Supplementary Information for Property Casualty Underwriters (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
SEC Schedule, 12-18, Supplemental Information, Property-Casualty Insurance Underwriters [Abstract]
Deferred Policy Acquisition Costs	$ 42,445	$ 64,894	$ 60,331
Reserves for Unpaid Claims and Claim Adjustment Expenses	850,599	832,404	759,904
Discount If Any Deducted	0	0	0
Unearned Premiums	182,852	269,353	316,566
Earned Premiums	473,357	602,471	595,610
Net Investment Income	55,444	27,627	37,020
Claims and Claim Adjustment Expense Incurred Related To Current Year	279,609	367,298	376,306
Claims and Claim Adjustment Expense Incurred Related To Prior Year	9,544	(8,070)	8,658
Amortization Of Deferred Policy Acquisition Costs	120,883	150,946	144,944
Paid Claims and Claim Adjustment Expenses	270,766	265,306	300,156
Premiums Written	$ 399,319	$ 591,331	$ 580,068