LHFI and ACL, LHFI - Loan Portfolio Held for Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Loan Portfolio [Abstract]
Total LHFI	$ 13,100,111		$ 12,950,524
Less ACL, LHFI	157,929	$ 154,685	139,367	$ 134,031	$ 129,298	$ 120,214
Net LHFI	12,942,182		12,811,157
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	614,787		642,886
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	647,843		622,397
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	2,247,163		2,282,318
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	1,475,798		1,312,551
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	973,469		867,793
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	3,582,552		3,489,434
Less ACL, LHFI	36,287	41,136	24,043	23,298	20,376	19,488
Commercial and Industrial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,767,079		1,922,910
Less ACL, LHFI	32,545	28,735	26,638	23,755	23,170	23,140
Consumer Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	152,611		165,734
Less ACL, LHFI	5,699	5,645	5,794	5,804	5,540	5,792
State and Other Political Subdivision Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	996,002		1,088,466
Less ACL, LHFI	1,166	625	646	665	676	885
Other Commercial Loans and Leases [Member]
Loan Portfolio [Abstract]
Total LHFI	642,807		556,035
Less ACL, LHFI	$ 6,728	$ 6,489	$ 7,072	$ 10,690	$ 5,607	$ 4,647