S000030192 [Member] Annual Total Returns |
12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| AMG GW&K Small/Mid Cap Growth Fund | CLASS N SHARES | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 11.03% | 9.27% | 21.13% | (22.28%) | 14.13% | 45.61% | 20.24% | (5.15%) | 18.69% | (5.42%) |