Deferred Policy Acquisition Costs - Summary of Activity in Deferred Policy Acquisition Costs (DPAC) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Insurance [Abstract]
Beginning Balance	$ 88,876	$ 74,895	$ 89,265	$ 77,211
Policy acquisition costs deferred	49,729	48,173	96,404	86,304
Amortization	(42,638)	(41,478)	(89,702)	(81,925)
Ending Balance	$ 95,967	$ 81,590	$ 95,967	$ 81,590