Guaranty Obligation and Allowance for Risk-Sharing Obligations - Schedule of Activity Related to Guaranty Obligation (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
GUARANTY OBLIGATION AND ALLOWANCE FOR RISK-SHARING OBLIGATIONS
Guaranty obligation, net of accumulated amortization - beginning balance	$ 28,552	$ 25,333	$ 27,570	$ 24,975
Additions, following the sale of loan	1,777	3,115	3,689	4,870
Amortization	(1,537)	(1,308)	(2,750)	(2,705)
Other	(386)		(103)
Guaranty obligation, net of accumulated amortization - ending balance	$ 28,406	$ 27,140	$ 28,406	$ 27,140