Commitments and Contingencies - Range of Environmental Liability and Number of Active Sites for Environmental Matters (Detail) - Environmental Related Matters [Member] $ in Millions	Dec. 31, 2015 USD ($) site	Dec. 31, 2014 USD ($) site
Environmental Matters Range Of Estimated Liability And Active Sites Numbers [Line Items]
High end range | $	$ 140.6	$ 160.3
Number of active environmental investigation and remediation sites | site	49	54