SELECTED QUARTERLY FINANCIAL DATA (unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Selected Quarterly Financial Results
Oil, natural gas, and natural gas liquids sales	$ 88,485		$ 118,028		$ 116,786		$ 118,042		$ 154,914		$ 156,014		$ 135,694		$ 158,901		$ 441,341	$ 605,523	$ 703,531
Costs and expenses associated directly with products sold from continuing operations	57,299	[1]	69,881	[1]	69,514	[1]	75,482	[1]	104,048	[1]	114,304	[1]	110,996	[1]	110,110	[1]
Earnings (loss) before income taxes	105,974	[2]	1,627	[2]	33,227	[2]	(67,611)	[2]	(288,365)	[2]	(451,272)	[2]	(344,099)	[2]	(31,758)	[2]	73,217	(1,115,494)	187,395
Net earnings (loss)	106,219	[2]	2,214	[2]	33,439	[2]	(67,948)	[2]	(286,533)	[2]	(458,552)	[2]	(511,173)	[2]	(32,673)	[2]	73,924	(1,288,931)	142,829
Basic and diluted earnings (loss) per share (in dollars per share)	$ 0.89		$ 0.02		$ 0.28		$ (0.59)		$ (2.48)		$ (3.97)		$ (4.44)		$ (0.29)
Gain on asset dispositions, net																	202,023	0	0
Texas Panhandle Area
Selected Quarterly Financial Results
Gain on asset dispositions, net	$ 193,000																$ 193,000

[1] Costs and expenses associated directly with products sold is comprised of lease operating expenses, production and property taxes, transportation and processing costs, depletion expense, and accretion of asset retirement obligations.

[2] Earnings (loss) before income taxes and net earnings (loss) have been impacted by non-cash ceiling test write-downs in every quarter of 2012 and the fourth quarter of 2013, as discussed in Note 1, and are also subject to large fluctuations due to Forest’s election not to use cash flow hedge accounting for derivative instruments as discussed in Note 9. Also impacting the fourth quarter of 2013 is a $193.0 million net gain on the Panhandle divestiture, as discussed in Note 2.