Schedule VI. Supplemental Information Concerning Property-Casualty Insurance Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Supplemental Information For Property Casualty Insurance Underwriters [Abstract]
Deferred Policy Acquisition Costs	$ 17,059	$ 17,810	$ 19,048
Reserves for Unpaid Loss and Loss Adjustment Expense	745,278	760,561	772,887
Unearned Premium	121,092	129,260	140,873
Net Premiums Earned	275,993	304,427	332,888
Net Investment Income	25,435	29,364	32,483
Loss and LAE Related to Current Period	222,715	220,710	241,344
Loss and LAE Related to Prior Periods	(61,917)	(63,484)	(65,002)
Amortization of Deferred Policy Acquisition Costs	(38,481)	(41,583)	(44,558)
Paid Claims and Claim Adjustment Expenses	189,640	179,916	189,991
Net Premiums Written	$ 267,825	$ 292,814	$ 324,465