LOAN SERVICING RIGHTS - Schedule of Activity of Servicing Rights (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			$ 136,542
Ending balance	$ 194,339		194,339
Residential mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	191,675	$ 91,381	130,630	$ 94,902
Additions	6,195	30,376	71,439	65,735
Amortization	(7,967)	(6,231)	(22,648)	(16,084)
Recoveries/(impairment)	(1,397)	(1,130)	9,085	(30,157)
Ending balance	188,506	114,396	188,506	114,396
Residential mortgage servicing valuation allowance
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	28,925	29,131	39,407	104
Additions	1,397	1,130	1,397	30,157
Recoveries/(impairment)	0	0	(10,482)	0
Ending balance	30,322	30,261	30,322	30,261
SBA servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	6,123	5,241	5,839	7,886
Additions	265	499	736	974
Purchase accounting adjustment	0	0	0	(1,214)
Amortization	(555)	(396)	(1,647)	(1,175)
Recoveries/(impairment)	0	718	905	(409)
Ending balance	5,833	6,062	5,833	6,062
SBA servicing valuation allowance
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	0	1,268	905	141
Additions	0	0	0	409
Recoveries/(impairment)	0	(718)	(905)	0
Ending balance	0	550	0	550
Indirect automobile
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	0	162	73	247
Amortization	0	(45)	(73)	(130)
Ending balance	$ 0	$ 117	$ 0	$ 117