Non Purchased Loans - Summary of Non-Purchased Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Loans, net of unearned income:
Gross loans	$ 10,024,981	$ 10,937,807
Unearned income	(4,067)	(4,160)
Loans, net of unearned income	10,020,914	10,933,647
Commercial, financial, agricultural
Loans, net of unearned income:
Gross loans	1,423,270	2,536,984
Loans, net of unearned income	1,423,270	2,536,984
Lease financing
Loans, net of unearned income:
Gross loans	80,192	80,022
Loans, net of unearned income	76,125	75,862
Real estate – construction:
Loans, net of unearned income:
Gross loans	1,104,896	858,104
Loans, net of unearned income	1,104,896	858,104
Real estate – construction: | Residential
Loans, net of unearned income:
Gross loans	302,275	246,673
Real estate – construction: | Commercial
Loans, net of unearned income:
Gross loans	802,621	611,431
Real estate – 1-4 family mortgage:
Loans, net of unearned income:
Gross loans	2,724,246	2,698,308
Loans, net of unearned income	2,724,246	2,698,308
Real estate – 1-4 family mortgage: | Primary
Loans, net of unearned income:
Gross loans	1,816,120	1,750,951
Real estate – 1-4 family mortgage: | Home equity
Loans, net of unearned income:
Gross loans	474,604	513,160
Real estate – 1-4 family mortgage: | Rental/investment
Loans, net of unearned income:
Gross loans	288,474	296,364
Real estate – 1-4 family mortgage: | Land development
Loans, net of unearned income:
Gross loans	145,048	137,833
Real estate – commercial mortgage:
Loans, net of unearned income:
Gross loans	4,549,037	4,554,852
Loans, net of unearned income	4,549,037	4,554,852
Real estate – commercial mortgage: | Land development
Loans, net of unearned income:
Gross loans	128,739	149,579
Real estate – commercial mortgage: | Owner-occupied
Loans, net of unearned income:
Gross loans	1,563,351	1,657,806
Real estate – commercial mortgage: | Non-owner occupied
Loans, net of unearned income:
Gross loans	2,856,947	2,747,467
Installment loans to individuals
Loans, net of unearned income:
Gross loans	143,340	209,537
Loans, net of unearned income	143,340	209,537
Non purchased loans and leases
Loans, net of unearned income:
Gross loans	9,015,078	9,423,700
Unearned income	(4,067)	(4,160)
Loans, net of unearned income	9,011,011	9,419,540
Non purchased loans and leases | Commercial, financial, agricultural
Loans, net of unearned income:
Gross loans	1,332,962	2,360,471
Non purchased loans and leases | Lease financing
Loans, net of unearned income:
Gross loans	80,192	80,022
Non purchased loans and leases | Real estate – construction:
Loans, net of unearned income:
Gross loans	1,099,902	827,152
Non purchased loans and leases | Real estate – construction: | Residential
Loans, net of unearned income:
Gross loans	300,988	243,814
Non purchased loans and leases | Real estate – construction: | Commercial
Loans, net of unearned income:
Gross loans	798,914	583,338
Non purchased loans and leases | Real estate – 1-4 family mortgage:
Loans, net of unearned income:
Gross loans	2,508,473	2,356,564
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Primary
Loans, net of unearned income:
Gross loans	1,682,050	1,536,181
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Home equity
Loans, net of unearned income:
Gross loans	423,108	432,768
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Rental/investment
Loans, net of unearned income:
Gross loans	268,245	264,436
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Land development
Loans, net of unearned income:
Gross loans	135,070	123,179
Non purchased loans and leases | Real estate – 1-4 family mortgage: | Land development
Loans, net of unearned income:
Gross loans	135,070	123,179
Non purchased loans and leases | Real estate – commercial mortgage:
Loans, net of unearned income:
Gross loans	3,885,984	3,649,629
Non purchased loans and leases | Real estate – commercial mortgage: | Owner-occupied
Loans, net of unearned income:
Gross loans	1,329,219	1,334,765
Non purchased loans and leases | Real estate – commercial mortgage: | Non-owner occupied
Loans, net of unearned income:
Gross loans	2,446,370	2,194,739
Non purchased loans and leases | Real estate – commercial mortgage: | Land development
Loans, net of unearned income:
Gross loans	110,395	120,125
Non purchased loans and leases | Installment loans to individuals
Loans, net of unearned income:
Gross loans	$ 107,565	$ 149,862