INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred Tax Assets:
Compensation related	$ 8,227	$ 16,753
Credit losses	3,133	1,202
Valuation allowance	(1,049)	(2,838)
Total deferred tax assets	10,311	15,117
Deferred Tax Liabilities:
Mark-to-market of derivatives and loans held for sale	(5,396)	(8,582)
Mortgage servicing rights related	(139,115)	(125,084)
Acquisition related	(7,292)	(4,396)
Depreciation	(1,812)	(2,005)
Other	(3,507)	(592)
Total deferred tax liabilities	(157,122)	(140,659)
Deferred tax liabilities, net	$ (146,811)	$ (125,542)