Commitments and Contingencies (Details) (USD $)	1 Months Ended			6 Months Ended
	Feb. 28, 2011	Oct. 13, 2010	May 31, 2007	Jun. 30, 2011	Feb. 17, 2011	May 18, 2010
Commitments and Contingencies (Textuals)
Number of cases in mass tort action		over 100
Number of counties that cases were filed in the mass tort action		17
Claims against damages, IDOT/Joliet Road lawsuit						$ 40,000,000
Payment to Illinois Department of Transportation (IDOT)					20,000,000	20,000,000
Complaints in Florida Antitrust Litigation				2
Self-insured retention amount					2,000,000
Number of arbitrations				2
Settlement awarded	$ 25,546,000
Number of other parties sued in the Lower Passaic River Clean-Up				300
Number of other companies to perform a Remedial Investigation/Feasibility Study related to the Lower Passaic River Clean-Up lawsuit			70