Loans - Schedule of Non-Purchased Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024
Summary of loans
Gross loans	$ 13,059,714	$ 12,889,500
Unearned income	(4,121)	(4,480)
Loans, net of unearned income	13,055,593	12,885,020	$ 12,500,525
Commercial, financial, agricultural
Summary of loans
Gross loans	1,888,580	1,885,817
Loans, net of unearned income	1,888,580		1,869,408
Lease financing
Summary of loans
Gross loans	89,533	95,071
Loans, net of unearned income	85,412		107,474
Real estate – construction:
Summary of loans
Gross loans	1,090,862	1,093,653
Loans, net of unearned income	1,090,862		1,243,535
Real estate – construction: | Residential
Summary of loans
Gross loans	273,583	256,655
Real estate – construction: | Commercial
Summary of loans
Gross loans	817,279	836,998
Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	3,583,080	3,488,877
Loans, net of unearned income	3,583,080		3,429,286
Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	2,471,818	2,428,076
Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	551,305	544,158
Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	434,069	402,938
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	125,888	113,705
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	125,888	113,705
Real estate – commercial mortgage:
Summary of loans
Gross loans	6,320,120	6,236,068
Loans, net of unearned income	6,320,120		5,753,230
Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	1,949,177	1,894,679
Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	4,262,145	4,226,937
Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	108,798	114,452
Installment loans to individuals
Summary of loans
Gross loans	87,539	$ 90,014
Loans, net of unearned income	$ 87,539		$ 97,592