SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Provision (Benefit) for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Components of Provision for Credit Losses
Provision for loan losses	$ 25	$ 79	$ 648	$ 66
Provision for risk-sharing obligations	936	721	2,988	257
Provision for credit losses	$ 961	$ 800	$ 3,636	$ 323