Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		$ 26,446	$ 26,137	$ 26,004	$ 27,069
Charge-offs		(642)	(860)	(721)	(2,335)
Recoveries		158	99	279	142
Provision		700	450	1,100	950
Allowance, Ending Balance		26,662	25,826	26,662	25,826
Commercial Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		10,861	8,586	9,971	9,140
Charge-offs		(400)	(78)	(400)	(1,331)
Recoveries		82	13	82	17
Provision		192	1,892	1,082	2,587
Allowance, Ending Balance		10,735	10,413	10,735	10,413
Commercial Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		1,505	1,643	1,195	1,758
Charge-offs		0	0	0	0
Recoveries		0	0	0	0
Provision		(305)	(739)	5	(854)
Allowance, Ending Balance		1,200	904	1,200	904
Commercial & Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	[1]	6,297	8,261	6,992	8,202
Charge-offs	[1]	(162)	(746)	(164)	(754)
Recoveries	[1]	47	62	154	88
Provision	[1]	885	(1,057)	85	(1,016)
Allowance, Ending Balance	[1]	7,067	6,520	7,067	6,520
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		18,663	18,490	18,158	19,100
Charge-offs		(562)	(824)	(564)	(2,085)
Recoveries		129	75	236	105
Provision		772	96	1,172	717
Allowance, Ending Balance		19,002	17,837	19,002	17,837
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		5,359	5,363	5,252	5,460
Charge-offs		(32)	(4)	(32)	(140)
Recoveries		24	2	28	4
Provision		18	108	121	145
Allowance, Ending Balance		5,369	5,469	5,369	5,469
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		2,424	2,284	2,594	2,509
Charge-offs		(48)	(32)	(125)	(110)
Recoveries		5	22	15	33
Provision		(90)	246	(193)	88
Allowance, Ending Balance		$ 2,291	$ 2,520	$ 2,291	$ 2,520

[1] Commercial & industrial loans.