Financial Instruments and Concentration of Risk (Narrative) (Details) (USD $)
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12 Months Ended | ||||||||||
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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Dec. 31, 2011
Commodity Swap Contract [Member]
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Dec. 31, 2010
Commodity Swap Contract [Member]
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Dec. 31, 2011
Other non-current assets [Member]
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Dec. 31, 2010
Other non-current assets [Member]
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Dec. 31, 2010
Other long-term obligations [Member]
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Oct. 13, 2010
Eastern Spruce/Pine [Member]
Commodity Swap Contract [Member]
mbf
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Sep. 30, 2011
Southern Yellow Pine [Member]
Commodity Swap Contract [Member]
mbf
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Oct. 18, 2010
Southern Yellow Pine [Member]
Commodity Swap Contract [Member]
mbf
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Derivatives, Fair Value [Line Items] | |||||||||||
Number of interest rate swap agreements | 8 | ||||||||||
Notional amounts | $ 63,250,000 | ||||||||||
Debentures | 22,500,000 | ||||||||||
Medium-term notes | 40,750,000 | ||||||||||
Swaps fixed interest rate, minimum | 6.95% | ||||||||||
Swaps fixed interest rate, maximum | 8.89% | ||||||||||
LIBOR variable interest rate, minimum | 4.738% | ||||||||||
LIBOR variable interest rate, maximum | 7.805% | ||||||||||
Fair Value of Derivative Assets | 2,409,000 | 62,000 | 2,400,000 | 100,000 | |||||||
Increase in carrying amount of debt | 2,400,000 | 200,000 | |||||||||
Fair Value of Derivative Liabilities | 0 | 2,876,000 | 300,000 | ||||||||
Unrealized Gain (Loss) Recorded in Interest Expense Due to Changes in Fair Value of the Derivative | 2,600,000 | (200,000) | |||||||||
Unrealized Gain (Loss) Recorded in Interest Expense Due to the Associated Change in the Carrying Amount of Hedged Debt | 2,600,000 | 200,000 | |||||||||
Net gain recognized resulting in reduction in interest expense | 1,000,000 | 500,000 | |||||||||
Derivative liability | 33,000 | 31,200 | 14,300 | ||||||||
Realized gain on settlement of commodity swap contract | 1,200,000 | ||||||||||
Unrealized gains | 3,300,000 | ||||||||||
Unrealized loss | $ 2,900,000 | ||||||||||
Customers accounting for 10% or more of revenues | 0 | 0 | 1 |