Derivative Financial Instruments (Details) - USD ($) $ in Thousands		1 Months Ended			12 Months Ended
	Nov. 28, 2018	Jul. 31, 2018	Dec. 31, 2017	Oct. 31, 2016	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2017
Derivative [Line Items]
Write off of deferred debt issuance cost		$ 2,581	$ 1,150	$ 1,844	$ 1,795	$ 0	$ 5,575
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months					$ 97
Description of Reclassification of Cash Flow Hedge Gain (Loss)					twelve months
Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Term of Contract	3 years
Derivative, Cap Interest Rate	3.50%
Derivative, Cost of Hedge Net of Cash Received	$ 2,235
Write off of deferred debt issuance cost					$ 1,118
Unamortized Premium, Interest Rate Cap					1,614
Amortization					496	$ 621
Foreign Exchange Forward [Member]
Derivative [Line Items]
Derivative, Notional Amount					5,542
Designated as Hedging Instrument [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 600,000
Prepaid Expenses and Other Current Assets [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Unamortized Premium, Interest Rate Cap					745
Other Noncurrent Assets [Member] | Interest Rate Cap [Member]
Derivative [Line Items]
Unamortized Premium, Interest Rate Cap					$ 869