v3.26.1
Shareholder Report, Average Annual Return (Details) 190991_Buffalo High Yield 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 High Yield Fund Institutional Class    
Average Annual Return, Percent 4.70% 4.90% 5.90%
Bloomberg U.S. Universal Bond Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Bloomberg U.S. Universal Bond Index    
Average Annual Return, Percent 4.64% 0.65% 1.50%
ICE BofA U.S. High Yield Index [Member]      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name ICE BofA U.S. High Yield Index    
Average Annual Return, Percent 6.98% 4.25% 4.75%