S000008596 [Member] Expense Example - William Blair Emerging Markets Growth Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Class N | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 126 |
| Expense Example, with Redemption, 3 Years | 434 |
| Expense Example, with Redemption, 5 Years | 764 |
| Expense Example, with Redemption, 10 Years | 1,697 |
| Class I | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 101 |
| Expense Example, with Redemption, 3 Years | 356 |
| Expense Example, with Redemption, 5 Years | 631 |
| Expense Example, with Redemption, 10 Years | 1,415 |
| Class R6 | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 96 |
| Expense Example, with Redemption, 3 Years | 323 |
| Expense Example, with Redemption, 5 Years | 569 |
| Expense Example, with Redemption, 10 Years | $ 1,273 |