Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		$ 26,174	$ 26,662	$ 26,488	$ 26,004
Charge-offs		(96)	(694)	(889)	(1,415)
Recoveries		81	40	160	319
Provision		350	1,300	750	2,400
Allowance, Ending Balance		26,509	27,308	26,509	27,308
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	[1]	12,443	11,935	12,729	11,166
Charge-offs	[1]	0	(535)	(627)	(935)
Recoveries	[1]	0	0	25	82
Provision	[1]	1,052	1,387	1,368	2,474
Allowance, Ending Balance	[1]	13,495	12,787	13,495	12,787
Commercial & Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	[2]	6,642	7,067	5,580	6,992
Charge-offs	[2]	(1)	(122)	(8)	(286)
Recoveries	[2]	71	8	104	162
Provision	[2]	535	(301)	1,571	(216)
Allowance, Ending Balance	[2]	7,247	6,652	7,247	6,652
Total Commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		19,085	19,002	18,309	18,158
Charge-offs		(1)	(657)	(635)	(1,221)
Recoveries		71	8	129	244
Provision		1,587	1,086	2,939	2,258
Allowance, Ending Balance		20,742	19,439	20,742	19,439
Residential Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		5,314	5,369	5,427	5,252
Charge-offs		(68)	0	(73)	(32)
Recoveries		0	1	0	29
Provision		(1,131)	70	(1,239)	191
Allowance, Ending Balance		4,115	5,440	4,115	5,440
Home Equity
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		1,375	1,927	2,412	1,889
Charge-offs		0	(18)	(111)	(79)
Recoveries		2	25	12	31
Provision		12	(27)	(924)	66
Allowance, Ending Balance		1,389	1,907	1,389	1,907
Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		400	364	340	705
Charge-offs		(27)	(19)	(70)	(83)
Recoveries		8	6	19	15
Provision		(118)	171	(26)	(115)
Allowance, Ending Balance		263	522	263	522
Total Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		1,775	2,291	2,752	2,594
Charge-offs		(27)	(37)	(181)	(162)
Recoveries		10	31	31	46
Provision		(106)	144	(950)	(49)
Allowance, Ending Balance		$ 1,652	$ 2,429	$ 1,652	$ 2,429

[1] Commercial real estate loans.

[2] Commercial & industrial loans.