Loans (Allowance for Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Allowance for Loans Losses [Roll Forward]
Beginning Balance	$ 42,431	$ 16,239	$ 16,278	$ 15,823
Provision for Loan Losses	4,500	2,800	15,550	3,725
Recoveries	159	114	377	404
Loans Charged-off	(322)	(3,284)	(1,090)	(4,083)
Ending Balance	46,768	15,869	46,768	15,869
Commercial and Industrial Loans and Leases
Allowance for Loans Losses [Roll Forward]
Beginning Balance		2,992	4,799	2,953
Provision for Loan Losses		4,468		4,512
Recoveries		2		53
Loans Charged-off		(2,859)		(2,915)
Ending Balance		4,603		4,603
Commercial Real Estate Loans
Allowance for Loans Losses [Roll Forward]
Beginning Balance	22,369	5,841	4,692	5,291
Provision for Loan Losses	5,931	(1,410)	16,145	(741)
Recoveries	91	5	106	24
Loans Charged-off	(9)	(136)	(9)	(274)
Ending Balance	28,382	4,300	28,382	4,300
Agricultural Loans
Allowance for Loans Losses [Roll Forward]
Beginning Balance	7,030	5,725	5,315	5,776
Provision for Loan Losses	(315)	(373)	(166)	(424)
Recoveries	0	0	0	0
Loans Charged-off	0	0	0	0
Ending Balance	6,715	5,352	6,715	5,352
Home Equity Loans
Allowance for Loans Losses [Roll Forward]
Beginning Balance	1,062	258	200	229
Provision for Loan Losses	0	(72)	65	(33)
Recoveries	0	8	0	8
Loans Charged-off	(67)	0	(67)	(10)
Ending Balance	995	194	995	194
Consumer Loans
Allowance for Loans Losses [Roll Forward]
Beginning Balance	496	422	434	420
Provision for Loan Losses	70	174	385	507
Recoveries	64	99	252	313
Loans Charged-off	(138)	(277)	(520)	(822)
Ending Balance	492	418	492	418
Residential Mortgage Loans
Allowance for Loans Losses [Roll Forward]
Beginning Balance	2,360	349	333	472
Provision for Loan Losses	(212)	25	104	(54)
Recoveries	1	0	2	6
Loans Charged-off	(8)	(12)	(39)	(62)
Ending Balance	2,141	362	2,141	362
Unallocated
Allowance for Loans Losses [Roll Forward]
Beginning Balance	0	652	505	682
Provision for Loan Losses	0	(12)	0	(42)
Recoveries	0	0	0	0
Loans Charged-off	0	0	0	0
Ending Balance	$ 0	$ 640	$ 0	$ 640

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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- Definition

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 credit loss expense (reversal of expense) for financing receivable.

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