GOODWILL AND INTANGIBLE ASSETS - Summary of Other Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets			$ 115,763
Accumulated Amortization	$ (45,729)		(41,360)
Net Intangible Assets	142,224		74,403
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Intangible Assets	190,753
Accumulated Amortization	(45,729)		(41,360)
Net Intangible Assets	145,024		74,403
Tradename
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived trademark	2,800
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	104,751		93,811
Accumulated Amortization	(32,599)		(30,103)
Net Intangible Assets	$ 72,152		63,708
Amortization Period	10 years	10 years
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	$ (32,599)		(30,103)
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	72,381		15,281
Accumulated Amortization	(9,218)		(7,876)
Net Intangible Assets	63,163		7,405
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	$ (9,218)		(7,876)
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	7 years	7 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	15 years	15 years
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 500
Accumulated Amortization	(125)
Net Intangible Assets	$ 375
Amortization Period	1 year
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	$ (125)
Loan servicing rights
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	10,321		6,671
Accumulated Amortization	(3,787)		(3,381)
Net Intangible Assets	6,534		3,290
Impairment loss reversal	100	$ 300
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	$ (3,787)		$ (3,381)
Loan servicing rights | Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	10 years	10 years
Loan servicing rights | Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization Period	25 years	25 years