Allowance for Credit Losses - Summary of Total Non Purchased and Purchased Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
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
Allowance for credit losses	(166,468)	(164,171)	(173,106)	$ (176,144)
Loans, net	10,146,991	9,856,743
Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
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
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	8,382	58,391
Commercial, financial, agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,445,607	1,423,270
Loans, net of unearned income	1,445,607		2,249,287
Allowance for credit losses	(33,606)	(33,922)	(37,592)	(39,031)
Commercial, financial, agricultural | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,336,239	1,332,962
Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	94,954	80,192
Loans, net of unearned income	89,842		75,256
Allowance for credit losses	(1,582)	(1,486)	(1,546)	(1,624)
Lease financing | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	94,954	80,192
Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,222,052	1,104,896
Loans, net of unearned income	1,222,052		955,918
Allowance for credit losses	(18,411)	(16,419)	(14,977)	(16,047)
Real estate – construction: | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,216,928	1,099,902
Real estate – construction: | Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	306,655	302,275
Real estate – construction: | Residential | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	305,396	300,988
Real estate – construction: | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	915,397	802,621
Real estate – construction: | Commercial | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	911,532	798,914
Real estate – 1-4 family mortgage:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,840,979	2,724,246
Loans, net of unearned income	2,840,979		2,686,061
Allowance for credit losses	(36,848)	(32,356)	(31,694)	(32,165)
Real estate – 1-4 family mortgage: | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,644,587	2,508,473
Real estate – 1-4 family mortgage: | Primary
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,925,813	1,816,120
Real estate – 1-4 family mortgage: | Primary | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,803,750	1,682,050
Real estate – 1-4 family mortgage: | Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	470,665	474,604
Real estate – 1-4 family mortgage: | Home equity | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	424,426	423,108
Real estate – 1-4 family mortgage: | Rental/investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	292,811	288,474
Real estate – 1-4 family mortgage: | Rental/investment | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	274,117	268,245
Real estate – 1-4 family mortgage: | Land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	151,690	145,048
Real estate – 1-4 family mortgage: | Land development | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	142,294	135,070
Real estate – commercial mortgage:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	4,577,864	4,549,037
Loans, net of unearned income	4,577,864		4,549,027
Allowance for credit losses	(65,231)	(68,940)	(76,225)	(76,127)
Real estate – commercial mortgage: | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	3,945,540	3,885,984
Real estate – commercial mortgage: | Land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	132,055	128,739
Real estate – commercial mortgage: | Owner-occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,538,693	1,563,351
Real estate – commercial mortgage: | Owner-occupied | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	1,318,446	1,329,219
Real estate – commercial mortgage: | Non-owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,907,116	2,856,947
Real estate – commercial mortgage: | Non-owner occupied | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	2,510,981	2,446,370
Installment loans to individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	137,115	143,340
Loans, net of unearned income	137,115		172,859
Allowance for credit losses	(10,790)	(11,048)	$ (11,072)	$ (11,150)
Installment loans to individuals | Non purchased loans and leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 105,754	$ 107,565