Debt (Deferred Financing Fees) (Details) - USD ($) $ in Thousands		12 Months Ended
	Apr. 01, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Schedule of debt deferred financing costs and discounts [Line Items]
Write off of deferred debt issuance cost		$ 1,333	$ 1,795		$ 0
Amortization of debt issuance costs and discounts		1,946	1,735	$ 1,991
Less unamortized deferred financing fees	$ (2,375)	(11,738)	(9,436)
2014 Term Loan, due December 20, 2024
Schedule of debt deferred financing costs and discounts [Line Items]
Less unamortized deferred financing fees		(11,738)	(9,436)
Securitization Facility, due April 1, 2024
Schedule of debt deferred financing costs and discounts [Line Items]
Unamortized Debt Issuance Expense	822
Other Current Liabilities | 2014 Term Loan, due December 20, 2024
Schedule of debt deferred financing costs and discounts [Line Items]
Less unamortized deferred financing fees		(1,866)	(2,112)
Other Noncurrent Liabilities | 2014 Term Loan, due December 20, 2024
Schedule of debt deferred financing costs and discounts [Line Items]
Less unamortized deferred financing fees		(9,872)	$ (7,324)
2014 Term Loan, due December 20, 2024
Schedule of debt deferred financing costs and discounts [Line Items]
Write off of deferred debt issuance cost	1,333
Term Loan [Member]
Schedule of debt deferred financing costs and discounts [Line Items]
Payments of Financing Costs	4,985
Unamortized Debt Issuance Expense	1,931
Term Loan [Member] | Interest Expense [Member]
Schedule of debt deferred financing costs and discounts [Line Items]
Debt Issuance Costs, Gross	$ 3,054
Loans Payable | Equipment Financing Due July 31 2029
Schedule of debt deferred financing costs and discounts [Line Items]
Unamortized Debt Issuance Expense		$ 453