Non Purchased Loans - Summary of Non-Purchased Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Summary of loans
Gross loans	$ 10,318,571	$ 10,024,981
Unearned income	(5,112)	(4,067)
Loans, net of unearned income	10,313,459	10,020,914	$ 10,688,408
Commercial, financial, agricultural
Summary of loans
Gross loans	1,445,607	1,423,270
Loans, net of unearned income	1,445,607		2,249,287
Lease financing
Summary of loans
Gross loans	94,954	80,192
Loans, net of unearned income	89,842		75,256
Real estate – construction:
Summary of loans
Gross loans	1,222,052	1,104,896
Loans, net of unearned income	1,222,052		955,918
Real estate – construction: | Residential
Summary of loans
Gross loans	306,655	302,275
Real estate – construction: | Commercial
Summary of loans
Gross loans	915,397	802,621
Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	2,840,979	2,724,246
Loans, net of unearned income	2,840,979		2,686,061
Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	1,925,813	1,816,120
Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	470,665	474,604
Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	292,811	288,474
Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	151,690	145,048
Real estate – commercial mortgage:
Summary of loans
Gross loans	4,577,864	4,549,037
Loans, net of unearned income	4,577,864		4,549,027
Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	132,055	128,739
Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	1,538,693	1,563,351
Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	2,907,116	2,856,947
Installment loans to individuals
Summary of loans
Gross loans	137,115	143,340
Loans, net of unearned income	137,115		$ 172,859
Non purchased loans and leases
Summary of loans
Gross loans	9,344,002	9,015,078
Unearned income	(5,112)	(4,067)
Loans, net of unearned income	9,338,890	9,011,011
Non purchased loans and leases | Paycheck Protection Program
Summary of loans
Loans, net of unearned income	8,382	58,391
Non purchased loans and leases | Commercial, financial, agricultural
Summary of loans
Gross loans	1,336,239	1,332,962
Non purchased loans and leases | Lease financing
Summary of loans
Gross loans	94,954	80,192
Non purchased loans and leases | Real estate – construction:
Summary of loans
Gross loans	1,216,928	1,099,902
Non purchased loans and leases | Real estate – construction: | Residential
Summary of loans
Gross loans	305,396	300,988
Non purchased loans and leases | Real estate – construction: | Commercial
Summary of loans
Gross loans	911,532	798,914
Non purchased loans and leases | Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	2,644,587	2,508,473
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	1,803,750	1,682,050
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	424,426	423,108
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	274,117	268,245
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	142,294	135,070
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	142,294	135,070
Non purchased loans and leases | Real estate – commercial mortgage:
Summary of loans
Gross loans	3,945,540	3,885,984
Non purchased loans and leases | Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	1,318,446	1,329,219
Non purchased loans and leases | Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	2,510,981	2,446,370
Non purchased loans and leases | Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	116,113	110,395
Non purchased loans and leases | Installment loans to individuals
Summary of loans
Gross loans	$ 105,754	$ 107,565