DEBT (Components of Debt) (Details) (USD $)	3 Months Ended		9 Months Ended									1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Credit Facility	Dec. 31, 2012 Credit Facility	Sep. 30, 2013 7% Senior Subordinated Notes due 2013		Dec. 31, 2012 7% Senior Subordinated Notes due 2013		Mar. 31, 2013 8 1/2% Senior Notes due 2014	Sep. 30, 2013 8 1/2% Senior Notes due 2014		Dec. 31, 2012 8 1/2% Senior Notes due 2014		Sep. 30, 2013 7 1/4% Senior Notes due 2019	Dec. 31, 2012 7 1/4% Senior Notes due 2019	Sep. 30, 2013 7 1/2% Senior Notes due 2020	Dec. 31, 2012 7 1/2% Senior Notes due 2020
Debt
Interest rate (as a percent)								7.00%		7.00%		8.50%			8.50%		7.25%	7.25%	7.50%	7.50%
Credit Facility	$ 115,000,000		$ 115,000,000		$ 65,000,000	$ 115,000,000	$ 65,000,000
Debt, Principal	1,615,000,000		1,615,000,000		1,865,012,000			0	[1]	12,000	[1]		0	[2]	300,000,000	[2]	1,000,000,000	1,000,000,000	500,000,000	500,000,000
Debt, Unamortized Premium (Discount)	322,000		322,000		(2,912,000)	0	0	0	[1]	0	[1]		0	[2]	(3,277,000)	[2]	322,000	365,000	0	0
Total debt	1,615,322,000		1,615,322,000		1,862,100,000			0	[1]	12,000	[1]		0	[2]	296,723,000	[2]	1,000,322,000	1,000,365,000	500,000,000	500,000,000
Less: current portion of debt, principal	0		0		(12,000)
Less: current portion of debt, unamortized premium (discount)	0		0		0
Current portion of debt	0		0		(12,000)
Long-term portion of debt, principal	1,615,000,000		1,615,000,000		1,865,000,000
Long-term portion of debt, unamortized premium (discount)	322,000		322,000		(2,912,000)
Long-term portion of debt	1,615,322,000		1,615,322,000		1,862,088,000
Redemption Price As Percentage Of Par (as a percent)												107.11%
Gain (Loss) On Redemption Of Senior Notes	$ 0	$ 0	$ (25,223,000)	$ 0								$ (25,223,000)

[1] In June 2013, Forest redeemed the 7% senior subordinated notes due 2013 at their maturity.

[2] In March 2013, Forest redeemed the 8½% senior notes due 2014 at 107.11% of par, recognizing a loss of $25.2 million upon redemption.