Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		$ 26,004	$ 27,069
Charge-offs		(79)	(1,475)
Recoveries		121	43
Provision		400	500
Allowance, Ending Balance		26,446	26,137
Commercial Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		9,971	9,140
Charge-offs		0	(1,253)
Recoveries		0	4
Provision		890	695
Allowance, Ending Balance		10,861	8,586
Commercial Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		1,195	1,758
Charge-offs		0	0
Recoveries		0	0
Provision		310	(115)
Allowance, Ending Balance		1,505	1,643
Commercial & Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance	[1]	6,992	8,202
Charge-offs	[1]	(2)	(8)
Recoveries	[1]	107	26
Provision	[1]	(800)	41
Allowance, Ending Balance	[1]	6,297	8,261
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		18,158	19,100
Charge-offs		(2)	(1,261)
Recoveries		107	30
Provision		400	621
Allowance, Ending Balance		18,663	18,490
Residential real estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		5,252	5,460
Charge-offs		0	(136)
Recoveries		4	2
Provision		103	37
Allowance, Ending Balance		5,359	5,363
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance, Beginning Balance		2,594	2,509
Charge-offs		(77)	(78)
Recoveries		10	11
Provision		(103)	(158)
Allowance, Ending Balance		$ 2,424	$ 2,284

[1] Commercial & industrial loans.