Shareholder Report, Line Graph (Details) - USD ($) |
12 Months Ended | 24 Months Ended | 36 Months Ended | 48 Months Ended | 60 Months Ended | 72 Months Ended | 84 Months Ended | 96 Months Ended | 108 Months Ended | 120 Months Ended | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Jun. 30, 2016 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2022 |
Jun. 30, 2023 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2026 |
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| Berkshire Focus Fund | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Berkshire Focus Fund | ||||||||||||
| Accumulated Value | [1] | $ 10,396 | $ 13,883 | $ 19,588 | $ 22,916 | $ 29,572 | $ 45,420 | $ 21,331 | $ 23,550 | $ 30,681 | $ 40,349 | $ 83,175 | |
| S&P 500® Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P 500® Index | ||||||||||||
| Accumulated Value | [1] | $ 10,079 | $ 11,189 | $ 12,456 | $ 13,249 | $ 15,151 | $ 21,807 | $ 20,222 | $ 22,758 | $ 29,414 | $ 34,010 | $ 42,271 | |
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