STOCKHOLDERS' DEFICIT - RSU, PSU activity (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025
Weighted Average Grant Date Fair Value
Taxes paid for restricted unit withholdings	$ 3.7	$ 4.4
RSU and PSU
Weighted Average Grant Date Fair Value
Taxes paid for restricted unit withholdings	$ 3.7
Restricted stock unit
Shares of RSU and PSU
Balance at the beginning of the period (in shares)	4,573,078
Granted (in shares)	8,993,593
Vested (in shares)	(942,900)
Cancelled (in shares)	(882,087)
Nonvested at the end of the period (in shares)	11,741,684
Weighted Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)	$ 4.73
Granted (in dollars per share)	2.91
Vested (in dollars per share)	5.82
Cancelled (in dollars per share)	5.95
Nonvested at the end of the period (in dollars per share)	$ 3.16
Total nonvested at September 30, 2026	11,741,684
Performance stock unit
Shares of RSU and PSU
Balance at the beginning of the period (in shares)	324,969
Granted (in shares)	10,512,864
Vested (in shares)	(119,307)
Cancelled (in shares)	(97,339)
Nonvested at the end of the period (in shares)	10,621,187
Weighted Average Grant Date Fair Value
Balance at the beginning of the period (in dollars per share)	$ 3.57
Granted (in dollars per share)	2.34
Vested (in dollars per share)	3.57
Cancelled (in dollars per share)	3.57
Nonvested at the end of the period (in dollars per share)	$ 2.35
Tranche Years 2027 and 2028 awarded under the 2026 PSU award and Tranche Year 2027 awarded under the 2025 PSU awards with grant date fair values to be determined in years 2027 and 2028, respectively	8,443,634
Total nonvested at September 30, 2026	19,064,821
Performance stock unit \| Special Award
Shares of RSU and PSU
Granted (in shares)	3,778,642
Vested (in shares)	(2,005,981)
Cancelled (in shares)	(1,772,661)
Weighted Average Grant Date Fair Value
Granted (in dollars per share)	$ 1.22
Vested (in dollars per share)	1.22
Cancelled (in dollars per share)	$ 1.22
2025 Performance share award \| Tranche Year 2027
Weighted Average Grant Date Fair Value
PSUs vesting as a percentage of performance target	100.00%
2026 Performance share award \| Cumulative Adjusted EBITDA Target
Weighted Average Grant Date Fair Value
Percentage of performance target	200.00%
2026 Performance share award \| Cumulative Adjusted Free Cash Flow Target
Weighted Average Grant Date Fair Value
Percentage of performance target	200.00%
Members of management and executive officers \| Performance stock unit \| Minimum
Weighted Average Grant Date Fair Value
PSUs vesting as a percentage of performance target	80.00%
Members of management and executive officers \| Performance stock unit \| Maximum
Weighted Average Grant Date Fair Value
PSUs vesting as a percentage of performance target	120.00%
Chief Executive Officer \| Members of management and executive officers \| 2026 Performance share award \| Meeting of strategic initiatives target
Weighted Average Grant Date Fair Value
Percentage of performance target	100.00%
Chief Financial Officer \| Members of management and executive officers \| 2026 Performance share award \| Meeting of strategic initiatives target
Weighted Average Grant Date Fair Value
Percentage of performance target	200.00%

Represents the percentage of PSUs vesting expressed as a percentage of performance target.

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Percentage of performance target.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of cancellation.

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Number of equity instruments other than options awarded for the next fiscal year; however, the grant date fair values are subject to determination in that particular fiscal year under the share-based compensation arrangement.

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Total number of equity instruments other than options outstanding including the awards for which the grant date fair values are subject to determination in that particular fiscal year under the share based compensation arrangement.

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Amount of cash outflow to satisfy grantee's tax withholding obligation for award under share-based payment arrangement.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The net total number of shares (or other type of equity) under an equity-based award plan, other than a stock option plan, that were granted, vested and forfeited during the reporting period.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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