Expected production commencement year.

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Pre-tax loss on sale of business.

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No definition available.

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

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No definition available.

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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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No definition available.

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination.

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Amount of liability recognized arising from contingent consideration in a business combination.

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The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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This element represents the cash inflow during the period from the sale of a component of the entity.

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Acquisitions and Divestitures - Additional Information (Detail) - USD ($)	1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2020	Jun. 30, 2019	Sep. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019
Business Acquisition [Line Items]
Specialty Fluids loss on sale and asset impairment				$ 1,000,000	$ 20,000,000	$ 1,000,000	$ 20,000,000
Specialty Fluids [Member] \| Sinomine (Hong Kong) Rare Metals Resources Co. Limited [Member]
Business Acquisition [Line Items]
Total proceeds from sale of Specialty Fluids business		$ 133,000,000
Pre-tax loss on sale of Specialty Fluids business				1,000,000				$ 9,000,000
Specialty Fluids loss on sale and asset impairment					20,000,000
NSCC Carbon (Jiangsu) Co. Ltd [Member]
Business Acquisition [Line Items]
Acquisition date			Sep. 30, 2018
Business acquisition, purchase price			$ 8,000,000
Expected production commencement year			2021
Transition related costs					$ 1,000,000	1,000,000	$ 3,000,000
NSCC Carbon (Jiangsu) Co. Ltd [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Transition related costs				1,000,000
Shenzhen Sanshun Nano New Materials Co., Ltd [Member]
Business Acquisition [Line Items]
Transition related costs						1,000,000
Shenzhen Sanshun Nano New Materials Co., Ltd [Member] \| Prepaid Expenses and Other Current Assets [Member]
Business Acquisition [Line Items]
Escrow deposit				$ 35,000,000		$ 35,000,000
Shenzhen Sanshun Nano New Materials Co., Ltd [Member] \| Subsequent Event [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price	$ 105,000,000
Business acquisition, cash consideration	90,000,000
Business acquisition, debt assumed	15,000,000
Business combination future contingent consideration milestone payment	$ 5,000,000