SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Provision (Benefit) for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Provision (Benefit) for Credit Losses
Provision (benefit) for loan losses	$ (100)	$ (49)	$ (290)	$ (287)
Provision for risk-sharing obligations	109	332	74	453
Provision (benefit) for credit losses	$ 9	$ 283	$ (216)	$ 166