LOANS - Total Loans Outstanding (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 4,758,290	$ 4,713,465
Percentage of loans receivable	100.00%	100.00%
Less: Allowance for credit losses	$ (71,215)	$ (72,606)	$ (67,526)	$ (67,773)
Net deferred loan fees	(3,362)	(3,069)
Loans, net	4,683,713	4,637,790
Total commercial loans | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 4,250,640	$ 4,217,824
Percentage of loans receivable	89.30%	89.50%
Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 507,650	$ 495,641
Percentage of loans receivable	10.70%	10.50%
Other consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 89,734	$ 88,075
Percentage of loans receivable	1.90%	1.90%
Commercial and industrial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 1,459,618	$ 1,493,049
Percentage of loans receivable	30.70%	31.70%
Commercial and industrial loans: | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less: Allowance for credit losses	$ (31,190)	$ (35,290)	(31,322)	(30,595)
Commercial and industrial loans: | Working capital lines of credit loans | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 636,171	$ 650,948
Percentage of loans receivable	13.40%	13.80%
Commercial and industrial loans: | Non-working capital loans | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 823,447	$ 842,101
Percentage of loans receivable	17.30%	17.90%
Commercial real estate and multi-family residential loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 2,265,756	$ 2,179,094
Percentage of loans receivable	47.50%	46.20%
Commercial real estate and multi-family residential loans: | Construction and land development loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 591,812	$ 517,664
Percentage of loans receivable	12.40%	11.00%
Commercial real estate and multi-family residential loans: | Owner occupied loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 750,840	$ 758,091
Percentage of loans receivable	15.80%	16.00%
Commercial real estate and multi-family residential loans: | Nonowner occupied loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 705,830	$ 706,107
Percentage of loans receivable	14.80%	15.00%
Commercial real estate and multi-family residential loans: | Multifamily loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 217,274	$ 197,232
Percentage of loans receivable	4.50%	4.20%
Agri-business and agricultural loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 392,982	$ 432,088
Percentage of loans receivable	8.30%	9.20%
Agri-business and agricultural loans: | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less: Allowance for credit losses	$ (4,621)	$ (4,429)	$ (4,761)	$ (5,034)
Agri-business and agricultural loans: | Loans secured by farmland | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 178,683	$ 201,200
Percentage of loans receivable	3.80%	4.30%
Agri-business and agricultural loans: | Loans for agricultural production | Commercial Portfolio Segment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 214,299	$ 230,888
Percentage of loans receivable	4.50%	4.90%
Other commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 132,284	$ 113,593
Percentage of loans receivable	2.80%	2.40%
Consumer 1-4 family mortgage loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 417,916	$ 407,566
Percentage of loans receivable	8.80%	8.60%
Consumer 1-4 family mortgage loans: | Closed end first mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 221,616	$ 212,742
Percentage of loans receivable	4.70%	4.50%
Consumer 1-4 family mortgage loans: | Open end and junior lien loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 175,907	$ 175,575
Percentage of loans receivable	3.70%	3.70%
Consumer 1-4 family mortgage loans: | Residential construction and land development loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable before allowance for credit loss	$ 20,393	$ 19,249
Percentage of loans receivable	0.40%	0.40%