Loans (Changes in the Allowance for Credit Losses) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		$ 46,316	$ 34,434	$ 40,076	$ 33,914
Allowance for loan losses, Charge-offs		(2,203)	(5,903)	(17,958)	(12,528)
Allowance for loan losses, Recoveries		1,715	1,293	6,541	4,891
Allowance for loan losses, Provision (credit)		3,567	1,844	20,736	5,391
Allowance for loan losses, Ending balance	$ 40,076	49,395	31,668	49,395	31,668
Beginning balance, prior to adoption of ASC 326	30,482	49,395		49,395
Impact of adopting ASC 326	9,594
Loans, Ending balance	3,179,465	3,532,874	3,114,733	3,532,874	3,114,733
Allowance for loan losses, Individually Evaluated for impairment			6,300		6,300
Allowance for loan losses, Collectively Evaluated for impairment			3,108,433		3,108,433
Allowance for loan losses, Individually Evaluated for impairment			1,564		1,564
Allowance for loan losses, Collectively Evaluated for impairment			30,104		30,104
Commercial Business [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		12,399	11,717	11,112	14,312
Allowance for loan losses, Charge-offs		(15)	(112)	(8,281)	(380)
Allowance for loan losses, Recoveries		103	102	1,644	333
Allowance for loan losses, Provision (credit)		507	448	8,519	(2,110)
Allowance for loan losses, Ending balance	11,112	12,994	12,155	12,994	12,155
Beginning balance, prior to adoption of ASC 326	11,358
Impact of adopting ASC 326	(246)
Loans, Ending balance	571,222	823,611	573,610	823,611	573,610
Allowance for loan losses, Individually Evaluated for impairment			3,010		3,010
Allowance for loan losses, Collectively Evaluated for impairment			570,600		570,600
Allowance for loan losses, Individually Evaluated for impairment			1,563		1,563
Allowance for loan losses, Collectively Evaluated for impairment			10,592		10,592
Commercial Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		15,666	8,790	12,991	5,219
Allowance for loan losses, Charge-offs		(640)	(2,994)	(1,712)	(2,997)
Allowance for loan losses, Recoveries		37	0	37	17
Allowance for loan losses, Provision (credit)		1,417	126	5,164	3,683
Allowance for loan losses, Ending balance	12,991	16,480	5,922	16,480	5,922
Beginning balance, prior to adoption of ASC 326	5,681
Impact of adopting ASC 326	7,310
Loans, Ending balance	1,108,315	1,204,353	1,037,304	1,204,353	1,037,304
Allowance for loan losses, Individually Evaluated for impairment			3,290		3,290
Allowance for loan losses, Collectively Evaluated for impairment			1,034,014		1,034,014
Allowance for loan losses, Individually Evaluated for impairment			1		1
Allowance for loan losses, Collectively Evaluated for impairment			5,921		5,921
Residential Real Estate Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		5,769	1,217	4,349	1,112
Allowance for loan losses, Charge-offs		0	(54)	(100)	(172)
Allowance for loan losses, Recoveries		7	14	25	31
Allowance for loan losses, Provision (credit)		(1,224)	6	278	212
Allowance for loan losses, Ending balance	4,349	4,552	1,183	4,552	1,183
Beginning balance, prior to adoption of ASC 326	1,059
Impact of adopting ASC 326	3,290
Loans, Ending balance	560,717	583,963	547,839	583,963	547,839
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			547,839		547,839
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			1,183		1,183
Residential Real Estate Lines [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		939	145	725	210
Allowance for loan losses, Charge-offs		0	(8)	0	(10)
Allowance for loan losses, Recoveries		0	1	3	6
Allowance for loan losses, Provision (credit)		(121)	8	90	(60)
Allowance for loan losses, Ending balance	725	818	146	818	146
Beginning balance, prior to adoption of ASC 326	118
Impact of adopting ASC 326	607
Loans, Ending balance	101,048	90,899	104,545	90,899	104,545
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			104,545		104,545
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			146		146
Consumer Indirect [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		11,222	12,157	10,618	12,572
Allowance for loan losses, Charge-offs		(1,388)	(2,420)	(7,366)	(8,102)
Allowance for loan losses, Recoveries		1,503	1,103	4,550	4,205
Allowance for loan losses, Provision (credit)		2,833	1,002	6,368	3,167
Allowance for loan losses, Ending balance	10,618	14,170	11,842	14,170	11,842
Beginning balance, prior to adoption of ASC 326	11,852
Impact of adopting ASC 326	(1,234)
Loans, Ending balance	822,179	813,345	834,968	813,345	834,968
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			834,968		834,968
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			11,842		11,842
Other Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Beginning balance		321	408	281	489
Allowance for loan losses, Charge-offs		(160)	(315)	(499)	(867)
Allowance for loan losses, Recoveries		65	73	282	299
Allowance for loan losses, Provision (credit)		155	254	317	499
Allowance for loan losses, Ending balance	281	381	420	381	420
Beginning balance, prior to adoption of ASC 326	414
Impact of adopting ASC 326	(133)
Loans, Ending balance	$ 15,984	$ 16,703	16,467	$ 16,703	16,467
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			16,467		16,467
Allowance for loan losses, Individually Evaluated for impairment			0		0
Allowance for loan losses, Collectively Evaluated for impairment			$ 420		$ 420

Financing receivable allowance for loan losses, provision (credit).

No definition available.

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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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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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

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Amount of credit loss expense (reversal of expense) for financing receivable from change in methodology.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount, before allowance for credit loss, of financing receivable.

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