Guarantees and Contingencies - Additional Information (Detail) $ in Millions			1 Months Ended
	Sep. 28, 2017 USD ($)	Mar. 04, 2016 USD ($)	Mar. 31, 2014 USD ($)	Jun. 30, 2018 Case
Loss Contingencies [Line Items]
Total number of remaining active cases filed | Case				4
Lower Passaic River
Loss Contingencies [Line Items]
Estimated remediation cost		$ 1,380.0
Gowanus Canal Superfund Site
Loss Contingencies [Line Items]
Estimated remediation cost			$ 506.0
Ector Drum, Inc. Superfund Site
Loss Contingencies [Line Items]
Estimated remediation cost	$ 3.5