Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2014

Asset Retirement Obligations

Schedule of changes in asset retirement obligations

	December 31,
	2014		2013
	(In thousands)
Asset retirement obligations:
Beginning asset retirement obligations	$	39,596	$	27,484
Liabilities incurred during period		—		8,558
Revisions in estimated retirement obligations		—		—
Accretion expense		4,427		3,554
Ending asset retirement obligations	$	44,023	$	39,596