Loans, Allowance for Credit Losses and Credit Quality Finance Receivable, Nonaccrual (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		$ 55,369
Financing Receivable, Nonaccrual, No Allowance		42,655
Tdrs Recorded Investment On Nonaccrual Status		23,810	$ 24,766
Financing Receivable, Nonaccrual	[1]	98,024	45,892
Commercial And Industrial [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		17,816
Financing Receivable, Nonaccrual, No Allowance		19,035
Financing Receivable, Nonaccrual		36,851	22,574
Commercial Real Estate [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		17,501
Financing Receivable, Nonaccrual, No Allowance		20,663
Financing Receivable, Nonaccrual		38,164	3,016
Small Business [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		542
Financing Receivable, Nonaccrual		542	311
Residential Real Estate [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		13,379
Financing Receivable, Nonaccrual, No Allowance		2,850
Financing Receivable, Nonaccrual		16,229	13,360
Home Equity Line of Credit [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		6,052
Financing Receivable, Nonaccrual, No Allowance		107
Financing Receivable, Nonaccrual		6,159	6,570
Consumer - Other [Member]
Financing Receivable, Nonaccrual [Line Items]
Finance Receivable, Nonaccrual, with allowance		79
Financing Receivable, Nonaccrual		$ 79	$ 61

[1] Included in these amounts were $23.8 million and $24.8 million of nonaccruing TDRs at September 30, 2020 and December 31, 2019, respectively.