S000049941 [Member] Annual Fund Operating Expenses - AMG GW&K SMALL/MID CAP CORE FUND |
Dec. 31, 2025 |
|---|---|
| Class I | |
| Prospectus [Line Items] | |
| Management Fees (as a percentage of Assets) | 0.62% |
| Distribution and Service (12b-1) Fees | 0.00% |
| Other Expenses (as a percentage of Assets): | 0.25% |
| Expenses (as a percentage of Assets) | 0.87% |
| Class N | |
| Prospectus [Line Items] | |
| Management Fees (as a percentage of Assets) | 0.62% |
| Distribution and Service (12b-1) Fees | 0.25% |
| Other Expenses (as a percentage of Assets): | 0.20% |
| Expenses (as a percentage of Assets) | 1.07% |
| Class Z | |
| Prospectus [Line Items] | |
| Management Fees (as a percentage of Assets) | 0.62% |
| Distribution and Service (12b-1) Fees | 0.00% |
| Other Expenses (as a percentage of Assets): | 0.20% |
| Expenses (as a percentage of Assets) | 0.82% |