Royce International Premier Fund Market Risk [Member] International Securities Risk [Member] Sector Risk [Member] Underperformance Risk [Member] Cybersecurity Risk [Member] Royce Micro-Cap Fund Micro Cap Risk [Member] Foreign Investments Risk [Member] Royce Premier Fund Small Cap Risk [Member] Royce Small-Cap Fund Royce Small-Cap Fund - Investment Class Royce Small-Cap Fund - Service Class Royce Small-Cap Fund - Institutional Class Royce Small-Cap Opportunity Fund Royce Small-Cap Special Equity Fund Royce Small-Cap Total Return Fund Royce Small-Cap Value Fund Equity Securities Risk [Member] Royce Smaller-Companies Growth Fund Royce SMid-Cap Total Return Fund Royce Smid-Cap Total Return Fund S Mid Cap Risk [Member] Royce Micro-Cap Fund - Consultant Class Royce Premier Fund - Consultant Class Royce Small-Cap Fund - Consultant Class U S Investments [Member] Royce Small-Cap Opportunity Fund - Consultant & R Class Royce Small-Cap Special Equity Fund - Consultant Class Royce Small-Cap Total Return Fund - Consultant & R Class Royce Premier Fund - A Class Royce Small-Cap Fund - A Class Royce Small-Cap Special Equity Fund - A Class Royce Small-Cap Special Equity Fund - A Class Royce International Premier Fund - Investment Class Royce International Premier Fund - Service Class Royce International Premier Fund - Institutional Class Royce Micro-Cap Fund - Investment Class Royce Micro-Cap Fund - Service Class Royce Premier Fund - Investment Class Royce Premier Fund - Service Class Royce Premier Fund - Institutional Class Royce Small-Cap Opportunity Fund - Investment Class Royce Small-Cap Opportunity Fund - Service Class Royce Small-Cap Opportunity Fund - Institutional Class Royce Small-Cap Special Equity Fund - Investment Class Royce Small-Cap Special Equity Fund - Service Class Royce Small-Cap Special Equity Fund - Institutional Class Royce Small-Cap Total Return Fund - Investment Class Royce Small-Cap Total Return Fund - Service Class Royce Small-Cap Total Return Fund - Institutional Class Royce Small-Cap Value Fund - Investment Class Royce Small-Cap Value Fund - Service Class Royce Smaller-Companies Growth Fund - Investment Class Royce Smaller-Companies Growth Fund - Service Class Royce Smaller-Companies Growth Fund - Institutional Class Royce Smid-Cap Total Return Fund - Investment Class Royce Smid-Cap Total Return Fund - Service Class Royce Micro-Cap Fund - Consultant Class Royce Premier Fund - Consultant Class Royce Small-Cap Fund - Consultant Class Royce Small-Cap Opportunity Fund - Consultant Class Royce Small-Cap Opportunity Fund - R Class Royce Small-Cap Special Equity Fund - Consultant Class Royce Small-Cap Total Return Fund - Consultant Class Royce Small-Cap Total Return Fund - R Class Royce Premier Fund - A Class Royce Small-Cap Fund - A Class MSCI ACWI ex USA IMI Index (Reflects no deductions for fees, expenses, or taxes) MSCI ACWI ex USA Small Cap Index (Reflects no deductions for fees, expenses, or taxes) Russell 3000 Index (Reflects no deductions for fees, expenses, or taxes) Russell Microcap Index (Reflects no deductions for fees, expenses, or taxes) Russell 2000 Index (Reflects no deductions for fees, expenses, or taxes) Russell 2000 Value Index (Reflects no deductions for fees, expenses, or taxes) Russell 2000 Growth Index (Reflects no deductions for fees, expenses, or taxes) Russell 2500 Index (Reflects no deductions for fees, expenses, or taxes) Russell 2500 Value Index (Reflects no deductions for fees, expenses, or taxes) Russell 3000 Index (Reflects no deductions for fees, expenses, or taxes) Russell 2000 Value Index (Reflects no deductions for fees, expenses, or taxes) Russell 2000 Index (Reflects no deductions for fees, expenses, or taxes) Royce Small-Cap Special Equity Fund - A Class [Default Label] Royce Micro-Cap Fund - Consultant Class [Default Label] Royce Premier Fund - Consultant Class [Default Label] Royce Small-Cap Fund - Consultant Class [Default Label] Royce Small-Cap Special Equity Fund - Consultant Class [Default Label] Royce Premier Fund - A Class [Default Label] Royce Small-Cap Fund - A Class [Default Label] Russell 3000 Index (Reflects no deductions for fees, expenses, or taxes) [Default Label] Russell 2000 Value Index (Reflects no deductions for fees, expenses, or taxes) [Default Label] Russell 2000 Index (Reflects no deductions for fees, expenses, or taxes) [Default Label]