STOCK-BASED COMPENSATION (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				6 Months Ended					3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended			6 Months Ended				3 Months Ended			6 Months Ended			3 Months Ended			6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011	Jun. 30, 2012 Stock Options	Jun. 30, 2011 Stock Options	Jun. 30, 2012 Stock Options	Jun. 30, 2011 Stock Options	Jun. 30, 2012 Restricted Stock	Jun. 30, 2011 Restricted Stock	Jun. 30, 2012 Restricted Stock	Jun. 30, 2011 Restricted Stock	Jun. 30, 2012 Performance Stock Units		Jun. 30, 2011 Performance Stock Units	Jun. 30, 2012 Performance Stock Units		Jun. 30, 2011 Performance Stock Units	Mar. 12, 2012 Performance Stock Units	Jun. 30, 2012 Phantom Stock Units		Jun. 30, 2011 Phantom Stock Units	Jun. 30, 2012 Phantom Stock Units		Jun. 30, 2011 Phantom Stock Units	Jun. 30, 2011 Cash-based long-term incentive award	Jun. 30, 2012 Employee Stock Purchase Plan	Jun. 30, 2011 Employee Stock Purchase Plan	Jun. 30, 2012 Employee Stock Purchase Plan	Jun. 30, 2011 Employee Stock Purchase Plan
Stock-based compensation
Total stock-based compensation costs	$ 7,042	[1],[2]	$ 4,888	[1],[2]	$ 12,963	[1],[2]	$ 12,647	[1],[2]		$ 0	$ 278	$ 0	$ 441	$ 4,943	$ 4,763	$ 8,719	$ 11,132	$ 3,145		$ 767	$ 4,357		$ 1,406		$ (1,046)		$ (920)	$ (113)		$ (332)	$ 200	$ 100	$ 100	$ 200	$ 300
Less: stock-based compensation costs capitalized	(1,595)	[1],[2]	(1,976)	[1],[2]	(4,192)	[1],[2]	(5,017)	[1],[2]		0	(155)	0	(226)	(1,487)	(1,937)	(3,195)	(4,528)	(477)		(251)	(867)		(430)		369		367	(130)		167
Stock-based compensation costs expensed	5,447	[1],[2]	2,912	[1],[2]	8,771	[1],[2]	7,630	[1],[2]		0	123	0	215	3,456	2,826	5,524	6,604	2,668		516	3,490		976		(677)		(553)	(243)		(165)
Unamortized stock-based compensation costs	34,799	[1],[2]			34,799	[1],[2]				0		0		23,081		23,081		7,178			7,178				4,540	[3]		4,540	[3]
Weighted average amortization period remaining (in years)					2 years	[1],[2]						0 years				2 years 1 month 4 days					2 years							1 year 7 months 6 days
Stock option activity
Options outstanding at beginning of period (in shares)					1,766,587
Granted (in shares)					0
Exercised (in shares)					0
Cancelled (in shares)					(11,906)
Options outstanding at end of period (in shares)	1,754,681				1,754,681
Stock Options, Weighted Average Exercise Price
Options outstanding, beginning of period (in dollars per share)					$ 14.55
Granted (in dollars per share)					$ 0.00
Exercised (in dollars per share)					$ 0.00
Cancelled (in dollars per share)					$ 21.86
Options outstanding, end of period (in dollars per share)	$ 14.50				$ 14.50
Stock Options, Aggregate Intrinsic Value
Aggregate intrinsic value for stock options at beginning of the period					2,731	[4]
Aggregate intrinsic value for stock options exercised					0	[4]
Aggregate intrinsic value for stock options at end of the period	0	[4]			0	[4]
Stock Options, Number of Options Exercisable
Options outstanding, exercisable number (in shares)	1,754,681				1,754,681				1,766,587
Share-based compensation plan activity
Unvested stock, beginning of period (in shares)																2,474,112					655,120	[5]						1,238,817	[6]
Awarded (in shares)																1,506,514					511,500	[5]						0	[6]
Vested (in shares)																(856,107)					(289,920)	[5]						(270,905)	[6]
Forfeited (in shares)																(264,270)					(181,680)	[5]						(58,524)	[6]
Unvested stock, end of period (in shares)														2,860,249		2,860,249		695,020	[5]		695,020	[5]			909,388	[6]		909,388	[6]
Weighted Average Grant Date Fair Value
Unvested at beginning of period (in dollars per share)																$ 24.00					$ 19.50							$ 14.32
Awarded (in dollars per share)																$ 10.20					$ 14.70							$ 0.00
Vested (in dollars per share)																$ 19.37					$ 18.16							$ 12.17
Forfeited (in dollars per share)																$ 19.66					$ 17.55							$ 15.87
Unvested at end of period (in dollars per share)														$ 18.52		$ 18.52		$ 17.04			$ 17.04				$ 14.86			$ 14.86
Vest Date Fair Value
Vested, Vest Date fair Value																$ 6,996					$ 0							$ 2,285
Number of shares of common stock to be received for each performance unit (in shares)																								1
Actual number of shares deliverable for each performance unit awarded, low end of range (as a percent)																								0.00%
Actual number of shares deliverable for each performance unit awarded, high end of range (as a percent)																								200.00%
Performance period (in months)																					36 months
Vested units settled in cash (in shares)																												264,825
Vested units settled in common stock (in shares)																												6,080

[1] In addition to the compensation costs set forth in the table above, in June 2011 and March 2012 the Company granted cash-based long-term incentive awards under which $.2 million in compensation cost was recognized during the three months ended June 30, 2012 and a negligible amount of compensation cost was recognized during the three months ended June 30, 2011 and March 31, 2012. These awards vested in June 2012 due to the involuntary termination of the holder of the awards. The awards were comprised of time-based and performance-based components, with cash payout dependent on the change in the market value of Forest’s common stock during the performance period and the total shareholder return on Forest’s common stock in comparison to that of a peer group during the performance period, respectively. As of June 30, 2012, there are no remaining cash-based long-term incentive awards of this type outstanding.

[2] The Company also maintains an employee stock purchase plan (which is not included in the table) under which $.1 million and $.2 million of compensation cost was recognized for the three and six month periods ended June 30, 2012, respectively, and $.1 million and $.3 million of compensation cost was recognized for the three and six month periods ended June 30, 2011, respectively.

[3] Based on the closing price of Forest’s common stock on June 30, 2012.

[4] The intrinsic value of a stock option is the amount by which the market value of the underlying stock, as of the date outstanding or exercised, exceeds the exercise price of the option.

[5] Forest granted 511,500 performance units on March 12, 2012, with a grant date fair value of $14.70 each. Under the terms of the award agreements, each performance unit represents a contractual right to receive one share of Forest’s common stock; provided that the actual number of shares that may be deliverable under an award will range from 0% to 200% of the number of performance units awarded, depending on Forest’s relative total shareholder return in comparison to an identified peer group during the thirty-six-month performance period ending on February 28, 2015.

[6] All of the unvested phantom stock units at June 30, 2012 must be settled in cash. The phantom stock units have been accounted for as a liability within the Condensed Consolidated Financial Statements. Of the 270,905 phantom stock units that vested during the six months ended June 30, 2012, 264,825 were settled in cash, while the remaining 6,080 were settled in shares.