Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Net premiums earned	$ 1,144,436	$ 980,903	$ 865,747
Net investment income	86,078	68,862	67,893
Net realized gains	588,515	64,222	17,885
Net unrealized gains (losses) on equity securities	(121,037)	65,258	32,101
Consolidated revenue	1,697,992	1,179,245	983,626
Losses and settlement expenses	514,376	456,602	442,884
Policy acquisition costs	369,632	317,468	286,438
Insurance operating expenses	82,212	76,907	66,828
Interest expense on debt	8,047	7,677	7,603
General corporate expenses	12,900	13,330	10,265
Total expenses	987,167	871,984	814,018
Equity in earnings of unconsolidated investees	9,853	37,060	20,233
Earnings (losses) before income taxes	720,678	344,321	189,841
Income tax expense (benefit):
Current	186,906	46,040	24,174
Deferred	(49,639)	18,927	8,576
Total tax expense	137,267	64,967	32,750
Net earnings (losses)	583,411	279,354	157,091
Other comprehensive earnings (loss), net of tax	(278,902)	(58,888)	56,219
Comprehensive earnings	$ 304,509	$ 220,466	$ 213,310
Basic net earnings per share	$ 12.86	$ 6.18	$ 3.49
Diluted net earnings per share	$ 12.74	$ 6.11	$ 3.46
Weighted average number of common shares outstanding:
Basic	45,368	45,230	45,000
Diluted	45,794	45,712	45,376