Summary of Principal Accounting Policies Summary of Principal Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2012 acre
Timber And Timberlands Acres Owned	1,420,000
Buildings and Structures Useful Life Minimum	30 years 0 months 0 days
Buildings and Structures Useful Life Maximum	40 years 0 months 0 days
Equipment Useful Life Minimum	2 years 0 months 0 days
Equipment Useful Life Maximum	25 years 0 months 0 days
Historic Average Annual Growth Rate for Merchantable Inventory Range, Minimum	2.00%
Historic Average Annual Growth Rate for Mechantable Inventory Range, Maximum	5.00%
Bridges, Culverts and Gravel Surfacing Useful Life Minimum	10 years 0 months 0 days
Bridges, Culverts and Gravel Surfacing Useful Life Maximum	20 years 0 months 0 days
1995 Stock Incentive Plan [Member]
Number Of Shares Originally Authorized (shares)	1,700,000
Number of Shares Authorized (shares)	0
2000 Stock Incentive Plan [Member]
Number Of Shares Originally Authorized (shares)	1,400,000
Number of Shares Authorized (shares)	0
2005 Stock Incentive Plan [Member]
Number Of Shares Originally Authorized (shares)	1,600,000
Number of Shares Authorized (shares)	335,000