S000000585 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 112 Months Ended | 120 Months Ended | 199 Months Ended | 310 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 3000® Growth Index (reflects no deduction for fees, expenses or taxes) | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 18.15% | 14.59% | 8.07% | 17.59% | ||||
| S&P 500 Index (reflects no deduction for fees, expenses or taxes) | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 17.88% | 14.42% | 8.42% | 14.82% | ||||
| BARON OPPORTUNITY FUND | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 19.43% | 9.80% | 19.83% | 10.42% | ||||
| Performance Inception Date | Feb. 29, 2000 | |||||||
| BARON OPPORTUNITY FUND | After Taxes on Distributions | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 18.27% | 8.79% | 18.01% | 9.50% | ||||
| Performance Inception Date | Feb. 29, 2000 | |||||||
| BARON OPPORTUNITY FUND | After Taxes on Distributions and Sales | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | 12.32% | 7.50% | 16.19% | 8.77% | ||||
| Performance Inception Date | Feb. 29, 2000 | |||||||
| Institutional Shares | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | [1] | 19.73% | 10.08% | 20.15% | 10.60% | |||
| Performance Inception Date | [1] | May 29, 2009 | ||||||
| R6 Shares | ||||||||
| Prospectus [Line Items] | ||||||||
| Average Annual Return, Percent | [1] | 19.72% | 10.08% | 10.61% | 20.16% | |||
| Performance Inception Date | [1] | Aug. 31, 2016 | ||||||
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