Summary of Significant Accounting Policies - Impact of Adoption (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary Of Significant Accounting Policies [Line Items]
Securities, available-for-sale, allowance for credit loss	$ 869
Allowance for credit losses, loans and leases	83,044	$ 35,331	$ 35,331	$ 29,364	$ 21,555
Reserve for unfunded commitments		420
Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		12,922
Reserve for unfunded commitments		1,145
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		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 leases	13,584	8,759	8,759	7,983	6,742
Commercial, Financial and Agricultural [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		5,284
Commercial, Financial and Agricultural [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		14,043
Real Estate-Commercial [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	52,230	15,750	15,750
Real Estate-Commercial [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		6,208
Real Estate-Commercial [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		21,958
Real Estate-Construction [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	3,298	2,446	2,446
Real Estate-Construction [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		29
Real Estate-Construction [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		2,475
Real Estate-Residential Secured for Business Purpose [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	7,317	2,622	2,622	2,236	1,661
Real Estate-Residential Secured for Business Purpose [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		2,502
Real Estate-Residential Secured for Business Purpose [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		5,124
Real Estate-Residential Secured for Personal Purpose [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	3,055	2,713	2,713
Real Estate-Residential Secured for Personal Purpose [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		(706)
Real Estate-Residential Secured for Personal Purpose [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		2,007
Real Estate-Home Equity Secured for Personal Purpose [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	1,176	1,076	1,076
Real Estate-Home Equity Secured for Personal Purpose [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		(364)
Real Estate-Home Equity Secured for Personal Purpose [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		712
Loans to Individuals [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	533	470	470	484	373
Loans to Individuals [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		104
Loans to Individuals [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		574
Lease Financings [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	1,701	1,311	1,311	1,288	1,132
Lease Financings [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		(135)
Lease Financings [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		1,176
Unallocated [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases	150	184	184	$ 271	$ 54
Unallocated [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		0
Unallocated [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, loans and leases		184
Corporate Bonds [Member]
Summary Of Significant Accounting Policies [Line Items]
Securities, available-for-sale, allowance for credit loss	$ 869	0	$ 0
Corporate Bonds [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Summary Of Significant Accounting Policies [Line Items]
Securities, available-for-sale, allowance for credit loss		300
Corporate Bonds [Member] | Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Summary Of Significant Accounting Policies [Line Items]
Securities, available-for-sale, allowance for credit loss		$ 300