Loans and Leases - Nonperforming Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	$ 36,626	$ 38,578
Accruing troubled debt restructured loans and lease modifications	54	54
Loans and lease 90 days or more past due and accruing interest	1,777	143
Total nonperforming loans and leases	38,457	38,775
Nonaccrual troubled debt restructured loans and lease modifications	13,700	13,800
Commercial Financial And Agricultural [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	3,934	3,442
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	0	20
Total nonperforming loans and leases	3,934	3,462
Real-Estate Commercial [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	28,827	27,928
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	722	0
Total nonperforming loans and leases	29,549	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	1,270	2,980
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	400	0
Total nonperforming loans and leases	1,670	2,980
Real Estate-Residential Secured For Personal Purpose [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	1,280	2,038
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	426	0
Total nonperforming loans and leases	1,706	2,038
Real Estate Home Equity Secured For Personal Purpose [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	820	1,427
Accruing troubled debt restructured loans and lease modifications	54	54
Loans and lease 90 days or more past due and accruing interest	0	0
Total nonperforming loans and leases	874	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	63	74
Total nonperforming loans and leases	63	74
Lease Financings [Member]
Nonperforming Loans And Leases [Line Items]
Total nonaccrual loans and lease	495	506
Accruing troubled debt restructured loans and lease modifications	0	0
Loans and lease 90 days or more past due and accruing interest	166	49
Total nonperforming loans and leases	$ 661	$ 555