Loans (Summary of Loans) (Details) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in Troubled Debt Restructuring, Recorded Investment		$ 21,500	$ 22,300
Total loans	[1]	$ 3,224,860	$ 3,234,371
Percent of Total Loans	[1]	100.00%	100.00%
Commercial Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,076,648	$ 1,074,186
Commercial Construction & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		123,841	121,371
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		562,010	576,109
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		1,100,435	1,094,824
Homeowner Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		30,775	27,924
Home Equity Lines [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		258,695	264,200
Home Equity Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		36,050	37,272
Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		36,406	38,485
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,762,499	$ 1,771,666
Percent of Total Loans		55.00%	55.00%
Commercial [Member] | Commercial Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[2]	$ 1,076,648	$ 1,074,186
Percent of Total Loans	[2]	33.00%	33.00%
Commercial [Member] | Commercial Construction & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[3]	$ 123,841	$ 121,371
Percent of Total Loans	[3]	4.00%	4.00%
Commercial [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[4]	$ 562,010	$ 576,109
Percent of Total Loans	[4]	18.00%	18.00%
Residential real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,131,210	$ 1,122,748
Percent of Total Loans		35.00%	35.00%
Residential real estate [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,100,435	$ 1,094,824
Percent of Total Loans		34.00%	34.00%
Residential real estate [Member] | Homeowner Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 30,775	$ 27,924
Percent of Total Loans		1.00%	1.00%
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 331,151	$ 339,957
Percent of Total Loans		10.00%	10.00%
Consumer [Member] | Home Equity Lines [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 258,695	$ 264,200
Percent of Total Loans		8.00%	8.00%
Consumer [Member] | Home Equity Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 36,050	$ 37,272
Percent of Total Loans		1.00%	1.00%
Consumer [Member] | Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[5]	$ 36,406	$ 38,485
Percent of Total Loans	[5]	1.00%	1.00%

[1] Includes net unamortized loan origination costs of $3.2 million and $3.0 million, respectively, at March 31, 2017 and December 31, 2016 and net unamortized premiums on purchased loans of $907 thousand and $783 thousand, respectively, at March 31, 2017 and December 31, 2016.

[2] Loans primarily secured by income producing property.

[3] Loans for construction of commercial properties, loans to developers for construction of residential properties and loans for land development.

[4] Loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate.

[5] Loans to individuals secured by general aviation aircraft and other personal installment loans.