Alger Spectra Fund Average Annual Total Returns - Class Y Shares [Member] |
12 Months Ended | 60 Months Ended | 85 Months Ended | |
|---|---|---|---|---|
Oct. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Russell 3000 Growth Index (reflects no deductions for fees, expenses or taxes)[Member] | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 18.15% | 14.59% | 18.55% | |
| S&P 500 Index (reflects no deductions for fees, expenses or taxes)[Member] | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 17.88% | 14.42% | 15.35% | |
| Class Y | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 29.92% | 13.29% | 17.89% | |
| Performance Inception Date | Dec. 03, 2018 | |||
| Class Y | After Taxes on Distributions | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 27.87% | 11.16% | 15.34% | |
| Class Y | After Taxes on Distributions and Sales | ||||
| Prospectus [Line Items] | ||||
| Average Annual Return, Percent | 19.08% | 10.09% | 13.97% |