v3.26.1
Shareholder Report
 6 Months Ended
Apr. 30, 2026
USD ($)
Holding
Shareholder Report [Line Items]  
Document Type N-CSRS
Amendment Flag false
Registrant Name ALGER FUNDS II
Entity Central Index Key 0000092751
Entity Investment Company Type N-1A
Document Period End Date Apr. 30, 2026
C000039961 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Responsible Investing Fund
Class Name Class A
Trading Symbol SPEGX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Responsible Investing Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Responsible Investing Fund
(Class A / SPEGX)		 $56 1.11%(a)
(a)
Annualized.
Expenses Paid, Amount $ 56
Expense Ratio, Percent 1.11% [1]
Net Assets $ 133,161,771
Holdings Count | Holding 59 [2]
Investment Company Portfolio Turnover 3.46%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $133,161,771
Total number of portfolio holdings1 59
Portfolio turnover rate 3.46%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.2%
Consumer Discretionary 10.7%
Consumer Staples 0.6%
Financials 6.1%
Health Care 4.6%
Industrials 7.1%
Information Technology 48.8%
Materials 0.4%
Real Estate 1.5%
Utilities 1.3%
Short-Term Investments and Other Net Assets 9.7%
100.0%
​†
Based on net assets
C000068369 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Responsible Investing Fund
Class Name Class C
Trading Symbol AGFCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Responsible Investing Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Responsible Investing Fund
(Class C / AGFCX)		 $102 2.04%(a)
(a)
Annualized.
Expenses Paid, Amount $ 102
Expense Ratio, Percent 2.04% [3]
Net Assets $ 133,161,771
Holdings Count | Holding 59 [4]
Investment Company Portfolio Turnover 3.46%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $133,161,771
Total number of portfolio holdings1 59
Portfolio turnover rate 3.46%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.2%
Consumer Discretionary 10.7%
Consumer Staples 0.6%
Financials 6.1%
Health Care 4.6%
Industrials 7.1%
Information Technology 48.8%
Materials 0.4%
Real Estate 1.5%
Utilities 1.3%
Short-Term Investments and Other Net Assets 9.7%
100.0%
​†
Based on net assets
C000068370 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Responsible Investing Fund
Class Name Class I
Trading Symbol AGIFX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Responsible Investing Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Responsible Investing Fund
(Class I / AGIFX)		 $56 1.11%(a)
(a)
Annualized.
Expenses Paid, Amount $ 56
Expense Ratio, Percent 1.11% [5]
Net Assets $ 133,161,771
Holdings Count | Holding 59 [6]
Investment Company Portfolio Turnover 3.46%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $133,161,771
Total number of portfolio holdings1 59
Portfolio turnover rate 3.46%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.2%
Consumer Discretionary 10.7%
Consumer Staples 0.6%
Financials 6.1%
Health Care 4.6%
Industrials 7.1%
Information Technology 48.8%
Materials 0.4%
Real Estate 1.5%
Utilities 1.3%
Short-Term Investments and Other Net Assets 9.7%
100.0%
​†
Based on net assets
C000174226 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Responsible Investing Fund
Class Name Class Z
Trading Symbol ALGZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Responsible Investing Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Responsible Investing Fund
(Class Z / ALGZX)		 $47 0.94%(a)
(a)
Annualized.
Expenses Paid, Amount $ 47
Expense Ratio, Percent 0.94% [7]
Net Assets $ 133,161,771
Holdings Count | Holding 59 [8]
Investment Company Portfolio Turnover 3.46%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $133,161,771
Total number of portfolio holdings1 59
Portfolio turnover rate 3.46%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.2%
Consumer Discretionary 10.7%
Consumer Staples 0.6%
Financials 6.1%
Health Care 4.6%
Industrials 7.1%
Information Technology 48.8%
Materials 0.4%
Real Estate 1.5%
Utilities 1.3%
Short-Term Investments and Other Net Assets 9.7%
100.0%
​†
Based on net assets
C000024978 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Spectra Fund
Class Name Class A
Trading Symbol SPECX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Spectra Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Spectra Fund
(Class A / SPECX)		 $75 1.53%(a)
(a)
Annualized.
Expenses Paid, Amount $ 75
Expense Ratio, Percent 1.53% [9]
Net Assets $ 4,294,094,753
Holdings Count | Holding 79 [10]
Investment Company Portfolio Turnover 21.01%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $4,294,094,753
Total number of portfolio holdings1 79
Portfolio turnover rate 21.01%
Long portfolio exposure 110.3%
Short portfolio exposure (9.4)%
Net portfolio exposure 100.9%
Other net assets (0.9)%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
Holdings [Text Block]
Sector Allocation †
Communication Services 11.0%
Consumer Discretionary 14.8%
Consumer Staples (0.2)%
Energy 1.0%
Financials 1.6%
Health Care 7.9%
Industrials 8.3%
Information Technology 55.9%
Market Indices (3.5)%
Materials 1.2%
Real Estate 0.3%
Utilities 2.5%
Short-Term Investments and Other Net Assets (0.8)%
100.0%
​†
Based on net assets
C000068367 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Spectra Fund
Class Name Class C
Trading Symbol ASPCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Spectra Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Spectra Fund
(Class C / ASPCX)		 $113 2.31%(a)
(a)
Annualized.
Expenses Paid, Amount $ 113
Expense Ratio, Percent 2.31% [11]
Net Assets $ 4,294,094,753
Holdings Count | Holding 79 [12]
Investment Company Portfolio Turnover 21.01%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $4,294,094,753
Total number of portfolio holdings1 79
Portfolio turnover rate 21.01%
Long portfolio exposure 110.3%
Short portfolio exposure (9.4)%
Net portfolio exposure 100.9%
Other net assets (0.9)%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
Holdings [Text Block]
Sector Allocation †
Communication Services 11.0%
Consumer Discretionary 14.8%
Consumer Staples (0.2)%
Energy 1.0%
Financials 1.6%
Health Care 7.9%
Industrials 8.3%
Information Technology 55.9%
Market Indices (3.5)%
Materials 1.2%
Real Estate 0.3%
Utilities 2.5%
Short-Term Investments and Other Net Assets (0.8)%
100.0%
​†
Based on net assets
C000068368 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Spectra Fund
Class Name Class I
Trading Symbol ASPIX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Spectra Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Spectra Fund
(Class I / ASPIX)		 $75 1.53%(a)
(a)
Annualized.
Expenses Paid, Amount $ 75
Expense Ratio, Percent 1.53% [13]
Net Assets $ 4,294,094,753
Holdings Count | Holding 79 [14]
Investment Company Portfolio Turnover 21.01%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $4,294,094,753
Total number of portfolio holdings1 79
Portfolio turnover rate 21.01%
Long portfolio exposure 110.3%
Short portfolio exposure (9.4)%
Net portfolio exposure 100.9%
Other net assets (0.9)%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
Holdings [Text Block]
Sector Allocation †
Communication Services 11.0%
Consumer Discretionary 14.8%
Consumer Staples (0.2)%
Energy 1.0%
Financials 1.6%
Health Care 7.9%
Industrials 8.3%
Information Technology 55.9%
Market Indices (3.5)%
Materials 1.2%
Real Estate 0.3%
Utilities 2.5%
Short-Term Investments and Other Net Assets (0.8)%
100.0%
​†
Based on net assets
C000095102 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Spectra Fund
Class Name Class Y
Trading Symbol ASPYX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Spectra Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Spectra Fund
(Class Y / ASPYX)		 $55 1.11%(a)
(a)
Annualized.
Expenses Paid, Amount $ 55
Expense Ratio, Percent 1.11% [15]
Net Assets $ 4,294,094,753
Holdings Count | Holding 79 [16]
Investment Company Portfolio Turnover 21.01%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $4,294,094,753
Total number of portfolio holdings1 79
Portfolio turnover rate 21.01%
Long portfolio exposure 110.3%
Short portfolio exposure (9.4)%
Net portfolio exposure 100.9%
Other net assets (0.9)%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
Holdings [Text Block]
Sector Allocation †
Communication Services 11.0%
Consumer Discretionary 14.8%
Consumer Staples (0.2)%
Energy 1.0%
Financials 1.6%
Health Care 7.9%
Industrials 8.3%
Information Technology 55.9%
Market Indices (3.5)%
Materials 1.2%
Real Estate 0.3%
Utilities 2.5%
Short-Term Investments and Other Net Assets (0.8)%
100.0%
​†
Based on net assets
C000206605 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Spectra Fund
Class Name Class Z
Trading Symbol ASPZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Spectra Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Spectra Fund
(Class Z / ASPZX)		 $57 1.17%(a)
(a)
Annualized.
Expenses Paid, Amount $ 57
Expense Ratio, Percent 1.17% [17]
Net Assets $ 4,294,094,753
Holdings Count | Holding 79 [18]
Investment Company Portfolio Turnover 21.01%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $4,294,094,753
Total number of portfolio holdings1 79
Portfolio turnover rate 21.01%
Long portfolio exposure 110.3%
Short portfolio exposure (9.4)%
Net portfolio exposure 100.9%
Other net assets (0.9)%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
Holdings [Text Block]
Sector Allocation †
Communication Services 11.0%
Consumer Discretionary 14.8%
Consumer Staples (0.2)%
Energy 1.0%
Financials 1.6%
Health Care 7.9%
Industrials 8.3%
Information Technology 55.9%
Market Indices (3.5)%
Materials 1.2%
Real Estate 0.3%
Utilities 2.5%
Short-Term Investments and Other Net Assets (0.8)%
100.0%
​†
Based on net assets
C000138115 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Emerging Markets Fund
Class Name Class Z
Trading Symbol AZEMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Emerging Markets Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Emerging Markets Fund
(Class Z / AZEMX)		 $53 0.99%(a)
(a)
Annualized.
Expenses Paid, Amount $ 53
Expense Ratio, Percent 0.99% [19]
Net Assets $ 21,647,190
Holdings Count | Holding 40 [20]
Investment Company Portfolio Turnover 28.74%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $21,647,190
Total number of portfolio holdings1 40
Portfolio turnover rate 28.74%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Geographical Allocation †
Argentina 1.5%
Brazil 7.8%
China 19.0%
Greece 3.4%
Hungary 2.9%
India 8.0%
Mexico 3.8%
Peru 2.1%
Philippines 2.4%
Poland 1.7%
Singapore 0.8%
South Africa 1.7%
South Korea 18.9%
Taiwan 17.0%
Turkey 1.8%
United States 4.0%
Short-Term Investments and Net Other Assets 3.2%
100.0%
​†
Based on net assets
C000095099 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Emerging Markets Fund
Class Name Class A
Trading Symbol AAEMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Emerging Markets Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Emerging Markets Fund
(Class A / AAEMX)		 $83 1.55%(a)
(a)
Annualized.
Expenses Paid, Amount $ 83
Expense Ratio, Percent 1.55% [21]
Net Assets $ 21,647,190
Holdings Count | Holding 40 [22]
Investment Company Portfolio Turnover 28.74%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $21,647,190
Total number of portfolio holdings1 40
Portfolio turnover rate 28.74%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Geographical Allocation †
Argentina 1.5%
Brazil 7.8%
China 19.0%
Greece 3.4%
Hungary 2.9%
India 8.0%
Mexico 3.8%
Peru 2.1%
Philippines 2.4%
Poland 1.7%
Singapore 0.8%
South Africa 1.7%
South Korea 18.9%
Taiwan 17.0%
Turkey 1.8%
United States 4.0%
Short-Term Investments and Net Other Assets 3.2%
100.0%
​†
Based on net assets
C000095100 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Emerging Markets Fund
Class Name Class C
Trading Symbol ACEMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Emerging Markets Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Emerging Markets Fund
(Class C / ACEMX)		 $122 2.30%(a)
(a)
Annualized.
Expenses Paid, Amount $ 122
Expense Ratio, Percent 2.30% [23]
Net Assets $ 21,647,190
Holdings Count | Holding 40 [24]
Investment Company Portfolio Turnover 28.74%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $21,647,190
Total number of portfolio holdings1 40
Portfolio turnover rate 28.74%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Geographical Allocation †
Argentina 1.5%
Brazil 7.8%
China 19.0%
Greece 3.4%
Hungary 2.9%
India 8.0%
Mexico 3.8%
Peru 2.1%
Philippines 2.4%
Poland 1.7%
Singapore 0.8%
South Africa 1.7%
South Korea 18.9%
Taiwan 17.0%
Turkey 1.8%
United States 4.0%
Short-Term Investments and Net Other Assets 3.2%
100.0%
​†
Based on net assets
C000095101 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Emerging Markets Fund
Class Name Class I
Trading Symbol AIEMX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Emerging Markets Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Emerging Markets Fund
(Class I / AIEMX)		 $77 1.45%(a)
(a)
Annualized.
Expenses Paid, Amount $ 77
Expense Ratio, Percent 1.45% [25]
Net Assets $ 21,647,190
Holdings Count | Holding 40 [26]
Investment Company Portfolio Turnover 28.74%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $21,647,190
Total number of portfolio holdings1 40
Portfolio turnover rate 28.74%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
Holdings [Text Block]
Geographical Allocation †
Argentina 1.5%
Brazil 7.8%
China 19.0%
Greece 3.4%
Hungary 2.9%
India 8.0%
Mexico 3.8%
Peru 2.1%
Philippines 2.4%
Poland 1.7%
Singapore 0.8%
South Africa 1.7%
South Korea 18.9%
Taiwan 17.0%
Turkey 1.8%
United States 4.0%
Short-Term Investments and Net Other Assets 3.2%
100.0%
​†
Based on net assets
C000078761 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Dynamic Opportunities Fund
Class Name Class A
Trading Symbol SPEDX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Dynamic Opportunities Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Dynamic Opportunities Fund
(Class A / SPEDX)		 $102 2.06%(a)
(a)
Annualized.
Expenses Paid, Amount $ 102
Expense Ratio, Percent 2.06% [27]
Net Assets $ 222,514,660
Holdings Count | Holding 141 [28]
Investment Company Portfolio Turnover 216.73%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $222,514,660
Total number of portfolio holdings1 141
Portfolio turnover rate 216.73%
Long portfolio exposure 100.6%
Short portfolio exposure (38.3)%
Net portfolio exposure 62.3%
Other net assets 37.7%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds, securities sold short, and derivatives.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.3%
Consumer Discretionary (0.7)%
Consumer Staples (1.6)%
Energy 1.7%
Financials 1.8%
Health Care 6.5%
Industrials 10.4%
Information Technology 32.1%
Market Indices (2.9)%
Materials (1.2)%
Real Estate 1.0%
Utilities 1.3%
Short-Term Investments, Derivatives and Other Net Assets 42.3%
100.0%
​†
Based on net assets
C000098121 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Dynamic Opportunities Fund
Class Name Class C
Trading Symbol ADOCX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Dynamic Opportunities Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Dynamic Opportunities Fund
(Class C / ADOCX)		 $139 2.83%(a)
(a)
Annualized.
Expenses Paid, Amount $ 139
Expense Ratio, Percent 2.83% [29]
Net Assets $ 222,514,660
Holdings Count | Holding 141 [30]
Investment Company Portfolio Turnover 216.73%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $222,514,660
Total number of portfolio holdings1 141
Portfolio turnover rate 216.73%
Long portfolio exposure 100.6%
Short portfolio exposure (38.3)%
Net portfolio exposure 62.3%
Other net assets 37.7%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds, securities sold short, and derivatives.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.3%
Consumer Discretionary (0.7)%
Consumer Staples (1.6)%
Energy 1.7%
Financials 1.8%
Health Care 6.5%
Industrials 10.4%
Information Technology 32.1%
Market Indices (2.9)%
Materials (1.2)%
Real Estate 1.0%
Utilities 1.3%
Short-Term Investments, Derivatives and Other Net Assets 42.3%
100.0%
​†
Based on net assets
C000095104 [Member]  
Shareholder Report [Line Items]  
Fund Name Alger Dynamic Opportunities Fund
Class Name Class Z
Trading Symbol ADOZX
Annual or Semi-Annual Statement [Text Block] This semi-annual shareholder report contains important information about the Alger Dynamic Opportunities Fund (“Fund”) for the period from November 1, 2025 to April 30, 2026.
Shareholder Report Annual or Semi-Annual semi-annual shareholder report
Additional Information [Text Block] You can find additional information about the Fund at www.alger.com/fundliterature. You can also request a copy of the semi-annual report by contacting us at (800) 992-3863.
Additional Information Phone Number (800) 992-3863
Additional Information Website www.alger.com/fundliterature
Expenses [Text Block]
What were the Fund costs for the last six months?
(Based on a hypothetical $10,000 investment)
Fund (Class/Ticker) Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment
Alger Dynamic Opportunities Fund
(Class Z / ADOZX)		 $86 1.74%(a)
(a)
Annualized.
Expenses Paid, Amount $ 86
Expense Ratio, Percent 1.74% [31]
Net Assets $ 222,514,660
Holdings Count | Holding 141 [32]
Investment Company Portfolio Turnover 216.73%
Additional Fund Statistics [Text Block]
Key Fund Statistics
The following table outlines key fund statistics as of the fiscal six-month period ended April 30, 2026.
Fund net assets $222,514,660
Total number of portfolio holdings1 141
Portfolio turnover rate 216.73%
Long portfolio exposure 100.6%
Short portfolio exposure (38.3)%
Net portfolio exposure 62.3%
Other net assets 37.7%
1
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds, securities sold short, and derivatives.
Holdings [Text Block]
Sector Allocation †
Communication Services 9.3%
Consumer Discretionary (0.7)%
Consumer Staples (1.6)%
Energy 1.7%
Financials 1.8%
Health Care 6.5%
Industrials 10.4%
Information Technology 32.1%
Market Indices (2.9)%
Materials (1.2)%
Real Estate 1.0%
Utilities 1.3%
Short-Term Investments, Derivatives and Other Net Assets 42.3%
100.0%
​†
Based on net assets
[1]
Annualized.
[2]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[3]
Annualized.
[4]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[5]
Annualized.
[6]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[7] Annualized.
[8] Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[9] Annualized.
[10] Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
[11] Annualized.
[12] Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
[13]
Annualized.
[14]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
[15]
Annualized.
[16]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
[17]
Annualized.
[18]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds and securities sold short.
[19] Annualized.
[20]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[21] Annualized.
[22] Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[23]
Annualized.
[24]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[25]
Annualized.
[26]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds.
[27]
Annualized.
[28]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds, securities sold short, and derivatives.
[29]
Annualized.
[30]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds, securities sold short, and derivatives.
[31]
Annualized.
[32]
Number of portfolio holdings is calculated at the issuer level. Excludes Money Market Funds, securities sold short, and derivatives.