Properties and Equipment, Net (Tables)

6 Months Ended

Jun. 30, 2015

Property, Plant and Equipment [Abstract]

Schedule of properties and equipment, net

Properties and equipment, net are comprised of the following:

(In thousands)	June 30, 2015			December 31, 2014
Proved oil and gas properties	$	8,531,171		$	7,984,979
Unproved oil and gas properties	451,332			492,208
Gathering and pipeline systems	242,371			241,272
Land, building and other equipment	114,809			109,758
	9,339,683			8,828,217
Accumulated depreciation, depletion and amortization	(4,207,028		)	(3,902,506		)
	$	5,132,655		$	4,925,711