S000020207 [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 Cap Value Fund | Class N | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 3.00% | 10.57% | 17.43% | (15.33%) | 32.93% | 3.29% | 28.64% | (19.00%) | 8.39% | 21.31% |