Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Fixed maturity securities, held-to-maturity, allowance for credit losses	$ 290	$ 195
Fixed maturity securities, fair value	545,425	575,850
Fixed maturity securities, available-for-sale, allowance for credit losses	0	0
Fixed maturity securities, amortized cost	342,784	324,597
Equity securities, cost	48,151	44,175
Amounts recoverable from reinsurers, allowance for credit losses	388	440
Premiums receivable, allowance for credit losses	$ 4,530	$ 4,386
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	50,000,000	50,000,000
Common stock, shares issued	20,622,565	20,622,304
Common stock, shares outstanding	19,320,422	19,364,054
Treasury stock, shares	1,302,143	1,258,250