Summary of Significant Accounting Policies - Schedule of Provision for Credit Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Provision for Credit Losses
Provision for loan losses	$ (36)	$ 423	$ 441
Provision for risk-sharing obligations	1,680	1,783	881
Provision for credit losses	$ 1,644	$ 2,206	$ 1,322