Reinsurance - Impact of the Reinsurance Contracts on Premiums Written and Earned (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Premiums Written:
Direct	$ 187,792	$ 143,224	$ 359,773	$ 253,355
Assumed	(1,640)	41,754	3,673	57,471
Gross written	186,152	184,978	363,446	310,826
Ceded	(56,205)	(46,436)	(109,367)	(89,535)
Net premiums written	129,947	138,542	254,079	221,291
Premiums Earned:
Direct	164,887	115,733	313,733	226,025
Assumed	16,237	23,707	46,316	44,357
Gross premiums earned	181,124	139,440	360,049	270,382
Ceded	(56,205)	(46,436)	(109,367)	(89,535)
Net premiums earned	$ 124,919	$ 93,004	$ 250,682	$ 180,847