Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2013

Asset Retirement Obligation Disclosure [Abstract]

Summary of Changes and Balances of Current and Long-term Portions in Asset Retirement Obligations

The following tables summarize the changes and the balances of current and long-term portions in the Company’s asset retirement obligations during the periods (in thousands):

	As of December 31,
	2013			2012
Asset retirement obligations at January 1	$	24,832		$	-
Property acquisition		-			23,785
Revisions in estimated liabilities		(6,466	)		-
Accretion		2,235			1,047
Asset retirement obligations at December 31	$	20,601		$	24,832
	As of December 31,
	2013			2012
Asset retirement obligations, current portion	$	12,479		$	-
Asset retirement obligations, long-term portion		8,122			24,832
	$	20,601		$	24,832