Condensed Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net premiums earned	$ 253,389	$ 216,630	$ 722,984	$ 640,946
Net investment income	17,844	16,543	50,929	51,238
Net realized gains	1,829	1,512	52,442	14,555
Net unrealized gains (losses) on equity securities	(2,592)	28,126	29,526	(27,564)
Consolidated revenue	270,470	262,811	855,881	679,175
Losses and settlement expenses	143,656	127,596	355,574	339,819
Policy acquisition costs	80,449	71,032	232,674	213,436
Insurance operating expenses	15,560	16,850	54,504	45,137
Interest expense on debt	1,906	1,901	5,711	5,701
General corporate expenses	2,505	2,668	9,533	6,417
Total expenses	244,076	220,047	657,996	610,510
Equity in earnings of unconsolidated investees	9,043	8,745	29,407	18,359
Earnings before income taxes	35,437	51,509	227,292	87,024
Income tax expense	6,194	9,122	43,222	13,738
Net earnings	29,243	42,387	184,070	73,286
Other comprehensive earnings (loss), net of tax	(12,240)	9,550	(41,810)	50,090
Comprehensive earnings	$ 17,003	$ 51,937	$ 142,260	$ 123,376
Basic net earnings per share	$ 0.65	$ 0.94	$ 4.07	$ 1.63
Diluted net earnings per share	$ 0.64	$ 0.93	$ 4.03	$ 1.62
Weighted average number of common shares outstanding:
Basic	45,243	45,014	45,216	44,962
Diluted	45,689	45,426	45,714	45,339