Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Schedule of Amortized Cost Basis of Loans on Nonaccrual Status (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	$ 21,365	$ 32,413
Total Nonaccrual	63,514	63,128
Loans Past Due 90 Days or More Still Accruing	2,593	1,576
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	5,885	5,756
Total Nonaccrual	6,109	5,985
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	1,629	1,895
Total Nonaccrual	3,964	4,487
Loans Past Due 90 Days or More Still Accruing	7	79
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	12,617	12,037
Total Nonaccrual	15,695	15,197
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	58	60
Total Nonaccrual	183	185
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual	15,036	11,807
Loans Past Due 90 Days or More Still Accruing	2,368	1,257
Commercial and Industrial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	1,176	12,665
Total Nonaccrual	12,776	15,618
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual	71	86
Loans Past Due 90 Days or More Still Accruing	218	240
State and Other Political Subdivision Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual	3,914	3,970
Other Commercial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual	$ 5,766	$ 5,793