Summary of Significant Accounting Policies - Schedule of Provision for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Provision for Credit Losses
Provision (benefit) for loan losses	$ 17	$ 340	$ (238)	$ 274
Provision for risk-sharing obligations	275	58	121	208
Provision (benefit) for credit losses	$ 292	$ 398	$ (117)	$ 482