Other Assets - Additional Information (Detail) $ in Thousands	1 Months Ended
	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($) Contract	Jul. 31, 2015 USD ($)
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Cash payments received from retrospective reinsurance contracts | $	$ 5,716	$ 37,800	$ 14,100
Number of retrospective reinsurance contracts | Contract		2