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Debt - Narrative (Details) |  |  |  |  | 1 Months Ended | 3 Months Ended | 9 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Aug. 05, 2025 USD ($) | Jul. 22, 2025 | Oct. 01, 2024 USD ($) | Nov. 02, 2021 USD ($) | Jul. 31, 2025 USD ($) | Apr. 30, 2021 USD ($) $ / shares | Sep. 30, 2025 USD ($) | Sep. 30, 2024 USD ($) | Sep. 30, 2025 USD ($) | Sep. 30, 2024 USD ($) | Dec. 09, 2022 USD ($) | Sep. 28, 2022 USD ($) | Jun. 14, 2022 USD ($) | Feb. 04, 2022 USD ($) | Nov. 30, 2013 USD ($)
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from issuance of Senior Notes due 2032 |  |  |  |  |  |  |  |  | $ 400,000,000.0 | $ 0 |  |  |  |  |
Loss on early extinguishment of debt |  |  |  |  |  |  | $ 6,200,000 | $ 0 | $ 6,200,000 | $ 0 |  |  |  |  |
Senior Secured Notes, 6.875% | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  |  |  | 6.875% |  | 6.875% |  | 6.875% |  |  |  |  |  |
Face amount |  |  |  |  | $ 400,000,000 |  |  |  |  |  |  |  |  |  |
Proceeds from issuance of Senior Notes due 2032 |  |  |  |  | $ 393,700,000 |  |  |  |  |  |  |  |  |  |
Senior Secured Notes, 6.875% | Senior notes | Level 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of debt instrument |  |  |  |  |  |  | $ 415,600,000 |  | $ 415,600,000 |  |  |  |  |  |
Senior secured notes, 7.5% | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  |  |  |  |  | 7.50% |  | 7.50% |  |  |  |  |  |
Redemption of debt | $ 261,100,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Redemption price, percentage | 101.875% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss on early extinguishment of debt | $ 6,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Early redemption premium | 4,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Write-off of deferred financing costs | $ 1,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior convertible notes, 2.75% | Senior notes |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  |  |  |  | 2.75% | 2.75% |  | 2.75% |  |  |  |  |  |
Face amount |  |  |  |  |  | $ 86,300,000 |  |  |  |  |  |  |  |  |
Percentage of principal amount redeemed |  |  |  |  |  | 100.00% |  |  |  |  |  |  |  |  |
Payment of deferred financing fees |  |  |  |  |  | $ 83,700,000 |  |  |  |  |  |  |  |  |
Conversion ratio |  |  |  |  |  | 0.0533547 |  |  |  |  |  |  |  |  |
Conversion price (in dollars per share) | $ / shares |  |  |  |  |  | $ 18.74 |  |  |  |  |  |  |  |  |
Value exceeding principal amount |  |  |  |  |  |  |  |  | $ 48,900,000 |  |  |  |  |  |
Senior convertible notes, 2.75% | Senior notes | Level 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of debt instrument |  |  |  |  |  |  | $ 140,700,000 |  | $ 140,700,000 |  |  |  |  |  |
U.S. revolving credit facility | U.S. revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  |  |  |  |  | 7.75% |  | 7.75% |  |  |  |  |  |
Credit facility maximum amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 250,000,000.0 |  |
Credit spread adjustment |  | 0.10% |  |  |  |  |  |  |  |  |  |  |  |  |
Outstanding borrowings |  |  |  |  |  |  | $ 0 |  | $ 0 |  |  |  |  |  |
Outstanding letters of credit issued |  |  |  |  |  |  | 49,500,000 |  | 49,500,000 |  |  |  |  |  |
Credit facility maximum amount |  |  |  |  |  |  | $ 250,000,000.0 |  | $ 250,000,000.0 |  |  |  |  |  |
U.S. revolving credit facility | Letter of credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Letter of credit sub-facility amount |  |  |  |  |  |  |  |  |  |  |  |  | $ 150,000,000.0 |  |
U.S. revolving credit facility | Foreign line of credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  |  |  |  |  | 7.66% |  | 7.66% |  |  |  |  |  |
Credit facility maximum amount |  |  |  |  |  |  | $ 100,000,000.0 |  | $ 100,000,000.0 |  |  | $ 100,000,000.0 |  |  | $ 50,000,000
Outstanding borrowings |  |  |  |  |  |  | 16,500,000 |  | 16,500,000 |  |  |  |  |  |
Outstanding letters of credit issued |  |  |  |  |  |  | 0 |  | 0 |  |  |  |  |  |
Credit facility maximum amount |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 80,000,000 |
Casthouse Facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Credit facility maximum amount |  |  |  | $ 130,000,000 |  |  |  |  |  |  |  |  |  |  |
Debt instrument, term |  |  |  | 8 years |  |  |  |  |  |  |  |  |  |  |
Debt instrument, quarterly installment fee |  |  |  | 1.739% |  |  |  |  |  |  |  |  |  |  |
Debt instrument, remaining payment after drawdown of funds |  |  |  | 60.00% |  |  |  |  |  |  |  |  |  |  |
Medium-term notes, outstanding borrowings |  |  |  |  |  |  | $ 115,000,000 |  | $ 115,000,000 |  |  |  |  |  |
Casthouse Facility | Foreign line of credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  |  |  |  |  | 7.89% |  | 7.89% |  |  |  |  |  |
Vlissingen Credit Facility | Foreign line of credit |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stated interest rate, percentage |  |  | 8.75% |  |  |  | 7.83% |  | 7.83% |  |  |  |  |  |
Face amount |  |  |  |  |  |  |  |  |  |  | $ 90,000,000 |  |  |  |
Credit facility maximum amount |  |  | $ 90,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Term extension |  |  | 2 years |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, basis spread on variable rate |  |  | 3.687% |  |  |  |  |  |  |  |  |  |  |  |
Vlissingen Credit Facility | Foreign line of credit | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Variable interest rate |  |  | 9.00% |  |  |  |  |  |  |  |  |  |  |  |
Vlissingen Credit Facility | Foreign line of credit | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Variable interest rate |  |  | 7.00% |  |  |  |  |  |  |  |  |  |  |  |
Industrial revenue bonds, variable |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum variable interest rate |  |  |  |  |  |  | 12.00% |  | 12.00% |  |  |  |  |  |
Surety Bond |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency accrual |  |  |  |  |  |  | $ 6,600,000 |  | $ 6,600,000 |  |  |  |  |  |

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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
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- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(f)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481544/470-10-50-6 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481544/470-10-50-6 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)(b)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
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