Discontinued Operations - Major Class of Assets and Liabilities Related to Discontinued Operations (Detail) - Aromatics [Member] - Discontinued Operations Disposed of by Sale [Member] - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Receivables, net		$ 17.6
Inventories	$ 0.6	18.5
Prepaid expenses and other		0.8
Property, plant and equipment, net		61.1
Other assets, net		0.9
Total assets	0.6	98.9
Accounts payable		3.2
Accrued compensation		2.0
Other accrued liabilities	5.5	10.3
Lease financing obligation		35.6
Total liabilities	5.5	51.1
Net assets (liabilities)	$ (4.9)	$ 47.8