Decommissioning Liabilities (Tables)

9 Months Ended

Sep. 30, 2011

Decommissioning Liabilities [Abstract]

Summary of activity for company's decommissioning liabilities

	Nine Months Ended
	September 30,
	2011			2010
Decommissioning liabilities, December 31, 2010 and 2009, respectively	$	117,716		$	—
Liabilities acquired and incurred		—			136,559
Accretion		5,038			5,361
Revision in estimated liabilities		(292	)		—
Total decommissioning liabilities, September 30, 2011 and 2010, respectively		122,462			141,920
Less: current portion of decommissioning liabilities at September 30, 2011 and 2010, respectively		17,090			25,804
Long-term decommissioning liabilities, September 30, 2011 and 2010, respectively	$	105,372		$	116,116