Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Earnings Per Share [Abstract]
Earnings available to stockholders	$ 258,631	$ 153,440	$ 340,280
Basic weighted average shares outstanding (in shares)	170,324,784	170,674,570	167,994,042
Diluted weighted average shares outstanding (in shares)	170,324,784	170,674,570	167,994,042
Basic earnings per share (in dollars per share)	$ 1.52	$ 0.90	$ 2.03
Diluted earnings per share (in dollars per share)	$ 1.52	$ 0.90	$ 2.03