Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Impact of Modifications Classified as Troubled Debt Restructurings (Details) - Troubled Debt Restructurings [Member] $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) Contract	Sep. 30, 2019 USD ($) Contract	Sep. 30, 2020 USD ($) Contract	Sep. 30, 2019 USD ($) Contract
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract	4	4	23	22
Pre-Modification Outstanding Recorded Investment	$ 135	$ 113	$ 6,491	$ 15,244
Post-Modification Outstanding Recorded Investment	$ 136	$ 102	$ 6,466	$ 15,119
Other Secured by 1-4 Family Residential Properties [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract	3	4	11	11
Pre-Modification Outstanding Recorded Investment	$ 87	$ 113	$ 794	$ 992
Post-Modification Outstanding Recorded Investment	$ 89	$ 102	$ 800	$ 980
Commercial and Industrial Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract	1		3	8
Pre-Modification Outstanding Recorded Investment	$ 48		$ 1,630	$ 9,167
Post-Modification Outstanding Recorded Investment	$ 47		$ 1,629	$ 9,054
Secured by Nonfarm, Nonresidential Properties [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract			1	1
Pre-Modification Outstanding Recorded Investment			$ 139	$ 5,055
Post-Modification Outstanding Recorded Investment			$ 139	$ 5,055
Consumer Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract			6	2
Pre-Modification Outstanding Recorded Investment			$ 26	$ 30
Post-Modification Outstanding Recorded Investment			$ 26	$ 30
State and Other Political Subdivision Loans [Member]
Financing Receivable Modifications [Line Items]
Number of Contracts | Contract			2
Pre-Modification Outstanding Recorded Investment			$ 3,902
Post-Modification Outstanding Recorded Investment			$ 3,872