Alger International Opportunities Fund Average Annual Total Returns - Class Z Shares [Member] |
12 Months Ended | 60 Months Ended | 120 Months Ended | |
|---|---|---|---|---|
Oct. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| MSCI ACWI ex USA Gross Index (reflects no deductions for fees, expenses or taxes)[Member] | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 33.11% | 8.46% | 8.95% | |
| Class Z | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 19.02% | 2.45% | 7.17% | |
| Performance Inception Date | Dec. 29, 2010 | |||
| Class Z | After Taxes on Distributions | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 16.20% | 1.33% | 5.88% | |
| Class Z | After Taxes on Distributions and Sales | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 13.43% | 1.86% | 5.35% |