MORTGAGE SERVICING RIGHTS - Presentation of Activity Related to MSR (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Servicing Asset at Fair Value, Amount [Roll Forward]
Fair value, beginning of period	$ 378,078	$ 557,813
Sales	(72,160)	0
Changes in valuation inputs or assumptions	(107,517)	(102,016)
Other changes, including realization of expected cash flows	(97,506)	(77,719)
Fair value, end of period	$ 100,895	$ 378,078