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Label Element Value
Risk/Return: rr_RiskReturnAbstract  
Registrant Name dei_EntityRegistrantName DFA INVESTMENT DIMENSIONS GROUP INC
Prospectus Date rr_ProspectusDate Feb. 28, 2012
Institutional Shares | DIMENSIONAL RETIREMENT FIXED INCOME FUND III | Institutional Class
 
Risk/Return: rr_RiskReturnAbstract  
Shareholder Fees (fees paid directly from your investment) rr_MaximumAccountFee none
Management Fee rr_ManagementFeesOverAssets 0.30%
Other Expenses rr_OtherExpensesOverAssets 0.08% [1]
Total Annual Fund Operating Expenses rr_ExpensesOverAssets 0.38%
1 Year rr_ExpenseExampleYear01 39
3 Years rr_ExpenseExampleYear03 122
Institutional Shares | DIMENSIONAL RETIREMENT FIXED INCOME FUND III
 
Risk/Return: rr_RiskReturnAbstract  
Risk/Return [Heading] rr_RiskReturnHeading
Objective [Heading] rr_ObjectiveHeading
Objective, Primary [Text Block] rr_ObjectivePrimaryTextBlock
Expense [Heading] rr_ExpenseHeading
Expense Narrative [Text Block] rr_ExpenseNarrativeTextBlock
Shareholder Fees Caption [Text] rr_ShareholderFeesCaption
Operating Expenses Caption [Text] rr_OperatingExpensesCaption
Portfolio Turnover [Heading] rr_PortfolioTurnoverHeading
Portfolio Turnover [Text Block] rr_PortfolioTurnoverTextBlock
Other Expenses, New Fund, Based on Estimates [Text] rr_OtherExpensesNewFundBasedOnEstimates The Retirement Fixed Income Portfolio III is a new portfolio, so the "Other Expenses" shown are based on anticipated fees and expenses for a full fiscal year
Expense Example [Heading] rr_ExpenseExampleHeading
Expense Example Narrative [Text Block] rr_ExpenseExampleNarrativeTextBlock
Strategy [Heading] rr_StrategyHeading
Strategy Narrative [Text Block] rr_StrategyNarrativeTextBlock
Risk [Heading] rr_RiskHeading
Risk Narrative [Text Block] rr_RiskNarrativeTextBlock
Risk Lose Money [Text] rr_RiskLoseMoney Because the value of your investment in the Portfolio will fluctuate, there is the risk that you will lose money.
Bar Chart and Performance Table [Heading] rr_BarChartAndPerformanceTableHeading
Performance Narrative [Text Block] rr_PerformanceNarrativeTextBlock
Performance One Year or Less [Text] rr_PerformanceOneYearOrLess Performance information is not available for the Retirement Fixed Income Portfolio III because it has not yet commenced operations.
Performance Availability Website Address [Text] rr_PerformanceAvailabilityWebSiteAddress www.dimensional.com
[1] The Retirement Fixed Income Portfolio III is a new portfolio, so the "Other Expenses" shown are based on anticipated fees and expenses for a full fiscal year.