Summary of Significant Accounting Policies - Impact of Adoption (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items]
Debt securities, available-for-sale, allowance for credit loss	$ 855
Allowance for credit losses, loans and lease	86,217		$ 35,331
Reserve for unfunded commitments			420
Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			12,922
Reserve for unfunded commitments			1,145
Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			48,253
Reserve for unfunded commitments			1,565
Commercial Financial And Agricultural [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			8,759
Commercial Financial And Agricultural [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			5,284
Commercial Financial And Agricultural [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			14,043
Real-Estate Commercial [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			15,750
Real-Estate Commercial [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			6,208
Real-Estate Commercial [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			21,958
Real-Estate Construction [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			2,446
Real-Estate Construction [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			29
Real-Estate Construction [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			2,475
Real Estate Residential Secured For Business Purpose [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			2,622
Real Estate Residential Secured For Business Purpose [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			2,502
Real Estate Residential Secured For Business Purpose [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			5,124
Real Estate Residential Secured For Personal Purpose [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			2,713
Real Estate Residential Secured For Personal Purpose [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			(706)
Real Estate Residential Secured For Personal Purpose [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			2,007
Real Estate Home Equity Secured For Personal Purpose [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			1,076
Real Estate Home Equity Secured For Personal Purpose [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			(364)
Real Estate Home Equity Secured For Personal Purpose [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			712
Loans to Individuals [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			470
Loans to Individuals [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			104
Loans to Individuals [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			574
Lease Financings [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			1,311
Lease Financings [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			(135)
Lease Financings [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			1,176
Unallocated [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			184
Unallocated [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			0
Unallocated [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and lease			184
Corporate Bonds [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt securities, available-for-sale, allowance for credit loss	$ 855	$ 897	0	$ 0
Corporate Bonds [Member] | Cumulative Effect, Period Of Adoption, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Debt securities, available-for-sale, allowance for credit loss			300
Corporate Bonds [Member] | Cumulative Effect, Period Of Adoption, Adjusted Balance
Summary Of Significant Accounting Policies [Line Items]
Debt securities, available-for-sale, allowance for credit loss			$ 300