Commitments and Contingencies - Narrative (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Facility	Dec. 31, 2013	Dec. 31, 2012
Commitments And Contingencies Disclosure [Abstract]
Authorized expenditures on incomplete projects for purchase of property, plant and equipment	$ 84.2
Committed total of property, plant and equipment expenditure	36.5
Severance payments related to restructuring	13.0
Commitments for outsourced services	90.7
Commitment to purchase natural gas	15.0
Operating lease commitments	448.9
Minimum non-cancelable sublease rental commitments	38.0
Rent expense	$ 173.2	$ 149.4	$ 143.7
Number of sites cited as potentially responsible party	12
Number of previously and currently owned sites with potential remediation obligations	10