Loans (Summary of Loans) (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	$ 3,556,203	$ 3,374,071
Percent of Total Loans	[1]	100.00%	100.00%
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[2]	$ 1,240,350	$ 1,210,495
Percent of Total Loans	[2]	35.00%	36.00%
Commercial & Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[3]	$ 656,882	$ 612,334
Percent of Total Loans	[3]	18.00%	18.00%
Total Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 1,897,232	$ 1,822,829
Percent of Total Loans		53.00%	54.00%
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[4]	$ 1,349,340	$ 1,227,248
Percent of Total Loans	[4]	38.00%	36.00%
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 282,331	$ 292,467
Percent of Total Loans		8.00%	9.00%
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[5]	$ 27,300	$ 31,527
Percent of Total Loans	[5]	1.00%	1.00%
Total Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 309,631	$ 323,994
Percent of Total Loans		9.00%	10.00%

[1] Includes net unamortized loan origination costs of $4.8 million and $3.8 million, respectively, at September 30, 2018 and December 31, 2017 and net unamortized premiums on purchased loans of $746 thousand and $878 thousand, respectively, at September 30, 2018 and December 31, 2017.

[2] Commercial real estate loans consist of commercial mortgages primarily secured by income producing property, as well as construction and development loans. Construction and development loans are made to businesses for land development or the on-site construction of industrial, commercial, or residential buildings.

[3] Commercial & industrial consist of loans to businesses and individuals, a substantial portion of which are fully or partially collateralized by real estate.

[4] Residential real estate loans consist of mortgage and homeowner construction loans secured by one- to four- family residential properties.

[5] Other consumer loans consists of loans to individuals secured by general aviation aircraft and other personal installment loans.