v3.25.4
Expense Example - William Blair Global Leaders Fund
Dec. 31, 2025
USD ($)
Class N  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 117
Expense Example, with Redemption, 3 Years 541
Expense Example, with Redemption, 5 Years 991
Expense Example, with Redemption, 10 Years 2,239
Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 92
Expense Example, with Redemption, 3 Years 462
Expense Example, with Redemption, 5 Years 856
Expense Example, with Redemption, 10 Years 1,962
Class R6  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 87
Expense Example, with Redemption, 3 Years 438
Expense Example, with Redemption, 5 Years 813
Expense Example, with Redemption, 10 Years $ 1,867