Loans Held for Investment (LHFI) and Allowance for Loan Losses, LHFI - Change in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 103,140	$ 104,032	$ 99,457	$ 117,306
Loans charged-off	(2,920)	(1,586)	(7,439)	(7,659)
Recoveries	1,911	4,119	8,257	11,410
Net (charge-offs) recoveries	(1,009)	2,533	818	3,751
PCL	12,919	(2,492)	14,775	(16,984)
Balance at end of period	115,050	104,073	115,050	104,073
Secured by 1-4 Family Residential Properties [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
PCL	3,800
Commercial and Industrial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
PCL		3,400		4,300
Allowance for Credit Losses, ACL [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	103,140	104,032	99,457	117,306
Loans charged-off	(2,920)	(1,586)	(7,439)	(7,659)
Recoveries	1,911	4,119	8,257	11,410
PCL	(12,919)	(2,492)	14,775	(16,984)
Balance at end of period	115,050	104,073	115,050	104,073
Allowance for Credit Losses, ACL [Member] | Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	7,301	5,110	6,079	6,854
Loans charged-off	(189)	(3)	(223)	(3)
Recoveries	43	391	1,230	1,470
PCL	3,096	(365)	3,165	(3,188)
Balance at end of period	10,251	5,133	10,251	5,133
Allowance for Credit Losses, ACL [Member] | Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	10,038	10,399	10,310	9,928
Loans charged-off	(33)	(7)	(95)	(91)
Recoveries	234	85	529	337
PCL	500	(254)	(5)	49
Balance at end of period	10,739	10,223	10,739	10,223
Allowance for Credit Losses, ACL [Member] | Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	12,250	2,910	2,706	5,143
Loans charged-off	(37)	(144)	(116)	(148)
Recoveries	125	15	135	123
PCL	3,057	(127)	12,670	(2,464)
Balance at end of period	15,395	2,654	15,395	2,654
Allowance for Credit Losses, ACL [Member] | Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	29,735	44,416	37,912	48,523
Loans charged-off	0	0		(79)
Recoveries	35	45	1,536	1,102
PCL	(3,846)	(1,155)	(13,524)	(6,240)
Balance at end of period	25,924	43,306	25,924	43,306
Allowance for Credit Losses, ACL [Member] | Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	3,297	5,311	4,713	7,382
Loans charged-off	0		(131)
Recoveries	4	4	11	15
PCL	(97)	(945)	(1,195)	(3,027)
Balance at end of period	3,398	4,370	3,398	4,370
Allowance for Credit Losses, ACL [Member] | Commercial and Industrial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	14,103	13,973	18,939	14,851
Loans charged-off	(191)	(5)	(566)	(3,702)
Recoveries	111	2,028	414	3,967
PCL	(10,081)	3,377	(5,317)	4,257
Balance at end of period	24,104	19,373	24,104	19,373
Allowance for Credit Losses, ACL [Member] | Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	14,397	6,530	5,968	8,158
Loans charged-off	(153)		(153)
Recoveries	1	2	205	46
PCL	(326)	(587)	7,899	(2,259)
Balance at end of period	13,919	5,945	13,919	5,945
Allowance for Credit Losses, ACL [Member] | Consumer Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	5,139	4,876	4,774	5,838
Loans charged-off	(458)	(287)	(1,394)	(1,120)
Recoveries	425	451	1,256	1,200
PCL	(78)	(178)	392	(1,056)
Balance at end of period	5,028	4,862	5,028	4,862
Allowance for Credit Losses, ACL [Member] | State and Other Political Subdivision Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	1,917	3,233	2,708	3,190
Loans charged-off	0
Recoveries	0
PCL	(323)	(269)	(1,114)	(226)
Balance at end of period	1,594	2,964	1,594	2,964
Allowance for Credit Losses, ACL [Member] | Other Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	4,963	7,274	5,348	7,439
Loans charged-off	(1,859)	(1,140)	(4,761)	(2,516)
Recoveries	933	1,098	2,941	3,150
PCL	661	(1,989)	1,170	(2,830)
Balance at end of period	$ 4,698	$ 5,243	$ 4,698	$ 5,243