NON-CONSOLIDATED VARIABLE INTEREST ENTITIES AND SERVICING ASSETS - Components of Net Servicing Income (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transfers and Servicing [Abstract]
Servicing fees		$ 8,704	$ 7,630	$ 7,606
Late charges and prepayment penalties		510	405	674
Adjustment to servicing assets for loans repurchased		(85)	395	256
Other	[1]	(8)	(35)	(1)
Servicing income, gross		9,121	8,395	8,535
Amortization and impairment of servicing assets		(1,606)	(4,702)	(3,554)
Servicing income, net		$ 7,515	$ 3,693	$ 4,981

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