Shareholder Report, Average Annual Return (Details)

12 Months Ended

60 Months Ended

120 Months Ended

Jun. 30, 2026

Jun. 30, 2026

Jun. 30, 2026

Berkshire Focus Fund

Average Annual Return [Line Items]

Line Graph and Table Measure Name

Berkshire Focus Fund

Average Annual Return, Percent

^[1]

83.44%

11.79%

23.59%

S&P 500® Index

Average Annual Return [Line Items]

Line Graph and Table Measure Name

S&P 500® Index

Average Annual Return, Percent

^[1]

22.32%

13.41%

15.51%

[1]	*The Fund’s past performance is not a good predictor of the Fund’s future performance.* The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares.