Derivatives - Interest Rate Swap Agreements (Schedule Of Location Of Derivatives On Income Statement) (Details) (Interest Rate [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Interest Rate [Member]
Derivative [Line Items]
Amount of loss recognized in OCI on derivative (effective portion)	$ 28,423	$ 18,255
Amount of loss reclassified from accumulated OCI into income (effective portion)	27,811	17,473
Amount of loss recognized in income on derivative (ineffective portion)	$ 169	$ 145
Derivative type for cash flow hedge	Interest Rate	Interest Rate
Location of loss reclassified from accumulated OCI into income (effective portion)	Interest Expense	Interest Expense
Location of gain (loss) recognized in income on derivative (ineffective portion)	Interest Expense	Interest Expense