Loans, Allowance for Loan Losses and Credit Quality (Summary of Nonaccrual Loans) (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Financing Receivable Impaired [Line Items]
Tdrs Recorded Investment On Nonaccrual Status		$ 23,842	$ 24,766
Financing Receivable, Nonaccrual	[1]	48,015	45,892
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		21,435	22,574
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		4,949	3,016
Construction Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		0	0
Small Business [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		450	311
Residential Real Estate [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		14,502	13,360
Consumer Home Equity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		6,571	6,570
Consumer - Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Nonaccrual		$ 108	$ 61

[1] (1)Included in these amounts were $23.8 million and $24.8 million of nonaccruing TDRs at March 31, 2020 and December 31, 2019, respectively.