Dividends and Share Repurchases (Details) - $ / shares						3 Months Ended		6 Months Ended
	Mar. 10, 2023	Oct. 15, 2022	Jul. 15, 2022	Apr. 15, 2022	Jan. 15, 2022	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Stockholders' Equity Note [Abstract]
Cash dividends per share (in dollars per share)	$ 0.25					$ 0.25	$ 0.24	$ 0.49	$ 0.47
Stock repurchased (in shares)						3,239
Average cost per share (in dollars per share)						$ 33.48
Remaining shares authorized to be repurchased (in shares)						3,676,260		3,676,260
Preferred stock dividends declared (in dollars per share)		$ 12.1875	$ 12.1875	$ 12.1875	$ 12.1875
Depository dividends declared (in dollars per share)		$ 0.30468750	$ 0.30468750	$ 0.30468750	$ 0.30468750