v3.24.4
Risk/Return Detail Data - FidelityAdvisorSeriesSmallCapFund-PRO
Jan. 29, 2025
USD ($)
Risk/Return:  
Registrant Name Fidelity Advisor Series I
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund  
Risk/Return:  
Risk/Return [Heading] Fund Summary Fund: Fidelity Advisor® Series Small Cap Fund
Objective [Heading] Investment Objective
Objective, Primary [Text Block] Fidelity Advisor® Series Small Cap Fund seeks long-term growth of capital.
Expense [Heading] Fee Table
Expense Narrative [Text Block] The following table describes the fees and expenses that may be incurred when you buy, hold, and sell shares of the fund.
Shareholder Fees Caption [Text] Shareholder fees
(fees paid directly from your investment) none
Operating Expenses Caption [Text] Annual Operating Expenses
Portfolio Turnover [Heading] Portfolio Turnover
Portfolio Turnover [Text Block] 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 higher taxes when fund shares are held in a taxable account. These costs, which are not reflected in annual operating expenses or in the example, affect the fund's performance. During the most recent fiscal year, the fund's portfolio turnover rate was 44 % of the average value of its portfolio.
Portfolio Turnover, Rate 44.00%
Expense Example Narrative [Text Block] This example helps compare the cost of investing in the fund with the cost of investing in other funds. Let's say, hypothetically, that the annual return for shares of the fund is 5% and that the fees and the annual operating expenses for shares of the fund are exactly as described in the fee table. This example illustrates the effect of fees and expenses, but is not meant to suggest actual or expected fees and expenses or returns, all of which may vary. For every $10,000 you invested, here's how much you would pay in total expenses if you sell all of your shares at the end of each time period indicated:
Strategy [Heading] Principal Investment Strategies
Strategy Narrative [Text Block] Normally investing primarily in common stocks. Normally investing at least 80% of assets in securities of companies with small market capitalizations (which, for purposes of this fund, are those companies with market capitalizations similar to companies in the Russell 2000® Index or the S&P SmallCap 600® Index). Effective December 11, 2025, derivative instruments that provide investment exposure to the investments above or exposure to one or more market risk factors associated with such investments are included in the fund's 80% policy, consistent with the fund's investment policies and limitations with respect to investments in derivatives. Investing in domestic and foreign issuers. Investing in either "growth" stocks or "value" stocks or both. Using fundamental analysis of factors such as each issuer's financial condition and industry position, as well as market and economic conditions, to select investments.
Risk [Heading] Principal Investment Risks
Bar Chart and Performance Table [Heading] Performance
Performance Narrative [Text Block] The following information is intended to help you understand the risks of investing in the fund. The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time. The additional index has characteristics relevant to the fund's investment strategies. Index descriptions appear in the "Additional Index Information" section of the prospectus. Past performance (before and after taxes) is not an indication of future performance. The performance shown does not reflect the impact of any fees paid at the fee-based account or plan level, if applicable. Visit institutional.fidelity.com for more recent performance information.
Performance Information Illustrates Variability of Returns [Text] The information illustrates the changes in the performance of the fund's shares from year to year and compares the performance of the fund's shares to the performance of a securities market index and an additional index over various periods of time.
Performance Availability Website Address [Text] institutional.fidelity.com
Performance Past Does Not Indicate Future [Text] Past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading] Year-by-Year Returns
Highest Quarterly Return, Label    Highest Quarter Return
Highest Quarterly Return, Date Jun. 30, 2020
Highest Quarterly Return 25.66%
Lowest Quarterly Return, Label    Lowest Quarter Return
Lowest Quarterly Return, Date Mar. 31, 2020
Lowest Quarterly Return (27.70%)
Performance Table Heading Average Annual Returns
Performance Table Uses Highest Federal Rate After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes.
Performance Table Not Relevant to Tax Deferred The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan).
Performance Table Explanation after Tax Higher Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
Performance Table Narrative After-tax returns are calculated using the historical highest individual federal marginal income tax rates, but do not reflect the impact of state or local taxes. Actual after-tax returns may differ depending on your individual circumstances. The after-tax returns shown are not relevant if you hold your shares in a retirement account or in another tax-deferred arrangement, such as an employee benefit plan (profit sharing, 401(k), or 403(b) plan). Return After Taxes on Distributions and Sale of Fund Shares may be higher than other returns for the same period due to a tax benefit of realizing a capital loss upon the sale of fund shares.
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund | Fidelity Advisor Series Small Cap Fund  
Risk/Return:  
Management fee none
Distribution and/or Service (12b-1) fees none
Other expenses 0.01%
Total annual operating expenses 0.01%
1 year $ 1
3 years 3
5 years 6
10 years $ 13
2015 (2.33%)
2016 9.91%
2017 14.50%
2018 (15.67%)
2019 33.40%
2020 18.65%
2021 32.80%
2022 (19.97%)
2023 19.24%
2024 11.98%
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund | Return Before Taxes | Fidelity Advisor Series Small Cap Fund  
Risk/Return:  
Label Return Before Taxes
Past 1 year 11.98%
Past 5 years 10.98%
Past 10 years 8.82%
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund | After Taxes on Distributions | Fidelity Advisor Series Small Cap Fund  
Risk/Return:  
Label Return After Taxes on Distributions
Past 1 year 6.69%
Past 5 years 7.97%
Past 10 years 6.65%
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund | After Taxes on Distributions and Sales | Fidelity Advisor Series Small Cap Fund  
Risk/Return:  
Label Return After Taxes on Distributions and Sale of Fund Shares
Past 1 year 10.11%
Past 5 years 8.29%
Past 10 years 6.70%
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund | RS003  
Risk/Return:  
Label Russell 3000® Index
Past 1 year 23.81%
Past 5 years 13.86%
Past 10 years 12.55%
FidelityAdvisorSeriesSmallCapFund-PRO | Fidelity Advisor Series Small Cap Fund | RS002  
Risk/Return:  
Label Russell 2000® Index
Past 1 year 11.54%
Past 5 years 7.40%
Past 10 years 7.82%