STOCKHOLDERS’ EQUITY AND EQUITY-BASED COMPENSATION- Narrative (Details)				3 Months Ended		9 Months Ended		12 Months Ended
	May 20, 2024 USD ($)	Jul. 13, 2021 $ / shares shares	Jul. 12, 2021 plan	Sep. 30, 2024 USD ($) vote shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) tradingDay vote shares	Sep. 30, 2023 USD ($)	Dec. 31, 2023 shares	Nov. 15, 2023 USD ($)	Sep. 20, 2023 USD ($)	Jun. 30, 2022 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock, shares authorized (in shares)				1,525,000,000		1,525,000,000
Common stock authorized (in shares)				1,500,000,000		1,500,000,000		1,500,000,000
Preferred stock authorized (in shares)				25,000,000		25,000,000
Voting rights, non-citizen investors						1.00%
Number of equity-based compensation plans | plan			9
Compensation expense | $				$ 7,885,000	$ 3,508,000	$ 33,364,000	$ 21,650,000
Shares withheld for employee taxes on vested equity (in shares)						439,451
Term Loan | Credit Agreement | Term Loan and Revolving Credit Facility
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Face amount | $									$ 390,000,000	$ 350,000,000
2021 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)				30,100,000		30,100,000
Common Stock available for awards (in shares)						25,000,000		2,415,000
2022 Inducement Grant Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Inducement grant plan (up to) (in shares)											205,128
WUP Profits Interests
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual term (in years)						6 years 9 months 18 days
Compensation expense | $				$ 0	0	$ 0	100,000
WUP Profits Interests | MIP Plan VII
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)				3,100,000		3,100,000
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $				$ 0	200,000	$ 0	1,100,000
Stock options | WUP Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized (in shares)				1,800,000		1,800,000
Service period (in years)						4 years
Vesting period (in years)						4 years
Expiration period (in years)						10 years
Aggregate intrinsic value | $				$ 0		$ 0
Weighted average remaining contractual term, exercisable (in years)						4 years 6 months
Weighted average remaining contractual term, outstanding (in years)						4 years 6 months
Stock options | 2021 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period (in years)						3 years
Vesting period (in years)						3 years
Aggregate intrinsic value | $				0		$ 0
Weighted average remaining contractual term, exercisable (in years)						3 years 1 month 6 days
Weighted average remaining contractual term, outstanding (in years)						3 years 1 month 6 days
RSUs | 2021 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation | $				$ 13,400,000		$ 13,400,000
Unrecognized compensation cost recognition period (in years)						2 years 8 months 12 days
Vested or will vest (in shares)						1,087,000
Nonvested awards (in shares)				5,012,000		5,012,000		1,848,000
RSUs | 2021 LTIP | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period (in years)						4 years
Vesting period (in years)						4 years
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation | $				$ 1,200,000		$ 1,200,000
Unrecognized compensation cost recognition period (in years)						2 years 2 months 12 days
PSUs | 2021 LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested or will vest (in shares)						0
Nonvested awards (in shares)				387,000		387,000		18,000
CEO Performance Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Inducement grant plan (up to) (in shares)				73,000,000		73,000,000
Executive Performance Award | 2022 CEO Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation | $				$ 164,400,000		$ 164,400,000
Unrecognized compensation cost recognition period (in years)						4 years 3 months 18 days
Number of trading day period prior to the applicable determination date | tradingDay						60
Vested or will vest (in shares)						0
Grant-date fair value | $	$ 43,900,000
Expected term (in years)	5 years 2 months 12 days
Compensation expense | $				6,300,000	0	$ 25,400,000	0
Executive Performance Award | 2022 CEO Awards | First share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage						25.00%
Executive Performance Award | 2022 CEO Awards | Second share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage						25.00%
Executive Performance Award | 2022 CEO Awards | Third share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage						25.00%
Executive Performance Award | 2022 CEO Awards | Fourth share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights percentage						25.00%
Executive Performance Award | CCO Performance Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	4 years 8 months 12 days
RSUs, PSUs, and Market-Based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $				1,700,000	3,300,000	$ 8,000,000.0	15,200,000
Earnout Share
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $				$ 0	$ 0	$ 0	$ 1,400,000
Nonvested awards (in shares)		900,000
Earnout Share | First share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested awards (in shares)				3,000,000		3,000,000
Earnout Share | Second share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested awards (in shares)				3,000,000		3,000,000
Earnout Share | Third share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested awards (in shares)				3,000,000		3,000,000
Profit Interest Based Award and Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual term (in years)						1 year 8 months 12 days
Compensation expense | $						$ 57,900,000
CK Wheels
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Voting restrictions				23.90%		23.90%
Delta
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Voting restrictions				29.90%		29.90%
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock authorized (in shares)				1,500,000,000		1,500,000,000
Voting rights per share | vote				1		1
Common Class A | Stock options | WUP Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock exercisable for each outstanding stock option (in shares)				1		1
Common Class A | Earnout Share | First share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting milestone (in dollars per share) | $ / shares		$ 125.00
Common Class A | Earnout Share | Second share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting milestone (in dollars per share) | $ / shares		150.00
Common Class A | Earnout Share | Third share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting milestone (in dollars per share) | $ / shares		$ 175.00
Common Class B | First share price vesting threshold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum threshold days (in days)		20 days
Number of consecutive trading days (in days)		30 days