Restructuring Costs - Additional Information (Detail) - Chemicals - Employee Severance $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended
	Jun. 30, 2015 USD ($)	Sep. 30, 2015 Employee	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Restructuring Cost And Reserve [Line Items]
Workforce reduction, number of individuals | Employee		160
Restructuring charges	$ 21.1		$ 21.5
Accrued severance costs, expected date to be paid			Jun. 30, 2018
Scenario Forecast
Restructuring Cost And Reserve [Line Items]
Future workforce reduction costs to be incurred				$ 0.1
Cost of sales
Restructuring Cost And Reserve [Line Items]
Restructuring charges			$ 10.7
Selling, general and administrative Expense
Restructuring Cost And Reserve [Line Items]
Restructuring charges			$ 10.8