Long-Term Debt - Rates and Ratios (Details)		6 Months Ended
	Mar. 10, 2022	Mar. 31, 2022	Sep. 30, 2021	Mar. 31, 2021	Feb. 26, 2021
Debt Instrument
Debt covenant, leverage ratio		6.00
Reduction in interest rate margin, basis points					100
Premium on early repayment of debt		1.00%
Term Loan
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage			4.75%
Term Loan | Base Rate
Debt Instrument
Basis spread on variable interest rate		3.00%
Term Loan | Eurodollar
Debt Instrument
Basis spread on variable interest rate		4.00%
Term Loan | Federal Funds
Debt Instrument
Basis spread on variable interest rate		0.50%
Term Loan | One-Month Eurodollar
Debt Instrument
Basis spread on variable interest rate		1.00%
Term Loan | One-Month Eurodollar | Minimum
Debt Instrument
Basis spread on variable interest rate		0.75%
Revolving Credit Facility
Debt Instrument
Unused capacity on line of credit commitment fee percentage		0.25%
Revolving Credit Facility | Minimum
Debt Instrument
Unused capacity on line of credit commitment fee percentage		0.25%
Revolving Credit Facility | Maximum
Debt Instrument
Unused capacity on line of credit commitment fee percentage	0.375%
Revolving Credit Facility | Base Rate
Debt Instrument
Basis spread on variable interest rate	2.00%
Revolving Credit Facility | Base Rate | Minimum
Debt Instrument
Basis spread on variable interest rate	2.00%
Revolving Credit Facility | Base Rate | Maximum
Debt Instrument
Basis spread on variable interest rate	2.75%
Revolving Credit Facility | SOFR Rate
Debt Instrument
Basis spread on variable interest rate	3.00%
Revolving Credit Facility | SOFR Rate | Minimum
Debt Instrument
Basis spread on variable interest rate	3.00%
Revolving Credit Facility | SOFR Rate | Maximum
Debt Instrument
Basis spread on variable interest rate	3.75%
Revolving Credit Facility | Eurodollar
Debt Instrument
Basis spread on variable interest rate	3.00%
Revolving Credit Facility | Eurodollar | Minimum
Debt Instrument
Basis spread on variable interest rate	3.00%
Revolving Credit Facility | Eurodollar | Maximum
Debt Instrument
Basis spread on variable interest rate	3.75%
Revolving Credit Facility | BritishPound Rate
Debt Instrument
Basis spread on variable interest rate	3.00%
Revolving Credit Facility | BritishPound Rate | Minimum
Debt Instrument
Basis spread on variable interest rate	3.00%
Revolving Credit Facility | BritishPound Rate | Maximum
Debt Instrument
Basis spread on variable interest rate	3.75%
Revolving Credit Facility | Excess Cash Flow Ratio
Debt Instrument
Debt covenant, leverage ratio		3.35
Old Revolving Credit Facility [Domain] | Minimum
Debt Instrument
Unused capacity on line of credit commitment fee percentage		0.25%
Old Revolving Credit Facility [Domain] | Maximum
Debt Instrument
Unused capacity on line of credit commitment fee percentage		0.50%
Old Revolving Credit Facility [Domain] | Base Rate | Minimum
Debt Instrument
Basis spread on variable interest rate		2.75%
Old Revolving Credit Facility [Domain] | Base Rate | Median
Debt Instrument
Basis spread on variable interest rate		3.00%
Old Revolving Credit Facility [Domain] | Base Rate | Maximum
Debt Instrument
Basis spread on variable interest rate		3.25%
Old Revolving Credit Facility [Domain] | Eurodollar | Minimum
Debt Instrument
Basis spread on variable interest rate		3.75%
Old Revolving Credit Facility [Domain] | Eurodollar | Median
Debt Instrument
Basis spread on variable interest rate		4.00%
Old Revolving Credit Facility [Domain] | Eurodollar | Maximum
Debt Instrument
Basis spread on variable interest rate		4.25%
Old Revolving Credit Facility [Domain] | High-End Ratio
Debt Instrument
Debt covenant, leverage ratio		3.50
Old Revolving Credit Facility [Domain] | Low-End Ratio
Debt Instrument
Debt covenant, leverage ratio		2.50
Senior Notes [Member] | 7.00% Senior Notes Maturing in March 2030
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage				7.00%