Schedule II. Condensed Financial Information of Registrant - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Fixed maturity securities—held-to-maturity, at amortized cost net of allowance for credit losses of $0 in 2021 and 2020, (fair value $0, and $361 in 2021 and 2020, respectively)	$ 549,231	$ 585,130
Fixed maturity securities—available-for-sale, at fair value (amortized cost $324,597, allowance for credit losses of $0 in 2021 and amortized cost $387,665, allowance for credit losses of $0 in 2020)	341,769	414,279
Equity securities, at fair value (cost $44,175 and $35,787 in 2021 and 2020, respectively)	64,140	43,437
Short-term investments	57,431	45,898
Total investments	1,012,571	1,088,744
Cash and cash equivalents	70,722	61,757
Deferred income taxes	14,384	13,665
Property and equipment, net	6,459	6,182
Federal income tax recoverable	6,414
Other assets	11,374	10,860
Total assets	1,402,724	1,470,855
Liabilities:
Accounts payable and other liabilities	37,773	38,880
Total liabilities	1,003,401	1,032,039
Shareholders' equity (net of Treasury stock of $22,370 at December 31, 2021 and 2020)	399,323	438,816	$ 430,215	$ 409,762
Total liabilities and shareholders’ equity	1,402,724	1,470,855
Parent Company [Member]
Assets
Fixed maturity securities—held-to-maturity, at amortized cost net of allowance for credit losses of $0 in 2021 and 2020, (fair value $0, and $361 in 2021 and 2020, respectively)		361
Fixed maturity securities—available-for-sale, at fair value (amortized cost $324,597, allowance for credit losses of $0 in 2021 and amortized cost $387,665, allowance for credit losses of $0 in 2020)	19,605	7,259
Equity securities, at fair value (cost $44,175 and $35,787 in 2021 and 2020, respectively)	14,092	11,503
Short-term investments	55,559	9,676
Investment in subsidiaries	290,077	384,774
Total investments	379,333	413,573
Cash and cash equivalents	18,825	23,562
Deferred income taxes	1,148
Notes receivable from subsidiaries	2,275	2,140
Property and equipment, net	2,003	1,605
Federal income tax recoverable	857	2,705
Other assets	1,295	1,420
Total assets	405,736	445,005
Liabilities:
Accounts payable and other liabilities	6,413	6,095
Deferred income taxes		94
Total liabilities	6,413	6,189
Shareholders' equity (net of Treasury stock of $22,370 at December 31, 2021 and 2020)	399,323	438,816
Total liabilities and shareholders’ equity	$ 405,736	$ 445,005