Loans, Allowance for Loan Losses and Credit Quality (Summary of Nonaccrual Loans) (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Financing Receivable Impaired [Line Items]
Tdrs Recorded Investment On Nonaccrual Status		$ 26,232	$ 29,348
Financing Receivable, Nonaccrual	[1]	43,360	45,413
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		23,507	26,310
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		1,666	3,015
Construction Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		0	311
Small Business [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		112	235
Residential Real Estate [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		11,281	8,251
Consumer Home Equity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		6,720	7,278
Consumer - Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		$ 74	$ 13

[1] (1)Included in these amounts were $26.2 million and $29.3 million of nonaccruing TDRs at September 30, 2019 and December 31, 2018, respectively.