S000049941 [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 CORE FUND | Class I | ||||||||||
| Prospectus [Line Items] | ||||||||||
| Annual Return [Percent] | 4.58% | 10.84% | 14.76% | (18.01%) | 25.91% | 23.31% | 30.86% | (8.15%) | 15.44% | 9.68% |