Discontinued Operations - Depreciation, Amortization and Capital Expenditures Associated with Discontinued Operations (Detail) - Aromatics [Member] - Discontinued Operations Disposed of by Sale [Member] - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
|
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | |||
| Depreciation and amortization | $ 1.9 | $ 2.0 | $ 1.2 |
| Capital expenditures | $ 1.0 | $ 8.0 | $ 7.1 |