Loans (Summary of Loans) (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	$ 3,374,071	$ 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		$ 1,072,487	$ 1,074,186
Commercial Construction & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		138,008	121,371
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		612,334	576,109
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		1,206,458	1,094,824
Homeowner Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		20,790	27,924
Home Equity Lines [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		258,114	264,200
Home Equity Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		34,353	37,272
Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		31,527	38,485
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,822,829	$ 1,771,666
Percent of total loans		54.00%	55.00%
Commercial [Member] | Commercial Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[2]	$ 1,072,487	$ 1,074,186
Percent of total loans	[2]	32.00%	33.00%
Commercial [Member] | Commercial Construction & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[3]	$ 138,008	$ 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]	$ 612,334	$ 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		$ 1,227,248	$ 1,122,748
Percent of total loans		36.00%	35.00%
Residential Real Estate [Member] | Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,206,458	$ 1,094,824
Percent of total loans		35.00%	34.00%
Residential Real Estate [Member] | Homeowner Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 20,790	$ 27,924
Percent of total loans		1.00%	1.00%
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 323,994	$ 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		$ 258,114	$ 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		$ 34,353	$ 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]	$ 31,527	$ 38,485
Percent of total loans	[5]	1.00%	1.00%

[1] Includes net unamortized loan origination costs of $3.8 million and $3.0 million, respectively, and net unamortized premiums on purchased loans of $878 thousand and $783 thousand, respectively, at December 31, 2017 and 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.