Debt (Tables)

6 Months Ended

Mar. 31, 2026

Debt Disclosure [Abstract]

Schedule of Debt

The following table represents our debt at carrying value at March 31, 2026 and September 30, 2025:

	March 31, 2026		September 30, 2025
	(In thousands)
Current maturities on debt:
The 2018 Senior Notes	$	—	$	400,000
Less: debt issuance costs	—		(459)
Current maturities on debt	—		399,541
Long-term debt:
Revolving line of credit	265,000		275,000
The 2019 Senior Notes and the 2021 Senior Notes	900,000		900,000
The 2025 Senior Notes	1,500,000		1,500,000
The 2026 Senior Notes	1,000,000		—
Less: debt issuance costs	(25,937)		(18,850)
Long-term debt	3,639,063		2,656,150
Total debt	$	3,639,063	$	3,055,691

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments

The following table presents the face values and fair values for the Senior Notes at March 31, 2026 and September 30, 2025:

	March 31, 2026				September 30, 2025
	Face Value		Fair Value		Face Value		Fair Value
	(In thousands)
The 2018 Senior Notes	$	—	$	—	$	400,000	$	399,500
The 2019 Senior Notes and the 2021 Senior Notes	900,000		868,500		900,000		875,250
The 2025 Senior Notes	1,500,000		1,456,875		1,500,000		1,518,750
The 2026 Senior Notes	1,000,000		972,500		—		—
Total	$	3,400,000	$	3,297,875	$	2,800,000	$	2,793,500