Document And Entity Information
| Document And Entity Information | Aug. 26, 2021 | May 27, 2021 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Aug. 26, 2021 | |
| Entity Registrant Name | TFS FINANCIAL CORPORATION | |
| Entity Incorporation, State or Country Code | X1 | |
| Entity File Number | 001-33390 | |
| Entity Tax Identification Number | 52-2054948 | |
| Entity Address, Address Line One | 7007 Broadway Ave., | |
| Entity Address, City or Town | Cleveland, | |
| Entity Address, State or Province | OH | |
| Entity Address, Postal Zip Code | 44105 | |
| City Area Code | (216) | |
| Local Phone Number | 441-6000 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false | |
| Title of 12(b) Security | Common Stock, par value $0.01 per share | |
| Trading Symbol | TFSL | |
| Security Exchange Name | NASDAQ | |
| Entity Central Index Key | 0001381668 | |
| Amendment Flag | false |