S000000584 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 119 Months Ended | 120 Months Ended | 199 Months Ended | 339 Months Ended | ||
|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
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| Russell 2000® Growth Index (reflects no deduction for fees, expenses or taxes) | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 13.01% | 3.18% | 6.67% | 9.57% | ||||
| Russell 3000® Index (reflects no deduction for fees, expenses or taxes) | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 17.15% | 13.15% | 9.16% | 14.29% | ||||
| BARON SMALL CAP FUND | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | (0.90%) | 2.51% | 10.71% | 9.73% | ||||
| Performance Inception Date | Sep. 30, 1997 | |||||||
| BARON SMALL CAP FUND | After Taxes on Distributions | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | (2.95%) | 0.54% | 8.10% | 8.41% | ||||
| Performance Inception Date | Sep. 30, 1997 | |||||||
| BARON SMALL CAP FUND | After Taxes on Distributions and Sales | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 0.93% | 1.89% | 8.27% | 8.28% | ||||
| Performance Inception Date | Sep. 30, 1997 | |||||||
| Institutional Shares | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | [1] | (0.66%) | 2.77% | 11.00% | 9.89% | |||
| Performance Inception Date | [1] | May 29, 2009 | ||||||
| R6 Shares | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | [1] | (0.66%) | 2.77% | 9.89% | 10.99% | |||
| Performance Inception Date | [1] | Jan. 29, 2016 | ||||||
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