Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended		1 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2011 Eastern Spruce/Pine [Member] Commodity Swap Contract [Member]	Jun. 30, 2011 Eastern Spruce/Pine [Member] Commodity Swap Contract [Member]	Oct. 30, 2010 Eastern Spruce/Pine [Member] Commodity Swap Contract [Member]	Feb. 28, 2011 Southern Yellow Pine [Member] Commodity Swap Contract [Member]	Jun. 30, 2011 Other Non-Current Assets [Member]	Jun. 30, 2011 Interest Rate Swap [Member] Maximum [Member]	Jun. 30, 2011 Interest Rate Swap [Member] Minimum [Member]	Jun. 30, 2011 Commodity Swap Contract [Member]	Jun. 30, 2011 Commodity Swap Contract [Member]
Number of interest rate swap agreements	8	8
Notional amounts	$ 63,250,000	$ 63,250,000
Debentures	22,500,000	22,500,000
Medium-term notes	40,750,000	40,750,000
Swaps fixed interest rate, minimum	6.95%	6.95%
Swaps fixed interest rate, maximum	8.89%	8.89%
LIBOR variable interest rate, minimum	4.738%	4.738%
LIBOR variable interest rate, maximum	7.805%	7.805%
Termination date				Sep. 30, 2011				Feb. 01, 2018	Jan. 01, 2012
Derivative asset							500,000
Increase in carrying amount of debt	500,000	500,000
Net gain recognized in income	1,200,000	700,000
Decrease in carrying amount of debt	1,200,000	700,000
Unrealized gain or loss recognized in income	0	0
Net gain recognized resulting in reduction in interest expense	300,000	500,000
Hedge ineffectiveness recognized	0	0
Commodity swap contract (in mbf)					33,000
Effective date				April 1, 2011
Commodity contracts cash settlements each month (in mbf)			5,500
Cash settlements			300,000
Realized gain on settlement of commodity swap contract	300,000	300,000
Remaining commodity swap contract cash settled (in mbf)						7,150
Cash payment						200,000
Unrealized gains										$ 2,100,000	$ 2,800,000