LHFI and ACL, LHFI - Loan Portfolio Held for Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Loan Portfolio [Abstract]
Total LHFI	$ 12,613,967		$ 12,204,039
Less ACL, LHFI	129,298	$ 122,239	120,214	$ 103,140	$ 98,734	$ 99,457
Net LHFI	12,484,669		12,083,825
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	649,336		690,616
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	592,289		590,790
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	2,261,893		2,185,057
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	954,410		742,538
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	1,073,321		1,028,926
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	3,471,728		3,278,830
Less ACL, LHFI	20,376	18,640	19,488	29,735	32,030	37,912
Commercial and Industrial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,883,480		1,821,259
Less ACL, LHFI	23,170	23,462	23,140	14,103	14,951	18,939
Consumer Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	167,540		170,230
Less ACL, LHFI	5,540	5,532	5,792	5,139	4,872	4,774
State and Other Political Subdivision Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,111,710		1,223,863
Less ACL, LHFI	676	729	885	1,917	2,371	2,708
Other Commercial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	448,260		471,930
Less ACL, LHFI	$ 5,607	$ 5,710	$ 4,647	$ 4,963	$ 4,077	$ 5,348