LONE PINE RESOURCES INC. INITIAL PUBLIC OFFERING (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended				1 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	May 31, 2011	Jun. 30, 2011 Lone Pine Resources Inc	Jun. 30, 2011 Lone Pine Resources Inc Initial Public Offering	Dec. 31, 2010 Lone Pine Resources Inc Initial Public Offering	Jun. 30, 2011 Lone Pine Resources Inc Initial Public Offering	Jun. 30, 2011 Lone Pine Resources Inc Initial Public Offering	Jun. 01, 2011 Lone Pine Resources Inc Initial Public Offering
Subsidiary Sale of Stock
Percentage of common stock sold (as a percent)								19.90%
Number of shares of common stock sold (in shares)							15
Common stock sold, price per share (in dollars per share)											$ 13.00
Common stock sold, price per share, net of underwriting discounts and commissions (in dollars per share)											$ 12.22
Percentage of ownership interest upon completion of offering (as a percent)							82.00%
Net proceeds from the offering after deducting underwriting discounts and commissions and offering expenses							$ 178,500,000
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
Dividend Tax Payable, Foreign					28,900,000
Effects of changes in Forest's ownership interest in Lone Pine on Forest's equity
Net earnings attributable to Forest Oil Corporation	38,910,000	33,254,000	35,580,000	142,416,000					38,910,000	35,580,000
Transfers from the noncontrolling interest:
Increase in Forest Oil Corporation's capital surplus for sale of 15,000,000 Lone Pine Resources Inc. common shares									112,879,000	112,879,000
Change from net earnings attributable to Forest Oil Corporation and transfers from noncontrolling interest									$ 151,789,000	$ 148,459,000