| Document and Entity Information | Jul. 29, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 29, 2021 |
| Entity Registrant Name | Strategic Education, Inc. |
| Entity Incorporation, State or Country Code | MD |
| Entity File Number | 0-21039 |
| Entity Tax Identification Number | 52-1975978 |
| Entity Address, Address Line One | 2303 Dulles Station Boulevard |
| Entity Address, City or Town | Herndon |
| Entity Address, State or Province | VA |
| Entity Address, Postal Zip Code | 20171 |
| City Area Code | 703 |
| Local Phone Number | 561-1600 |
| 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 | 0001013934 |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | STRA |
| Security Exchange Name | NASDAQ |
| Entity Information, Former Legal or Registered Name | N/A |
