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	Sep. 30, 2020 USD ($)
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	$ 41,167
Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	21,277
Equipment and Machinery [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	798
Inventory and Receivables [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	7,157
Vehicles [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	155
Miscellaneous [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	11,780
Construction, Land Development and Other Land [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,024
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,024
Other Secured by 1-4 Family Residential Properties [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	474
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	474
Secured by Nonfarm, Nonresidential Properties [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	13,527
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	13,527
Other Real Estate Secured [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	61
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	61
Secured by 1-4 Family Residential Properties [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,453
Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,453
Commercial and Industrial Loans [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	14,883
Commercial and Industrial Loans [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	96
Commercial and Industrial Loans [Member] | Equipment and Machinery [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	798
Commercial and Industrial Loans [Member] | Inventory and Receivables [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	5,174
Commercial and Industrial Loans [Member] | Vehicles [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	155
Commercial and Industrial Loans [Member] | Miscellaneous [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	8,660
State and Other Political Subdivision Loans [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	4,019
State and Other Political Subdivision Loans [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	4,019
Other Commercial Loans [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	5,726
Other Commercial Loans [Member] | Loans Secured by Real Estate [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	623
Other Commercial Loans [Member] | Inventory and Receivables [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	1,983
Other Commercial Loans [Member] | Miscellaneous [Member]
Financing Receivable Impaired [Line Items]
Collateral-Dependent Loans	$ 3,120