Shareholder Report, Average Annual Return (Details) 190993_Buffalo Mid Cap Growth Fund_Investor Class_TSR Annual {Investor Class} |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2026 |
Mar. 31, 2026 |
|
| Investor Class | |||
| Average Annual Return [Line Items] | |||
| Line Graph and Table Measure Name | Buffalo Mid Cap Growth Fund Investor Class | ||
| Average Annual Return, Percent | (6.59%) | (0.86%) | 7.75% |
| 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% | 13.72% |
| 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% | 11.69% |