LHFI and ACL, LHFI - Loan Portfolio Held for Investment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Loan Portfolio [Abstract]
Total LHFI	$ 13,057,943	$ 12,950,524
Less ACL, LHFI	142,998	139,367	$ 122,239	$ 120,214
Net LHFI	12,914,945	12,811,157
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	617,008	642,886
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	625,387	622,397
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	2,266,094	2,282,318
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	1,384,610	1,312,551
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	922,453	867,793
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	3,543,235	3,489,434
Less ACL, LHFI	33,292	24,043	18,640	19,488
Commercial and Industrial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,922,711	1,922,910
Less ACL, LHFI	27,930	26,638	23,462	23,140
Consumer Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	159,340	165,734
Less ACL, LHFI	5,523	5,794	5,532	5,792
State and Other Political Subdivision Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,052,844	1,088,466
Less ACL, LHFI	638	646	729	885
Other Commercial Loans and Leases [Member]
Loan Portfolio [Abstract]
Total LHFI	564,261	556,035
Less ACL, LHFI	$ 6,056	$ 7,072	$ 5,710	$ 4,647