LHFI and ACL, LHFI - Loan Portfolio Held for Investment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Loan Portfolio [Abstract]
Total LHFI	$ 10,247,829	$ 9,824,524
Less ACL, LHFI	99,457	117,306
Net LHFI	10,148,372	9,707,218
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	596,968	514,056
Other Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	517,683	524,732
Secured by 1-4 Family Residential Properties [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	1,460,310	1,216,400
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	726,043	1,065,964
Other Construction [Member] | Other Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	711,813	794,983
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member]
Loan Portfolio [Abstract]
Total LHFI	2,977,084	2,709,026
Commercial and Industrial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,414,279	1,309,078
Consumer Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	162,555	164,386
State and Other Political Subdivision Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	1,146,251	1,000,776
Other Commercial Loans [Member]
Loan Portfolio [Abstract]
Total LHFI	$ 534,843	$ 525,123