Loans and Leases - Nonperforming Loans and Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	$ 26,141	$ 38,578
Accruing troubled debt restructured loans and lease modifications	53	54
Loans and lease 90 days or more past due and accruing interest	1,193	143
Total nonperforming loans and leases	27,387	38,775
Nonaccrual troubled debt restructured loans and lease modifications	14,100	13,800
Commercial Financial And Agricultural [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	4,208	3,442
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	309	20
Total nonperforming loans and leases	4,517	3,462
Real-Estate Commercial [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	17,568	27,928
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	54	0
Total nonperforming loans and leases	17,622	27,928
Real-Estate Construction [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	0	257
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	0	0
Total nonperforming loans and leases	0	257
Real Estate Residential Secured For Business Purpose [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	1,754	2,980
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	468	0
Total nonperforming loans and leases	2,222	2,980
Real Estate-Residential Secured For Personal Purpose [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	1,268	2,038
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	0	0
Total nonperforming loans and leases	1,268	2,038
Real Estate Home Equity Secured For Personal Purpose [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	977	1,427
Accruing troubled debt restructured loans and lease modifications	53	54
Loans and lease 90 days or more past due and accruing interest	0	0
Total nonperforming loans and leases	1,030	1,481
Loans to Individuals [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	0	0
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	93	74
Total nonperforming loans and leases	93	74
Lease Financings [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	366	506
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	269	49
Total nonperforming loans and leases	$ 635	$ 555