| Label                                        | **Element**              | Value                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|----------------------------------------------|--------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Risk/Return:**                             | rr_RiskReturnAbstract    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Registrant Name                              | dei_EntityRegistrantName | FIDELITY INVESTMENT TRUST                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Prospectus Date                              | rr_ProspectusDate        | Dec. 29,				 2012                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| A T C | Fidelity Total Emerging Markets Fund |                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| **Risk/Return:**                             | rr_RiskReturnAbstract    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Supplement [Text Block]                      | fit_SupplementTextBlock  | **Supplement to the Fidelity Advisor® Total Emerging Markets Fund Class A, Class T, and Class C December 29, 2012 Prospectus**The following information replaces similar information found in the "Fund Summary" section under the heading "Fee Table" beginning on page 3.  **Class A****Class T****Class C** Sell All SharesHold SharesSell All SharesHold SharesSell All SharesHold Shares1 year$	733$	733$	536$	536$	343$	2433 years$	1,105$	1,105$	963$	963$	792$	7925 years$	1,505$	1,505$	1,419$	1,419$	1,371$	1,37110 years$	2,619$	2,619$	2,678$	2,678$	2,944$	2,944 |

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