Investment Risks	May 01, 2026
Royce International Premier Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce International Premier Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce International Premier Fund \| International Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	In addition to general market risk, the prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes. Furthermore, securities of international companies may be subject to different risks than investments in U.S. securities, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular country or region. Prices of international securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. To the extent the Fund focuses its investments in issuers located in a particular country or region, the Fund is subject to greater risks of volatile economic cycles and/or conditions and developments that may be particular to that country or region. For example, the Fund may be subject to greater risk of adverse securities markets, exchange rates, social, political, regulatory, economic, business, environmental or other developments, or natural disasters. The Fund’s investments are usually denominated in or tied to the currencies of the countries in which they are primarily traded. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar. This may occur even if the value of the investment in the currency’s home country has not declined. These risk factors may affect the prices of international securities issued by companies headquartered in developing countries more than those headquartered in developed countries. For example, many developing countries have in the past experienced high rates of inflation or sharply devalued their currencies against the U.S. dollar, thereby causing the value of investments in companies located in those countries to decline. Transaction costs are often higher in developing countries, and there may be delays in settlement procedures. To the extent that the Fund’s investments in the securities of international companies consist of non-U.S. headquartered companies that trade on a U.S. exchange, some or all of the above-stated risks of investing in international companies may not apply.
Royce International Premier Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in companies headquartered in Japan. Japan’s persistent underlying systemic risks, including high levels of government debt, large structural budget deficits, stubbornly high inflation, an aging and declining population, an uncertain financial sector, low domestic consumption, and certain corporate structural weaknesses, may adversely affect the market performance of companies headquartered in Japan. The Fund’s investment in a limited number of issuers may involve considerably more risk to investors than funds that invest in a larger number of issuers because it may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Information Technology sectors. Industrials sector companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, companies from the Information Technology sector can be significantly affected by the obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants, and general economic conditions.
Royce International Premier Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce International Premier Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce International Premier Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce International Premier Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Micro-Cap Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Micro-Cap Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Micro-Cap Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Information Technology and Industrials sectors. Information Technology sector companies can be significantly affected by the obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants, and general economic conditions. In addition, companies from the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Micro-Cap Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Micro-Cap Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Micro-Cap Fund \| Micro Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of micro-cap securities are generally more volatile than those of larger-cap securities. In addition, because micro-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Micro-Cap Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Micro-Cap Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Micro-Cap Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Premier Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Premier Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Premier Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The Fund’s investment in a limited number of issuers may involve considerably more risk to investors than funds that invest in a larger number of issuers because it may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials sector. These companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Premier Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Premier Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Premier Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Premier Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Premier Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Premier Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Financials sectors. Companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets.
Royce Small-Cap Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Small-Cap Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Opportunity Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Opportunity Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Opportunity Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Information Technology sectors. Industrials sector companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, companies from the Information Technology sector can be significantly affected by the obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants, and general economic conditions.
Royce Small-Cap Opportunity Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The Fund’s opportunistic value investment approach may not be successful and could result in portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “value” stocks may remain undervalued for long periods (particularly during times of low or declining interest rates), undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Opportunity Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Opportunity Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Opportunity Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Opportunity Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Special Equity Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Special Equity Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Special Equity Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Consumer Discretionary sectors. Companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, Consumer Discretionary companies can be significantly affected by the performance of the overall economy, particularly the level of consumer inflation, interest rates, competition, consumer confidence and spending, and changes in demographics and consumer tastes.
Royce Small-Cap Special Equity Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund held a significant portion of its assets in cash and/or cash equivalents (i.e., repurchase agreements). Such an investment approach may result in lower returns and can expose the fund to inflation risk, as the purchasing power of cash may erode over time. Additionally, repurchase agreements involve certain risks, including the risk that the counterparty may default on its obligations. The Fund’s intensive value investment approach may not be successful and could result in portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “value” stocks may remain undervalued for long periods (particularly during times of low or declining interest rates), undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Special Equity Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Special Equity Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Special Equity Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Special Equity Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Total Return Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Total Return Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Total Return Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Financials and Industrials sectors. Companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets. In addition, Industrials sector companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Small-Cap Total Return Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, there is no guarantee that the “Special Situation” companies will take the necessary steps to increase the value of their stocks or that the steps taken will have the intended results. Further, selecting stocks based, in part, on a history of paying dividends may cause the Fund to underperform relative to similar funds that do not select stocks on this basis. Finally, various factors may lead a company to unexpectedly reduce or eliminate dividend payments, which could adversely affect the market price of its securities. Therefore, securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Total Return Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Total Return Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Small-Cap Total Return Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes. There is no assurance that there will be net investment income to distribute and/or that the Fund will achieve its investment goals.
Royce Small-Cap Total Return Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply
Royce Small-Cap Total Return Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Value Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Value Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Value Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Consumer Discretionary and Financials sectors. Consumer Discretionary companies can be significantly affected by the performance of the overall economy, particularly the level of consumer inflation, interest rates, competition, consumer confidence and spending, and changes in demographics and consumer tastes. Companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets.
Royce Small-Cap Value Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “value” stocks may remain undervalued for long periods (particularly during times of low or declining interest rates), undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Value Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Value Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Small-Cap Value Fund \| Equity Securities Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Value Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Value Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Smaller-Companies Growth Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Smaller-Companies Growth Fund is subject to market risk— the possibility that common stock prices will decline over short and/ or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Smaller-Companies Growth Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Information Technology and Health Care sectors. Information Technology sector companies can be significantly affected by the obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants, and general economic conditions. Health Care sector companies are subject to government regulation and reimbursement rates, as well as government approval of products and services, which could have a significant effect on price and availability, and can be significantly affected by product liability claims, rapid obsolescence, and patent expirations.
Royce Smaller-Companies Growth Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s growth prospects and/or current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “growth” stocks are typically more sensitive to market movements and high or increasing interest rates because their market prices tend to reflect future expectations. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Smaller-Companies Growth Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Smaller-Companies Growth Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Smaller-Companies Growth Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of equity securities of companies with stock market capitalizations up to $7.5 billion are generally more volatile than those of larger-cap securities. In addition, because these securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Smaller-Companies Growth Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Smaller-Companies Growth Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce SMid-Cap Total Return Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce SMid-Cap Total Return Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce SMid-Cap Total Return Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Financials and Industrials sectors. Companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets. In addition, companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce SMid-Cap Total Return Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, there is no guarantee that the “Special Situation” companies will take the necessary steps to increase the value of their stocks or that the steps taken will have the intended results. Further, selecting stocks based, in part, on a history of paying dividends may cause the Fund to underperform relative to funds that do not select stocks on this basis. Finally, various factors may lead a company to unexpectedly reduce or eliminate dividend payments, which could adversely affect the market price of its securities. Therefore, securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce SMid-Cap Total Return Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce SMid-Cap Total Return Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce SMid-Cap Total Return Fund \| S Mid Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of equity securities of smid-cap companies are generally more volatile than those of larger-cap securities. In addition, because these securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes. There is no assurance that there will be net investment income to distribute and/or that the Fund will achieve its investment goals.
Royce SMid-Cap Total Return Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce SMid-Cap Total Return Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Micro-Cap Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Information Technology and Industrials sectors. Information Technology sector companies can be significantly affected by the obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants, and general economic conditions. In addition, companies from the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Micro Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of micro-cap securities are generally more volatile than those of larger-cap securities. In addition, because micro-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Micro-Cap Fund - Consultant Class \| Royce Micro-Cap Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Premier Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The Fund’s investment in a limited number of issuers may involve considerably more risk to investors than funds that invest in a larger number of issuers because it may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials sector. These companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger- cap companies or other asset classes.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Premier Fund - Consultant Class \| Royce Premier Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Financials sectors. Companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| U S Investments [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar. Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values. Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Fund - Consultant Class \| Royce Small-Cap Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Opportunity Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Information Technology sectors. Industrials sector companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, companies from the Information Technology sector can be significantly affected by the obsolescence of existing technology, short product cycles, falling prices and profits, competition from new market entrants, and general economic conditions.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The Fund’s opportunistic value investment approach may not be successful and could result in portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “value” stocks may remain undervalued for long periods (particularly during times of low or declining interest rates), undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Opportunity Fund - Consultant & R Class \| Royce Small-Cap Opportunity Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Special Equity Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Consumer Discretionary sectors. Companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, Consumer Discretionary companies can be significantly affected by the performance of the overall economy, particularly the level of consumer inflation, interest rates, competition, consumer confidence and spending, and changes in demographics and consumer tastes.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund held a significant portion of its assets in cash and/or cash equivalents (i.e., repurchase agreements). Such an investment approach may result in lower returns and can expose the fund to inflation risk, as the purchasing power of cash may erode over time. Additionally, repurchase agreements involve certain risks, including the risk that the counterparty may default on its obligations. The Fund’s intensive value investment approach may not be successful and could result in portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “value” stocks may remain undervalued for long periods (particularly during times of low or declining interest rates), undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Special Equity Fund - Consultant Class \| Royce Small-Cap Special Equity Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Total Return Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Financials and Industrials sectors. Companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets. In addition, Industrials sector companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, there is no guarantee that
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes. There is no assurance that there will be net investment income to distribute and/or that the Fund will achieve its investment goals.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Total Return Fund - Consultant & R Class \| Royce Small-Cap Total Return Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Premier Fund - A Class \| Royce Premier Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Premier Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Premier Fund - A Class \| Royce Premier Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The Fund’s investment in a limited number of issuers may involve considerably more risk to investors than funds that invest in a larger number of issuers because it may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials sector. These companies can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control.
Royce Premier Fund - A Class \| Royce Premier Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Premier Fund - A Class \| Royce Premier Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Premier Fund - A Class \| Royce Premier Fund \| Foreign Investments Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar.
Royce Premier Fund - A Class \| Royce Premier Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Premier Fund - A Class \| Royce Premier Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Premier Fund - A Class \| Royce Premier Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	A significant portion of the Fund’s assets may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Financials sectors. Companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, companies in the Financials sector are subject to extensive government regulation, can be significantly affected by changes in interest rates, the availability and cost of capital, the rate of corporate and consumer debt defaults, and price competition. They can also be subject to relatively rapid change due to government interventions in capital, credit, and currency markets.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Investment in foreign securities involves risks that may not be encountered in U.S. investments, including adverse political, social, economic, environmental, public health, and/or other developments that are unique to a particular region or country. Prices of foreign securities in particular countries or regions may, at times, move in a different direction and/or be more volatile than those of U.S. securities. Because the Fund does not intend to hedge its foreign currency exposure, the U.S. dollar value of the Fund’s investments may be harmed by declines in the value of foreign currencies in relation to the U.S. dollar. Royce’s estimate of a company’s current worth may prove to be inaccurate, or this estimate may not be recognized by other investors, which could lead to portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark index. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values. Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. 6 \| The Royce Fund Prospectus 2026 In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Fund - A Class \| Royce Small-Cap Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Market Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As with any mutual fund that invests primarily in common stocks, Royce Small-Cap Special Equity Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Sector Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund invested a significant portion of its assets in a limited number of issuers. Such a portfolio may involve considerably more risk to investors than one that invests in a larger number of issuers because such a portfolio may be more susceptible to any single corporate, economic, political, regulatory, or market event. A significant portion of the Fund’s assets also may, from time to time, be invested in companies from a single sector or a limited number of sectors. Such an investment approach may involve considerably more risk to investors than one that is more broadly diversified across economic sectors because it may be more susceptible to corporate, economic, political, regulatory, or market events that adversely affect the relevant sector(s). As of December 31, 2025, the Fund invested a significant portion of its assets in companies from the Industrials and Consumer Discretionary sectors. Companies in the Industrials sector can be significantly affected by general economic trends, commodity prices, legislation, government regulation and spending, import and export controls, worldwide competition, changes in consumer sentiment and spending, and liability for environmental damage, depletion of resources, and mandated expenditures for safety and pollution control. In addition, Consumer Discretionary companies can be significantly affected by the performance of the overall economy, particularly the level of consumer inflation, interest rates, competition, consumer confidence and spending, and changes in demographics and consumer tastes.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Underperformance Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	As of December 31, 2025, the Fund held a significant portion of its assets in cash and/or cash equivalents (i.e., repurchase agreements). Such an investment approach may result in lower returns and can expose the fund to inflation risk, as the purchasing power of cash may erode over time. Additionally, repurchase agreements involve certain risks, including the risk that the counterparty may default on its obligations. The Fund’s intensive value investment approach may not be successful and could result in portfolio losses or underperformance relative to similar funds and/or the Fund’s benchmark indexes. Additionally, “value” stocks may remain undervalued for long periods (particularly during times of low or declining interest rates), undervaluation may become more severe, or perceived undervaluation may actually represent intrinsic value. Securities in the Fund’s portfolio may not increase as much as the market as a whole, or perform negatively, and some securities may continue to be undervalued for long periods of time or may never reach what Royce believes are their full market values.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Cybersecurity Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	Cybersecurity incidents may allow an unauthorized party to gain access to Fund assets, Fund or investor data, or proprietary information. Such incidents may also cause the Fund, Royce, and/or their service providers to suffer data breaches, data corruption, or loss of operational functionality. In addition, cybersecurity incidents may prevent Fund investors from purchasing, redeeming, or exchanging shares, as well as from receiving distributions. The Fund and Royce have limited ability to prevent or mitigate cybersecurity incidents affecting third-party service providers, and such third-party service providers may have limited indemnification obligations to the Fund or Royce. Cybersecurity incidents may result in significant financial losses to the Fund and its shareholders, and substantial costs may be incurred in order to prevent any future cybersecurity incidents. Issuers of securities in which the Fund invests are also subject to cybersecurity risks, and the value of these securities could decline if the issuers are affected by cybersecurity incidents.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Small Cap Risk [Member]
Prospectus [Line Items]
Risk [Text Block]	The prices of small-cap securities are generally more volatile than those of larger-cap securities. In addition, because small-cap securities tend to have significantly lower trading volumes than larger-cap securities, the Fund may have difficulty selling holdings or may only be able to sell holdings at prices substantially lower than what Royce believes they are worth. Therefore, the Fund may involve considerably more risk of loss and its returns may differ significantly from funds investing in larger-cap companies or other asset classes.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Risk Lose Money [Member]
Prospectus [Line Items]
Risk [Text Block]	As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.
Royce Small-Cap Special Equity Fund - A Class \| Royce Small-Cap Special Equity Fund \| Risk Not Insured [Member]
Prospectus [Line Items]
Risk [Text Block]	Investments in the Fund are not bank deposits and are not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. This Prospectus is not a contract.

Investment Risks

May 01, 2026

As with any mutual fund that invests primarily in common stocks, Royce International Premier Fund is subject to market risk—the possibility that common stock prices will decline over short and/or extended periods of time due to overall market, financial, economic, and political conditions or events; changes in investor sentiment; governmental or central bank actions and/or market interventions; banking instability; trade disputes, tariffs, trade barriers, and economic sanctions and corresponding countermeasures; major cybersecurity events; acts of terrorism; armed conflicts; pandemics or epidemics; natural disasters; and other events or factors that may or may not be directly related to the issuer of a security held by the Fund. Economies and financial markets throughout the world are increasingly interconnected, and events or changes in one country or region could have significant adverse effects on global economies, markets, industries, and individual companies in ways that cannot necessarily be foreseen. As a result, the value of your investment in the Fund will fluctuate, sometimes sharply and unpredictably, and you could lose money over short and/or long periods of time.

Royce International Premier Fund | International Securities Risk [Member]