Condensed Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Net premiums earned	$ 379,065	$ 322,280	$ 739,741	$ 630,003
Net investment income	33,961	28,788	66,808	55,872
Net realized gains (losses)	(192)	5,580	5,802	20,200
Net unrealized gains on equity securities	3,608	25,214	48,922	40,710
Consolidated revenue	416,442	381,862	861,273	746,785
Losses and settlement expenses	167,799	153,943	311,623	268,431
Policy acquisition costs	113,921	102,626	224,375	204,070
Insurance operating expenses	27,321	24,510	56,024	48,411
Interest expense on debt	1,604	2,047	3,222	4,055
General corporate expenses	4,140	4,219	9,150	8,433
Total expenses	314,785	287,345	604,394	533,400
Equity in earnings of unconsolidated investees	1,646	1,514	6,415	5,437
Earnings (loss) before income taxes	103,303	96,031	263,294	218,822
Income tax expense	21,311	18,379	53,402	42,359
Net earnings (loss)	81,992	77,652	209,892	176,463
Other comprehensive earnings (loss), net of tax	(7,843)	(19,721)	(20,514)	17,986
Comprehensive earnings	$ 74,149	$ 57,931	$ 189,378	$ 194,449
Basic net earnings per share	$ 1.79	$ 1.70	$ 4.59	$ 3.87
Diluted net earnings per share	$ 1.78	$ 1.69	$ 4.55	$ 3.83
Weighted average number of common shares outstanding:
Basic	45,737	45,591	45,709	45,560
Diluted	46,179	46,044	46,169	46,045