Guarantees and Contingencies - Additional Information (Detail) - USD ($)			1 Months Ended		3 Months Ended	6 Months Ended
	Jan. 18, 2017	Mar. 04, 2016	Apr. 30, 2014	Mar. 31, 2014	Mar. 31, 2017	Jun. 30, 2017
Lower Passaic River
Loss Contingencies [Line Items]
Estimated remediation cost		$ 1,380,000,000	$ 1,700,000,000
Gowanus Canal Superfund Site
Loss Contingencies [Line Items]
Estimated remediation cost				$ 506,000,000
Facilities in North Dakota​
Loss Contingencies [Line Items]
Penalty assessed under consent decree	$ 922,000
Initial penalty payment under consent decree					$ 55,000
Consent decree expected reduction in reminder penalty						$ 745,000