v3.26.1
Shareholder Report, Average Annual Return (Details)
12 Months Ended 60 Months Ended 120 Months Ended
Jun. 30, 2026
Jun. 30, 2026
Jun. 30, 2026
C000032269      
Average Annual Return [Line Items]      
Line Graph and Table Measure Name Sit Mid Cap Growth Fund    
Without Sales Load [Member] | C000032269      
Average Annual Return [Line Items]      
Average Annual Return, Percent 19.35% 7.16% 11.99%
Russell 3000® Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 22.82% 12.31% 15.06%
Russell Midcap® Growth Index      
Average Annual Return [Line Items]      
Average Annual Return, Percent 6.17% 6.03% 13.04%