Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Schedule of Amortized Cost Basis of Collateral-Dependent Loans by Class of Loans and Collateral Type (Details) $ in Thousands	Mar. 31, 2021 USD ($)
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	$ 40,696
Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	24,748
Equipment and Machinery [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	115
Inventory and Receivables [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	4,280
Vehicles [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	101
Miscellaneous [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	11,452
Construction, Land Development and Other Land [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	5,885
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	5,885
Other Secured by 1-4 Family Residential Properties [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	216
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	216
Secured by Nonfarm, Nonresidential Properties [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	12,617
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	12,617
Other Real Estate Secured [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	58
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	58
Secured by 1-4 Family Residential Properties [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,413
Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,413
Commercial and Industrial Loans [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	10,983
Commercial and Industrial Loans [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	44
Commercial and Industrial Loans [Member] | Equipment and Machinery [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	115
Commercial and Industrial Loans [Member] | Inventory and Receivables [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	2,322
Commercial and Industrial Loans [Member] | Vehicles [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	101
Commercial and Industrial Loans [Member] | Miscellaneous [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	8,401
State and Other Political Subdivision Loans [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	3,914
State and Other Political Subdivision Loans [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	3,914
Other Commercial Loans [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	5,610
Other Commercial Loans [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	601
Other Commercial Loans [Member] | Inventory and Receivables [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,958
Other Commercial Loans [Member] | Miscellaneous [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	$ 3,051