RESERVE FOR LOSS ON REPURCHASED LOANS - Summary of Activities in Reserve for Loss Reimbursements on Sold Loans (Details) - Representations and Warranties Obligations and Corporate Guarantees - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Loss Contingency Accrual [Roll Forward]
Balance at beginning of year	$ 2,506	$ 6,306	$ 7,974
Initial provision for loan repurchases	4,563	126	1,622
Subsequent change in the reserve	(660)	(2,488)	(1,812)
Utilization of reserve for loan repurchases	(208)	(1,438)	(2,238)
Other adjustments	0	0	760
Balance at end of year	$ 6,201	$ 2,506	$ 6,306

RESERVE FOR LOSS ON REPURCHASED LOANS - Summary of Activities in Reserve for Loss Reimbursements on Sold Loans (Details) - Representations and Warranties Obligations and Corporate Guarantees - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Loss Contingency Accrual [Roll Forward]

Balance at beginning of year

$ 2,506

$ 6,306

$ 7,974

Initial provision for loan repurchases

4,563

126