| Document and Entity Information | Apr. 29, 2020 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Dec. 14, 2020 |
| Entity File Number | 1-33891 |
| Entity Registrant Name | ORION GROUP HOLDINGS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 26-0097459 |
| Entity Address, Address Line One | 12000 Aerospace |
| Entity Address, Adress Line Two | Suite 300 |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77034 |
| City Area Code | 713 |
| Local Phone Number | 852-6500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.01 par value per share |
| Trading Symbol | ORN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001402829 |
| Amendment Flag | false |
