SHAREHOLDERS' EQUITY (Lone Pine Initial Public Offering and Spin-off) (Details) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2012	Sep. 30, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 01, 2011
Initial Public Offering and Spin-off - Lone Pine Resources Inc.
Percentage of subsidiary common stock sold in initial public offering (as a percent)						18.00%
Dividend tax payable to Canadian federal tax authorities	$ 28,900,000
Partial consideration for Forest's contribution of Forest's direct and indirect interest in its Canadian operations	29,200,000
Outstanding indebtedness owed to Forest	400,500,000
Percentage of subsidiary stock distributed to shareholders in spin-off (as a percent)		82.00%
Common stock conversion ratio		0.61248511
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net
Net earnings attributable to Forest Oil Corporation common shareholders		118,375,000	73,924,000	(1,288,931,000)	137,842,000
Transfers from (to) the noncontrolling interest:
Increase in Forest Oil Corporation's capital surplus for sale of 15 million Lone Pine Resources Inc. common shares	178,175,000	112,610,000			178,175,000
Decrease in Forest Oil Corporation’s capital surplus for spin-off of 70 million Lone Pine Resources Inc. common shares		(333,568,000)			(469,935,000)
Change from net earnings attributable to Forest Oil Corporation common shareholders and transfers from (to) noncontrolling interest		$ (102,583,000)
Number of shares of common stock sold in IPO resulting in a change in capital surplus of parent (in shares)		15,000,000
Common shares spun off resulting in a change in capital surplus of parent (in shares)		70,000,000