Royce Capital Fund - Micro-Cap Portfolio Royce Capital Fund - Small-Cap Portfolio Royce Capital Fund - Small-Cap Portfolio - Investment Class Royce Capital Fund - Small-Cap Portfolio - Service Class Royce Capital Fund - Micro-Cap Portfolio - Investment Class Royce Capital Fund - Micro-Cap Portfolio - Service Class Market Risk [Member] Microcap Risk [Member] Sector Risk [Member] Foreign Investment Risk [Member] Allocation Adjustment Risk [Member] Underperformance Risk [Member] Cybersecurity Risk [Member] Russell 3000 Index (Reflects no deductions for fees, expenses, or taxes) [Member] Russell Microcap Index (Reflects no deductions for fees, expenses, or taxes) [Member] Russell 2000 Index (Reflects no deductions for fees, expenses, or taxes) [Member] Russell 3000 Index (Reflects no deductions for fees, expenses, or taxes) [Member] Russell 2000 Value Index (Reflects no deductions for fees, expenses, or taxes) [Member] Russell 2000 Index (Reflects no deductions for fees, expenses, or taxes) [Member] Russell 3000 Index (Reflects no deductions for fees, expenses, or taxes) [Member] [Default Label] Russell 2000 Index (Reflects no deductions for fees, expenses, or taxes) [Member] [Default Label]