Insurance Activity - Summary of Losses and Loss Adjustment Reserve Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017		Dec. 31, 2016
Liability For Unpaid Claims And Claims Adjustment Expense Net [Abstract]
Balance at beginning of period	$ 811	[1]	$ 5,063
Released - prior periods	94		(669)
Paid or terminated - prior periods	(282)		(3,583)
Total losses and loss adjustment reserves	$ 623		$ 811	[1]

[1] Balances derived from audited financial statements as of December 31, 2016.