Loans - Summary of Non-Purchased Loans and Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Summary of loans
Gross loans	$ 11,938,144	$ 11,585,458
Unearned income	(7,628)	(7,154)
Loans, net of unearned income	11,930,516	11,578,304	$ 10,603,744
Commercial, financial, agricultural
Summary of loans
Gross loans	1,729,070	1,673,883
Loans, net of unearned income	1,729,070		1,497,272
Lease financing
Summary of loans
Gross loans	129,998	122,167
Loans, net of unearned income	122,370		101,350
Real estate – construction:
Summary of loans
Gross loans	1,369,019	1,330,337
Loans, net of unearned income	1,369,019		1,126,363
Real estate – construction: | Residential
Summary of loans
Gross loans	308,401	355,500
Real estate – construction: | Commercial
Summary of loans
Gross loans	1,060,618	974,837
Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	3,348,654	3,216,263
Loans, net of unearned income	3,348,654		3,030,083
Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	2,372,739	2,222,856
Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	502,341	501,906
Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	335,509	334,382
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	138,065	157,119
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	138,065	157,119
Real estate – commercial mortgage:
Summary of loans
Gross loans	5,252,479	5,118,063
Loans, net of unearned income	5,252,479		4,717,513
Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	1,553,890	1,539,296
Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	3,585,160	3,452,910
Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	113,429	125,857
Installment loans to individuals
Summary of loans
Gross loans	108,924	$ 124,745
Loans, net of unearned income	$ 108,924		$ 131,163