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GOODWILL AND OTHER INTANGIBLE ASSETS--Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended
	Dec. 31, 2021	Aug. 30, 2019	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Goodwill			$ (790)	$ 0	$ 63,000
Intangible assets amortization			$ 2,914	$ 2,479
Core deposits
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization method			accelerated basis
Estimated weighted average life (in years)			6 years
Customer lists
Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization method			straight-line basis
Estimated weighted average life (in years)	12 years	11 years
Customer lists \| Summit Funding Group
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Net	$ 30,100		$ 29,500		30,100
Customer lists \| Bannockburn [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Net	$ 31,100		$ 30,200		$ 31,100