Fair Value Disclosures (Summary Of Gains (Losses) Due To Changes In Instrument Specific Credit Risk For Loans and Other Receivables And Loan Commitments Measured At Fair Value Under Fair Value Option) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financial Instruments [Line Items]
Loans and other receivables	$ (5,127)	$ (15,462)
Financial Instruments Sold [Member]
Financial Instruments [Line Items]
Loans	(27)	48
Loan commitments	871	(3,746)
Long-term Debt [Member]
Financial Instruments [Line Items]
Loan commitments	(16,040)	(302)
Other changes in fair value	$ 3,417	$ 6,858