| Cover Page | Apr. 27, 2022 |
| Entity Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Apr. 27, 2022 |
| Entity File Number | 001-33749 |
| Entity Registrant Name | RETAIL OPPORTUNITY INVESTMENTS CORP. |
| Entity Central Index Key | 0001407623 |
| Entity Tax Identification Number | 26-0500600 |
| Entity Incorporation, State or Country Code | MD |
| Entity Address, Address Line One | 11250 El Camino Real |
| Entity Address, Address Line Two | Suite 200 |
| Entity Address, City or Town | San Diego |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92130 |
| City Area Code | (858) |
| Local Phone Number | 677-0900 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | ROIC |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Company Name L L P [Member] | |
| Entity Information [Line Items] | |
| Entity Registrant Name | RETAIL OPPORTUNITY INVESTMENTS PARTNERSHIP, LP |
| Incorporation State L L P [Member] | |
| Entity Information [Line Items] | |
| Entity Central Index Key | 0001577230 |
| Entity Incorporation, State or Country Code | DE |
| File Number L L P [Member] | |
| Entity Information [Line Items] | |
| Entity File Number | 333-189057-01 |
| Id Number L L P [Member] | |
| Entity Information [Line Items] | |
| Entity Tax Identification Number | 94-2969738 |
