Allowance for Loan and Lease Losses - Allowance for Credit Losses - Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 11,453	$ 9,438	$ 9,923	$ 9,750	$ 9,750
Charge-offs	(353)	(816)	(995)	(1,946)	(4,873)
Recoveries	260	861	632	1,379	2,496
Provision	2,200	400	4,000	700	2,550
Ending balance	13,560	9,883	13,560	9,883	9,923
Commercial, Residential, and Farm Land Real Estate Portfolio Segment [Member] \| Real Estate Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	7,315	6,094	5,635	5,831	5,831
Charge-offs					(1,190)
Recoveries	3	153	74	329	647
Provision	1,532	(278)	3,141	(191)	347
Ending balance	8,850	5,969	8,850	5,969	5,635
Agricultural Portfolio Segment [Member] \| Agricultural Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	235	219	193	256	256
Provision	(3)	(18)	39	(55)	(63)
Ending balance	232	201	232	201	193
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,754	1,914	2,685	2,394	2,394
Charge-offs	(67)	(254)	(92)	(832)	(1,274)
Recoveries	20	431	48	472	690
Provision	908	478	974	535	875
Ending balance	3,615	2,569	3,615	2,569	2,685
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,137	1,129	1,278	1,239	1,239
Charge-offs	(286)	(562)	(903)	(1,114)	(2,409)
Recoveries	237	277	510	578	1,159
Provision	(239)	288	(36)	429	1,289
Ending balance	849	1,132	849	1,132	1,278
Unallocated [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	12	82	132	30	30
Provision	2	(70)	(118)	(18)	102
Ending balance	$ 14	$ 12	$ 14	$ 12	$ 132

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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