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	Jun. 30, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	$ 24,451
Total Nonaccrual	49,994	$ 53,226
Loans Past Due 90 Days or More Still Accruing	807
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	575
Total Nonaccrual	932	897
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	496
Total Nonaccrual	4,441
Loans Past Due 90 Days or More Still Accruing	51
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	5,389
Total Nonaccrual	7,883	7,700
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	63
Total Nonaccrual	881	1,032
Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual		16,810
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	1,480
Total Nonaccrual	12,523
Loans Past Due 90 Days or More Still Accruing	528
Commercial and Industrial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	16,436
Total Nonaccrual	18,181	21,775
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual	120	108
Loans Past Due 90 Days or More Still Accruing	217
State and Other Political Subdivision Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Nonaccrual	4,049	$ 4,079
Other Commercial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Nonaccrual With No ACL	12
Total Nonaccrual	984
Loans Past Due 90 Days or More Still Accruing	$ 11