PROPERTY AND EQUIPMENT (Details) (USD $)	3 Months Ended								3 Months Ended		12 Months Ended	15 Months Ended			12 Months Ended	15 Months Ended	3 Months Ended	12 Months Ended	15 Months Ended	12 Months Ended	3 Months Ended		15 Months Ended		3 Months Ended		15 Months Ended		12 Months Ended		3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 7 1/4% Senior Notes due 2019	Dec. 31, 2013 7 1/4% Senior Notes due 2019	Mar. 31, 2014 7 1/2% Senior Notes due 2020	Dec. 31, 2013 7 1/2% Senior Notes due 2020	Nov. 30, 2013 7 1/4% Senior Notes Due 2019 and 7 1/2% Senior Notes due 2020	Mar. 31, 2013 8 1/2% Senior Notes due 2014	Mar. 31, 2014 Texas Panhandle		Dec. 31, 2013 Texas Panhandle	Mar. 31, 2014 Texas Panhandle		Oct. 31, 2013 Texas Panhandle	Dec. 31, 2013 Texas Panhandle Oil and Gas Properties	Mar. 31, 2014 Texas Panhandle Oil and Gas Properties	Mar. 31, 2014 Texas Panhandle General and Administrative Expense	Dec. 31, 2013 Texas Panhandle General and Administrative Expense	Mar. 31, 2014 Texas Panhandle General and Administrative Expense	Dec. 31, 2013 Texas Panhandle Other, net	Mar. 31, 2014 Texas Panhandle One-time Employee Termination Benefits		Mar. 31, 2014 Texas Panhandle One-time Employee Termination Benefits		Mar. 31, 2014 Texas Panhandle Other Associated Costs		Mar. 31, 2014 Texas Panhandle Other Associated Costs		Dec. 31, 2013 South Texas	Jan. 31, 2013 South Texas	Mar. 31, 2013 South Texas One-time Employee Termination Benefits
Property, Plant and Equipment [Line Items]
General and administrative costs (including stock-based compensation) capitalized to oil and gas properties	$ 4,600,000	$ 12,300,000
Interest costs capitalized to unproved oil and gas properties	0	191,000
Discount factor used in full cost ceiling test (as a percent)	10.00%
Threshold for the amount of reserve quanties of a cost center for a sale that would not cause a signficant alteration between capitalized costs and estimated reserves attributable to a cost center (as a percent)	25.00%
Divestitures
Sales price of oil and natural gas properties														1,000,000,000																325,000,000
Proceeds from sale of oil and natural gas properties												965,100,000																	320,900,000
Escrow deposit related to sale of properties									32,900,000			32,900,000
Escrow deposit for post-closing indemnities									10,000,000			10,000,000
Redeemed Principal Amount of Senior Notes							700,000,000	300,000,000
Interest rate (as a percent)			7.25%	7.25%	7.50%	7.50%		8.50%
Gain (loss) on disposition, net	(794,000)	0							(794,000)		193,000,000
Costs incurred, net																															5,700,000
Exit costs reconciliation
Total expected amount												12,579,000	[1]										4,612,000	[1]			7,967,000	[1],[2]
Remaining costs to be accrued												100,000
Liability balance at beginning of period									6,935,000												1,095,000				5,840,000	[2]
Costs incurred									544,000	[3]		12,521,000	[3]		1,100,000	1,200,000	500,000	5,000,000	5,500,000	5,800,000	544,000	[3]	4,554,000	[3]	0	[2],[3]	7,967,000	[2],[3]			7,500,000
Costs paid									(6,814,000)												(1,057,000)				(5,757,000)	[2]
Liability balance at end of period									$ 665,000	[4]	$ 6,935,000	$ 665,000	[4]								$ 582,000	[4]	$ 582,000	[4]	$ 83,000	[2],[4]	$ 83,000	[2],[4]

[1] Of the $12.6 million total expected costs, the remaining $.1 million will be accrued in the second quarter of 2014 over the remaining retention period of the affected employees.

[2] Other associated costs consist of financial advisor fees and retention bonuses paid to certain employees.

[3] Of the $12.5 million costs incurred, (i) $5.5 million was recognized in “General and administrative” expense, $5.0 million during the year ended December 31, 2013 and $.5 million during the quarter ended March 31, 2014, (ii) $5.8 million was recognized in “Other, net” during the year ended December 31, 2013, and (iii) $1.2 million was capitalized in “Oil and natural gas properties” pursuant to the full cost method of accounting, $1.1 million during the year ended December 31, 2013 and the remainder during the quarter ended March 31, 2014.

[4] The March 31, 2014 estimated liability balance is included in “Accounts payable and accrued liabilities” in the Condensed Consolidated Balance Sheet, and Forest expects it will be paid in the second quarter of 2014.