LHFI and ACL, LHFI - Loan Portfolio Held for Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Loan Portfolio [Abstract]
Total LHFI	$ 13,155,418		$ 12,950,524
Less ACL, LHFI	154,685	$ 142,998	139,367	$ 129,298	$ 122,239	$ 120,214
Net LHFI	13,000,733		12,811,157
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	616,528		642,886
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	642,765		622,397
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	2,235,530		2,282,318
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	1,344,968		1,312,551
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	1,022,444		867,793
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	3,598,647		3,489,434
Less ACL, LHFI	41,136	33,292	24,043	20,376	18,640	19,488
Commercial and Industrial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,880,607		1,922,910
Less ACL, LHFI	28,735	27,930	26,638	23,170	23,462	23,140
Consumer Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	156,709		165,734
Less ACL, LHFI	5,645	5,523	5,794	5,540	5,532	5,792
State and Other Political Subdivision Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,053,015		1,088,466
Less ACL, LHFI	625	638	646	676	729	885
Other Commercial Loans and Leases [Member]
Loan Portfolio [Abstract]
Total LHFI	604,205		556,035
Less ACL, LHFI	$ 6,489	$ 6,056	$ 7,072	$ 5,607	$ 5,710	$ 4,647