2.4.0.8000049 - Disclosure - Risk/Return Detail Data {Elements} - Fidelity Emerging Markets Discovery Fund Institutional Classtruetruefalse1false falsefalseDuration_30Dec2011_29Dec2012http://www.sec.gov/CIK0000744822duration2011-12-30T00:00:002012-12-29T00:00:001true 2rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Risk/Return:2false 3dei_EntityRegistrantNamedei_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00FIDELITY INVESTMENT TRUSTfalsefalsefalsexbrli:normalizedStringItemTypenormalizedstringThe exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation 12B -Number 240 -Section 12b -Subsection 1 false0Registrant Name3false 3rr_ProspectusDaterr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse002012-12-29falsefalsetruexbrli:dateItemTypedateThe date of the prospectus.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 1 -Subsection a -Paragraph 3 false0Prospectus Date4false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2false truefalseDuration_30Dec2011_29Dec2012S000034264_MemberInst_Memberhttp://www.sec.gov/CIK0000744822duration2011-12-30T00:00:002012-12-29T00:00:00falsefalseInstdei_DocumentInformationDocumentAxisxbrldihttp://xbrl.org/2006/xbrldifit_InstMemberdei_DocumentInformationDocumentAxisexplicitMemberfalsefalseFidelity Emerging Markets Discovery Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldifit_S000034264Memberdei_LegalEntityAxisexplicitMembernanafalse0Inst | Fidelity Emerging Markets Discovery Fund5true 2rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Risk/Return:6false 3fit_SupplementTextBlockfit_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00<font style="FONT-FAMILY: Times New Roman" size="5"><b>Supplement to the<br/> Fidelity Advisor^&reg; Emerging Markets Discovery Fund<br/> Institutional Class<br/> December 29, 2012<br/> Prospectus</b></font> <br/><br/><div align="left"><font style="FONT-FAMILY: Times New Roman" size="3">The following information replaces similar information found in the &quot;Fund Summary&quot; section under the heading &quot;Fee Table&quot; on page 4. </font></div> <br/><table width="95%" border="1"> <tr> <td align="left" valign="bottom"> <div align="left"><font style="FONT-FAMILY: Times New Roman" size="-1">1 year</font> </div> </td> <td align="left" valign="bottom"> <div align="right"><font style="FONT-FAMILY: Times New Roman" size="-1">$ 153</font> </div> </td> </tr> <tr> <td align="left" valign="bottom"> <div align="left"><font style="FONT-FAMILY: Times New Roman" size="-1">3 years</font> </div> </td> <td align="left" valign="bottom"> <div align="right"><font style="FONT-FAMILY: Times New Roman" size="-1">$ 810</font> </div> </td> </tr> <tr> <td align="left" valign="bottom"> <div align="left"><font style="FONT-FAMILY: Times New Roman" size="-1">5 years</font> </div> </td> <td align="left" valign="bottom"> <div align="right"><font style="FONT-FAMILY: Times New Roman" size="-1">$ 1,523</font> </div> </td> </tr> <tr> <td align="left" valign="bottom"> <div align="left"><font style="FONT-FAMILY: Times New Roman" size="-1">10 years</font> </div> </td> <td align="left" valign="bottom"> <div align="right"><font style="FONT-FAMILY: Times New Roman" size="-1">$ 3,416</font> </div> </td> </tr> </table>falsefalsefalsenonnum:textBlockItemTypenaSupplement Text BlockNo definition available.false0Supplement [Text Block]falseRisk/Return Detail Data - Fidelity Emerging Markets Discovery Fund Institutional ClassUnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.fidelity.com/role/DisclosureRiskReturnDetailDataElementsFidelityEmergingMarketsDiscoveryFundInstitutionalClass16