Allowance for Credit Losses on Loans (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Jan. 01, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	$ 42,137	$ 39,665	$ 44,106	$ 27,014
Adoption of Topic 326					$ 6,501
Charge-offs	(317)	(326)	(381)	(961)
Recoveries	59	18	105	30
Provision	0	2,084	(1,951)	8,857
Allowance, Ending Balance	41,879	41,441	41,879	41,441
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	21,297	19,736	22,065	14,741
Adoption of Topic 326					3,405
Charge-offs	0	(19)	0	(172)
Recoveries	0	0	0	0
Provision	153	566	(615)	2,309
Allowance, Ending Balance	21,450	20,283	21,450	20,283
Commercial & Industrial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	12,389	10,331	12,228	3,921
Adoption of Topic 326					3,029
Charge-offs	(303)	(289)	(306)	(583)
Recoveries	1	5	3	9
Provision	(370)	1,231	(208)	4,902
Allowance, Ending Balance	11,717	11,278	11,717	11,278
Total Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	33,686	30,067	34,293	18,662
Adoption of Topic 326					6,434
Charge-offs	(303)	(308)	(306)	(755)
Recoveries	1	5	3	9
Provision	(217)	1,797	(823)	7,211
Allowance, Ending Balance	33,167	31,561	33,167	31,561
Residential Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	6,469	7,729	8,042	6,615
Adoption of Topic 326					221
Charge-offs	0	0	(50)	0
Recoveries	47	0	80	0
Provision	361	324	(1,195)	1,217
Allowance, Ending Balance	6,877	8,053	6,877	8,053
Home Equity
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	1,431	1,435	1,300	1,390
Adoption of Topic 326					(106)
Charge-offs	0	(1)	0	(174)
Recoveries	4	6	6	7
Provision	(95)	(46)	34	277
Allowance, Ending Balance	1,340	1,394	1,340	1,394
Other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	551	434	471	347
Adoption of Topic 326					(48)
Charge-offs	(14)	(17)	(25)	(32)
Recoveries	7	7	16	14
Provision	(49)	9	33	152
Allowance, Ending Balance	495	433	495	433
Total Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, Beginning Balance	1,982	1,869	1,771	1,737
Adoption of Topic 326					$ (154)
Charge-offs	(14)	(18)	(25)	(206)
Recoveries	11	13	22	21
Provision	(144)	(37)	67	429
Allowance, Ending Balance	$ 1,835	$ 1,827	$ 1,835	$ 1,827

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 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 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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