Derivative, Notional Amount, Annual Decrease

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- Definition

Derivative, Number of Open Contracts

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- Definition

Long-term Debt, Percentage Bearing Fixed Interest, Fair Value Disclosure

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- Definition

Face (par) amount of debt instrument at time of issuance.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
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- Definition

Amount of hedged item in hedging relationship. Excludes hedged asset or liability.

+ References

No definition available.

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- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

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- Definition

Stated rate on an interest rate forward or futures contract.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
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-Paragraph 4A
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- Definition

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.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

The number of derivative instruments of a particular group held by the entity.

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- Definition

The estimated net amount of unrealized gains or losses on foreign currency cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

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Financial Instruments and Risk Management - Narrative (Details)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) derivative_instrument Contract	Mar. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) derivative_instrument Contract	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 22, 2024 USD ($)	Jan. 22, 2021 USD ($)	Dec. 22, 2020 USD ($)	Sep. 30, 2020 USD ($)	Apr. 01, 2019 USD ($)	Mar. 31, 2018 USD ($)	Feb. 28, 2018 USD ($)
Derivative [Line Items]
Notional value							$ 100,000,000.0
Unrecognized pre-tax loss	$ 5,600,000			$ (16,900,000)		$ 7,300,000
Portion or pre-tax gain included in AOCI expected to be included in earnings		$ (4,300,000)		(4,300,000)
Gain (Loss) Recognized in Income		0	$ 0	0	$ (2,200,000)
Interest Rate Contracts
Derivative [Line Items]
Notional value		$ 550,000,000.0		$ 550,000,000.0				$ 700,000,000.0	$ 550,000,000.0		$ 50,000,000.0		$ 400,000,000.0
Notional value decrease each year								$ 100,000,000.0
Forward interest rate													2.47%
Interest Rate Contracts \| LIBOR
Derivative [Line Items]
Fixed interest rate		0.95%		0.95%					0.95%
Line of Credit \| Senior Secured Term Loan B Facility, net of discount, due 2022
Derivative [Line Items]
Face amount of debt		$ 1,287,000,000.0		$ 1,287,000,000.0
Estimate of Fair Value
Derivative [Line Items]
Fair market value of fixed rate long-term debt		2,206,000,000.0		2,206,000,000.0						$ 2,858,300,000
Reported Value Measurement
Derivative [Line Items]
Fair market value of fixed rate long-term debt		2,162,500,000		2,162,500,000						2,761,900,000
Senior Secured Term Loan B Facility, Due 2022 \| Senior Secured Term Loan B Facility, net of discount, due 2022 \| Interest Rate Contracts
Derivative [Line Items]
Variable rate debt hedged												$ 200,000,000.0
Fixed interest rate												2.03%
Designated as Hedging Instrument \| Cash Flow Hedging
Derivative [Line Items]
Derivatives - Foreign Currency contracts		21,200,000		21,200,000						(7,800,000)
Designated as Hedging Instrument \| Cash Flow Hedging \| Zinc contracts
Derivative [Line Items]
Derivatives - Foreign Currency contracts		$ 8,500,000		$ 8,500,000						4,400,000
Derivative, Number of Open Contracts \| Contract		12		12
Notional value		$ 27,000,000		$ 27,000,000
Designated as Hedging Instrument \| Cash Flow Hedging \| Foreign currency contracts
Derivative [Line Items]
Derivatives - Foreign Currency contracts		(4,200,000)		(4,200,000)						(4,900,000)
Designated as Hedging Instrument \| Cash Flow Hedging \| Foreign Exchange Forward
Derivative [Line Items]
Notional value		$ 173,000,000		$ 173,000,000
Number of open contracts \| derivative_instrument		64		64
Not Designated as Hedging Instrument \| Foreign currency contracts
Derivative [Line Items]
Derivatives - Foreign Currency contracts		$ 300,000		$ 300,000						$ (200,000)
Gain (Loss) Recognized in Income		300,000	$ (700,000)	(600,000)	$ (1,600,000)
Not Designated as Hedging Instrument \| Foreign Exchange Forward
Derivative [Line Items]
Notional value		$ 57,000,000		$ 57,000,000
Number of open contracts \| derivative_instrument		6		6