Allowance for Loan Losses Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Impaired Loans, Including Restructured Loans) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Loans and Leases Receivable, Allowance [Abstract]
Impaired loans with an allowance for loan loss required	[1]	$ 49,961	$ 69,487
Impaired loans with no allowance for loan loss required		51,294	57,925
Total impaired loans	[2]	101,255	127,412
Allowance for loan losses related to impaired loans		6,380	6,270
TDRs		51,853	82,275
Reduction of interest income from non-accrual loans		3,006	2,222
Interest income recognized on impaired loans		$ 6,198	$ 7,190	$ 8,900

[1] These impaired loans require an allowance for loan losses because the estimated fair value of the loans or related collateral is less than the recorded investment in the loans.

[2] Impaired loans are considered by the Company to be non-accrual loans, TDRs or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest.