Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Prospectus Date	rr_ProspectusDate	Feb. 26, 2021
Vanguard Explorer Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	<span style="color:#000000;font-family:Arial;font-size:13pt;font-weight:bold;margin-left:0%;">Fund Summary</span>
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The Fund seeks to provide long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Fees and Expenses</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold, and sell Investor Shares or Admiral Shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;margin-left:0%;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;">(Fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;margin-left:0%;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:8.5pt;">(Expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.5pt;margin-left:0%;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in more taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the previous expense examples, reduce the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 43% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	43.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.5pt;margin-left:0%;">Examples</span>
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	The following examples are intended to help you compare the cost of investing in the Fund’s Investor Shares or Admiral Shares with the cost of investing in other mutual funds. They illustrate the hypothetical expenses that you would incur over various periods if you were to invest $10,000 in the Fund's shares. These examples assume that the shares provide a return of 5% each year and that total annual fund operating expenses remain as stated in the preceding table. You would incur these hypothetical expenses whether or not you were to redeem your investment at the end of the given period. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests mainly in the stocks of small and mid-size companies. These companies tend to be unseasoned but are considered by the Fund’s advisors to have superior growth potential. Also, these companies often provide little or no dividend income. The Fund uses multiple investment advisors. Each advisor independently selects and maintains a portfolio of common stocks for the Fund.
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Principal Risks</span>
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the Fund could lose money over short or long periods of time.You should expect the Fund's share price and total return to fluctuate within a wide range. The Fund is subject to the following risks, which could affect the Fund's performance:•  Stock market risk , which is the chance that stock prices overall will decline. Stock markets tend to move in cycles, with periods of rising prices and periods of falling prices.•  Investment style risk , which is the chance that returns from small- and mid- capitalization growth stocks will trail returns from the overall stock market. Historically, small- and mid-cap stocks have been more volatile in price than the large-cap stocks that dominate the overall market, and they often perform quite differently. The stock prices of small and mid-size companies tend to experience greater volatility because, among other things, these companies tend to be more sensitive to changing economic conditions.•  Manager risk , which is the chance that poor security selection will cause the Fund to underperform relevant benchmarks or other funds with a similar investment objective. In addition, significant investments in the industrials and information technology sectors subject the Fund to proportionately higher exposure to the risks of these sectors.An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Risk Lose Money [Text]	rr_RiskLoseMoney	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">An investment in the Fund could lose money over short or long periods of time.</span>
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	<span style="color:#000000;font-family:Arial;font-size:9.5pt;font-weight:bold;">An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Annual Total Returns</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the share classes presented compare with those of a relevant market index and another comparative index, which have investment characteristics similar to those of the Fund. Keep in mind that the Fund's past performance (before and after taxes) does not indicate how the Fund will perform in the future. Updated performance information is available on our website at vanguard.com/performance or by calling Vanguard toll-free at 800-662-7447.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">The following bar chart and table are intended to help you understand the risks of investing in the Fund. The bar chart shows how the performance of the Fund‘s Investor Shares has varied from one calendar year to another over the periods shown. The table shows how the average annual total returns of the share classes presented compare with those of a relevant market index and another comparative index, which have investment characteristics similar to those of the Fund.</span>
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">800-662-7447</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="color:#000000;font-family:Arial;font-size:9.5pt;font-style:italic;">vanguard.com/performance</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.5pt;"> Keep in mind that the Fund's past performance (before and after taxes) </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">does not indicate how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="color:#000000;font-family:Arial;font-size:8pt;font-weight:bold;">Annual Total Returns — Vanguard Explorer Fund Investor Shares</span>
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the bar chart, the highest and lowest returns for a calendar quarter were:
Performance Table Heading	rr_PerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:8.5pt;font-weight:bold;">Average Annual Total Returns for Periods Ended December 31, 2020</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">When after-tax returns are calculated, it is </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">assumed that the shareholder was in the highest individual federal marginal income tax bracket at the time of each distribution of income or capital gains or upon redemption. State and local income taxes are not reflected in the calculations. </span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">After-tax returns are not relevant for a </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">shareholder who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan. </span>
Performance Table One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Please note that after-tax returns are shown only for the Investor </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;">Shares and may differ for each share class. </span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Arial;font-size:9.5pt;">Also, figures captioned </span><span style="color:#000000;font-family:Arial;font-size:9.5pt;font-style:italic;">Return After Taxes on Distributions and Sale of Fund Shares</span><span style="color:#000000;font-family:Arial;font-size:9.5pt;"> may be higher than other figures for the same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.</span>
Performance Table Closing [Text Block]	rr_PerformanceTableClosingTextBlock	Actual after-tax returns depend on your tax situation and may differ from those shown in the preceding table. When after-tax returns are calculated, it is assumed that the shareholder was in the highest individual federal marginal income tax bracket at the time of each distribution of income or capital gains or upon redemption. State and local income taxes are not reflected in the calculations. Please note that after-tax returns are shown only for the Investor Shares and may differ for each share class. After-tax returns are not relevant for a shareholder who holds fund shares in a tax-deferred account, such as an individual retirement account or a 401(k) plan. Also, figures captioned Return After Taxes on Distributions and Sale of Fund Shares may be higher than other figures for the same period if a capital loss occurs upon redemption and results in an assumed tax deduction for the shareholder.
Vanguard Explorer Fund | Investor Shares
Risk Return Abstract	rr_RiskReturnAbstract
Purchase Fee	rr_MaximumCumulativeSalesChargeOverOther	none
Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Account Service Fee Per Year (for certain fund account balances below $10,000)	rr_MaximumAccountFee	$ 20
Management Fees	rr_ManagementFeesOverAssets	0.40%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.41%
1 Year	rr_ExpenseExampleYear01	$ 42
3 Years	rr_ExpenseExampleYear03	132
5 Years	rr_ExpenseExampleYear05	230
10 Years	rr_ExpenseExampleYear10	$ 518
2011	rr_AnnualReturn2011	(1.72%)
2012	rr_AnnualReturn2012	15.07%
2013	rr_AnnualReturn2013	44.59%
2014	rr_AnnualReturn2014	4.08%
2015	rr_AnnualReturn2015	(4.22%)
2016	rr_AnnualReturn2016	12.47%
2017	rr_AnnualReturn2017	23.10%
2018	rr_AnnualReturn2018	(2.39%)
2019	rr_AnnualReturn2019	31.40%
2020	rr_AnnualReturn2020	31.48%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="color:#000000;font-family:Arial;font-size:8pt;padding-left:0.0%;">Highest</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	32.76%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="color:#000000;font-family:Arial;font-size:8pt;padding-left:0.0%;">Lowest</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(26.74%)
1 Year	rr_AverageAnnualReturnYear01	31.33%
5 Years	rr_AverageAnnualReturnYear05	18.34%
10 Years	rr_AverageAnnualReturnYear10	14.15%
Vanguard Explorer Fund | Admiral Shares
Risk Return Abstract	rr_RiskReturnAbstract
Purchase Fee	rr_MaximumCumulativeSalesChargeOverOther	none
Sales Charge (Load) Imposed on Purchases	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Sales Charge (Load) Imposed on Reinvested Dividends	rr_MaximumSalesChargeOnReinvestedDividendsAndDistributionsOverOther	none
Redemption Fee	rr_RedemptionFeeOverRedemption	none
Account Service Fee Per Year (for certain fund account balances below $10,000)	rr_MaximumAccountFee	$ 20
Management Fees	rr_ManagementFeesOverAssets	0.29%
12b-1 Distribution Fee	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.30%
1 Year	rr_ExpenseExampleYear01	$ 31
3 Years	rr_ExpenseExampleYear03	97
5 Years	rr_ExpenseExampleYear05	169
10 Years	rr_ExpenseExampleYear10	$ 381
1 Year	rr_AverageAnnualReturnYear01	31.48%
5 Years	rr_AverageAnnualReturnYear05	18.48%
10 Years	rr_AverageAnnualReturnYear10	14.30%
Vanguard Explorer Fund | Return After Taxes on Distributions | Investor Shares
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	29.28%
5 Years	rr_AverageAnnualReturnYear05	16.13%
10 Years	rr_AverageAnnualReturnYear10	12.05%
Vanguard Explorer Fund | Return After Taxes on Distributions and Sale of Fund Shares | Investor Shares
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.84%
5 Years	rr_AverageAnnualReturnYear05	14.19%
10 Years	rr_AverageAnnualReturnYear10	11.05%
Vanguard Explorer Fund | Russell 2500 Growth Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	40.47%
5 Years	rr_AverageAnnualReturnYear05	18.68%
10 Years	rr_AverageAnnualReturnYear10	15.00%
Vanguard Explorer Fund | Dow Jones U.S. Total Stock Market Float Adjusted Index (reflects no deduction for fees, expenses, or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.79%
5 Years	rr_AverageAnnualReturnYear05	15.36%
10 Years	rr_AverageAnnualReturnYear10	13.74%