| Document and Entity Information | Dec. 29, 2020 |
| Cover Abstract | |
| Document Type | 8-K |
| Document Period End Date | Dec. 29, 2020 |
| Entity File Number | 001-36437 |
| Entity Registrant Name | DORIAN LPG LTD. |
| Entity Incorporation, State or Country Code | 1T |
| Entity Tax Identification Number | 66-0818228 |
| Entity Address, Address Line One | 27 Signal Road |
| Entity Address, City or Town | Stamford |
| Entity Address, State or Province | CT |
| Entity Address, Postal Zip Code | 06902 |
| City Area Code | 203 |
| Local Phone Number | 674-9900 |
| 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 $0.01 per share |
| Trading Symbol | LPG |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001596993 |
| Amendment Flag | false |
