LOAN SERVICING RIGHTS - Schedule of Activity of Servicing Rights (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning carrying value, net	$ 103,035
Amortization	(1,640)
Ending carrying value, net	136,542	$ 103,035
Residential mortgage
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning carrying value, net	94,902	11,814	$ 5,262
Additions	98,182	12,559	7,502
Addition due to acquisition	0	78,855	0
Amortization	(23,151)	(8,222)	(950)
(Impairment)/recoveries	(39,303)	(104)	0
Ending carrying value, net	130,630	94,902	11,814
Residential mortgage servicing impairment
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning carrying value, net	104	0	0
Additions	39,303	104	0
(Impairment)/recoveries	0	0	0
Ending carrying value, net	39,407	104	0
SBA
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning carrying value, net	7,886	3,012	1,988
Additions	1,571	1,004	1,714
Addition due to acquisition	0	5,242	0
Purchase accounting adjustment	(1,214)	0	0
Amortization		(1,231)	(690)
(Impairment)/recoveries	(764)	(141)	0
Ending carrying value, net	5,839	7,886	3,012
SBA servicing impairment
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning carrying value, net	141	0	0
Additions	764	141	0
(Impairment)/recoveries	0	0	0
Ending carrying value, net	905	141	0
Indirect automobile
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning carrying value, net	247	0	0
Addition due to acquisition	0	777	0
Amortization	(174)	(268)	0
(Impairment)/recoveries	0	(262)	0
Ending carrying value, net	$ 73	$ 247	$ 0