Shareholder Report, Average Annual Return (Details) 190994_Buffalo Mid Cap Discovery Fund_Institutional Class_TSR Annual {Institutional Class} |
12 Months Ended | 60 Months Ended | 81 Months Ended |
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
|
| Institutional Class | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Buffalo Mid Cap Discovery Fund Institutional Class | ||
| Average Annual Return, Percent | (6.63%) | (2.11%) | 3.65% |
| Russell 3000 Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Russell 3000 Index | ||
| Average Annual Return, Percent | 18.09% | 10.87% | 13.56% |
| Russell Midcap Growth Index [Member] | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Russell Midcap Growth Index | ||
| Average Annual Return, Percent | 9.56% | 5.37% | 9.69% |