Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
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 |
|
| William Blair Global Leaders Fund | Class N | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 14.82% | 7.47% | 22.67% | (29.49%) | 16.55% | 31.50% | 31.57% | (8.23%) | 30.31% | 0.62% |