Alger International Opportunities Fund Average Annual Total Returns - Class A B C 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 A | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 12.34% | 0.94% | 6.14% | |
| Performance Inception Date | Dec. 31, 1996 | |||
| Class A | After Taxes on Distributions | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 9.67% | (0.16%) | 4.93% | |
| Class A | After Taxes on Distributions and Sales | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 9.37% | 0.70% | 4.54% | |
| Class B | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 14.48% | 1.88% | 6.50% | |
| Performance Inception Date | Dec. 31, 1996 | |||
| Class C | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 16.61% | 1.26% | 6.01% | |
| Performance Inception Date | Jul. 31, 1997 |