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, 2012	Dec. 31, 2011	Dec. 31, 2010
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)	0	0	(424)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at beginning of period			(1,688)
Reclassified into interest expense for settled contracts			2,112
Included in other comprehensive income (loss)			(424)
Balance at end of period			$ 0