Liability for Unpaid Claims and Claim Adjustment Expenses - Schedule of Reconciliation of Net Incurred and Paid Claims Development Tables to Liability for Claims and Claim Adjustment Expenses in Consolidated Statement of Financial Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	$ 995,986
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	247,081
Insurance lines other than short-duration	191,123
Unallocated claims adjustment expenses	55,789
Total claim adjustment expenses	246,912
Total gross liability for unpaid claims and claim adjustment expense	1,489,979	$ 1,481,294
Credit Property and Casualty
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	21,089
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	14,110
Credit Life
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	1,192
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	768
Credit Health
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	5,126
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	2,113
Auto Liability
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	466,481
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	11,979
Non-Auto Liability
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	266,892
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	44,709
Commercial Multi-Peril
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	94,515
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	2,326
Homeowners
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	79,903
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	2,512
Short Tail Property
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	33,097
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	3,907
Health
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	25,860
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	157,714
Other
Net outstanding liabilities
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	1,831
Reinsurance recoverable on unpaid claims
Total reinsurance recoverable on unpaid claims	$ 6,943