Debt Obligations - Narrative (Details) - USD ($)		1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 01, 2021	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Debt Instrument [Line Items]
Interest expense				$ 12,050,000	$ 11,442,000	$ 38,159,000	$ 39,648,000
Interest expense, related party				(4,496,000)	(4,167,000)	(13,229,000)	(13,903,000)
Interest payable, current		$ 3,500,000		3,500,000		3,500,000		$ 8,500,000
Repayments of financing obligations			$ 10,200,000
Financing obligation, right-of-use asset, writeoff		48,100,000
Financing obligation, writeoff		55,200,000
Loss on termination of leaseback obligation						3,100,000
New Term Loan
Debt Instrument [Line Items]
ABL Facility (Fifth Amendment)	$ 700,000,000
Debt instrument, mandatory quarterly amortization payment	17,500,000
Proceeds from issuance of debt	674,900,000
Term loan, original issue discount	21,000,000
Debt issuance costs	$ 4,100,000
Payments of financing costs						4,200,000
Unamortized debt issuance expense		$ 2,500,000		2,500,000		2,500,000
Interest expense, related party				$ (4,500,000)	$ (4,200,000)	$ (13,200,000)	$ (13,900,000)
Debt instrument, covenant, leverage ratio to EBITDA, maximum		3.0		3.0		3.0
New Term Loan | General and administrative
Debt Instrument [Line Items]
Payments of financing costs						$ 1,700,000
New Term Loan | LIBOR +
Debt Instrument [Line Items]
Rate	8.50%					8.50%
New Term Loan | Base Rate
Debt Instrument [Line Items]
Rate	7.50%
New Term Loan | Affiliated Entity
Debt Instrument [Line Items]
Debt instrument, percent ownership	38.40%	31.20%		31.20%		31.20%
Senior Term Loan
Debt Instrument [Line Items]
Debt issuance costs	$ 100,000
Repayment of debt	449,600,000
Interest expense	400,000
Unamortized debt issuance expense		$ 100,000		$ 100,000		$ 100,000
Term loan, debt issuance costs								$ 400,000
Write off of deferred debt issuance costs						300,000
Senior Term Loan | LIBOR +
Debt Instrument [Line Items]
Rate								9.00%
Revolving Credit Facility | ABL Facility | Line of Credit
Debt Instrument [Line Items]
Debt issuance costs	2,400,000
Maximum revolver amount	175,000,000
Debt issuance costs, line of credit	$ 900,000
Debt issuance costs, line of credit, balance		2,900,000		2,900,000		2,900,000		$ 2,500,000
Current borrowing capacity		$ 92,100,000		$ 92,100,000		$ 92,100,000
Debt instrument, covenant, fixed charge coverage ratio required, minimum		1.00		1.00		1.00
Debt instrument, covenant, remaining borrowing capacity required, minimum		$ 14,000,000		$ 14,000,000		$ 14,000,000
Debt instrument, covenant, remaining borrowing capacity required for U.S excess availability, minimum		$ 10,000,000		$ 10,000,000		$ 10,000,000
Revolving Credit Facility | ABL Facility | Line of Credit | LIBOR +
Debt Instrument [Line Items]
Rate	3.00%
Line of credit facility, unused capacity, commitment fee percentage	0.375%
Revolving Credit Facility | ABL Facility | Line of Credit | Base Rate
Debt Instrument [Line Items]
Rate	2.00%