FAIR VALUE MEASUREMENTS (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013		Nov. 30, 2013
7 1/4% Senior Notes due 2019
Fair value and carrying value of financial instruments
Senior notes, carrying amount	$ 578,076		$ 578,092
Senior notes, fair value	572,499	[1]	568,147	[1]
Interest rate (as a percent)	7.25%		7.25%		7.25%
7 1/2% Senior Notes due 2020
Fair value and carrying value of financial instruments
Senior notes, carrying amount	222,087		222,087
Senior notes, fair value	221,116	[1]	224,030	[1]
Interest rate (as a percent)	7.50%		7.50%		7.50%
Carrying Amount
Fair value and carrying value of financial instruments
Derivative Asset	758		5,592
Derivative Liability	15,443		4,542
Fair Value
Fair value and carrying value of financial instruments
Derivative Asset	758	[1]	5,592	[1]
Derivative Liability	15,443	[1]	4,542	[1]
Using Quoted Prices in Active Markets for Identical Assets (Level 1) | 7 1/4% Senior Notes due 2019
Fair value and carrying value of financial instruments
Senior notes, fair value	572,499		568,147
Using Quoted Prices in Active Markets for Identical Assets (Level 1) | 7 1/2% Senior Notes due 2020
Fair value and carrying value of financial instruments
Senior notes, fair value	221,116		224,030
Using Significant Other Observable Inputs (Level 2) | Fair Value
Fair value and carrying value of financial instruments
Derivative Asset	758		5,592
Derivative Liability	$ 15,443		$ 4,542

[1] Forest used various assumptions and methods in estimating the fair values of its financial instruments. The fair values of the senior notes were estimated based on quoted market prices. The methods used to determine the fair values of the derivative instruments are discussed above. See also Note 8 for more information on the derivative instruments.