Restructuring Costs - Additional Information (Detail) - Chemicals - Employee Severance	3 Months Ended			9 Months Ended	12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Employee	Dec. 31, 2015 USD ($)
Restructuring Cost And Reserve [Line Items]
Workforce reduction, number of individuals | Employee				160
Restructuring charges	$ 200,000	$ 400,000	$ 21,100,000		$ 21,700,000
Workforce reduction costs to be incurred	$ 0			$ 0	$ 0
Accrued severance costs, expected date to be paid					Sep. 30, 2018
Cost of sales
Restructuring Cost And Reserve [Line Items]
Restructuring charges					$ 10,800,000
Selling, general and administrative Expense
Restructuring Cost And Reserve [Line Items]
Restructuring charges					$ 10,900,000