Performance Management - BERKSHIRE FUNDS |
May 01, 2026 |
|---|---|
| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | PERFORMANCE |
| Performance Narrative [Text Block] | The following bar chart and table provide some indication of the risk of investing in the Fund. The bar chart shows changes in the Fund’s performance from calendar year to year for the past ten years, together with the best and worst quarters during that time. The table shows how the Fund’s average annual returns (before and after taxes) for the periods of one year, five years, and ten years, compared to those of broad-based securities market indices. All presentations assume reinvestment of dividends and distributions. As with all mutual funds, past performance (before and after taxes) is not necessarily an indication of future results.
You can obtain updated performance information on our website at berkshirefunds.com, or by calling 877.526.0707. |
| Performance Past Does Not Indicate Future [Text] | As with all mutual funds, past performance (before and after taxes) is not necessarily an indication of future results. |
| Performance Information Illustrates Variability of Returns [Text] | The bar chart shows changes in the Fund’s performance from calendar year to year for the past ten years, together with the best and worst quarters during that time. |
| Bar Chart [Heading] | CALENDAR YEAR TOTAL RETURNS |
| Bar Chart Closing [Text Block] | Best Quarter (6/30/25) +44.28% Worst Quarter (6/30/22) -43.06%
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| Performance Table Heading | Average Annual Total Return (for periods ended 12/31/25) |
| Performance Table Uses Highest Federal Rate | 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. |
| Performance Table Not Relevant to Tax Deferred | After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. |
| Performance Table Closing [Text Block] | 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. Your actual after-tax returns will depend on your tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. |
| Performance Availability Website Address [Text] | berkshirefunds.com |
| Performance Availability Phone [Text] | 877.526.0707 |
| Berkshire Focus Fund Shares | |
| Prospectus [Line Items] | |
| Highest Quarterly Return, Label [Optional Text] | Best Quarter |
| Highest Quarterly Return | 44.28% |
| Highest Quarterly Return, Date | Jun. 30, 2025 |
| Lowest Quarterly Return, Label [Optional Text] | Worst Quarter |
| Lowest Quarterly Return | (43.06%) |
| Lowest Quarterly Return, Date | Jun. 30, 2022 |