PROPERTY AND EQUIPMENT (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009
Oil and gas properties:
Proved	$ 9,696,498,000		$ 8,825,142,000
Unproved	277,798,000		675,995,000
Accumulated depletion	(8,237,186,000)		(6,901,997,000)
Net oil and natural gas properties	1,737,110,000		2,599,140,000
Other property and equipment:
Gas gathering, furniture and fixtures, computer hardware and software, and other equipment	64,036,000		99,965,000
Accumulated depreciation and amortization	(46,908,000)		(47,989,000)
Net other property and equipment	17,128,000		51,976,000
Net property and equipment	1,754,238,000	[1]	2,651,116,000	[1]
Total net property and equipment located in foreign countries			98,700,000
Capitalized Costs of Unproved Properties
Acquisition costs unproved properties	14,136,000		46,729,000		15,530,000	155,781,000
Total cumulative capitalized acquisition costs in unproved properties	232,176,000
Exploration costs unproved properties	37,614,000		3,940,000		641,000	3,427,000
Total cumulative capitalized exploration costs in unproved properties	45,622,000
Total acquisition and exploration costs unproved properties	51,750,000		50,669,000		16,171,000	159,208,000
Unproved	$ 277,798,000		$ 675,995,000
Company expects substantially all of its unproved costs wil be reclassified to proved properties (in years)	10 years

[1] At December 31, 2011, $98.7 million of the Company’s total net property and equipment was located in foreign countries. This balance was written off during 2012 when the South African properties were impaired and the Italian natural gas reserves were reclassified from proved to probable, causing a full ceiling test write-down of the Italian cost center, both of which are discussed in Note 1.