Losses and Loss Adjustment Expenses - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Unpaid claims and claim adjustment expenses overall development	$ (650)	$ 2,877	$ 1,625	$ 5,552
Accidental Year 2019 and Prior [Member]
Reserves For Losses And Loss Adjustment Expenses [Line Items]
Unpaid claims and claim adjustment expenses overall development	$ (650)		$ 1,625