v3.26.1
S000039473 [Member] Average Annual Total Returns
12 Months Ended 45 Months Ended 60 Months Ended 120 Months Ended 156 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses or taxes)          
Prospectus [Line Items]          
Average Annual Return, Percent [1] 7.30%   (0.36%) 2.01%  
Bloomberg 1-3 Year Government/Credit Index (reflects no deduction for fees, expenses or taxes)          
Prospectus [Line Items]          
Average Annual Return, Percent [2] 5.35%   1.97% 2.09%  
Sit Quality Income Fund - Class S          
Prospectus [Line Items]          
Average Annual Return, Percent 6.30%   2.91% 2.34%  
Performance Inception Date         Dec. 31, 2012
Sit Quality Income Fund - Class S | After Taxes on Distributions          
Prospectus [Line Items]          
Average Annual Return, Percent 4.48%   1.45% 1.32%  
Performance Inception Date         Dec. 31, 2012
Sit Quality Income Fund - Class S | After Taxes on Distributions and Sales          
Prospectus [Line Items]          
Average Annual Return, Percent 3.70%   1.61% 1.36%  
Performance Inception Date         Dec. 31, 2012
Sit Quality Income Fund - Class Y          
Prospectus [Line Items]          
Average Annual Return, Percent 6.45%    
Performance Inception Date   Mar. 31, 2022      
[1]
A broad-based securities market index that represents the overall domestic debt markets.
[2]
A more narrowly-based index that reflects the market sectors in which the Fund invests.