Loans (Summary of Loans) (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[1]	$ 3,738,469	$ 3,680,360
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[2]	1,463,682	1,392,408
Commercial & Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[3]	610,608	620,704
Total Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		2,074,290	2,013,112
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[4]	1,359,072	1,360,387
Home Equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		279,938	280,626
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	[5]	25,169	26,235
Total Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans		$ 305,107	$ 306,861

[1] Includes net unamortized loan origination costs of $4.9 million and $4.7 million, respectively, at March 31, 2019 and December 31, 2018 and net unamortized premiums on purchased loans of $668 thousand and $703 thousand, respectively, at March 31, 2019 and December 31, 2018.

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

[4] Consists of mortgage and homeowner construction loans secured by one- to four-family residential properties.

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