Related Party Transactions (Schedule Of Cash Contributions From The Predecessor) (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended	3 Months Ended		12 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2011
Related Party Transactions [Abstract]
Cash receipts	$ (5,971)	$ (109,274)	$ (204,898)
Borrowings under Predecssor's credit facility	(23,000)
Production expenses paid	2,559	41,528	80,889
Derivative buyup payment			42,653
Interest paid	321	4,050	9,981
Acquisition of Melrose property	77,763
Capital expenditures paid	907	28,723	45,868
Contributions from (distributions to) the Predecessor	$ 52,579	$ (34,973)	$ (25,507)	$ (34,973)	$ (25,507)