Reinsurance - Schedule of the Amounts Recoverable from Reinsurers (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Unpaid losses recoverable:
Case basis	$ 66,061	$ 49,361
Incurred but not reported	18,828	28,895
Paid losses recoverable	554	485
Experience-rated commissions recoverable	4,690	4,925
Total reinsurance recoverables	$ 90,133	$ 83,666