Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Net premiums earned	$ 1,526,406	$ 1,294,306	$ 1,144,436
Net investment income	142,278	120,383	86,078
Net realized gains	19,966	32,518	588,515
Net unrealized gains (losses) on equity securities	81,734	64,787	(121,037)
Consolidated revenue	1,770,384	1,511,994	1,697,992
Losses and settlement expenses	739,253	604,413	514,376
Policy acquisition costs	464,040	418,325	369,632
Insurance operating expenses	112,460	98,383	82,212
Interest expense on debt	6,331	7,301	8,047
General corporate expenses	15,880	15,917	12,900
Total expenses	1,337,964	1,144,339	987,167
Equity in earnings of unconsolidated investees	(4,869)	9,610	9,853
Earnings before income taxes	427,551	377,265	720,678
Income tax expense (benefit):
Current	71,720	64,944	186,906
Deferred	10,052	7,710	(49,639)
Income tax expense	81,772	72,654	137,267
Net income (loss)	345,779	304,611	583,411
Other comprehensive earnings (loss), net of tax	(7,420)	62,773	(278,902)
Comprehensive earnings	$ 338,359	$ 367,384	$ 304,509
Basic net earnings per share	$ 3.78	$ 3.34	$ 6.43
Diluted net earnings per share	$ 3.74	$ 3.31	$ 6.37
Weighted average number of common shares outstanding:
Basic	91,529	91,191	90,735
Diluted	92,451	92,155	91,589