Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenues
Net premiums earned	$ 1,034,587	$ 951,541	$ 962,823
Investment income, net of investment expenses	59,606	44,932	55,778
Net investment gains (losses) (includes reclassifications for net unrealized gains (losses) on available-for-sale securities of $(718) in 2023; $(1,323) in 2022; and $2,256 in 2021 previously included in accumulated other comprehensive income)	1,274	(15,892)	47,383
Other income (loss)	0	(295)	207
Total revenues	1,095,467	980,286	1,066,191
Benefits, losses and expenses
Losses and loss settlement expenses	769,414	637,301	652,155
Amortization of deferred policy acquisition costs	244,991	213,075	203,432
Other underwriting expenses (includes reclassifications for employee benefit costs of $(207) in 2023; $(3,601) in 2022; and $(6,603) in 2021 previously included in accumulated other comprehensive income)	115,800	115,169	110,103
Interest Expense	3,260	3,188	3,187
Other nonunderwriting expenses	1,723	(524)	471
Total benefits, losses and expenses	1,135,188	968,209	969,348
Income (loss) before income taxes	(39,721)	12,077	96,843
Federal income tax expense (benefit) (includes reclassifications of $194 in 2023; $1,034 in 2022 and $913 in 2021 previously included in accumulated other comprehensive income)	10,021	2,954	(16,249)
Net income (loss)	(29,700)	15,031	80,594
Other comprehensive income (loss)
Change in net unrealized appreciation on investments	26,373	(176,181)	(39,901)
Change in liability for underfunded employee benefit plans	18,953	(8,278)	19,633
Other comprehensive income (loss), before tax and reclassification adjustments	45,326	(184,459)	(20,268)
Income tax effect	(9,518)	38,736	4,260
Other comprehensive income (loss), after tax, before reclassification adjustments	35,808	(145,723)	(16,008)
Reclassification adjustment for net (gains) losses included in income	718	1,323	(2,256)
Reclassification adjustment for employee benefit costs included in expense	207	3,601	6,603
Total reclassification adjustments, before tax	925	4,924	4,347
Income tax effect	(194)	(1,034)	(913)
Total reclassification adjustments, after tax	731	3,890	3,434
Comprehensive income (loss)	$ 6,839	$ (126,802)	$ 68,020
Earnings (loss) per common share:
Basic (in dollars per share)	$ (1.18)	$ 0.60	$ 3.21
Diluted (in dollars per share)	$ (1.18)	$ 0.59	$ 3.16