S000009910 [Member] Expense Example - AMG Frontier Small Cap Growth Fund |
Oct. 31, 2025
USD ($)
|
|---|---|
| Class I | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 102 |
| Expense Example, with Redemption, 3 Years | 361 |
| Expense Example, with Redemption, 5 Years | 640 |
| Expense Example, with Redemption, 10 Years | 1,437 |
| Class N | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 132 |
| Expense Example, with Redemption, 3 Years | 454 |
| Expense Example, with Redemption, 5 Years | 800 |
| Expense Example, with Redemption, 10 Years | 1,773 |
| Class Z | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 92 |
| Expense Example, with Redemption, 3 Years | 330 |
| Expense Example, with Redemption, 5 Years | 587 |
| Expense Example, with Redemption, 10 Years | $ 1,322 |