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| **Risk/Return:**                                | rr_RiskReturnAbstract    |                                                                                                                                                                                                                                                                                                                                                                                        |
| Registrant Name                                 | dei_EntityRegistrantName | FIDELITY INVESTMENT TRUST                                                                                                                                                                                                                                                                                                                                                                   |
| Prospectus Date                                 | rr_ProspectusDate        | Dec. 30,				 2013                                                                                                                                                                                                                                                                                                                                                                           |
| Inst | Fidelity Emerging Markets Discovery Fund |                          |                                                                                                                                                                                                                                                                                                                                                                                        |
| **Risk/Return:**                                | rr_RiskReturnAbstract    |                                                                                                                                                                                                                                                                                                                                                                                        |
| Supplement [Text Block]                         | fit_SupplementTextBlock  | **Supplement to theFidelity Advisor® Emerging Markets Discovery FundInstitutional ClassDecember 30, 2013Prospectus**
The following information replaces similar information for found in the "Fund Summary" section under the heading "Principal Investment Strategies" on page 4.
-  Allocating the fund's assets across emerging markets sectors, using different Fidelity managers. |

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