Debt - Schedule of Long-term Debt Obligations (Details) - USD ($) $ in Thousands		Mar. 31, 2025	Sep. 30, 2024	Feb. 13, 2020
Debt Instrument [Line Items]
Total debt		$ 1,392,500	$ 1,752,625
Unamortized debt issuance costs for the senior notes	[1]	(3,107)	(4,053)
Total debt, net of issuance costs	[2]	1,389,393	1,748,572
4.000% Senior Notes Due 2028
Debt Instrument [Line Items]
Senior Notes				$ 500,000
3.625% Senior Notes Due 2025
Debt Instrument [Line Items]
Senior Notes				$ 500,000
Long-term Debt | Revolver Credit Facility
Debt Instrument [Line Items]
Payment to credit facility revolver	[3],[4]	411,250	262,000
Long-term Debt | Secured Debt
Debt Instrument [Line Items]
Payment to credit facility revolver	[3],[4]	481,250	490,625
Long-term Debt | 4.000% Senior Notes Due 2028
Debt Instrument [Line Items]
Senior Notes		500,000	500,000
Long-term Debt | 3.625% Senior Notes Due 2025
Debt Instrument [Line Items]
Senior Notes		$ 0	$ 500,000

[1] unamortized debt issuance costs for the senior notes were included in Long-term debt on the Consolidated Balance Sheet. As of September 30, 2024, $0.4 million of unamortized debt issuance costs for the senior notes was included in Current portion of long-term debt and $3.6 million was included in Long-term debt on the Consolidated Balance Sheet.

[2] As of March 31, 2025, $25.0 million of debt associated with the credit facility term loan was classified as short term. As of September 30, 2024, $521.5 million of debt was classified as short term, including $499.6 million associated with the 2025 senior notes and related debt issuance costs and $21.9 million associated with the credit facility term loan.

[3] The stated maturity date under the credit facility on which both the revolver line and the term loan will mature and all amounts then outstanding will become due and payable is January 3, 2028. The term loan began amortizing in March 2024, with payments of $12.5 million remaining in 2025, $25.0 million in 2026 and 2027, and $418.7 million in 2028.

[4] Unamortized debt issuance costs related to the credit facility were $2.7 million included in Other current assets and $4.7 million included in Other assets on the Consolidated Balance Sheet as of March 31, 2025 and $2.3 million included in Other current assets and $5.2 million included in Other assets on the Consolidated Balance Sheet as of September 30, 2024.