Shareholder Report, Line Graph (Details) 190997_Buffalo Early Stage Growth Fund_Institutional Class_TSR Annual {Institutional Class} - USD ($) |
12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
Mar. 31, 2023 |
Mar. 31, 2022 |
Mar. 31, 2021 |
Mar. 31, 2020 |
Jul. 01, 2019 |
Mar. 31, 2026 |
|
| Institutional Class | ||||||||
| Account Value [Line Items] | ||||||||
| Line Graph and Table Measure Name | Buffalo Early Stage Growth Fund Institutional Class | |||||||
| Accumulated Value | $ 315,085 | $ 340,819 | $ 317,178 | $ 369,025 | $ 425,150 | $ 199,364 | $ 250,000 | $ 342,594 |
| Russell 3000 Index [Member] | ||||||||
| Account Value [Line Items] | ||||||||
| Line Graph and Table Measure Name | Russell 3000 Index | |||||||
| Accumulated Value | 499,505 | 465,873 | 360,323 | 394,141 | 352,149 | 216,670 | 250,000 | $ 589,843 |
| Russell 2000 Growth Index [Member] | ||||||||
| Account Value [Line Items] | ||||||||
| Line Graph and Table Measure Name | Russell 2000 Growth Index | |||||||
| Accumulated Value | $ 329,546 | $ 346,378 | $ 287,817 | $ 321,929 | $ 375,766 | $ 197,562 | $ 250,000 | $ 407,241 |