Insurance Activity - Summary of Losses and Loss Adjustment Reserve Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Liability For Unpaid Claims And Claims Adjustment Expense Net [Abstract]
Balance at beginning of period	$ 5,063	$ 18,947
Released - prior periods	(669)	(1,115)
Paid or terminated - prior periods	(3,583)	(12,769)
Total losses and loss adjustment reserves	$ 811	$ 5,063