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Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Mar. 31, 2025 | Mar. 31, 2024 | Sep. 30, 2024 | Sep. 30, 2023
Income Taxes [Line Items] |  |  |  |  |  |
Interest expense carryovers |  |  |  |  | $ 9,258 | $ 6,457
Operating loss carryforwards, valuation allowance |  |  |  |  | 41,600 | 21,100
Unrecognized tax benefits if unrecognized, the balance of uncertain tax benefits would impact the effective tax rate |  |  |  |  | 4,900 | $ 4,900
Effective tax rate (ETR) from continuing operations | 6.20% | 0.60% | 3.10% | (2.10%) |  |
State net operating loss carryforwards | $ 500 |  | $ 500 |  |  |
Domestic Tax Authority [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Net operating loss carryforwards not subject to expiration |  |  |  |  | $ 194,200 |
Effective income tax rate reconciliation, at federal statutory income tax rate, percent |  |  |  |  | 80.00% |
Interest expense carryovers |  |  |  |  | $ 41,700 |
Domestic Tax Authority [Member] | 2030-2038 [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Net operating loss carryforwards | 276,200 |  | 276,200 |  | 511,700 |
State and Local Jurisdiction [Member] | 2024-2043 [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Net operating loss carryforwards | $ 146,600 |  | $ 146,600 |  | $ 226,900 |
Minimum [Member] | Domestic Tax Authority [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Operating loss carryforwards, expiration year |  |  | 2030 |  | 2027 |
Minimum [Member] | State and Local Jurisdiction [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Operating loss carryforwards, expiration year |  |  | 2024 |  | 2024 |
Maximum [Member] | Domestic Tax Authority [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Operating loss carryforwards, expiration year |  |  | -2038 |  | 2038 |
Maximum [Member] | State and Local Jurisdiction [Member] |  |  |  |  |  |
Income Taxes [Line Items] |  |  |  |  |  |
Operating loss carryforwards, expiration year |  |  | -2043 |  | 2044 |

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- Definition Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible interest carryforward. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-6 + Details
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-6 + Details
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- Definition Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-12 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 231 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482663/740-10-55-231 + Details
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- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 12 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-12 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 55 -Paragraph 231 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482663/740-10-55-231 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 6.I.1.Q1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479360/740-10-S99-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1 + Details
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- Definition The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-2 + Details
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