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S000004423 [Member] Average Annual Total Returns
12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Russell 3000 Index (reflects no deductions for fees, expenses or taxes)      
Prospectus [Line Items]      
Average Annual Return, Percent 23.81% 13.86% 12.55%
Russell Microcap Index (reflects no deductions for fees, expenses or taxes)      
Prospectus [Line Items]      
Average Annual Return, Percent 13.70% 6.97% 6.77%
Class N      
Prospectus [Line Items]      
Average Annual Return, Percent 17.55% 16.73% 7.12%
Class N | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent [1] 16.55% 13.92% 5.35%
Class N | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent [1] 10.53% 12.71% 5.15%
[1] After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement plans.