Allowance for Loan Losses Allowance for Losses on Lending-Related Commitments and Impaired Loans (Narrative) (Details)		12 Months Ended
		Dec. 31, 2015 USD ($) contracts Rate	Dec. 31, 2014 USD ($) contracts Rate	Dec. 31, 2013 USD ($) contracts Rate
Financing Receivable, Allowance for Credit Losses [Line Items]
Average recorded investment		$ 107,170,000	$ 134,967,000	$ 170,700,000
Impaired Financing Receivable, Interest Income, Accrual Method		6,198,000	7,190,000	$ 8,900,000
Financing Receivable, Modifications, Recorded Investment		$ 51,853,000	$ 82,275,000
Financing Receivable, Modifications, Number of Contracts | contracts	[1],[2],[3],[4]	12	21	35
Allowance for loan losses related to impaired loans		$ 6,380,000	$ 6,270,000
Financing Receivable, Modifications, Post-Modification Recorded Investment	[1],[2],[3],[4]	$ 2,034,000	$ 11,967,000	$ 22,680,000
Financing Receivables, Modifications, Weighted Average Extension Term		45 months	19 months	18 months
Weighted Average Stated Interest Rate Basis Points | Rate		3.58%	1.70%	1.84%
Financing Receivables, Modifications, Weighted Average Interest Only Term		17 months	7 months	11 months
Loan Forgiveness		$ 0	$ 0	$ 1,000,000
Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Modifications, Number of Contracts | contracts		102
Allowance for loan losses related to impaired loans		$ 1,800,000
Loans and Leases Receivable, Impaired, Interest Income Recognized, Change in Present Value Attributable to Passage of Time		573,000	$ 724,000
Residential Real Estate | Financing Receivable
Financing Receivable, Allowance for Credit Losses [Line Items]
Other real estate owned		$ 14,200,000

[1] Balances represent the recorded investment in the loan at the time of the restructuring.

[2] Balances represent the recorded investment in the loan at the time of the restructuring.

[3] TDRs may have more than one modification representing a concession. As such, TDRs during the period may be represented in more than one of the categories noted above.

[4] Total TDRs represent all loans restructured in TDRs during the year indicated.