Fair-Value Measurements (Reconciliation Of Changes In Fair Value Of The Beginning And Ending Balances For Our Derivatives Measured At Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2009
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Reclassified into interest expense for settled contracts	$ (2,112)
Included in other comprehensive income (loss)	(424)	(508)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning Balance	(1,688)	(1,964)
Reclassified into interest expense for settled contracts	2,112	784
Included in other comprehensive income (loss)	(424)	(508)
Ending Balance		$ (1,688)