Loans - Summary of Non-Purchased Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Summary of loans
Gross loans	$ 11,773,553	$ 11,585,458
Unearned income	(7,128)	(7,154)
Loans, net of unearned income	11,766,425	11,578,304	$ 10,313,459
Commercial, financial, agricultural
Summary of loans
Gross loans	1,740,778	1,673,883
Loans, net of unearned income	1,740,778		1,445,607
Lease financing
Summary of loans
Gross loans	128,274	122,167
Loans, net of unearned income	121,146		89,842
Real estate – construction:
Summary of loans
Gross loans	1,424,352	1,330,337
Loans, net of unearned income	1,424,352		1,222,052
Real estate – construction: | Residential
Summary of loans
Gross loans	333,439	355,500
Real estate – construction: | Commercial
Summary of loans
Gross loans	1,090,913	974,837
Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	3,278,980	3,216,263
Loans, net of unearned income	3,278,980		2,840,979
Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	2,288,592	2,222,856
Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	497,925	501,906
Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	344,705	334,382
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	147,758	157,119
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	147,758	157,119
Real estate – commercial mortgage:
Summary of loans
Gross loans	5,085,813	5,118,063
Loans, net of unearned income	5,085,813		4,577,864
Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	1,521,327	1,539,296
Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	3,447,217	3,452,910
Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	117,269	125,857
Installment loans to individuals
Summary of loans
Gross loans	115,356	$ 124,745
Loans, net of unearned income	$ 115,356		$ 137,115