S000016733 [Member] Expense Example - AMG River Road Small-Mid Cap Value Fund |
Oct. 31, 2025
USD ($)
|
|---|---|
| CLASS N SHARES | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | $ 130 |
| Expense Example, with Redemption, 3 Years | 406 |
| Expense Example, with Redemption, 5 Years | 702 |
| Expense Example, with Redemption, 10 Years | 1,545 |
| CLASS I SHARES | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 104 |
| Expense Example, with Redemption, 3 Years | 325 |
| Expense Example, with Redemption, 5 Years | 563 |
| Expense Example, with Redemption, 10 Years | 1,248 |
| CLASS Z Shares | |
| Prospectus [Line Items] | |
| Expense Example, with Redemption, 1 Year | 99 |
| Expense Example, with Redemption, 3 Years | 309 |
| Expense Example, with Redemption, 5 Years | 536 |
| Expense Example, with Redemption, 10 Years | $ 1,190 |