Allowance for Loan and Lease Losses - Allowance for Credit Losses - Reserves (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Specific	$ 1,359		$ 827	$ 1,322
General	12,201		9,096	8,561
Ending balance	13,560	$ 11,453	9,923	9,883	$ 9,438	$ 9,750
Commercial, Residential, and Farm Land Real Estate Portfolio Segment [Member] | Real Estate Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Specific	593		493	881
General	8,257		5,142	5,088
Ending balance	8,850	7,315	5,635	5,969	6,094	5,831
Agricultural Portfolio Segment [Member] | Agricultural Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Specific			1	1
General	232		192	200
Ending balance	232	235	193	201	219	256
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Specific	671		219	303
General	2,944		2,466	2,266
Ending balance	3,615	2,754	2,685	2,569	1,914	2,394
Consumer Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Specific	95		114	137
General	754		1,164	995
Ending balance	849	1,137	1,278	1,132	1,129	1,239
Unallocated [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
General	14		132	12
Ending balance	$ 14	$ 12	$ 132	$ 12	$ 82	$ 30