S000001114 [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 Growth Fund | CLASS N SHARES | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 16.19% | 14.35% | 34.17% | (26.83%) | 25.53% | 31.85% | 32.52% | (1.72%) | 23.35% | (2.64%) |