v3.26.1
S000069167 [Member] Shareholder Fees - William Blair Emerging Markets Debt Fund
Dec. 31, 2025
Class R6  
Prospectus [Line Items]  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 0.00%
Redemption Fee (as a percentage of Amount Redeemed) 0.00%
Class I  
Prospectus [Line Items]  
Maximum Sales Charge Imposed on Purchases (as a percentage of Offering Price) 0.00%
Redemption Fee (as a percentage of Amount Redeemed) 0.00%