LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Nonaccrual Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	$ 18,515	$ 13,387
Nonaccrual Loans with Related Allowance	7,760	10,740
Total Nonaccrual Loans	26,275	24,127
Commercial and industrial
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	3,787	1,824
Nonaccrual Loans with Related Allowance	4,022	6,534
Total Nonaccrual Loans	7,809	8,358
Paycheck Protection Program (PPP)
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	0	0
Nonaccrual Loans with Related Allowance	0	0
Total Nonaccrual Loans	0	0
Real estate: \| Commercial real estate (including multi-family residential)
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	12,540	9,018
Nonaccrual Loans with Related Allowance	2,719	3,621
Total Nonaccrual Loans	15,259	12,639
Real estate: \| Commercial real estate construction and land development
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	0	63
Nonaccrual Loans with Related Allowance	0	0
Total Nonaccrual Loans	0	63
Real estate: \| 1-4 family residential (including home equity)
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	2,046	2,324
Nonaccrual Loans with Related Allowance	1,019	551
Total Nonaccrual Loans	3,065	2,875
Real estate: \| Residential construction
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	0	0
Nonaccrual Loans with Related Allowance	0	0
Total Nonaccrual Loans	0	0
Consumer and other
Financing Receivable Nonaccrual Status [Line Items]
Nonaccrual Loans with No Related Allowance	142	158
Nonaccrual Loans with Related Allowance	0	34
Total Nonaccrual Loans	$ 142	$ 192

Allegiance Bancshares, Inc. 10-Q