PROPERTY AND EQUIPMENT (Details) (USD $) Share data in Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Property, Plant and Equipment [Abstract]
General and administrative costs (including stock-based compensation) capitalized to oil and gas properties from continuing operations	$ 8,800,000		$ 10,000,000	$ 20,300,000	$ 22,100,000
Interest costs capitalized to unproved oil and gas properties from continuing operations	1,900,000		2,500,000	4,100,000	4,500,000
Discount factor used in full cost ceiling test (as a percent)				10.00%
Ceiling test write-down of oil and natural gas properties	348,976,000	34,800,000	0	383,793,000	0
Costs Incurred, Acquisition of Oil and Gas Properties
Common stock issued for acquisition of unproved oil and natural gas properties				36,431,000	0
Common Stock
Costs Incurred, Acquisition of Oil and Gas Properties
Common stock issued for acquisition of unproved oil and natural gas properties (in shares)				2,657
Common stock issued for acquisition of unproved oil and natural gas properties				$ 266,000