Business Combinations (Schedule Of Purchase Price Allocation) (Details) (USD $) In Thousands, unless otherwise specified			0 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	May 31, 2012 Alba Field [Member]
Business Acquisition [Line Items]
Purchase price			$ 255,400
Purchase price adjustment for estimated after-tax cash flows from the acquired asset and interest costs from economic date of January 1, 2011 to closing			(25,823)
Total purchase price			229,577
Property and equipment			191,507
Goodwill	259,238	262,764	47,353
Current assets			24,632
Current liabilities			(12,815)
Deferred tax liability			(6,999)
Other long-term liabilities			(14,101)
Total purchase price			$ 229,577