S000003468 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended | 373 Months Ended | |||||
|---|---|---|---|---|---|---|---|---|---|
Mar. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2024 |
Dec. 31, 2024 |
Dec. 31, 2024 |
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| Prospectus [Line Items] | |||||||||
| Average Annual Return, Percent | |||||||||
| Bloomberg Municipal Bond Index (reflects no deduction for fees, expenses or taxes) | |||||||||
| Prospectus [Line Items] | |||||||||
| Average Annual Return, Percent | [1] | 1.17% | 0.91% | 1.67% | |||||
| Bloomberg 5-Year Municipal Bond Index (reflects no deduction for fees, expenses or taxes) | |||||||||
| Prospectus [Line Items] | |||||||||
| Average Annual Return, Percent | [2] | 1.05% | 0.99% | 2.25% | |||||
| Sit Minnesota Tax-Free Income Fund | |||||||||
| Prospectus [Line Items] | |||||||||
| Average Annual Return, Percent | 4.01% | 0.61% | 2.00% | ||||||
| Performance Inception Date | Dec. 01, 1993 | ||||||||
| Sit Minnesota Tax-Free Income Fund | After Taxes on Distributions | |||||||||
| Prospectus [Line Items] | |||||||||
| Average Annual Return, Percent | 4.00% | 0.59% | 1.99% | ||||||
| Performance Inception Date | Dec. 01, 1993 | ||||||||
| Sit Minnesota Tax-Free Income Fund | After Taxes on Distributions and Sales | |||||||||
| Prospectus [Line Items] | |||||||||
| Average Annual Return, Percent | 3.69% | 1.12% | 2.23% | ||||||
| Performance Inception Date | Dec. 01, 1993 | ||||||||
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