Derivative Instruments (Detail Effect Of Derivative Assets And Liabilities In Statement Of Operations) (Details) (USD $) In Thousands	4 Months Ended	9 Months Ended	3 Months Ended		4 Months Ended	9 Months Ended	3 Months Ended		4 Months Ended	9 Months Ended	3 Months Ended		4 Months Ended	9 Months Ended	3 Months Ended		4 Months Ended	9 Months Ended	4 Months Ended	9 Months Ended	3 Months Ended		4 Months Ended	9 Months Ended	4 Months Ended
	Sep. 30, 2010 Successor [Member] Interest Rate [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Expense, Net [Member]	Sep. 30, 2011 Successor [Member] Interest Rate [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Expense, Net [Member]	Sep. 30, 2011 Successor [Member] Interest Rate [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Expense, Net [Member]	Sep. 30, 2010 Successor [Member] Interest Rate [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Expense, Net [Member]	Sep. 30, 2010 Successor [Member] Interest Rate [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Expense, Net [Member]	Sep. 30, 2011 Successor [Member] Interest Rate [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Expense, Net [Member]	Sep. 30, 2011 Successor [Member] Commodity Derivatives [Member] Derivatives In Cash Flow Hedging Relationship [Member] Revenues [Member]	Sep. 30, 2010 Successor [Member] Commodity Derivatives [Member] Derivatives In Cash Flow Hedging Relationship [Member] Revenues [Member]	Sep. 30, 2010 Successor [Member] Commodity Derivatives [Member] Derivatives In Cash Flow Hedging Relationship [Member] Revenues [Member]	Sep. 30, 2011 Successor [Member] Commodity Derivatives [Member] Derivatives In Cash Flow Hedging Relationship [Member] Revenues [Member]	Sep. 30, 2011 Successor [Member] Commodity Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Revenues [Member]	Sep. 30, 2010 Successor [Member] Commodity Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Revenues [Member]	Sep. 30, 2010 Successor [Member] Commodity Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Revenues [Member]	Sep. 30, 2011 Successor [Member] Commodity Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Revenues [Member]	Sep. 30, 2011 Successor [Member] Embedded Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Other Income and Deductions, Net [Member]	Sep. 30, 2010 Successor [Member] Embedded Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Other Income and Deductions, Net [Member]	Sep. 30, 2010 Successor [Member] Embedded Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Other Income and Deductions, Net [Member]	Sep. 30, 2011 Successor [Member] Embedded Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Other Income and Deductions, Net [Member]	Sep. 30, 2010 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	Sep. 30, 2011 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	Sep. 30, 2011 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	Sep. 30, 2010 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	Sep. 30, 2010 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	Sep. 30, 2011 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	May 25, 2010 Predecessor [Member] Interest Rate [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Expense, Net [Member]	May 25, 2010 Predecessor [Member] Interest Rate [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Expense, Net [Member]	May 25, 2010 Predecessor [Member] Commodity Derivatives [Member] Derivatives In Cash Flow Hedging Relationship [Member] Revenues [Member]	May 25, 2010 Predecessor [Member] Commodity Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Revenues [Member]	May 25, 2010 Predecessor [Member] Embedded Derivatives [Member] Derivatives Not Designated In A Hedging Relationships [Member] Other Income and Deductions, Net [Member]	May 25, 2010 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	May 25, 2010 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member]
Change in value recognized in OCI on derivatives (effective portion)							$ 10,287	$ 0	$ 0	$ (5,179)																	$ 14,371
Amount of gain (loss) reclassified from AOCI into income (effective portion)	0	0					(5,282)	0	0	(14,276)									0	(14,276)					(1,060)		(5,200)			(6,260)
Amount of gain (loss) recognized in income on ineffective portion							21	0	0	(253)																	(799)
Amount of gain (loss) from designation amortized from AOCI into income													0	0														4,115
Amount of gain (loss) recognized in income on derivatives			$ 99	$ (1,795)	$ (3,510)	$ (388)					$ (119)	$ (6,218)	$ (6,348)	$ (107)	$ 15,230	$ 7,321	$ 3,715	$ 20,755			$ 15,210	$ (692)	$ (6,143)	$ 20,260		$ (824)		$ 1,168	$ (4,039)		$ (3,695)