| OPPENHEIMER DISCOVERY MID CAP GROWTH FUND | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>The Fund Summary </b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>Investment Objective.</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The Fund seeks capital appreciation. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>Fees and Expenses of the Fund.</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| This table describes the fees and expenses that you may pay if you buy and hold or redeem shares of the Fund. You may qualify for sales charge discounts if you (or you and your spouse) invest, or agree to invest in the future, at least $25,000 in certain funds in the Oppenheimer family of funds. More information about these and other discounts and sales charge waivers is available from your financial professional and in the section “About Your Account” beginning on page 13 of the prospectus, in the appendix to the prospectus titled “Special Sales Charge Arrangements and Waivers” and in the section “How to Buy Shares” beginning on page 43 in the Fund’s Statement of Additional Information. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>Shareholder Fees </b><br/>(fees paid directly from your investment) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| <b>Annual Fund Operating Expenses</b><br/> (expenses that you pay each year as a percentage of the value of your investment) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| <b>Example.</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The following Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in a class of shares of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Any applicable fee waivers and/or expense reimbursements are reflected in the below examples for the first year only. Although your actual costs may be higher or lower, based on these assumptions your expenses would be as follows: | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>If shares are redeemed </b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| <b>If shares are not redeemed</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| <b>Portfolio Turnover. </b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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 the annual fund operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 108% of the average value of its portfolio. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>Principal Investment Strategies.</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The Fund mainly invests in common stocks of U.S. companies that the portfolio managers expect to have above-average growth rates. The Fund seeks to invest in newer companies or in more established companies that are in the early growth phase of their business cycle, which is typically marked by above-average growth rates. Under normal circumstances, the Fund will invest at least 80% of its net assets (plus any borrowings for investment purposes) in equity securities of “mid-cap” issuers. The Fund defines mid-cap issuers as those issuers that are within the range of market capitalizations of the Russell Midcap® Growth Index. This range is subject to change at any time due to market activity or changes in the composition of that index. The range of the Russell Midcap Growth Index is reconstituted annually to preserve its capitalization characteristics. The Fund may invest up to 20% of its net assets in companies in other market capitalization ranges. The Fund measures a company’s capitalization at the time the Fund buys a security, and is not required to sell a security if the issuer’s capitalization moves outside of the Fund’s definition of mid-cap issuers. The Fund invests primarily in U.S. companies but may also purchase securities of issuers in any country, including developed countries and emerging markets. The Fund has no limits on the amount of its assets that can be invested in foreign securities. In selecting investments for the Fund, the portfolio managers look for companies with high growth potential using a “bottom-up” stock selection process. The “bottom-up” approach focuses on fundamental analysis of individual issuers before considering the impact of overall economic, market or industry trends. This approach includes analysis of a company’s financial statements and management structure and consideration of the company’s operations, product development, and its industry position. The portfolio managers currently focus on high-growth companies that are characterized by industry leadership, market share growth, high caliber management teams, sustainable competitive advantages, and strong growth themes or new innovative products or services. The portfolio managers monitor individual issuers for changes in the factors above, which may trigger a decision to sell a security, but does not require a decision to do so. The factors considered by the portfolio managers may vary in particular cases and may change over time. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>Principal Risks.</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The price of the Fund’s shares can go up and down substantially. The value of the Fund’s investments may fall due to adverse changes in the markets in which the Fund invests or because of poor investment selection, which could cause the Fund to underperform other funds with similar investment objectives. There is no assurance that the Fund will achieve its investment objective. When you redeem your shares, they may be worth less than what you paid for them. These risks mean that you can lose money by investing in the Fund. Risks of Investing in Stocks. The value of the Fund’s portfolio may be affected by changes in the stock markets. Stock markets may experience significant short-term volatility and may fall sharply at times. Adverse events in any part of the equity or fixed-income markets may have unexpected negative effects on other market segments. Different stock markets may behave differently from each other and U.S. stock markets may move in the opposite direction from one or more foreign stock markets. The prices of individual stocks generally do not all move in the same direction at the same time. A variety of factors can negatively affect the price of a particular company’s stock. These factors may include, but are not limited to: poor earnings reports, a loss of customers, litigation against the company, general unfavorable performance of the company’s sector or industry, or changes in government regulations affecting the company or its industry. To the extent that securities of a particular type are emphasized (for example foreign stocks, stocks of small- or mid-cap companies, growth or value stocks, or stocks of companies in a particular industry), fund share values may fluctuate more in response to events affecting the market for those types of securities. Risks of Mid-Cap Companies. Mid-cap companies generally involve greater risk of loss than larger companies. The prices of securities issued by mid-sized companies may be more volatile and their securities may be less liquid and more difficult to sell than those of larger companies. They may have less established markets, fewer customers and product lines, less management depth and more limited access to financial resources. Mid-cap companies may not pay dividends for some time, if at all. Risks of Growth Investing. If a growth company’s earnings or stock price fails to increase as anticipated, or if its business plans do not produce the expected results, its securities may decline sharply. Growth companies may be newer or smaller companies that may experience greater stock price fluctuations and risks of loss than larger, more established companies. Newer growth companies tend to retain a large part of their earnings for research, development or investments in capital assets. Therefore, they may not pay any dividends for some time. Growth investing has gone in and out of favor during past market cycles and is likely to continue to do so. During periods when growth investing is out of favor or when markets are unstable, it may be more difficult to sell growth company securities at an acceptable price. Growth stocks may also be more volatile than other securities because of investor speculation. Risks of Foreign Investing. Foreign securities are subject to special risks. Securities traded in foreign markets may be less liquid and more volatile than those traded in U.S. markets. Foreign issuers are usually not subject to the same accounting and disclosure requirements that U.S. companies are subject to, which may make it difficult for the Fund to evaluate a foreign company’s operations or financial condition. A change in the value of a foreign currency against the U.S. dollar will result in a change in the U.S. dollar value of investments denominated in that foreign currency and in the value of any income or distributions the Fund may receive on those investments. The value of foreign investments may be affected by exchange control regulations, foreign taxes, higher transaction and other costs, delays in the settlement of transactions, changes in economic or monetary policy in the United States or abroad, expropriation or nationalization of a company’s assets, or other political and economic factors. In addition, due to the inter-relationship of global economies and financial markets, changes in political and economic factors in one country or region could adversely affect conditions in another country or region. Investments in foreign securities may also expose the Fund to time-zone arbitrage risk. Foreign securities may trade on weekends or other days when the Fund does not price its shares. As a result, the value of the Fund’s net assets may change on days when you will not be able to purchase or redeem the Fund’s shares. At times, the Fund may emphasize investments in a particular country or region and may be subject to greater risks from adverse events that occur in that country or region. Foreign securities and foreign currencies held in foreign banks and securities depositories may be subject to only limited or no regulatory oversight. Industry and Sector Focus. At times the Fund may increase the relative emphasis of its investments in a particular industry or sector. The prices of stocks of issuers in a particular industry or sector may go up and down in response to changes in economic conditions, government regulations, availability of basic resources or supplies, or other events that affect that industry or sector more than others. To the extent that the Fund increases the relative emphasis of its investments in a particular industry or sector, its share values may fluctuate in response to events affecting that industry or sector. To some extent that risk may be limited by the Fund’s policy of not concentrating its investments in any one industry. Cyclical Opportunities. At times, the Fund might seek to take advantage of short-term market movements or changes in the business cycle by investing in companies or industries that are sensitive to those changes. For example, when the economy is expanding, companies in consumer durables and the technology sector might benefit. There is a risk that, if a cyclical event does not have the anticipated effect or when the issuer or industry is out of phase in the business cycle, the value of the Fund’s investment could fall. Who Is the Fund Designed For? The Fund is designed primarily for investors seeking capital appreciation. Those investors should be willing to assume the risks of short-term share price fluctuations and losses that are typical for an aggressive growth fund emphasizing mid-cap stock investments. The Fund does not seek current income and is not designed for investors needing current income. The Fund is not a complete investment program. You should carefully consider your own investment goals and risk tolerance before investing in the Fund. An investment in the Fund is not a deposit of any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>The Fund’s Past Performance.</b> | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The bar chart and table below provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance (for Class A Shares) from calendar year to calendar year and by showing how the Fund’s average annual returns for the periods of time shown in the table compare with those of a broad measure of market performance. The Fund’s past investment performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Sales charges and taxes are not reflected in the bar chart and if those charges were included, returns would be less than those shown. More recent performance information is available by calling the toll-free number on the back of this prospectus and on the Fund’s website: https://www.oppenheimerfunds.com/fund/DiscoveryMidCapGrowthFund | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Sales charges and taxes are not included and the returns would be lower if they were. During the period shown, the highest return for a calendar quarter was 16.11% (1st Qtr 12) and the lowest return for a calendar quarter was -25.50% (4th Qtr 08). For the period from January 1, 2018 to September 30, 2018 the return before sales charges and taxes was 15.20%. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| The following table shows the average annual total returns for each class of the Fund’s shares. After-tax returns are calculated using the highest individual federal marginal income tax rates and do not reflect the impact of state or local taxes. Your actual after-tax returns, depending on your individual tax situation, may differ from those shown and after-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns are shown for only one class and after-tax returns for other classes will vary. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| <b>Average Annual Total Returns</b> for the periods ended December 31, 2017 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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