2.4.0.8020001 - Disclosure - Risk/Return Detail Data {Elements} - FPA Crescent Fundtruetruefalse1false falsefalseS000009495Memberhttp://www.sec.gov/CIK0000924727duration2012-12-31T00:00:002012-12-31T00:00:001false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse1false truefalseS000009495Memberhttp://www.sec.gov/CIK0000924727duration2012-12-31T00:00:002012-12-31T00:00:00falsefalseFPA Crescent Funddei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldick0000924727_S000009495Memberdei_LegalEntityAxisexplicitMembernanafalse0FPA Crescent Fund2true 3rr_RiskReturnAbstractrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Risk/Return:3false 4ck0000924727_SupplementTextBlockck0000924727_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00<p style="margin: 0pt 0pt 18pt 0pt;" align="center"> <font style="font-size: 10pt; font-family: Times New Roman PS Std, Times New Roman PS, Times New Roman, Times;"><strong>FPA FUNDS TRUST'S FPA CRESCENT FUND<br /> SUPPLEMENT DATED AUGUST 15, 2013, TO PROSPECTUS DATED APRIL 30, 2013</strong></font> </p> <br/><p style="margin:0pt 0pt 6pt 0pt;"> <font style="font-size:10pt; font-family: Times New Roman PS Std, Times New Roman PS, Times New Roman, Times;">The Board of Trustees of FPA Funds Trust has approved a change in the investment objective of FPA Crescent Fund (the "Fund"). First Pacific Advisors, LLC, the Fund's investment adviser, does not anticipate that the change to the Fund's investment objective will impact the management of the Fund's portfolio.</font> </p> <br/><p style="margin:0pt 0pt 6pt 0pt;"> <font style="font-size:10pt; font-family: Times New Roman PS Std, Times New Roman PS, Times New Roman, Times;">The Fund's Prospectus is revised as described below.</font> </p>falsefalsefalsenonnum:textBlockItemTypenaNo authoritative reference available.No definition available.false0Supplement [Text Block]4false 4rr_RiskReturnHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00FPA Crescent Fundfalsefalsefalsexbrli:stringItemTypestringRisk/Return Summary Investment Objectives/Goals Include the following information, in plain English under rule 421(d) under the Securities Act, in the order and subject matter indicatedReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 false0Risk/Return [Heading]5false 4rr_ObjectiveHeadingrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00The sections of the Fund's Prospectus entitled "Investment Objective" in the "SUMMARY SECTION" of the Prospectus and under "INVESTMENT OBJECTIVE, PRINCIPAL INVESTMENT STRATEGIES, AND PRINCIPAL RISKS" are deleted and replaced as follows:falsefalsefalsexbrli:stringItemTypestringInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a false0Objective [Heading]6false 4rr_ObjectivePrimaryTextBlockrr_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00<p style="margin: 0pt 0pt 6pt 0pt;"> <font style="font-size: 10pt; font-family: Times New Roman PS Std, Times New Roman PS, Times New Roman, Times;">The Fund seeks to generate equity-like returns over the long-term, take less risk than the market and avoid permanent impairment of capital. The Fund may change its investment objective without shareholder approval.</font> </p>falsefalsefalsenonnum:textBlockItemTypenaInvestment Objectives/Goals. Disclose the Fund's investment objectives or goals. A Fund also may identify its type or category (e.g., that it is a Money Market Fund or a balanced fund).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Form -Number N-1A -Chapter A -Section 2 -Subsection a false0Objective, Primary [Text Block]falseRisk/Return Detail Data - FPA Crescent Fund (FPA Crescent Fund)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://fpafunds.com/20130815/role/DisclosureRiskReturnDetailDataElementsFPACrescentFund16