SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Provision (Benefit) for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Provision (Benefit) for Credit Losses
Provision (benefit) for loan losses	$ 79	$ (215)	$ 66	$ (190)
Provision (benefit) for risk-sharing obligations	721	122	257	(35)
Provision (benefit) for credit losses	$ 800	$ (93)	$ 323	$ (225)