Loans Receivable and Credit Quality Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 5,719,212	$ 5,269,936
Commercial Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,111,555	953,085
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,914,134	1,788,403
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	183,434	125,349
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,229,540	2,132,095
Home Equity Line of Credit [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	119,828	114,859
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 160,721	$ 156,145