Loans, Allowance for Loan Losses and Credit Quality (Weighted Average FICO Scores and the Weighted Average Combined LTV Ratio) (Details) - score		Mar. 31, 2018	Dec. 31, 2017
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable With Quality Of Loan Based On Weighted Average Fico Rating	[1]	747	745
Financing Receivable With Credit Quality Of Loan Based Upon the Weighted Average Loan-To-Value Ratio	[2]	58.20%	59.20%
Consumer Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable With Quality Of Loan Based On Weighted Average Fico Rating	[1]	768	766
Financing Receivable With Credit Quality Of Loan Based Upon the Weighted Average Loan-To-Value Ratio	[2],[3]	48.70%	50.10%

[1] The average FICO scores at March 31, 2018 are based upon rescores available from February 2018 and origination score data for loans booked in March 2018. The average FICO scores at December 31, 2017 are based upon rescores available from August 2017 and origination score data for loans booked between September and December 2017.

[2] The combined LTV ratios for March 31, 2018 are based upon updated automated valuations as of February 2018, when available or the most current valuation data available. The combined LTV ratios for December 31, 2017 are based upon updated automated valuations as of August 2017, when available, or the most current valuation data available. The updated automated valuations provides new information on loans that may be available since the previous valuation was obtained. If no new information is available, the valuation will default to the previously obtained data or most recent appraisal.

[3] For home equity loans and lines in a subordinate lien, the LTV data represents a combined LTV, taking into account the senior lien data for loans and lines.