Condensed Consolidated Statements of Earnings and Comprehensive Earnings - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Net premiums earned	$ 228,595	$ 215,582
Net investment income	16,424	17,778
Net realized gains	14,150	15,152
Net unrealized gains (losses) on equity securities	28,162	(130,395)
Consolidated revenue	287,331	118,117
Losses and settlement expenses	104,892	111,021
Policy acquisition costs	74,990	72,941
Insurance operating expenses	18,796	14,381
Interest expense on debt	1,901	1,897
General corporate expenses	3,342	1,755
Total expenses	203,921	201,995
Equity in earnings of unconsolidated investees	6,424	4,514
Earnings (loss) before income taxes	89,834	(79,364)
Income tax expense (benefit)	16,822	(18,097)
Net earnings (loss)	73,012	(61,267)
Other comprehensive earnings (loss), net of tax	(44,747)	(13,031)
Comprehensive earnings (loss)	$ 28,265	$ (74,298)
Basic net earnings (loss) per share	$ 1.62	$ (1.36)
Diluted net earnings (loss) per share	$ 1.60	$ (1.36)
Weighted average number of common shares outstanding:
Basic	45,178	44,920
Diluted	45,674	44,920