v3.26.1
S000003467 [Member] Shareholder Fees - Sit Tax-Free Income Fund
Mar. 31, 2026
USD ($)
Sit Tax-Free Income Fund - Class S  
Prospectus [Line Items]  
Shareholder Fee, Other $ 0
Sit Tax-Free Income Fund - Class Y  
Prospectus [Line Items]  
Shareholder Fee, Other $ 0