Liability for Unpaid Claims and Claim Adjustment Expenses - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Insurance [Abstract]
Description of increase (decrease) in claims and claim adjustment expenses	The net and gross reserve calculations have shown favorable development as a result of favorable loss emergence compared to what was implied by the loss development patterns used in the original estimation of losses in prior years.
Decrease in claims and claim adjustments expenses amount	$ 17,296,000	$ 752,000
Short-duration health insurance claims	$ 29,539,000