LOANS AND ALLOWANCE FOR CREDIT LOSSES - Narrative (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) contract	Dec. 31, 2021 USD ($) contract	Dec. 31, 2020 USD ($)
Accounts Notes And Loans Receivable [Line Items]
Loans secured by owner-occupied properties	45.30%
Accrued interest receivable	$ 34,100,000	$ 26,000,000
Interest on nonaccrual loans, original term	1,700,000	948,000
Provision for credit losses on loans	44,032,000	(2,923,000)	$ 26,543,000
Non accrual loans interest income	0	0
Recorded investment	48,400,000	19,200,000
Troubled debt restructurings, reserve	5,400,000	1,900,000
Troubled debt restructuring, write-down	$ 891,000	$ 620,000	3,200,000
Number of defaults on loan that were modified as troubled debt restructurings during the preceding 12 months | contract	1	3
Troubled debt restructuring, addition	$ 136,000	$ 247,000
Modification of outstanding recorded investment	11,896,000	3,436,000	11,804,000
CBTX
Accounts Notes And Loans Receivable [Line Items]
Provision for credit losses on loans	28,200,000
Financial Asset Acquired with Credit Deterioration
Accounts Notes And Loans Receivable [Line Items]
Unfunded commitments, allowance for credit loss	3,100,000
Unfunded Loan Commitment
Accounts Notes And Loans Receivable [Line Items]
Unfunded commitments, allowance for credit loss	12,000,000	5,300,000
Unfunded Loan Commitment | Financial Asset Acquired with Credit Deterioration | CBTX
Accounts Notes And Loans Receivable [Line Items]
Provision for credit losses on loans	5,000,000
Troubled debt restructurings added in reporting period
Accounts Notes And Loans Receivable [Line Items]
Recorded investment	9,600,000	2,600,000
Paycheck Protection Program (PPP)
Accounts Notes And Loans Receivable [Line Items]
Provision for credit losses on loans	0	0	0
Modification of outstanding recorded investment	$ 0	$ 0	$ 0
Minimum
Accounts Notes And Loans Receivable [Line Items]
Owner-occupied commercial real estate loans, amortization period	10 years
Mortgage loan, term	5 years
Mortgage loan, amortization period	10 years
Consumer loan, term	12 months
Maximum
Accounts Notes And Loans Receivable [Line Items]
Owner-occupied commercial real estate loans, amortization period	20 years
Mortgage loan, term	7 years
Mortgage loan, amortization period	30 years
Consumer loan, term	60 months