Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Basic Earnings Per Share
Net income	$ 311,292	$ 271,860
Less: Income allocated to participating securities	186	167
Income available to common shareholders	$ 311,106	$ 271,693
Basic weighted average shares outstanding (in shares)	149,796	141,820
Net income per share - Basic (USD per share)	$ 2.08	$ 1.92
Diluted Earnings Per Share
Income available to common shareholders	$ 311,106	$ 271,693
Effect of dilutive shares	0	0
Income available to common shareholders	$ 311,106	$ 271,693
Basic weighted average shares outstanding (in shares)	149,796	141,820
Dilutive shares (in shares)	0	117
Diluted weighted average shares outstanding (in shares)	149,796	141,937
Net income per share - Diluted (USD per share)	$ 2.08	$ 1.91