COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Contract amount of commitments and contingencies	$ 1,486,563,000	$ 1,352,781,000
Unused lines of credit	25,000,000.0
Federal Home Loan Bank unused borrowing capacity	1,710,000,000
Federal Reserve unused borrowing capacity	247,700,000
Federal Reserve required average total reserve	0	0
Litigation accrual	(100,000)	2,950,000	$ 0
Litigation settlement amount	2,900,000
Adjustment to the Company's litigation accrual	100,000
Minimum
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability	0
Maximum
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Range of reasonably possible losses for such matters in the aggregate, beyond the existing recorded liability	1,000,000
Commitments to Extend Credit
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Contract amount of commitments and contingencies	1,443,879,000	1,313,568,000
Standby Letters of Credit
COMMITMENTS, CONTINGENT LIABILITIES AND RESTRICTIONS.
Contract amount of commitments and contingencies	$ 42,684,000	$ 39,213,000