Segment Information - Reportable Segment Data (Details) $ in Millions	3 Months Ended
Mar. 31, 2019 USD ($) segment	Mar. 31, 2018 USD ($)
Operating segment information
Number of reportable segments \| segment	2
Net Sales
Revenues	$ 469.5	$ 431.5
Adjusted EBIT
Total	104.4	95.8
Reconciliation of operating segment data to financial statements
Costs related to legacy matters	46.9	2.0
Restructuring and repositioning expenses	(2.3)	(5.6)
Third-party acquisition-related costs	(0.3)	(0.9)
Interest expense, net	(19.3)	(18.9)
Net income (loss) attributable to noncontrolling interests	(0.1)	(0.2)
Income (loss) before income taxes	$ 35.5	68.2
Catalysts Technologies
Operating segment information
Number of reportable segments \| segment	1
Number of operating segments \| segment	2
Net Sales
Revenues	$ 349.7	315.8
Materials Technologies
Net Sales
Revenues	119.8	115.7
Corporate
Adjusted EBIT
Operating income	(16.2)	(16.6)
Certain pension costs	(4.8)	(3.8)
Operating Segments \| Catalysts Technologies
Net Sales
Revenues	349.7	315.8
Adjusted EBIT
Operating income	101.4	92.1
Operating Segments \| Materials Technologies
Net Sales
Revenues	119.8	115.7
Adjusted EBIT
Operating income	$ 24.0	$ 24.1

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Certain Pension Costs

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Costs related to legacy matters

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Net Income (Loss) Attributable to Noncontrolling Interest, Reconciliation of Operating Segment Data

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Sum of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses related to spin off.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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Amount of interest revenue (income derived from investments in debt securities and on cash and cash equivalents) net of interest expense (cost of borrowed funds accounted for as interest).

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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The net result for the period of deducting operating expenses from operating revenues.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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