LOAN SERVICING RIGHTS - Schedule of Activity of Servicing Rights (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			$ 103,035
Ending balance	$ 120,575		120,575
Residential mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	91,381	$ 11,185	94,902	$ 11,814
Additions	30,376	4,962	65,735	6,661
Addition due to acquisition	0	78,855	0	78,855
Amortization	(6,231)	(3,564)	(16,084)	(4,432)
(Impairment)/recoveries	(1,130)	1,460	(30,157)	0
Ending balance	114,396	92,898	114,396	92,898
Residential mortgage servicing impairment
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	29,131	1,460	104	0
Additions	1,130	0	30,157	0
(Impairment)/recoveries	0	(1,460)	0	0
Ending balance	30,261	0	30,261	0
SBA servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	5,241	3,110	7,886	3,012
Additions	499	155	974	783
Addition due to acquisition	0	5,242	0	5,242
Purchase accounting adjustment	0	0	(1,214)	0
Amortization	(396)	(167)	(1,175)	(556)
(Impairment)/recoveries	718	0	(409)	(141)
Ending balance	6,062	8,340	6,062	8,340
SBA servicing impairment
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	1,268	0	141	0
Additions	0	141	409	141
(Impairment)/recoveries	(718)	0	0	0
Ending balance	550	141	550	141
Indirect automobile
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	162	0	247	0
Addition due to acquisition	0	777	0	777
Amortization	(45)	(125)	(130)	(125)
Ending balance	$ 117	$ 652	$ 117	$ 652