Deferred tax liabilities: Unrealized gains on equity securities 17,774 8,667 Deferred policy acquisition costs, net of ceding commissions 22,945 18,563 Property and equipment 3,263 3,005 Other 1,435 1,583 Total deferred tax liabilities 45,417 31,818 Net deferred tax asset $ 60,215 $ 55,699

Reserves for unpaid losses an_2

Reserves for unpaid losses and loss adjustment expenses (Tables)	12 Months Ended
	Dec. 31, 2024
Liability for Unpaid Claims and Claims Adjustment Expense, Activity in Liability [Abstract]
Unpaid Losses and Loss Adjustment Expenses	The following table presents a reconciliation of consolidated beginning and ending reserves for unpaid losses and loss adjustment expenses: December 31, 2024 2023 2022 (in thousands) Gross reserves for unpaid losses and loss adjustment expenses, beginning of year $ 1,692,875 $ 1,238,402 $ 881,344 Less: reinsurance recoverable on unpaid losses 241,357 177,039 117,561 Net reserves for unpaid losses and loss adjustment expenses, beginning of year 1,451,518 1,061,363 763,783 Incurred losses and loss adjustment expenses: Current year 810,554 635,993 493,800 Prior years (37,655) (35,774) (35,887) Total net losses and loss adjustment expenses incurred 772,899 600,219 457,913 Payments: Current year 49,747 38,565 49,205 Prior years 212,062 171,499 111,128 Total payments 261,809 210,064 160,333 Net reserves for unpaid losses and loss adjustment expenses, end of year 1,962,608 1,451,518 1,061,363 Reinsurance recoverable on unpaid losses, net of allowance 323,060 241,357 177,039 Gross reserves for unpaid losses and loss adjustment expenses, end of year $ 2,285,668 $ 1,692,875 $ 1,238,402
Claims Development
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability	The reconciliation of the net incurred and paid claims development tables to the liability for unpaid claims and claim adjustment expenses in the consolidated statement of financial position is as follows: (in thousands) December 31, 2024 Net outstanding liabilities Property $ 116,112 Casualty - claims made 262,470 Casualty - occurrence 1,385,847 Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance 1,764,429 Reinsurance recoverable on unpaid claims Property 99,478 Casualty - claims made 21,051 Casualty - occurrence 203,463 Allowance for credit losses (932) Total reinsurance recoverable on unpaid claims 323,060 Unallocated claims adjustment expenses 197,247 Allowance for credit losses 932 Gross liability for unpaid claims and claim adjustment expense $ 2,285,668
Property [Member]
Claims Development
Short-duration Insurance Contracts, Claims Development	Property Incurred Claims and Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2024 Accident Year 2020 2021 2022 2023 2024 Total of IBNR Liabilities Plus Expected Development on Reported Claims Cumulative Number of Reported Claims ($ in thousands) 2020 $ 40,612 $ 37,939 $ 36,807 $ 37,078 $ 42,287 $ — 2,309 2021 36,531 33,518 29,750 31,392 1,087 1,146 2022 67,127 53,676 53,527 4,131 2,346 2023 75,517 54,503 24,306 979 2024 112,051 61,791 1,376 Total $ 293,760 Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2020 2021 2022 2023 2024 ($ in thousands) 2020 $ 19,897 $ 30,321 $ 31,765 $ 35,023 $ 41,696 2021 14,268 21,257 27,324 30,200 2022 33,004 46,965 48,030 2023 20,267 26,434 2024 31,303 Total 177,663 All outstanding liabilities before 2020, net of reinsurance 15 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 116,112
Short-duration Insurance Contracts, Schedule of Historical Claims Duration	The following is supplementary information about average historical claims duration as of December 31, 2024: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (Unaudited) Years 1 2 3 4 5 Property 43.9 % 21.1 % 8.2 % 8.4 % 15.8 %
Casualty - claims made [Member]
Claims Development
Short-duration Insurance Contracts, Claims Development	Casualty - Claims Made Incurred Claims and Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2024 Accident Year 2015 Unaudited 2016 Unaudited 2017 Unaudited 2018 Unaudited 2019 Unaudited 2020 Unaudited 2021 Unaudited 2022 Unaudited 2023 Unaudited 2024 Total of IBNR Liabilities Plus Expected Development on Reported Claims Cumulative Number of Reported Claims ($ in thousands) 2015 $ 18,883 $ 16,777 $ 14,896 $ 13,583 $ 13,942 $ 13,548 $ 13,414 $ 13,066 $ 12,759 $ 12,679 $ 20 260 2016 19,170 14,693 14,675 14,322 13,583 13,602 13,228 12,707 12,703 12 312 2017 18,116 17,097 16,120 15,794 14,989 13,698 13,471 12,840 39 372 2018 22,429 20,234 18,612 17,057 14,411 14,272 14,186 840 466 2019 34,693 29,056 26,426 24,489 21,788 22,839 2,583 565 2020 55,630 44,641 38,287 33,667 28,877 5,467 787 2021 84,018 66,191 52,935 36,710 18,461 1,081 2022 101,064 81,394 60,873 32,026 1,234 2023 115,858 91,516 61,696 1,467 2024 123,511 103,838 1,461 Total $ 416,734 Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2015 Unaudited 2016 Unaudited 2017 Unaudited 2018 Unaudited 2019 Unaudited 2020 Unaudited 2021 Unaudited 2022 Unaudited 2023 Unaudited 2024 ($ in thousands) 2015 $ 217 $ 4,496 $ 7,563 $ 9,238 $ 11,372 $ 11,522 $ 12,142 $ 12,463 $ 12,474 $ 12,659 2016 1,158 3,015 6,907 9,839 11,381 12,105 12,299 12,691 12,691 2017 340 4,897 8,252 10,484 11,357 12,235 12,335 12,779 2018 507 5,030 8,931 10,330 11,205 12,623 13,247 2019 2,487 6,005 10,123 14,476 15,406 16,598 2020 1,002 7,446 12,551 18,589 22,445 2021 1,146 8,437 12,895 16,294 2022 3,052 12,381 24,033 2023 4,830 16,895 2024 6,755 Total 154,396 All outstanding liabilities before 2015, net of reinsurance 132 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 262,470
Casualty - occurrence [Member]
Claims Development
Short-duration Insurance Contracts, Claims Development	Casualty - Occurrence Incurred Claims and Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, As of December 31, 2024 Accident Year 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 Total of IBNR Liabilities Plus Expected Development on Reported Claims Cumulative Number of Reported Claims ($ in thousands) 2015 $ 59,717 $ 51,739 $ 49,122 $ 52,100 $ 54,697 $ 54,090 $ 54,090 $ 54,637 $ 55,259 $ 56,101 $ 3,740 1,947 2016 61,440 55,680 53,549 55,534 57,401 60,861 64,612 65,323 65,025 5,511 1,694 2017 71,126 67,151 68,985 70,641 71,117 69,911 76,715 79,203 9,117 2,288 2018 86,157 78,331 78,386 83,952 93,215 97,005 101,939 13,824 2,585 2019 112,266 109,994 108,138 107,480 115,681 120,003 26,442 2,535 2020 154,619 136,212 131,082 135,045 140,203 69,005 3,072 2021 200,598 190,879 193,722 204,787 127,633 3,228 2022 272,692 271,399 287,977 199,307 3,832 2023 372,245 372,413 322,319 3,813 2024 490,719 471,397 2,513 Total $ 1,918,370 Cumulative Paid Claims and Allocated Claim Adjustment Expenses, Net of Reinsurance For the Years Ended December 31, Accident Year 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 ($ in thousands) 2015 $ 941 $ 3,161 $ 12,685 $ 28,385 $ 37,690 $ 41,724 $ 44,161 $ 47,106 $ 49,147 $ 51,010 2016 1,099 6,015 17,225 28,924 34,437 43,311 51,533 55,595 57,421 2017 1,581 9,352 22,407 37,736 46,025 52,069 61,108 66,435 2018 2,638 10,995 22,860 35,138 54,441 72,174 82,927 2019 3,944 16,687 30,518 46,478 69,384 84,496 2020 2,400 8,673 17,805 32,606 55,548 2021 3,205 12,944 31,494 57,465 2022 4,658 23,084 56,201 2023 4,329 21,930 2024 6,032 Total 539,465 All outstanding liabilities before 2015, net of reinsurance 6,942 Liabilities for claims and claim adjustment expenses, net of reinsurance $ 1,385,847
Casualty [Member]
Claims Development
Short-duration Insurance Contracts, Schedule of Historical Claims Duration	The following is supplementary information about average historical claims duration as of December 31, 2024: Average Annual Percentage Payout of Incurred Claims by Age, Net of Reinsurance (Unaudited) Years 1 2 3 4 5 6 7 8 9 10 Casualty - claims made 5.0 % 22.4 % 21.9 % 16.1 % 9.9 % 5.8 % 2.9 % 3.0 % — % 1.5 % Casualty - occurrence 1.9 % 6.7 % 12.6 % 16.3 % 15.0 % 11.7 % 9.7 % 6.1 % 3.2 % 3.3 %

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2024
Reinsurance Disclosures [Abstract]
Effects of Reinsurance on Premiums Written and Earned	The following table summarizes the effect of reinsurance on premiums written and earned: Year Ended December 31, 2024 2023 2022 (in thousands) Written: Direct $ 1,870,341 $ 1,568,815 $ 1,102,092 Ceded (392,993) (304,185) (165,282) Net written $ 1,477,348 $ 1,264,630 $ 936,810 Earned: Direct $ 1,743,243 $ 1,367,141 $ 950,145 Ceded (392,773) (294,604) (156,026) Net earned $ 1,350,470 $ 1,072,537 $ 794,119
Reinsurance Recoverables	The following table presents reinsurance recoverables on paid and unpaid losses as of December 31, 2024 and 2023: December 31, 2024 December 31, 2023 (in thousands) Reinsurance recoverables on paid losses $ 14,831 $ 6,479 Reinsurance recoverables on unpaid losses 323,060 241,357 Reinsurance recoverables $ 337,891 $ 247,836

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2024
Equity, Attributable to Parent [Abstract]
Share-based Compensation, Stock Options, Activity	A summary of option activity as of December 31, 2024 and changes during the year then ended is presented below: Number of Shares Weighted-average exercise price Weighted-average remaining years of contractual life Aggregate intrinsic value (in thousands) Outstanding at December 31, 2023 201,560 $ 16.00 Granted — — Forfeited — — Exercised (83,092) 16.00 Outstanding at December 31, 2024 118,468 $ 16.00 1.6 $ 53,208 Exercisable at December 31, 2024 118,468 $ 16.00 1.6 $ 53,208
Nonvested Restricted Stock Shares Activity	A summary of restricted stock activity under the equity compensation plans for the year ended is as follows: December 31, 2024 Number of Shares Weighted Average Grant Date Fair Value per Share Nonvested outstanding at the beginning of the period 107,822 $ 250.86 Granted 47,689 $ 502.43 Vested (41,872) $ 230.81 Forfeited (3,516) $ 308.84 Nonvested outstanding at the end of the period 110,123 $ 366.73

Earnings per share (Tables)

Earnings per share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	The following table represents a reconciliation of the numerator and denominator of the basic and diluted earnings per share computations contained in the consolidated financial statements: Year ended December 31, 2024 2023 2022 (in thousands, except per share data) Net income $ 414,843 $ 308,093 $ 159,114 Weighted average common shares outstanding - basic 23,153 23,045 22,815 Dilutive effect of shares issued under stock compensation arrangements: Stock options 136 214 269 Restricted stock awards 43 48 41 Total dilutive effect of shares issued under stock compensation arrangements 179 262 310 Weighted average common shares outstanding - diluted 23,332 23,307 23,125 Earnings per common share: Basic $ 17.92 $ 13.37 $ 6.97 Diluted $ 17.78 $ 13.22 $ 6.88

Other comprehensive income (l_2

Other comprehensive income (loss) (Tables)	12 Months Ended
	Dec. 31, 2024
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other Comprehensive Income (Loss)	The following table summarizes the components of other comprehensive (loss) income: Year Ending December 31, 2024 2023 2022 (in thousands) Unrealized (losses) gains on fixed-maturity securities arising during the period, before income taxes: $ (2,921) $ 49,384 $ (193,970) Income tax benefit (expense) 613 (10,371) 40,734 Unrealized (losses) gains arising during the period, net of income taxes (2,308) 39,013 (153,236) Less reclassification adjustment: Net realized investment (losses) gains on available-for-sale investments (170) (1,443) 121 Income tax benefit (expense) 36 303 (25) Reclassification adjustment included in net income (134) (1,140) 96 Change in allowance for credit losses on investments, before income taxes 526 (187) (366) Income tax (expense) benefit (111) 39 77 Reclassification adjustment included in net income 415 (148) (289) Other comprehensive (loss) income $ (2,589) $ 40,301 $ (153,043)

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	Year Ended December 31, 2024 2023 2022 (in thousands) Revenues: Net earned premiums $ 1,350,470 $ 1,072,537 $ 794,119 Fee income 34,118 27,026 19,604 Net investment income 150,287 102,335 51,282 Change in fair value of equity securities 43,367 15,277 (27,723) Net realized investment gains 6,831 6,040 1,191 Change in allowance for credit losses on investments 526 (187) (366) Other income (1) 1,926 1,421 697 Total revenues 1,587,525 1,224,449 838,804 Expenses: Losses and loss adjustment expenses - current year 785,036 631,407 467,182 Losses and loss adjustment expenses - catastrophes 25,518 4,586 26,618 Losses and loss adjustment expenses - prior year development (37,655) (35,774) (35,887) Net commissions incurred 134,184 113,717 93,756 Salaries, employee benefits and bonus expense 109,319 85,689 64,765 Credit loss expense - premiums receivable 17,397 9,790 5,988 Depreciation (2) 4,686 2,655 2,267 Interest expense 10,134 10,301 4,284 Other segment items (3) 24,190 18,061 14,267 Income tax expense 99,873 75,924 36,450 Segment net income 414,843 308,093 159,114 Reconciliation of profit or loss: Adjustments and reconciling items — — — Consolidated net income $ 414,843 $ 308,093 $ 159,114 (1) Other income primarily includes income generated from the Company's real estate operations. (2) Excludes depreciation expense allocated to loss adjustment expenses and investment expenses (3) Other segment items primarily includes other general and administrative expenses such as technology costs, facility expenses and audit and inspection costs.

Underwriting information (Table

Underwriting information (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Gross Written Premiums by Underwriting Division	Gross written premiums by underwriting division are presented below: Year Ended December 31, 2024 2023 2022 (in thousands) Commercial: Commercial Property $ 456,170 $ 411,956 $ 181,505 Excess Casualty 245,137 194,049 147,485 Small Business Casualty 195,593 174,080 149,366 General Casualty 169,162 118,745 69,784 Construction 148,333 137,887 122,524 Allied Health 83,058 67,808 58,839 Small Business Property 76,800 43,893 21,002 Products Liability 67,035 61,786 60,374 Entertainment 58,506 39,218 22,268 Energy 42,710 38,637 32,217 Life Sciences 36,252 41,379 41,346 Commercial Auto 35,047 19,050 5,950 Professional Liability 34,841 35,743 30,313 Excess Professional 32,633 24,033 22,826 Environmental 30,372 25,938 19,455 Inland Marine 27,184 18,669 14,396 Health Care 23,179 20,378 16,916 Management Liability 21,705 26,617 28,856 Public Entity 20,047 20,028 15,512 Aviation 8,591 6,453 4,424 Ocean Marine 3,655 2,339 765 Agribusiness 2,775 — — Product Recall 2,397 1,637 1,419 Railroad 225 15 — Total commercial 1,821,407 1,530,338 1,067,542 Personal: High Value Homeowners 26,844 14,295 3,261 Personal Insurance 22,090 24,182 31,289 Total personal 48,934 38,477 34,550 Total $ 1,870,341 $ 1,568,815 $ 1,102,092

Statutory financial informati_2

Statutory financial information (Tables)	12 Months Ended
	Dec. 31, 2024
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments [Abstract]
Statutory Net Income and Statutory Capital and Surplus	Statutory net income and statutory capital and surplus for Kinsale Insurance as of December 31, 2024, 2023, and 2022 and for the years then ended are summarized as follows: Year ended December 31, 2024 2023 2022 (in thousands) Statutory net income $ 357,896 $ 259,042 $ 151,105 Statutory capital and surplus $ 1,525,851 $ 1,167,382 $ 835,664

Schedule II - Condensed Finan_2

Schedule II - Condensed Financial Information of Registrant (Tables)	12 Months Ended
	Dec. 31, 2024
Condensed Financial Information Disclosure [Abstract]
Condensed Balance Sheet	December 31, 2024 2023 (in thousands) Assets Cash and cash equivalents $ 12,336 $ 17,082 Due from subsidiaries 52,296 26,479 Investment in subsidiaries 1,604,811 1,230,371 Deferred income tax asset, net 2,527 1,673 Other assets 664 410 Total assets $ 1,672,634 $ 1,276,015 Liabilities and Stockholders' Equity Liabilities: Accounts payable and accrued expenses $ 2,001 $ 2,042 Income taxes payable 2,842 3,201 Debt 184,122 183,846 Other liabilities 108 94 Total liabilities 189,073 189,183 Stockholders’ equity: Common stock 233 232 Additional paid-in capital 361,398 352,970 Retained earnings 1,229,136 828,247 Accumulated other comprehensive loss (97,206) (94,617) Treasury stock, at cost (10,000) — Stockholders’ equity 1,483,561 1,086,832 Total liabilities and stockholders’ equity $ 1,672,634 $ 1,276,015
Condensed Income Statement	Years Ended December 31, 2024 2023 2022 (in thousands) Revenues: Management fees from subsidiaries $ 16,769 $ 11,918 $ 8,686 Net investment income 641 — 121 Net realized investment gains — — 8 Total revenues 17,410 11,918 8,815 Expenses: Operating expenses 17,193 13,007 9,765 Interest expense 10,134 10,301 4,284 Other expenses 615 — — Total expenses 27,942 23,308 14,049 Loss before income taxes (10,532) (11,390) (5,234) Income tax benefit (12,346) (7,324) (5,387) Income (loss) before equity in net income of subsidiaries 1,814 (4,066) 153 Equity in undistributed earnings of subsidiaries 413,029 312,159 158,961 Net income 414,843 308,093 159,114 Other comprehensive income (loss): Equity in other comprehensive (losses) income of subsidiaries (2,589) 40,301 (153,043) Total comprehensive income $ 412,254 $ 348,394 $ 6,071
Condensed Cash Flow Statement	Years Ended December 31, 2024 2023 2022 (in thousands) Operating activities Net income $ 414,843 $ 308,093 $ 159,114 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Deferred tax benefit (854) (372) (367) Stock compensation expense 14,146 9,361 6,678 Equity in undistributed earnings of subsidiaries (413,029) (312,159) (158,961) Changes in operating assets and liabilities (25,795) 55,893 (71,639) Current taxes payable (359) — — Change in accounts payable and accrued expenses (41) — — Dividends received from subsidiary 47,000 — — Net cash provided by (used in) operating activities 35,911 60,816 (65,175) Investing activities Contributions to subsidiary (11,000) (50,000) (100,624) Net cash used in investing activities (11,000) (50,000) (100,624) Financing activities Common stock issued, net of transaction costs — — 47,498 Proceeds from credit facility — — 73,000 Proceeds from notes payable — 50,000 125,000 Repayment of credit facility — (62,000) (43,000) Debt issuance costs — (164) (2,381) Payroll taxes withheld and remitted on share-based payments (7,047) (4,282) (3,288) Common stock issued, stock options exercised 1,330 877 1,090 Dividends paid (13,940) (12,954) (11,927) Treasury stock acquired — share repurchases (10,000) — — Net cash (used in) provided by financing activities (29,657) (28,523) 185,992 Net change in cash and cash equivalents (4,746) (17,707) 20,193 Cash and cash equivalents at beginning of year 17,082 34,789 14,596 Cash and cash equivalents at end of year $ 12,336 $ 17,082 $ 34,789

Description of business - (Deta

Description of business - (Details)	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of states in which company is authorized to write business	50

Summary of significant accoun_3

Summary of significant accounting policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Accounting Policies [Abstract]
Premium Receivable, Allowance for Credit Loss, Beginning Balance	$ 13,383	$ 8,067
Premium Receivable, Credit Loss Expense (Reversal)	17,397	9,790
Premium Receivable, Allowance for Credit Loss, Writeoff	(3,854)	(4,474)
Premium Receivable, Allowance for Credit Loss	$ 26,926	$ 13,383

Intangible assets and other inf

Intangible assets and other information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Excess and surplus lines insurance authorization [Member]
Indefinite-lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 0	$ 0	$ 0

Summary of significant accoun_4

Summary of significant accounting policies Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 100,291	$ 74,969
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(17,367)	(11,565)
Property, Plant and Equipment, Net	82,924	63,404
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 37,190	37,181
Building [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	39 years
Parking [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 5,072	5,072
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,068	3,068
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	4,401	3,958
Software Development [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	20,203	15,375
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 3,200	3,065
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 153	153
Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 474	474
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Technology Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Technology Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 26,530	$ 6,623

Investments, Available-for-sale

Investments, Available-for-sale Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	$ 3,663,031	$ 2,834,463
Gross Unrealized Gains	11,601	10,377
Gross Unrealized Losses	137,042	132,528
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	(27)	(553)	$ (366)
Estimated Fair Value	3,537,563	2,711,759
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	15,465	28,003
Gross Unrealized Gains	0	57
Gross Unrealized Losses	417	806
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Estimated Fair Value	15,048	27,254
Obligations of states, municipalities and political subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	168,894	191,080
Gross Unrealized Gains	46	212
Gross Unrealized Losses	22,633	20,248
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	(3)	0
Estimated Fair Value	146,304	171,044
Corporate and other securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	2,037,372	1,437,468
Gross Unrealized Gains	5,779	5,532
Gross Unrealized Losses	53,638	54,755
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	(23)	(552)
Estimated Fair Value	1,989,490	1,387,693
Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	729,658	641,700
Gross Unrealized Gains	4,606	2,833
Gross Unrealized Losses	1,522	2,773
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Estimated Fair Value	732,742	641,760
Residential mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	502,121	463,904
Gross Unrealized Gains	747	1,732
Gross Unrealized Losses	53,994	48,530
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Estimated Fair Value	448,874	417,106
Commercial mortgage-backed aecurities [Member]
Debt Securities, Available-for-sale [Line Items]
Total fixed maturities, Amortized Cost	209,521	72,308
Gross Unrealized Gains	423	11
Gross Unrealized Losses	4,838	5,416
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	(1)	(1)
Estimated Fair Value	$ 205,105	$ 66,902

Investments, Available-for-sa_2

Investments, Available-for-sale Securities in a Loss Position (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) security Rate	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	$ 1,053,882	$ 444,461
Less than 12 months, Gross Unrealized Losses	13,406	2,641
12 Months or Longer, Estimated Fair Value	938,410	1,331,943
12 Months or Longer, Gross Unrealized Losses	123,636	129,887
Total Estimated Fair Value	1,992,292	1,776,404
Total gross unrealized losses	(137,042)	(132,528)
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 1,992,292	1,776,404
Number of available-for-sale securities in unrealized loss positions	1,031
Number of available-for-sale securities in unrealized loss positions, greater than one year	616
Debt Instrument, Covenant Description	In October 2024, the covenants limiting restricted payments under the Note Purchase Agreement and Amended and Restated Credit Agreement were amended. The amendments allow the Company to make restricted payments so long as the aggregate amount of all such restricted payments does not exceed the greater of $300.0 million and 6.5% of the total assets of the Company and its subsidiaries at the end of the most recently completed fiscal quarter.
Debt Securities Available For Sale Allowance For Credit Loss Number Of Securities | security	4
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Not Previously Recorded	$ 3	1
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Securities Sold	(479)	(12)
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Period Increase (Decrease)	(50)	198
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	$ 27	553	$ 366
Debt Securities Available For Sale Allowance For Credit Loss Number Of Securities | security	4
Fixed Maturities [Member]
Debt Securities, Available-for-sale [Line Items]
Percentage of securities rated A- or better | Rate	79.80%
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	$ 838	0
Less than 12 months, Gross Unrealized Losses	13	0
12 Months or Longer, Estimated Fair Value	14,210	15,484
12 Months or Longer, Gross Unrealized Losses	404	806
Total Estimated Fair Value	15,048	15,484
Total gross unrealized losses	(417)	(806)
Debt Securities, Available-for-Sale, Unrealized Loss Position	15,048	15,484
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Obligations of states, municipalities and political subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	27,049	20,886
Less than 12 months, Gross Unrealized Losses	417	221
12 Months or Longer, Estimated Fair Value	114,620	121,911
12 Months or Longer, Gross Unrealized Losses	22,216	20,027
Total Estimated Fair Value	141,669	142,797
Total gross unrealized losses	(22,633)	(20,248)
Debt Securities, Available-for-Sale, Unrealized Loss Position	141,669	142,797
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	3	0
Corporate and other securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	667,645	246,355
Less than 12 months, Gross Unrealized Losses	9,139	1,444
12 Months or Longer, Estimated Fair Value	493,598	651,525
12 Months or Longer, Gross Unrealized Losses	44,499	53,311
Total Estimated Fair Value	1,161,243	897,880
Total gross unrealized losses	(53,638)	(54,755)
Debt Securities, Available-for-Sale, Unrealized Loss Position	1,161,243	897,880
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	23	552
Asset-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	121,371	142,287
Less than 12 months, Gross Unrealized Losses	943	872
12 Months or Longer, Estimated Fair Value	24,656	217,401
12 Months or Longer, Gross Unrealized Losses	579	1,901
Total Estimated Fair Value	146,027	359,688
Total gross unrealized losses	(1,522)	(2,773)
Debt Securities, Available-for-Sale, Unrealized Loss Position	146,027	359,688
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Residential mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	144,955	26,158
Less than 12 months, Gross Unrealized Losses	1,934	49
12 Months or Longer, Estimated Fair Value	237,514	268,891
12 Months or Longer, Gross Unrealized Losses	52,060	48,481
Total Estimated Fair Value	382,469	295,049
Total gross unrealized losses	(53,994)	(48,530)
Debt Securities, Available-for-Sale, Unrealized Loss Position	382,469	295,049
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0	0
Commercial mortgage-backed aecurities [Member]
Debt Securities, Available-for-sale [Line Items]
Less than 12 Months, Estimated Fair Value	92,024	8,775
Less than 12 months, Gross Unrealized Losses	960	55
12 Months or Longer, Estimated Fair Value	53,812	56,731
12 Months or Longer, Gross Unrealized Losses	3,878	5,361
Total Estimated Fair Value	145,836	65,506
Total gross unrealized losses	(4,838)	(5,416)
Debt Securities, Available-for-Sale, Unrealized Loss Position	145,836	65,506
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	$ 1	$ 1

Investments, Contractual Maturi

Investments, Contractual Maturities of Available-for-sale Fixed Maturity Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Amortized Cost [Abstract]
Due in one year or less, Amortized Cost	$ 415,494
Due after one year through five years, Amortized Cost	1,070,687
Due after five years through ten years, Amortized Cost	513,549
Due after ten years, Amortized Cost	222,001
Total fixed maturities, Amortized Cost	3,663,031	$ 2,834,463
Estimated Fair Value [Abstract]
Due in one year or less, Estimated Fair Value	415,674
Due after one year through five years, Estimated Fair Value	1,058,729
Due after five years through ten years, Estimated Fair Value	496,044
Due after ten years, Estimated Fair Value	180,395
Estimated Fair Value	3,537,563	2,711,759
Asset-backed securities [Member]
Amortized Cost [Abstract]
Without single maturity date, Amortized Cost	729,658
Total fixed maturities, Amortized Cost	729,658	641,700
Estimated Fair Value [Abstract]
Without single maturity date, Estimated Fair Value	732,742
Estimated Fair Value	732,742	641,760
Residential mortgage-backed securities [Member]
Amortized Cost [Abstract]
Without single maturity date, Amortized Cost	502,121
Total fixed maturities, Amortized Cost	502,121	463,904
Estimated Fair Value [Abstract]
Without single maturity date, Estimated Fair Value	448,874
Estimated Fair Value	448,874	417,106
Commercial mortgage-backed aecurities [Member]
Amortized Cost [Abstract]
Without single maturity date, Amortized Cost	209,521
Total fixed maturities, Amortized Cost	209,521	72,308
Estimated Fair Value [Abstract]
Without single maturity date, Estimated Fair Value	205,105
Estimated Fair Value	$ 205,105	$ 66,902

Investments, Net Investment Inc

Investments, Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest [Abstract]
Taxable bonds	$ 143,242	$ 92,227	$ 44,806
Municipal bonds (tax exempt)	1,592	2,217	3,380
Cash equivalents and short-term investments	3,012	3,004	1,251
Dividends on equity securities	6,442	5,097	4,406
Real estate investment income	154,441	106,261	54,077
Investment expenses	(4,154)	(3,926)	(2,795)
Net investment income	150,287	102,335	51,282
Real Estate Investment
Interest [Abstract]
Real estate investment income	153	3,716	234
Investment expenses	$ 0	$ (500)	$ (200)

Investments Realized Investment

Investments Realized Investment Gains and Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fixed-maturity securities - realized gains (losses) [Abstract]
Realized gains	$ 1,151	$ 1,852	$ 1,078
Realized losses	(1,131)	(2,374)	(904)
Net realized gains from fixed-maturity securities	20	(522)	174
Equity securities - realized gains (losses) [Abstract]
Realized gains	7,271	7,678	1,363
Realized losses	(455)	(5,329)	(297)
Net realized gains (losses) from equity securities	6,816	2,349	1,066
SalesOfShort-termAndOtherSecuritiesNetRealizedGains(Losses)	0	(37)	(49)
Gains (Losses) on Sales of Investment Real Estate	(5)	4,250	0
Gain (Loss) on Investments, Total	$ 6,831	$ 6,040	$ 1,191

Investments, Unrealized Gain (L

Investments, Unrealized Gain (Losses) on Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Change in unrealized gains (losses), fixed-maturity securities	$ (3.3)	$ 51	$ (193.7)

Investments Investment Deposits

Investments Investment Deposits and Payables (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Invested assets on deposit with state regulatory authorities	$ 3.7	$ 5.8
Payable for investments purchased	$ 0	$ 12.3

Investments (Details), Real Est

Investments (Details), Real Estate - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Real Estate Properties [Line Items]
Real Estate Investment Property, Accumulated Depreciation	$ 0	$ 0
Real Estate Investments, Net	15,045	14,791
Gains (Losses) on Sales of Investment Real Estate	(5)	4,250	$ 0
Proceeds from Sale, Real Estate, Held-for-Investment		62,000
Investment Income, Investment Expense	4,154	3,926	2,795
Land and Land Improvements	15,000	14,800
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	17,367	11,565
Real Estate Investment
Real Estate Properties [Line Items]
Investment Income, Investment Expense	$ 0	$ 500	$ 200

Fair value measurements (Detail

Fair value measurements (Details) - Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 3,939,636	$ 2,952,161
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	390,688	225,737
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,548,948	2,726,424
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Fixed Maturities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	3,537,563	2,711,759
Fixed Maturities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	15,048	22,235
Fixed Maturities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	3,522,515	2,689,524
Fixed Maturities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	15,048	27,254
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	15,048	22,235
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	5,019
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Obligations of states, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	146,304	171,044
Obligations of states, municipalities and political subdivisions [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Obligations of states, municipalities and political subdivisions [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	146,304	171,044
Obligations of states, municipalities and political subdivisions [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Corporate and other securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,989,490	1,387,693
Corporate and other securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Corporate and other securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	1,989,490	1,387,693
Corporate and other securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Asset-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	732,742	641,760
Asset-backed securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Asset-backed securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	732,742	641,760
Asset-backed securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Residential mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	448,874	417,106
Residential mortgage-backed securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Residential mortgage-backed securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	448,874	66,902
Residential mortgage-backed securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Commercial mortgage-backed aecurities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	205,105	66,902
Commercial mortgage-backed aecurities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Commercial mortgage-backed aecurities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	205,105	417,106
Commercial mortgage-backed aecurities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated Fair Value	0	0
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	398,359	234,813
Equity Securities [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	371,926	201,640
Equity Securities [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	26,433	33,173
Equity Securities [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Exchange Traded Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	129,731	106,300
Exchange Traded Fund [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	129,731	106,300
Exchange Traded Fund [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Exchange Traded Fund [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Nonredeemable Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	26,433	33,173
Nonredeemable Preferred Stock [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Nonredeemable Preferred Stock [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	26,433	33,173
Nonredeemable Preferred Stock [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Common Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	242,195	95,340
Common Stock [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	242,195	95,340
Common Stock [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Common Stock [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	0
Short-Term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,714	5,589
Short-Term Investments | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3,714	1,862
Short-Term Investments | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	0	3,727
Short-Term Investments | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 0	$ 0

Fair value measurements 2 (Deta

Fair value measurements 2 (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents, Fair Value Disclosure	$ 16,100,000	$ 11,800,000
Fair Value, Nonrecurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on a nonrecurring basis	0	0
Liabilities measured at fair value on a nonrecurring basis	0	0
Reported Value Measurement | Senior Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	175,000,000
Estimate of Fair Value Measurement | Senior Notes | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	$ 168,600,000	$ 171,600,000

Deferred policy acquisition c_3

Deferred policy acquisition costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Movement analysis of deferred policy acquisition costs [Roll Forward]
Balance, beginning of period	$ 88,395	$ 61,594	$ 41,968
Policy acquisition costs deferred:
Direct commissions deferred	274,124	227,755	160,523
Ceding commissions deferred	(120,459)	(88,449)	(48,022)
Other underwriting and policy acquisition costs deferred	14,215	10,982	8,155
Policy acquisition costs deferred	167,880	150,288	120,656
Amortization of net policy acquisition costs	(147,012)	(123,487)	(101,030)
Balance, end of period	$ 109,263	$ 88,395	$ 61,594

Underwriting, acquisition and_3

Underwriting, acquisition and insurance expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Underwriting, Acquisition and Insurance Expenses [Abstract]
Direct commissions	$ 254,523	$ 198,715	$ 138,451
Ceding commissions	(120,339)	(84,998)	(44,695)
Other expenses	151,624	115,253	86,566
Total	285,808	228,970	180,322
Salaries, employee benefits and bonus expense	$ 109,300	$ 85,700	$ 64,800

Income taxes (Details)

Income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Components of income tax expense
Current federal income tax expense	$ 103,701	$ 85,353	$ 50,641
Deferred federal income tax benefit	(3,828)	(9,429)	(14,191)
Income Tax Expense (Benefit), Total	99,873	75,924	36,450
Federal income taxes paid	$ 104,100	$ 84,600	43,100
Statutory income tax rate, percent	21%	21%
Effective income tax rate reconciliation, amount [Abstract]
Income tax expense at federal income tax	$ 108,090	$ 80,644	41,068
Stock options exercised	(7,972)	(3,676)	(3,240)
Restricted stock award vesting	(2,147)	(1,256)	(1,048)
Tax-exempt investment income	(249)	(347)	(527)
Other	2,151	559	197
Income Tax Expense (Benefit), Total	99,873	75,924	$ 36,450
Unrecognized tax positions	0	0
Taxes Payable	$ 2,800	$ 3,200

Income taxes - Deferred Tax Ass

Income taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets [Abstract]
Deferred Tax Assets, Investments	$ 26,343	$ 25,655
Unpaid losses and loss adjustment expenses	36,491	27,422
Unearned premiums	32,580	27,251
State operating loss carryforwards	8,859	6,012
Stock compensation	3,276	2,155
Allowance for credit losses	5,210	2,810
Other	1,939	2,394
Deferred tax assets before allowance	114,698	93,699
Less: valuation allowance	(9,066)	(6,182)
Total deferred tax assets	105,632	87,517
Deferred tax liabilities [Abstract]
Unrealized gains on equity securities	17,774	8,667
Deferred policy acquisition costs, net of ceding commissions	22,945	18,563
Property and equipment	3,263	3,005
Other	1,435	1,583
Total deferred tax liabilities	45,417	31,818
Deferred income tax asset, net	60,215	55,699
State Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 186,900	$ 126,800

Reserves for unpaid losses an_3

Reserves for unpaid losses and loss adjustment expenses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of consolidated beginning and ending reserves for unpaid losses and loss adjustment expenses [Roll Forward]
Gross reserves for unpaid losses and loss adjustment expenses, beginning of year		$ 2,285,668	$ 1,692,875	$ 1,238,402	$ 881,344
Allowance for credit losses - reinsurance recoverables	$ 932	744
Net reserves for unpaid losses and loss adjustment expenses, beginning of period	$ 1,962,608	1,451,518	1,061,363	763,783
Incurred losses and loss adjustment expenses [Abstract]
Current year		810,554	635,993	493,800
Prior year losses and loss adjustment expense		(37,655)	(35,774)	(35,887)
Total net losses and loss adjustment expenses incurred		772,899	600,219	457,913
Payments [Abstract]
Current year		49,747	38,565	49,205
Prior years		212,062	171,499	111,128
Total payments		261,809	210,064	160,333
Net reserves for unpaid losses and loss adjustment expenses, end of period		1,962,608	1,451,518	1,061,363
Reinsurance recoverable for unpaid Claims losses, net, ending balance		323,060	241,357	177,039
Gross reserves for unpaid losses and loss adjustment expenses, end of year		$ 2,285,668	$ 1,692,875	$ 1,238,402

Reserves for unpaid losses an_4

Reserves for unpaid losses and loss adjustment expenses Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	$ (37,655)	$ (35,774)	$ (35,887)
Current year	810,554	635,993	493,800
Catastrophe [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Current year	25,500		26,600
Accident Years 2020 and 2021
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense			$ (41,800)
Accident Years 2021 and 2022
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense		$ (49,000)
Accident Years 2021 through 2023
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Prior Year Claims and Claims Adjustment Expense	$ (57,600)

Reserves for unpaid losses an_5

Reserves for unpaid losses and loss adjustment expenses Reserve Development (Details)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Claims Development
Liability for claims and claim adjustment expense, net	$ 1,764,429,000
Property [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	177,663,000
All outstanding liabilities not separately presented, net of reinsurance	15,000
Liability for claims and claim adjustment expense, net	116,112,000
Incurred claims and claim adjustment expense, net	293,760,000
Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	154,396,000
All outstanding liabilities not separately presented, net of reinsurance	132,000
Liability for claims and claim adjustment expense, net	262,470,000
Incurred claims and claim adjustment expense, net	416,734,000
Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	539,465,000
All outstanding liabilities not separately presented, net of reinsurance	6,942,000
Liability for claims and claim adjustment expense, net	1,385,847,000
Incurred claims and claim adjustment expense, net	1,918,370,000
Accident Year 2015 [Member] | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	12,659,000	$ 12,474,000	$ 12,463,000	$ 12,142,000	$ 11,522,000	$ 11,372,000	$ 9,238,000	$ 7,563,000	$ 4,496,000	$ 217,000
Incurred claims and claim adjustment expense, net	12,679,000	12,759,000	13,066,000	13,414,000	13,548,000	13,942,000	13,583,000	14,896,000	16,777,000	18,883,000
Total of IBNR liabilities plus expected development on reported claims	$ 20,000
Cumulative number of reported claims	260
Accident Year 2015 [Member] | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 51,010,000	49,147,000	47,106,000	44,161,000	41,724,000	37,690,000	28,385,000	12,685,000	3,161,000	941,000
Incurred claims and claim adjustment expense, net	56,101,000	55,259,000	54,637,000	54,090,000	54,090,000	54,697,000	52,100,000	49,122,000	51,739,000	$ 59,717,000
Total of IBNR liabilities plus expected development on reported claims	$ 3,740,000
Cumulative number of reported claims	1,947
Accident Year 2016 [Member] | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 12,691,000	12,691,000	12,299,000	12,105,000	11,381,000	9,839,000	6,907,000	3,015,000	1,158,000
Incurred claims and claim adjustment expense, net	12,703,000	12,707,000	13,228,000	13,602,000	13,583,000	14,322,000	14,675,000	14,693,000	19,170,000
Total of IBNR liabilities plus expected development on reported claims	$ 12,000
Cumulative number of reported claims	312
Accident Year 2016 [Member] | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 57,421,000	55,595,000	51,533,000	43,311,000	34,437,000	28,924,000	17,225,000	6,015,000	1,099,000
Incurred claims and claim adjustment expense, net	65,025,000	65,323,000	64,612,000	60,861,000	57,401,000	55,534,000	53,549,000	55,680,000	$ 61,440,000
Total of IBNR liabilities plus expected development on reported claims	$ 5,511,000
Cumulative number of reported claims	1,694
Accident Year 2017 [Member] | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 12,779,000	12,335,000	12,235,000	11,357,000	10,484,000	8,252,000	4,897,000	340,000
Incurred claims and claim adjustment expense, net	12,840,000	13,471,000	13,698,000	14,989,000	15,794,000	16,120,000	17,097,000	18,116,000
Total of IBNR liabilities plus expected development on reported claims	$ 39,000
Cumulative number of reported claims	372
Accident Year 2017 [Member] | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 66,435,000	61,108,000	52,069,000	46,025,000	37,736,000	22,407,000	9,352,000	1,581,000
Incurred claims and claim adjustment expense, net	79,203,000	76,715,000	69,911,000	71,117,000	70,641,000	68,985,000	67,151,000	$ 71,126,000
Total of IBNR liabilities plus expected development on reported claims	$ 9,117,000
Cumulative number of reported claims	2,288
Accident Year 2018 [Member] | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 13,247,000	12,623,000	11,205,000	10,330,000	8,931,000	5,030,000	507,000
Incurred claims and claim adjustment expense, net	14,186,000	14,272,000	14,411,000	17,057,000	18,612,000	20,234,000	22,429,000
Total of IBNR liabilities plus expected development on reported claims	$ 840,000
Cumulative number of reported claims	466
Accident Year 2018 [Member] | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 82,927,000	72,174,000	54,441,000	35,138,000	22,860,000	10,995,000	2,638,000
Incurred claims and claim adjustment expense, net	101,939,000	97,005,000	93,215,000	83,952,000	78,386,000	78,331,000	$ 86,157,000
Total of IBNR liabilities plus expected development on reported claims	$ 13,824,000
Cumulative number of reported claims	2,585
Accident Year 2019 [Member] | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 16,598,000	15,406,000	14,476,000	10,123,000	6,005,000	2,487,000
Incurred claims and claim adjustment expense, net	22,839,000	21,788,000	24,489,000	26,426,000	29,056,000	34,693,000
Total of IBNR liabilities plus expected development on reported claims	$ 2,583,000
Cumulative number of reported claims	565
Accident Year 2019 [Member] | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 84,496,000	69,384,000	46,478,000	30,518,000	16,687,000	3,944,000
Incurred claims and claim adjustment expense, net	120,003,000	115,681,000	107,480,000	108,138,000	109,994,000	$ 112,266,000
Total of IBNR liabilities plus expected development on reported claims	$ 26,442,000
Cumulative number of reported claims	2,535
Accident Year 2020 [Member] | Property [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 41,696,000	35,023,000	31,765,000	30,321,000	19,897,000
Incurred claims and claim adjustment expense, net	42,287,000	37,078,000	36,807,000	37,939,000	40,612,000
Total of IBNR liabilities plus expected development on reported claims	$ 0
Cumulative number of reported claims	2,309
Accident Year 2020 [Member] | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 22,445,000	18,589,000	12,551,000	7,446,000	1,002,000
Incurred claims and claim adjustment expense, net	28,877,000	33,667,000	38,287,000	44,641,000	55,630,000
Total of IBNR liabilities plus expected development on reported claims	$ 5,467,000
Cumulative number of reported claims	787
Accident Year 2020 [Member] | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 55,548,000	32,606,000	17,805,000	8,673,000	2,400,000
Incurred claims and claim adjustment expense, net	140,203,000	135,045,000	131,082,000	136,212,000	$ 154,619,000
Total of IBNR liabilities plus expected development on reported claims	$ 69,005,000
Cumulative number of reported claims	3,072
Accident Year 2021 | Property [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 30,200,000	27,324,000	21,257,000	14,268,000
Incurred claims and claim adjustment expense, net	31,392,000	29,750,000	33,518,000	36,531,000
Total of IBNR liabilities plus expected development on reported claims	$ 1,087,000
Cumulative number of reported claims	1,146
Accident Year 2021 | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 16,294,000	12,895,000	8,437,000	1,146,000
Incurred claims and claim adjustment expense, net	36,710,000	52,935,000	66,191,000	84,018,000
Total of IBNR liabilities plus expected development on reported claims	$ 18,461,000
Cumulative number of reported claims	1,081
Accident Year 2021 | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 57,465,000	31,494,000	12,944,000	3,205,000
Incurred claims and claim adjustment expense, net	204,787,000	193,722,000	190,879,000	$ 200,598,000
Total of IBNR liabilities plus expected development on reported claims	$ 127,633,000
Cumulative number of reported claims	3,228
Accident Year 2022 | Property [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 48,030,000	46,965,000	33,004,000
Incurred claims and claim adjustment expense, net	53,527,000	53,676,000	67,127,000
Total of IBNR liabilities plus expected development on reported claims	$ 4,131,000
Cumulative number of reported claims	2,346
Accident Year 2022 | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 24,033,000	12,381,000	3,052,000
Incurred claims and claim adjustment expense, net	60,873,000	81,394,000	101,064,000
Total of IBNR liabilities plus expected development on reported claims	$ 32,026,000
Cumulative number of reported claims	1,234
Accident Year 2022 | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 56,201,000	23,084,000	4,658,000
Incurred claims and claim adjustment expense, net	287,977,000	271,399,000	$ 272,692,000
Total of IBNR liabilities plus expected development on reported claims	$ 199,307,000
Cumulative number of reported claims	3,832
Accident Year 2023 | Property [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 26,434,000	20,267,000
Incurred claims and claim adjustment expense, net	54,503,000	75,517,000
Total of IBNR liabilities plus expected development on reported claims	$ 24,306,000
Cumulative number of reported claims	979
Accident Year 2023 | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 16,895,000	4,830,000
Incurred claims and claim adjustment expense, net	91,516,000	115,858,000
Total of IBNR liabilities plus expected development on reported claims	$ 61,696,000
Cumulative number of reported claims	1,467
Accident Year 2023 | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 21,930,000	4,329,000
Incurred claims and claim adjustment expense, net	372,413,000	$ 372,245,000
Total of IBNR liabilities plus expected development on reported claims	$ 322,319,000
Cumulative number of reported claims	3,813
Accident Year 2024 | Property [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 31,303,000
Incurred claims and claim adjustment expense, net	112,051,000
Total of IBNR liabilities plus expected development on reported claims	$ 61,791,000
Cumulative number of reported claims	1,376
Accident Year 2024 | Casualty - claims made [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 6,755,000
Incurred claims and claim adjustment expense, net	123,511,000
Total of IBNR liabilities plus expected development on reported claims	$ 103,838,000
Cumulative number of reported claims	1,461
Accident Year 2024 | Casualty - occurrence [Member]
Claims Development
Cumulative paid claims and allocated claim adjustment expense, net	$ 6,032,000
Incurred claims and claim adjustment expense, net	490,719,000
Total of IBNR liabilities plus expected development on reported claims	$ 471,397,000
Cumulative number of reported claims	2,513

Reserves for unpaid losses an_6

Reserves for unpaid losses and loss adjustment expenses Historical Claims Duration (Details)	Dec. 31, 2024 Rate
Property [Member]
Historical Claims Duration [Line Items]
Historical Claims Duration, Year One	43.90%
Historical Claims Duration, Year Two	21.10%
Historical Claims Duration, Year Three	8.20%
Historical Claims Duration, Year Four	8.40%
Historical Claims Duration, Year Five	15.80%
Casualty - claims made [Member]
Historical Claims Duration [Line Items]
Historical Claims Duration, Year One	5%
Historical Claims Duration, Year Two	22.40%
Historical Claims Duration, Year Three	21.90%
Historical Claims Duration, Year Four	16.10%
Historical Claims Duration, Year Five	9.90%
Historical Claims Duration, Year Six	5.80%
Historical Claims Duration, Year Seven	2.90%
Historical Claims Duration, Year Eight	3%
Historical Claims Duration, Year Nine	0%
Historical Claims Duration, Year Ten	1.50%
Casualty - occurrence [Member]
Historical Claims Duration [Line Items]
Historical Claims Duration, Year One	1.90%
Historical Claims Duration, Year Two	6.70%
Historical Claims Duration, Year Three	12.60%
Historical Claims Duration, Year Four	16.30%
Historical Claims Duration, Year Five	15%
Historical Claims Duration, Year Six	11.70%
Historical Claims Duration, Year Seven	9.70%
Historical Claims Duration, Year Eight	6.10%
Historical Claims Duration, Year Nine	3.20%
Historical Claims Duration, Year Ten	3.30%

Reserves for unpaid losses an_7

Reserves for unpaid losses and loss adjustment expenses Reconciliation of Claims Development to Liability (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for claims and claim adjustment expense, net	$ 1,764,429
Reinsurance recoverable for unpaid losses	323,060	$ 241,357	$ 177,039	$ 117,561
Reinsurance Recoverable, Allowance for Credit Loss	(932)	$ (744)
Unallocated claim adjustment expenses	197,247
Property [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for claims and claim adjustment expense, net	116,112
Reinsurance recoverable for unpaid losses	99,478
Casualty - claims made [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for claims and claim adjustment expense, net	262,470
Reinsurance recoverable for unpaid losses	21,051
Casualty - occurrence [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Liability for claims and claim adjustment expense, net	1,385,847
Reinsurance recoverable for unpaid losses	$ 203,463

Reinsurance, Effects of Reinsur

Reinsurance, Effects of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Written [Abstract]
Direct	$ 1,870,341	$ 1,568,815	$ 1,102,092
Ceded	(392,993)	(304,185)	(165,282)
Net written premiums	1,477,348	1,264,630	936,810
Earned [Abstract]
Direct	1,743,243	1,367,141	950,145
Ceded	(392,773)	(294,604)	(156,026)
Net earned premiums	1,350,470	1,072,537	794,119
Ceded incurred losses and loss adjustment expenses	$ 125,400	$ 115,900	$ 117,900

Reinsurance Reinsurance Balance

Reinsurance Reinsurance Balances (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reinsurance Disclosure [Abstract]
Reinsurance recoverables on paid losses, gross	$ 14,831	$ 6,479
Reinsurance recoverable for unpaid losses	323,060	241,357	$ 177,039	$ 117,561
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	337,891	247,836
Reinsurance Recoverable, Allowance for Credit Loss	932	744
Concentration Risk [Line Items]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	337,891	247,836
Ceded unearned premiums	52,736	$ 52,516
Credit Risk Reinsurer One [Member]
Reinsurance Disclosure [Abstract]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	83,800
Concentration Risk [Line Items]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	83,800
Ceded unearned premiums	11,500
Credit Risk Reinsurer Two [Member]
Reinsurance Disclosure [Abstract]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	37,600
Concentration Risk [Line Items]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	37,600
Ceded unearned premiums	6,300
Credit Risk Reinsurer Three [Member]
Reinsurance Disclosure [Abstract]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	34,300
Concentration Risk [Line Items]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	34,300
Ceded unearned premiums	5,500
Credit Risk Reinsurer Four [Member]
Reinsurance Disclosure [Abstract]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	30,000
Concentration Risk [Line Items]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	30,000
Ceded unearned premiums	4,800
Credit Risk Reinsurer Five [Member]
Reinsurance Disclosure [Abstract]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	20,500
Concentration Risk [Line Items]
Reinsurance recoverables, net of allowance for credit losses of $932 in 2024 and $744 in 2023	20,500
Ceded unearned premiums	$ 4,700
Prepaid reinsurance premiums ceded to five reinsurers as a percentage of total ceded unearned premium balance [Member] | Major Reinsurers [Member] | Reinsurer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	62.20%
Reinsurance recoverables on paid and unpaid losses from the Company’s five largest reinsurers as percent of total reinsurance recoverables [Member] | Major Reinsurers [Member] | Reinsurer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	61%

Stockholders' Equity Capital St

Stockholders' Equity Capital Stock (Details) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
Equity, Attributable to Parent [Abstract]
Preferred stock, shares issued	0	0
Common stock, shares authorized (in shares)	400,000,000	400,000,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, outstanding (in shares)	0	0
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01

Stockholders' Equity, Public Of

Stockholders' Equity, Public Offering (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Nov. 15, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity, Attributable to Parent [Abstract]
Stock issued, shares	155,000
Share price (in dollars per share)	$ 308.30
Net proceeds from public offering, net of discounts, commissions and other offering costs	$ 47,500	$ 0	$ 0	$ 47,498

Stockholders' Equity, Equity-ba

Stockholders' Equity, Equity-based Compensation, Options (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 27, 2016	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation		$ 14,100	$ 9,400	$ 6,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Intrinsic value of options exercised		$ 38,200	$ 17,700
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term of option granted	10 years
Award vesting period	4 years
Granted (in dollars per share)	$ 2.71
Options outstanding, number of awards [Roll Forward]
Options, beginning of the year (in shares)		201,560
Granted, shares		0
Forfeited (in shares)		0
Exercised (in shares)		(83,092)
Options, end of year (in shares)		118,468	201,560
Exercisable, shares		118,468
Options outstanding, weighted average exercise price [Abstract]
Options beginning of the year (in dollars per share)		$ 16
Granted	$ 16	0
Forfeited		0
Exercised		16
Options end of the year (in dollars per share)		16	$ 16
Exercisable		$ 16
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, weighted average remaining contractual term		1 year 7 months 6 days
Exercisable, weighted average remaining contractual term		1 year 7 months 6 days
Outstanding, aggregate intrinsic value		$ 53,208
Exercisable, aggregate intrinsic value		$ 53,208
2016 Omnibus Incentive Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance	2,073,832
2016 Omnibus Incentive Plan [Member] | Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in shares)	1,036,916

Stockholders' Equity - Equity-b

Stockholders' Equity - Equity-based Compensation, Restricted Stock (Details) - Restricted Stock [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares withheld for taxes	14,401
Vested in period, fair value	$ 20	$ 12.8	$ 10
Nonvested Restricted Stock, Number of Shares [Roll Forward]
Nonvested outstanding at the beginning of the period, shares		107,822
Granted, shares	47,689
Vested, shares	(41,872)
Forfeited, shares	(3,516)
Nonvested outstanding at the end of the period, shares	110,123
Nonvested Restricted Stock, Weighted Average Grant Date Fair Value [Abstract]
Nonvested outstanding at the beginning of the period	$ 250.86
Granted	502.43	$ 313.35	$ 211.86
Vested	230.81
Forfeited	308.84
Nonvested outstanding at the end of the period	$ 366.73	$ 250.86
Unrecognized stock-based compensation expense	$ 28.3
Compensation cost not yet recognized, period	2 years 2 months 12 days
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	1 year
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	4 years

Stockholders' Equity - Subseque

Stockholders' Equity - Subsequent Event (Details) - $ / shares			12 Months Ended
	Feb. 10, 2025	Jan. 01, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Subsequent Event [Member] | O2025Q1DividendMember
Subsequent Event [Line Items]
Dividend declared date	Feb. 10, 2025
Dividends payable, per share	$ 0.17
Dividend payable date	Mar. 13, 2025
Dividend record date	Feb. 27, 2025
Restricted Stock [Member]
Subsequent Event [Line Items]
Grant date fair value			$ 502.43	$ 313.35	$ 211.86
Restricted Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Granted		3,186
Grant date fair value		$ 465.13

Stockholders' Equity (Details)

Stockholders' Equity (Details) - Treasury Stock $ in Millions	Dec. 31, 2024 USD ($)
Equity [Abstract]
Share Repurchase Program, Authorized, Amount	$ 100

Earnings per share (Details)

Earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Reconciliation of numerator and denominator of the basic and diluted earnings per share computations [Abstract]
Net income	$ 414,843	$ 308,093	$ 159,114
Basic earnings per share [Abstract]
Earnings per share - basic	$ 17.92	$ 13.37	$ 6.97
Diluted earnings per share [Abstract]
Earnings per share - diluted	$ 17.78	$ 13.22	$ 6.88
Basic weighted average shares outstanding [Abstract]
Weighted average shares outstanding - basic	23,153,000	23,045,000	22,815,000
Dilutive effect of shares issued under stock compensation arrangements [Abstract]
Dilutive effect of shares issued under stock compensation arrangements (in shares)	179,000	262,000	310,000
Diluted weighted average shares outstanding [Abstract]
Weighted average shares outstanding - diluted (in shares)	23,332,000	23,307,000	23,125,000
Antidilutive securities (in shares)	43,000	1,000	0
Stock options [Member]
Dilutive effect of shares issued under stock compensation arrangements [Abstract]
Dilutive effect of shares issued under stock compensation arrangements (in shares)	136,000	214,000	269,000
Restricted Stock [Member]
Dilutive effect of shares issued under stock compensation arrangements [Abstract]
Dilutive effect of shares issued under stock compensation arrangements (in shares)	43,000	48,000	41,000

Debt (Details)

Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Repayments of Long-Term Lines of Credit	$ 0	$ 62,000	$ 43,000
Proceeds from Lines of Credit	0	0	73,000
Interest Paid, Excluding Capitalized Interest, Operating Activities	10,300	10,500	$ 2,400
Debt Issuance Costs, Net	(1,878)	(2,154)
Long-Term Debt	$ 184,122	183,846
Debt Instrument, Covenant Description	In October 2024, the covenants limiting restricted payments under the Note Purchase Agreement and Amended and Restated Credit Agreement were amended. The amendments allow the Company to make restricted payments so long as the aggregate amount of all such restricted payments does not exceed the greater of $300.0 million and 6.5% of the total assets of the Company and its subsidiaries at the end of the most recently completed fiscal quarter.
Senior Notes
Debt Instrument [Line Items]
Debt instrument borrowing capacity	$ 200,000
Line of Credit
Debt Instrument [Line Items]
Maturity date	Jul. 22, 2027
Accordion feature	$ 30,000
Line of Credit Facility, Commitment Fee Percentage	0.25%
Credit facility	$ 11,000	11,000
Interest rate description	The loans under the Amended and Restated Credit Agreement bear interest, at the Company's option, at a rate equal to the Adjusted Term SOFR Rate (as defined therein) plus 1.625% or the Alternate Base Rate (as defined therein) plus 0.625%.
Current borrowing capacity	$ 100,000
Weighted average interest rate	6.91%
2034 Series A Notes | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	Jul. 22, 2022
Debt Instrument, Face Amount	$ 125,000	125,000
Debt Instrument, Interest Rate, Stated Percentage	5.15%
Debt Instrument, Maturity Date	Jul. 22, 2034
Debt Instrument, Date of First Required Payment	Jul. 22, 2030
Debt Instrument, Periodic Payment, Principal	$ 25,000
2034 Series B Notes | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	Sep. 18, 2023
Debt Instrument, Face Amount	$ 50,000	$ 50,000
Debt Instrument, Interest Rate, Stated Percentage	6.21%
Debt Instrument, Maturity Date	Jul. 22, 2034
Debt Instrument, Date of First Required Payment	Jul. 22, 2030
Debt Instrument, Periodic Payment, Principal	$ 10,000

Employee benefit plan (Details)

Employee benefit plan (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Expenses related to employee benefit plan	$ 5	$ 3.8	$ 3.1

Other comprehensive income (l_3

Other comprehensive income (loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gains (losses) arising during the period, before income taxes	$ (2,921)	$ 49,384	$ (193,970)
Income taxes	613	(10,371)	40,734
Unrealized gains (losses) arising during the period, net of income tax	(2,308)	39,013	(153,236)
Less reclassification adjustment [Abstract]
Net realized investment gains	(170)	(1,443)	121
Income taxes	36	303	(25)
Reclassification adjustment included in net income	(134)	(1,140)	96
Allowance for Credit losses expense, before Tax	526	(187)	(366)
Income taxes	(111)	39	77
Reclassification adjustment included in net income	415	(148)	(289)
Other comprehensive income (loss)	$ (2,589)	$ 40,301	$ (153,043)

Segment Reporting (Details)

Segment Reporting (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting [Abstract]
Number of operating segments	1
Segment Reporting Information [Line Items]
Premiums Earned, Net	$ 1,350,470	$ 1,072,537	$ 794,119
Insurance Fee Income	34,118	27,026	19,604
Net investment income	150,287	102,335	51,282
Change in the fair value of equity securities	43,367	15,277	(27,723)
Net realized investment gains	6,831	6,040	1,191
Change in allowance for credit losses on investments	526	(187)	(366)
Other income	1,926	1,421	697
Revenues	1,587,525	1,224,449	838,804
Current year	810,554	635,993	493,800
Prior year losses and loss adjustment expense	(37,655)	(35,774)	(35,887)
Net commissions incurred		113,717	93,756
Salaries, employee benefits and bonus expense	109,300	85,700	64,800
Depreciation and amortization	5,802	3,274	2,721
Interest expense	10,134	10,301	4,284
Income tax expense	99,873	75,924	36,450
Net income	414,843	308,093	159,114
Catastrophe [Member]
Segment Reporting Information [Line Items]
Current year	25,500		26,600
Segments [Axis]
Segment Reporting Information [Line Items]
Net commissions incurred	134,184
Segments [Axis] | Excess and Surplus Lines Segment
Segment Reporting Information [Line Items]
Premiums Earned, Net	1,350,470	1,072,537	794,119
Insurance Fee Income	34,118	27,026	19,604
Net investment income	150,287	102,335	51,282
Change in the fair value of equity securities	43,367	15,277	(27,723)
Net realized investment gains	6,831	6,040	1,191
Change in allowance for credit losses on investments	526	(187)	(366)
Other income	1,926	1,421	697
Revenues	1,587,525	1,224,449	838,804
Current year	785,036	631,407	467,182
Prior year losses and loss adjustment expense	(37,655)	(35,774)	(35,887)
Salaries, employee benefits and bonus expense	109,319	85,689	64,765
Additions amounts charged to expense	17,397	9,790	5,988
Depreciation and amortization	4,686	2,655	2,267
Interest expense	10,134
Selling, General and Administrative Expense	24,190	18,061	14,267
Income tax expense	99,873	75,924	36,450
Net income	414,843	308,093	159,114
Segments [Axis] | Excess and Surplus Lines Segment | Catastrophe [Member]
Segment Reporting Information [Line Items]
Current year	$ 25,518	$ 4,586	$ 26,618

Underwriting information (Detai

Underwriting information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) Rate	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Revenue from External Customer [Line Items]
Gross written premiums	$ 1,870,341	$ 1,568,815	$ 1,102,092
Commercial Property [Member]
Revenue from External Customer [Line Items]
Gross written premiums	456,170	411,956	181,505
Excess Casualty [Member]
Revenue from External Customer [Line Items]
Gross written premiums	245,137	194,049	147,485
Small Business [Member]
Revenue from External Customer [Line Items]
Gross written premiums	195,593	174,080	149,366
Construction [Member]
Revenue from External Customer [Line Items]
Gross written premiums	148,333	137,887	122,524
Allied Health [Member]
Revenue from External Customer [Line Items]
Gross written premiums	83,058	67,808	58,839
Products Liability [Member]
Revenue from External Customer [Line Items]
Gross written premiums	67,035	61,786	60,374
Life Sciences [Member]
Revenue from External Customer [Line Items]
Gross written premiums	36,252	41,379	41,346
General Casualty [Member]
Revenue from External Customer [Line Items]
Gross written premiums	169,162	118,745	69,784
Management Liability [Member]
Revenue from External Customer [Line Items]
Gross written premiums	21,705	26,617	28,856
Energy [Member]
Revenue from External Customer [Line Items]
Gross written premiums	42,710	38,637	32,217
Environmental [Member]
Revenue from External Customer [Line Items]
Gross written premiums	30,372	25,938	19,455
Entertainment
Revenue from External Customer [Line Items]
Gross written premiums	58,506	39,218	22,268
Health Care [Member]
Revenue from External Customer [Line Items]
Gross written premiums	23,179	20,378	16,916
Inland Marine [Member]
Revenue from External Customer [Line Items]
Gross written premiums	27,184	18,669	14,396
Public Entity [Member]
Revenue from External Customer [Line Items]
Gross written premiums	20,047	20,028	15,512
Personal Insurance [Member]
Revenue from External Customer [Line Items]
Gross written premiums	22,090	24,182	31,289
Small Property
Revenue from External Customer [Line Items]
Gross written premiums	76,800	43,893	21,002
Commercial Auto
Revenue from External Customer [Line Items]
Gross written premiums	35,047	19,050	5,950
Aviation
Revenue from External Customer [Line Items]
Gross written premiums	8,591	6,453	4,424
Product Recall
Revenue from External Customer [Line Items]
Gross written premiums	2,397	1,637	1,419
Ocean Marine
Revenue from External Customer [Line Items]
Gross written premiums	3,655	2,339	765
Railroad
Revenue from External Customer [Line Items]
Gross written premiums	225	15	0
Excess Professional
Revenue from External Customer [Line Items]
Gross written premiums	32,633	24,033	22,826
High Value Homeowners
Revenue from External Customer [Line Items]
Gross written premiums	26,844	14,295	3,261
Commercial [Member]
Revenue from External Customer [Line Items]
Gross written premiums	1,821,407	1,530,338	1,067,542
Personal [Member]
Revenue from External Customer [Line Items]
Gross written premiums	48,934	38,477	34,550
Professional Liability Insurance
Revenue from External Customer [Line Items]
Gross written premiums	34,841	35,743	30,313
Agribusiness
Revenue from External Customer [Line Items]
Gross written premiums	$ 2,775	$ 0	$ 0
Revenue Benchmark [Member]
Revenue from External Customer [Line Items]
Number of insurance brokers	3
Insurance brokers greater than 10% of gross written premium	0
Major Insurance Brokers, Group One [Member] | Revenue Benchmark [Member]
Revenue from External Customer [Line Items]
Gross written premiums	$ 366,400
Major Insurance Brokers, Group One [Member] | Revenue Benchmark [Member] | Customer Concentration Risk
Revenue from External Customer [Line Items]
Concentration risk, percentage | Rate	19.60%
Major Insurance Brokers, Group Two [Member] | Revenue Benchmark [Member]
Revenue from External Customer [Line Items]
Gross written premiums	$ 325,500
Major Insurance Brokers, Group Two [Member] | Revenue Benchmark [Member] | Customer Concentration Risk
Revenue from External Customer [Line Items]
Concentration risk, percentage | Rate	17.40%
Major Insurance Brokers, Group Three [Member] | Revenue Benchmark [Member]
Revenue from External Customer [Line Items]
Gross written premiums	$ 213,900
Major Insurance Brokers, Group Three [Member] | Revenue Benchmark [Member] | Customer Concentration Risk
Revenue from External Customer [Line Items]
Concentration risk, percentage | Rate	11.40%

Statutory financial informati_3

Statutory financial information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statutory Accounting Practices, Statutory Amount Available for Dividend Payments [Abstract]
Statutory net income	$ 357,896	$ 259,042	$ 151,105
Statutory capital and surplus	$ 1,525,851	$ 1,167,382	$ 835,664
Percentage of policyholder surplus as of end of prior year used in determining maximum dividend distribution	10%
Maximum dividend distribution that can be paid without prior approval	$ 351,900

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Subsequent Events [Abstract]
Current year		$ 810,554	$ 635,993	$ 493,800
Subsequent Event [Line Items]
Current year		810,554	$ 635,993	493,800
Catastrophe [Member]
Subsequent Events [Abstract]
Current year		25,500		26,600
Subsequent Event [Line Items]
Current year		$ 25,500		$ 26,600
Catastrophe [Member] | Forecast | Subsequent Event [Member]
Subsequent Events [Abstract]
Current year	$ 25,000
Subsequent Event [Line Items]
Current year	$ 25,000

Schedule I-Summary of Investmen

Schedule I-Summary of Investments-Other than Related Parties (Details) $ in Thousands	Dec. 31, 2024 USD ($)
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	$ 3,995,512
Amount	3,954,681
Fixed Maturities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	3,663,031
Fair Value	3,537,563
Amount	3,537,563
US Treasury and Government [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	15,465
Fair Value	15,048
Amount	15,048
US States and Political Subdivisions Debt Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	168,894
Fair Value	146,304
Amount	146,304
Debt Security, Corporate, US [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	2,037,372
Fair Value	1,989,490
Amount	1,989,490
Asset-backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	729,658
Fair Value	732,742
Amount	732,742
Residential Mortgage Backed Securities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	502,121
Fair Value	448,874
Amount	448,874
Commercial mortgage-backed aecurities [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	209,521
Fair Value	205,105
Amount	205,105
Equity Securities, Investment Summary [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	313,722
Fair Value	398,359
Amount	398,359
Exchange Traded Funds [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	72,773
Fair Value	129,731
Amount	129,731
Banks, Trust and Insurance, Equities
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	47,994
Fair Value	58,777
Amount	58,777
Industrial, Miscellaneous, and All Others
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	165,017
Fair Value	183,418
Amount	183,418
Nonredeemable Preferred Stock [Member]
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	27,938
Fair Value	26,433
Amount	26,433
Short-Term Investments
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]
Cost	3,714
Fair Value	3,714
Amount	$ 3,714

Schedule II - Condensed Finan_3

Schedule II - Condensed Financial Information of Registrant, Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Assets
Deferred income tax asset, net	$ 60,215	$ 55,699
Other assets	87,774	66,443
Total assets	4,886,704	3,772,974
Liabilities:
Accounts payable and accrued expenses	55,159	44,922
Long-Term Debt	184,122	183,846
Other liabilities	5,786	15,566
Total liabilities	3,403,143	2,686,142
Stockholders' Equity [Abstract]
Common stock	233	232
Additional paid-in capital	361,398	352,970
Retained earnings	1,229,136	828,247
Accumulated other comprehensive loss	(97,206)	(94,617)
Stockholders' equity	1,483,561	1,086,832	$ 745,449	$ 699,335
Total liabilities and stockholders' equity	4,886,704	3,772,974
Treasury Stock, Value	(10,000)	0
Parent Company [Member]
Assets
Cash and cash equivalents	12,336	17,082	$ 34,789	$ 14,596
Investment in subsidiaries	1,604,811	1,230,371
Deferred income tax asset, net	2,527	1,673
Other assets	664	410
Total assets	1,672,634	1,276,015
Liabilities:
Accounts payable and accrued expenses	2,001	2,042
Income tax payable	2,842	3,201
Long-Term Debt	184,122	183,846
Other liabilities	108	94
Total liabilities	189,073	189,183
Stockholders' Equity [Abstract]
Common stock	233	232
Additional paid-in capital	361,398	352,970
Retained earnings	1,229,136	828,247
Accumulated other comprehensive loss	(97,206)	(94,617)
Stockholders' equity	1,483,561	1,086,832
Total liabilities and stockholders' equity	1,672,634	1,276,015
Treasury Stock, Value	(10,000)	0
Parent Company [Member] | Related Party
Assets
Due from subsidiaries	$ 52,296	$ 26,479

Schedule II - Condensed Finan_4

Schedule II - Condensed Financial Information of Registrant, Statements of Income and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues:
Revenues	$ 1,587,525	$ 1,224,449	$ 838,804
Net investment income	150,287	102,335	51,282
Expenses [Abstract]
Other expenses	3,968	942	721
Total expenses	1,072,809	840,432	643,240
Income tax benefit	99,873	75,924	36,450
Net income	414,843	308,093	159,114
Other Comprehensive Income (Loss) [Abstract]
Comprehensive income	412,254	348,394	6,071
Interest expense	10,134	10,301	4,284
Parent Company [Member]
Revenues:
Revenues	17,410	11,918	8,815
Net investment income	641	0	121
Realized Investment Gains (Losses)	0	0	8
Expenses [Abstract]
Other operating expenses	17,193	13,007	9,765
Other expenses	615	0	0
Total expenses	27,942	23,308	14,049
Loss before equity in net income of subsidiaries	(10,532)	(11,390)	(5,234)
Income tax benefit	(12,346)	(7,324)	(5,387)
Income before equity in net income of subsidiaries	1,814	(4,066)	153
Equity in net income of subsidiaries	413,029	312,159	158,961
Net income	414,843	308,093	159,114
Other Comprehensive Income (Loss) [Abstract]
Equity in other comprehensive earnings (losses) of subsidiaries	(2,589)	40,301	(153,043)
Comprehensive income	412,254	348,394	6,071
Interest expense	10,134	10,301	4,284
Parent Company [Member] | Related Party
Revenues:
Revenues	$ 16,769	$ 11,918	$ 8,686

Schedule II - Condensed Finan_5

Schedule II - Condensed Financial Information of Registrant, Statements of Cash Flows (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 15, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating activities:
Net income		$ 414,843	$ 308,093	$ 159,114
Adjustments to reconcile net income to net cash used in operating activities:
Deferred tax (benefit) expense		(3,828)	(9,429)	(14,191)
Stock compensation expense		14,146	9,361	6,678
Income taxes (recoverable) payable		(359)	742	7,518
Net cash provided by operating activities		976,301	859,835	557,815
Net Cash Provided by (Used in) Investing Activities [Abstract]
Net cash provided by (used in) investing activities		(960,125)	(860,892)	(708,573)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	$ 47,500	0	0	47,498
Proceeds from Lines of Credit		0	0	73,000
Dividends paid		(13,940)	(12,954)	(11,927)
Proceeds from Issuance of Long-Term Debt		0	50,000	125,000
Repayments of Long-Term Lines of Credit		0	(62,000)	(43,000)
Debt issuance costs		0	(164)	(2,381)
Payroll taxes withheld and remitted on share-based payments		(7,047)	(4,282)	(3,288)
Common stock issued, stock options exercised		1,330	877	1,090
Net cash provided by (used in) financing activities		(29,657)	(28,523)	185,992
Net change in cash and cash equivalents		(13,481)	(29,580)	35,234
Payments for Repurchase of Common Stock		(10,000)	0	0
Accounts payable and accrued expenses		8,936	12,519	8,111
Dividends received from subsidiary				0
Parent Company [Member]
Operating activities:
Net income		414,843	308,093	159,114
Adjustments to reconcile net income to net cash used in operating activities:
Deferred tax (benefit) expense		(854)	(372)	(367)
Stock compensation expense		14,146	9,361	6,678
Equity in undistributed earnings of subsidiaries		(413,029)	(312,159)	(158,961)
Changes in operating assets and liabilities		(25,795)	55,893	(71,639)
Income taxes (recoverable) payable		(359)	0	0
Net cash provided by operating activities		35,911	60,816	(65,175)
Net Cash Provided by (Used in) Investing Activities [Abstract]
Contribution to subsidiary		(11,000)	(50,000)	(100,624)
Net cash provided by (used in) investing activities		(11,000)	(50,000)	(100,624)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs		0	0	47,498
Proceeds from Lines of Credit		0	0	73,000
Dividends paid		(13,940)	(12,954)	(11,927)
Proceeds from Issuance of Long-Term Debt		0	50,000	125,000
Repayments of Long-Term Lines of Credit		0	(62,000)	(43,000)
Debt issuance costs		0	(164)	(2,381)
Payroll taxes withheld and remitted on share-based payments		(7,047)	(4,282)	(3,288)
Common stock issued, stock options exercised		1,330	877	1,090
Net cash provided by (used in) financing activities		(29,657)	(28,523)	185,992
Net change in cash and cash equivalents		(4,746)	(17,707)	20,193
Cash and cash equivalents at beginning of period		17,082	34,789	14,596
Cash and cash equivalents at end of period		12,336	17,082	34,789
Payments for Repurchase of Common Stock		(10,000)	0	0
Accounts payable and accrued expenses		(41)	0	0
Dividends received from subsidiary		$ 47,000	$ 0	$ 0

Schedule II - Condensed Finan_6

Schedule II - Condensed Financial Information of Registrant, Notes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Financial Information Disclosure [Abstract]
Interest expense	$ 10,134	$ 10,301	$ 4,284
Interest Paid, Excluding Capitalized Interest, Operating Activities	10,300	10,500	2,400
Cash dividends paid to parent company by consolidated subsidiaries			0
Repayments of Long-Term Lines of Credit	$ 0	$ (62,000)	$ (43,000)

Schedule V - Valuation and Qu_2

Schedule V - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Allowance for Premiums Receivable [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 13,383	$ 8,067	$ 3,391
Additions amounts charged to expense	17,397	9,790	5,988
Deductions amounts written off or disposals	(3,854)	(4,474)	(1,312)
Balance at end of period	26,926	13,383	8,067
Valuation Allowance for Deferred Tax Assets [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	6,182	5,188	4,159
Additions amounts charged to expense	2,884	994	1,029
Deductions amounts written off or disposals	0	0	0
Balance at end of period	9,066	6,182	5,188
Allowance for Reinsurance Recoverable [Member]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	744	459	400
Additions amounts charged to expense	188	285	59
Deductions amounts written off or disposals	0	0	0
Balance at end of period	932	744	459
SEC schedule, 12-09 Allowance Fixed-Maturity Securities
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	553	366	0
Additions amounts charged to expense	(47)	199	366
Deductions amounts written off or disposals	(479)	(12)	0
Balance at end of period	$ 27	$ 553	$ 366