v3.26.1
S000039569 [Member] Expense Example - AMG TimesSquare International Small Cap Fund
Dec. 31, 2025
USD ($)
Class Z  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 107
Expense Example, with Redemption, 3 Years 345
Expense Example, with Redemption, 5 Years 601
Expense Example, with Redemption, 10 Years 1,336
Class N  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 132
Expense Example, with Redemption, 3 Years 423
Expense Example, with Redemption, 5 Years 735
Expense Example, with Redemption, 10 Years 1,620
Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 112
Expense Example, with Redemption, 3 Years 360
Expense Example, with Redemption, 5 Years 628
Expense Example, with Redemption, 10 Years $ 1,393