CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - shares	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Statement of Stockholders' Equity [Abstract]
Purchase of treasury stock (in shares)	173,576	709,970	393,864
Issuance of treasury stock (in shares)	12,125	3,782	326,827
Cancellation of treasury stock (in shares)	23,461	20,114	6,756
Contribution of treasury stock (in shares)	668,000