Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2007 Companies mi	Sep. 30, 2011	Mar. 31, 2011	Sep. 30, 2012 Complaints	Sep. 30, 2011	Dec. 31, 2009 Entity	Jun. 18, 2012 Company	May 25, 2012 Directors	May 18, 2010
Commitments and Contingencies [Line Items]
Claims against damages, IDOT/Joliet Road lawsuit									$ 40,000,000
Settlement awarded		24,111,000	25,546,000
Attorney's fees and interest					3,254,000
Number of putative class-action complaints				2
Number of complaints filed				2
Number of former directors in Ireland lawsuit								2
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
Number of miles of the River used in the Remedial Investigation/Feasibility Study	17
Range of estimated cost, minimum				900,000,000
Range of estimated cost, maximum				$ 2,300,000,000
Number of other companies entered into agreement related to the Lower Passaic River Clean-Up							69