v3.26.1
S000025838 [Member] Expense Example - AMG GW&K Municipal Bond Fund
Dec. 31, 2025
USD ($)
Class I  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 40
Expense Example, with Redemption, 3 Years 141
Expense Example, with Redemption, 5 Years 251
Expense Example, with Redemption, 10 Years 572
Class N  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 75
Expense Example, with Redemption, 3 Years 248
Expense Example, with Redemption, 5 Years 437
Expense Example, with Redemption, 10 Years $ 983