NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES (Details)		1 Months Ended	12 Months Ended
	Oct. 01, 2022 $ / shares shares	Feb. 28, 2023 office	Dec. 31, 2022 USD ($) office Segment $ / shares	Dec. 31, 2021 USD ($) $ / shares
New Accounting Pronouncement Early Adoption [Line Items]
Number of offices in which entity operates | office			60
Common stock, par value (in dollars per share) | $ / shares	$ 1.00		$ 0.01	$ 0.01
Shares to be received, per current shares (in shares) | shares	1.4184
Accrued interest receivable | $			$ 34,100,000	$ 26,000,000
Debt securities available for sale, accrued interest receivable | $			$ 10,600,000
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]			Available for sale securities
Other real estate owned | $			$ 0
Percentage of recognition threshold for which the largest amount of tax benefit is realized upon ultimate settlement with the related tax authority			50.00%
Number of reportable segments | Segment			1
Financial Asset Acquired with Credit Deterioration
New Accounting Pronouncement Early Adoption [Line Items]
Provision for credit loss | $			$ 27,000,000
PCD loans, allowance for credit loss | $			$ 3,100,000
Subsequent Event
New Accounting Pronouncement Early Adoption [Line Items]
Number of banking centers consolidated | office		5
Minimum
New Accounting Pronouncement Early Adoption [Line Items]
Premises and equipment, useful life			3 years
Minimum | Collateral Dependent Loans Specific Allocation of Allowance for Credit Losses on Loans
New Accounting Pronouncement Early Adoption [Line Items]
Percentage of estimated selling and closing costs of collateral			5.00%
Minimum | Core Deposits
New Accounting Pronouncement Early Adoption [Line Items]
Intangibles, useful life			7 years
Maximum
New Accounting Pronouncement Early Adoption [Line Items]
Premises and equipment, useful life			39 years
Maximum | Collateral Dependent Loans Specific Allocation of Allowance for Credit Losses on Loans
New Accounting Pronouncement Early Adoption [Line Items]
Percentage of estimated selling and closing costs of collateral			10.00%
Maximum | Core Deposits
New Accounting Pronouncement Early Adoption [Line Items]
Intangibles, useful life			10 years
Houston Metropolitan
New Accounting Pronouncement Early Adoption [Line Items]
Number of offices in which entity operates | office			43
Beaumont-Port Arthur
New Accounting Pronouncement Early Adoption [Line Items]
Number of offices in which entity operates | office			16
Dallas
New Accounting Pronouncement Early Adoption [Line Items]
Number of offices in which entity operates | office			1