Loans - Schedule of Non-Purchased Loans and Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Summary of loans
Gross loans	$ 12,632,494	$ 12,358,017
Unearned income	(4,846)	(6,787)
Loans, net of unearned income	12,627,648	12,351,230	$ 12,168,023
Commercial, financial, agricultural
Summary of loans
Gross loans	1,804,961	1,871,821
Loans, net of unearned income	1,804,961		1,819,891
Lease financing
Summary of loans
Gross loans	103,005	122,807
Loans, net of unearned income	98,159		120,724
Real estate – construction:
Summary of loans
Gross loans	1,198,838	1,333,397
Loans, net of unearned income	1,198,838		1,407,364
Real estate – construction: | Residential
Summary of loans
Gross loans	258,356	269,616
Real estate – construction: | Commercial
Summary of loans
Gross loans	940,482	1,063,781
Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	3,440,038	3,439,919
Loans, net of unearned income	3,440,038		3,398,876
Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	2,409,912	2,422,482
Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	537,372	522,688
Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	390,029	373,755
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	102,725	120,994
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	102,725	120,994
Real estate – commercial mortgage:
Summary of loans
Gross loans	5,995,152	5,486,550
Loans, net of unearned income	5,995,152		5,313,166
Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	1,845,791	1,648,961
Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	4,045,666	3,733,174
Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	103,695	104,415
Installment loans to individuals
Summary of loans
Gross loans	90,500	$ 103,523
Loans, net of unearned income	$ 90,500		$ 108,002