LOAN SERVICING RIGHTS - Schedule of Activity of Servicing Rights (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 136,542
Ending balance	161,220
Residential mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	130,630	$ 94,902
Additions	21,867	16,061
Amortization	(7,484)	(4,166)
Recoveries/(impairment)	9,733	(20,875)
Ending balance	154,746	85,922
Residential mortgage servicing valuation allowance
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	39,407	104
Additions	0	20,875
Recoveries/(impairment)	(9,733)	0
Ending balance	29,674	20,979
SBA servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	5,839	7,886
Additions	230	375
Purchase accounting adjustment	0	(1,214)
Amortization	(529)	(363)
Recoveries/(impairment)	905	(1,290)
Ending balance	6,445	5,394
SBA servicing valuation allowance
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	905	141
Additions	0	1,290
Recoveries/(impairment)	(905)	0
Ending balance	0	1,431
Indirect automobile
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	73	247
Amortization	(44)	(43)
Ending balance	$ 29	$ 204