Debt - Schedule of Long-term Debt Obligations (Details) - USD ($) $ in Thousands		Mar. 31, 2026	Sep. 30, 2025	Feb. 13, 2020
Debt Instrument [Line Items]
Total debt		$ 1,200,000	$ 1,200,000
Unamortized debt issuance costs for the senior notes	[1]	(2,028)	(2,566)
Total debt, net of issuance costs	[2]	1,197,972	1,197,434
4.000% Senior Notes Due 2028
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]	243,750	231,250
Long-term Debt | Secured Debt
Debt Instrument [Line Items]
Payment to credit facility revolver	[3],[4]	456,250	468,750
Long-term Debt | 4.000% Senior Notes Due 2028
Debt Instrument [Line Items]
Senior Notes		$ 500,000	$ 500,000

[1] As of March 31, 2026 and September 30, 2025, all unamortized debt issuance costs for the senior notes were included in Long-term debt on the Consolidated Balance Sheets.

[2] As of March 31, 2026 and September 30, 2025, $25.0 million of debt associated with the credit facility term loan was classified as short term.

[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 remaining of $12.5 million in 2026, $25.0 million in 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 $2.9 million included in Other assets on the Consolidated Balance Sheet as of March 31, 2026 and $2.7 million included in Other current assets and $3.3 million included in Other assets on the Consolidated Balance Sheet as of September 30, 2025.