Long-Term Debt (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 21, 2019	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Debt Instrument
Debt, long-term and short-term, combined amount, total		$ 865,000	$ 939,000
Unamortized debt issuance expense		(8,200)	(9,500)
Long-term debt		856,800	929,500
Payments of Financing Costs			1,500
Loss on extinguishment and refinancing of debt, net		0	17,600	$ 1,600
Long-Term Debt, Maturity, Year One		0
Long-Term Debt, Maturity, Year Two		0
Long-Term Debt, Maturity, Year Three		0
Long-Term Debt, Maturity, Year Four		25,000
Long-Term Debt, Maturity, Year Five		0
Estimated future interest payments on debt		303,200
Estimated future interest payments on debt, next 12 months		61,500
Term Loan
Debt Instrument
Proceeds from issuance of long-term debt	$ 700,000
Repayments of Debt			(519,800)
Loss on extinguishment and refinancing of debt, net			(17,600)
Periodic payment of long-term debt principal				8,750
Excess cash flow prepayment			81,400	28,800
Write-off of Unamortized Debt Premium			6,900
Write-off of Interest Rate Swap Loss, previously recorded in AOCI			6,100
Write off of Deferred Debt Issuance Cost			4,600
Letter of Credit
Debt Instrument
Maximum borrowing capacity on line of credit		20,000
Revolving Credit Facility
Debt Instrument
Debt, long-term and short-term, combined amount, total		25,000	99,000
Maximum borrowing capacity on line of credit		250,000
Proceeds from borrowing under line of credit		115,000	164,000
Repayments of lines of credit		(189,000)	(65,000)
Remaining borrowing capacity on line of credit		225,000	151,000
Letters of credit outstanding, amount			0
7.00% Senior Notes Maturing in March 2030
Debt Instrument
Debt, long-term and short-term, combined amount, total		$ 840,000	840,000
Long-term Debt, Gross			840,000
Old Revolving Credit Facility
Debt Instrument
Maximum borrowing capacity on line of credit				200,000
Proceeds from borrowing under line of credit				20,000
Repayments of lines of credit				(50,000)
Letter of Credit - Old Credit Agreement
Debt Instrument
Maximum borrowing capacity on line of credit				$ 20,000
Senior Notes [Member] | 7.00% Senior Notes Maturing in March 2030
Debt Instrument
Long-term Debt, Gross			840,000
Payments of debt issuance costs and deferred financing fees			$ (10,200)