Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| SIT U S GOVERNMENT SECURITIES FUND INC | Sit U.S. Government Securities Fund - Class S | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 2.40% | 3.22% | (4.45%) | (0.96%) | 3.62% | 3.34% | 1.77% | 1.33% | 0.69% | 1.42% |