Loans and Leases - Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	$ 30,019	$ 38,578
Total nonaccrual loans (excluding leases)	29,767
Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	27,417
Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	1,784
None
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	566
Commercial Financial And Agricultural [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	3,809	3,442
Commercial Financial And Agricultural [Member] | Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	1,459
Commercial Financial And Agricultural [Member] | Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	1,784
Commercial Financial And Agricultural [Member] | None
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	566
Real-Estate Commercial [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	20,464	27,928
Real-Estate Commercial [Member] | Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	20,464
Real-Estate Commercial [Member] | Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real-Estate Commercial [Member] | None
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real Estate Residential Secured For Business Purpose [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	2,151	2,980
Real Estate Residential Secured For Business Purpose [Member] | Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	2,151
Real Estate Residential Secured For Business Purpose [Member] | Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real Estate Residential Secured For Business Purpose [Member] | None
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real Estate Residential Secured For Personal Purpose [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	2,395	2,038
Real Estate Residential Secured For Personal Purpose [Member] | Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	2,395
Real Estate Residential Secured For Personal Purpose [Member] | Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real Estate Residential Secured For Personal Purpose [Member] | None
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real Estate Home Equity Secured For Personal Purpose [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	948	$ 1,427
Real Estate Home Equity Secured For Personal Purpose [Member] | Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	948
Real Estate Home Equity Secured For Personal Purpose [Member] | Other
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	0
Real Estate Home Equity Secured For Personal Purpose [Member] | None
Financing Receivable, Allowance for Credit Loss [Line Items]
Total nonaccrual loans	$ 0