Expense Example - BERKSHIRE FUNDS - Berkshire Focus Fund Shares	May 01, 2026 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 198
Expense Example, with Redemption, 3 Years	612
Expense Example, with Redemption, 5 Years	1,052
Expense Example, with Redemption, 10 Years	$ 2,275

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