Shareholders' Equity - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023	Nov. 14, 2025	Dec. 03, 2024
Class of Stock [Line Items]
Forward sales equity agreement, settlement in cash	$ 1,558,522
Net proceeds from equity offering	$ 698,462	$ 749,987	$ 806,949
Shelf Registration Statement
Class of Stock [Line Items]
Debt and equity securities, authorized for issuance					$ 8,000,000
Shelf Registration Statement | Subsequent Event
Class of Stock [Line Items]
Debt and equity securities, authorized for issuance value remaining				$ 5,200,000
At-The-Market
Class of Stock [Line Items]
Value of shares authorized for issuance					$ 1,700,000
Forward sales equity agreement, shares (in shares)	5,967,768
Forward sales equity agreement, settlement in cash	$ 871,500
Shares issued (in shares)	5,931,289
Net proceeds from equity offering	$ 698,500
Value of shares available for issuance	$ 828,500