S000072753 [Member] Expense Example - William Blair China Growth Fund |
Dec. 31, 2025
USD ($)
|
|---|---|
| Class I | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 101 |
| Expense Example, with Redemption, 3 Years | 1,815 |
| Expense Example, with Redemption, 5 Years | 3,410 |
| Expense Example, with Redemption, 10 Years | 6,929 |
| Class R6 | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 96 |
| Expense Example, with Redemption, 3 Years | 1,811 |
| Expense Example, with Redemption, 5 Years | 3,407 |
| Expense Example, with Redemption, 10 Years | $ 6,927 |