Accrued And Other Liabilities (Schedule Of Accrued And Other Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Accrued And Other Liabilities [Line Items]
Accrued lease operating expenses	$ 14,545		$ 11,173
Accrued capital spending	6,998		6,109
Distributions payable	6,490	[1]	3,500	[1]
Gas imbalance liability	6,277		5,351
Accrued production taxes	5,895		7,401
Senior notes accrued interest	4,548		11,563
Other	5,091		1,187
Accrued and other liabilities	49,844		46,284
Class C Preferred Convertible Unitholder [Member]
Accrued And Other Liabilities [Line Items]
Distributions payable	3,500
Class B Convertible Unitholder [Member]
Accrued And Other Liabilities [Line Items]
Distributions payable	$ 3,000

[1] For the period ended March 31, 2013, the balance includes Class C preferred distributions payable to affiliates of $3.5 million and $3.0 million of distributions payable to the general partner on the Class B units related to the fourth quarter 2012