Allowance for Loan Losses (Allowance for Loan Losses Rollforward Analysis) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		$ 26,004		$ 27,069		$ 28,023
Charge-offs		(2,462)		(7,012)		(2,305)
Recoveries		346		297		301
Provision		2,600		5,650		1,050
Ending Balance		26,488		26,004		27,069
Commercial Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		9,971		9,140		8,202
Charge-offs		(1,867)		(5,816)		(809)
Recoveries		82		56		92
Provision		3,460		6,591		1,655
Ending Balance		11,646		9,971		9,140
Commercial Construction & Development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		1,195		1,758		1,300
Charge-offs		0		0		0
Recoveries		0		0		0
Provision		(112)		(563)		458
Ending Balance		1,083		1,195		1,758
Commercial & Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		6,992	[1]	8,202	[1],[2]	7,987	[2]
Charge-offs		(336)	[1]	(759)	[1]	(671)	[2]
Recoveries		169	[1]	156	[1]	87	[2]
Provision		(1,245)	[1]	(607)	[1]	799	[2]
Ending Balance	[1]	5,580		6,992		8,202	[2]
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		18,158		19,100		17,489
Charge-offs		(2,203)		(6,575)		(1,480)
Recoveries		251		212		179
Provision		2,103		5,421		2,912
Ending Balance		18,309		18,158		19,100
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		5,252		5,460		5,430
Charge-offs		(74)		(200)		(207)
Recoveries		39		11		28
Provision		210		(19)		209
Ending Balance		5,427		5,252		5,460
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance		2,594		2,509		2,713
Charge-offs		(185)		(237)		(618)
Recoveries		56		74		94
Provision		287		248		320
Ending Balance		$ 2,752		2,594		2,509
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance				$ 0		2,391
Charge-offs						0
Recoveries						0
Provision						(2,391)
Ending Balance						$ 0

[1] Commercial & industrial loans.

[2] Commercial & industrial loans.