Shareholders' Equity - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Nov. 14, 2023	Mar. 31, 2023
Class of Stock [Line Items]
Forward sales equity agreement, settlement in cash	$ 466,803
Net proceeds from equity offering	$ 806,949	$ 776,805	$ 606,667
Shelf Registration Statement
Class of Stock [Line Items]
Debt and equity securities, authorized for issuance					$ 5,000,000
Shelf Registration Statement | Subsequent Event
Class of Stock [Line Items]
Debt and equity securities, authorized for issuance value remaining				$ 3,100,000
At-The-Market
Class of Stock [Line Items]
Value of shares authorized for issuance					$ 1,000,000
Forward sales equity agreement, shares (in shares)	4,207,126
Forward sales equity agreement, settlement in cash	$ 496,500
Shares issued (in shares)	7,272,261
Net proceeds from equity offering	$ 806,900
Value of shares available for issuance	$ 760,500