Derivative Financial Instruments And Hedging Activities Derivative (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Restricted Cash - Derivative Collateral	$ 3,900	$ 4,200
Foreign Exchange Contract [Member]
Derivative [Line Items]
Fair Value Hedge Assets	2,221
Fair Value Hedge Liabilities	2,257
Other Assets [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Derivatives	1,500,000
EuroDollar [Member] | Other Assets [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Derivatives	750,000
United Kingdom, Pounds | Other Assets [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Derivatives	331,000
Norway, Krone | Other Assets [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional Amount of Interest Rate Derivatives	$ 229,000