Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2011	May 31, 2007 Entity mi	Mar. 31, 2013	Dec. 31, 2009 Entity	Jul. 18, 2012 Entity	May 25, 2012 Director
Commitments and Contingencies [Line Items]
Period of letters of credit			1 year
Letter of credit outstanding			$ 56,932,000
Amount of bank credit facility	600,000,000		500,000,000
Line of credit, expiration date	Dec. 15, 2016		Mar. 12, 2018
Number of Former Directors in Ireland's Lawsuit						2
Number of other parties sued in the Lower Passaic River Clean-Up				300
Number of other third party defendants that have reached tentative settlement with original plaintiffs				200
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			$ 3,500,000,000
Number of Other Companies Entered in to Administrative Settlement Agreement and Order					69