| Document and Entity Information | Jul. 21, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 21, 2020 |
| Entity Registrant Name | Ollie's Bargain Outlet Holdings, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-37501 |
| Entity Tax Identification Number | 80-0848819 |
| Entity Address, Address Line One | 6295 Allentown Boulevard |
| Entity Address, Address Line Two | Suite 1 |
| Entity Address, City or Town | Harrisburg |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 17112 |
| City Area Code | 717 |
| Local Phone Number | 657-2300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001639300 |
| Title of 12(b) Security | Common Stock, $0.001 par value |
| Trading Symbol | OLLI |
| Security Exchange Name | NASDAQ |
