Financial Instruments (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended					9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Feb. 29, 2012 Southern Yellow Pine [Member] Commodity Swap Contract [Member] mbf	Sep. 30, 2011 Southern Yellow Pine [Member] Commodity Swap Contract [Member] mbf	Oct. 18, 2010 Southern Yellow Pine [Member] Commodity Swap Contract [Member] mbf	Sep. 30, 2012 Maximum [Member] Interest Rate Swap [Member]	Sep. 30, 2012 Minimum [Member] Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative, Maturity Date								Feb. 01, 2018	Dec. 01, 2015
Number of interest rate swap agreements	6		6
Notional amounts	$ 46,750,000		$ 46,750,000
Debentures	22,500,000		22,500,000
Medium-term notes	24,250,000		24,250,000
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	6.518%		6.518%
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments	0	0	0
Derivative liability					22,500	31,200	14,300
Gain (Loss) on Interest Rate Fair Value Hedge Ineffectiveness	$ 0	$ 0	$ 0	$ 0