v3.26.1
Shareholder Report, Line Graph (Details) 190988_Buffalo International Fund_Investor Class_TSR Annual {Investor Class} - USD ($)
12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2023
Mar. 31, 2022
Mar. 31, 2021
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2016
Mar. 31, 2026
Investor Class                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     Buffalo International Fund Investor Class
Accumulated Value $ 20,796 $ 21,261 $ 19,173 $ 19,213 $ 18,847 $ 12,417 $ 13,448 $ 13,424 $ 11,346 $ 10,000 $ 22,711
FTSE Global All Cap ex US Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     FTSE Global All Cap ex US Index
Accumulated Value 18,556 17,464 15,359 16,236 16,308 10,704 12,704 13,283 11,367 10,000 $ 23,355
FTSE All-World ex US Index [Member]                      
Account Value [Line Items]                      
Line Graph and Table Measure Name                     FTSE All-World ex US Index
Accumulated Value $ 18,839 $ 17,665 $ 15,497 $ 16,281 $ 16,379 $ 10,849 $ 12,771 $ 13,274 $ 11,385 $ 10,000 $ 23,654