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Shareholder Report, Line Graph (Details) 190991_Buffalo High Yield 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 High Yield Fund Institutional Class
Accumulated Value $ 351,569 $ 327,185 $ 291,498 $ 295,900 $ 289,748 $ 227,648 $ 250,000 $ 368,106
Bloomberg U.S. Universal Bond Index [Member]                
Account Value [Line Items]                
Line Graph and Table Measure Name               Bloomberg U.S. Universal Bond Index
Accumulated Value 264,228 251,064 244,533 256,359 267,672 259,995 250,000 $ 276,500
ICE BofA U.S. High Yield Index [Member]                
Account Value [Line Items]                
Line Graph and Table Measure Name               ICE BofA U.S. High Yield Index
Accumulated Value $ 319,658 $ 296,871 $ 267,163 $ 276,850 $ 277,666 $ 225,181 $ 250,000 $ 341,971