GOODWILL AND OTHER INTANGIBLE ASSETS--Schedule of Other Intangibles (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 129,408	$ 129,408
Finite-Lived Intangible Assets, Accumulated Amortization	(43,517)	(40,510)
Core deposits
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	45,256	45,256
Finite-Lived Intangible Assets, Accumulated Amortization	(27,710)	(26,911)
Customer lists
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	69,563	69,563
Finite-Lived Intangible Assets, Accumulated Amortization	(9,886)	(8,362)
Other
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	14,589	14,589
Finite-Lived Intangible Assets, Accumulated Amortization	$ (5,921)	$ (5,237)