Purchased Loans - Summary of Purchased Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021
Summary of loans
Gross loans	$ 10,603,744	$ 10,020,914	$ 10,149,242
Commercial, financial, agricultural
Summary of loans
Gross loans	1,497,272		1,634,633
Real estate – construction:
Summary of loans
Gross loans	1,126,363		1,051,359
Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	3,030,083		2,702,091
Real estate – commercial mortgage:
Summary of loans
Gross loans	4,717,513		4,530,169
Installment loans to individuals
Summary of loans
Gross loans	131,163		$ 156,987
Purchased loans
Summary of loans
Gross loans	911,628	1,009,903
Purchased loans | Commercial, financial, agricultural
Summary of loans
Gross loans	91,630	90,308
Purchased loans | Real estate – construction:
Summary of loans
Gross loans	5,246	4,994
Purchased loans | Real estate – construction: | Residential
Summary of loans
Gross loans	1,254	1,287
Purchased loans | Real estate – construction: | Commercial
Summary of loans
Gross loans	3,992	3,707
Purchased loans | Real estate – 1-4 family mortgage:
Summary of loans
Gross loans	180,408	215,773
Purchased loans | Real estate – 1-4 family mortgage: | Primary
Summary of loans
Gross loans	108,543	134,070
Purchased loans | Real estate – 1-4 family mortgage: | Home equity
Summary of loans
Gross loans	45,003	51,496
Purchased loans | Real estate – 1-4 family mortgage: | Rental/investment
Summary of loans
Gross loans	17,915	20,229
Purchased loans | Real estate – 1-4 family mortgage: | Land development
Summary of loans
Gross loans	8,947	9,978
Purchased loans | Real estate – commercial mortgage:
Summary of loans
Gross loans	606,842	663,053
Purchased loans | Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	13,908	18,344
Purchased loans | Real estate – commercial mortgage: | Owner-occupied
Summary of loans
Gross loans	210,086	234,132
Purchased loans | Real estate – commercial mortgage: | Non-owner occupied
Summary of loans
Gross loans	382,848	410,577
Purchased loans | Real estate – commercial mortgage: | Land development
Summary of loans
Gross loans	13,908	18,344
Purchased loans | Installment loans to individuals
Summary of loans
Gross loans	$ 27,502	$ 35,775