| Form N-CSR Cover | 12 Months Ended |
| Oct. 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | ALGER INSTITUTIONAL FUNDS |
| Entity Central Index Key | 0000911415 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Oct. 31, 2024 |
| Shareholder Report | 12 Months Ended | |
| Oct. 31, 2024 USD ($) Holding | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSR | |
| Amendment Flag | false | |
| Registrant Name | ALGER INSTITUTIONAL FUNDS | |
| Entity Central Index Key | 0000911415 | |
| Entity Investment Company Type | N-1A | |
| Document Period End Date | Oct. 31, 2024 | |
| C000122071 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Focus Equity Fund | |
| Class Name | Class A | |
| Trading Symbol | ALAFX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Focus Equity Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Focus Equity Fund $ 0.95 % | |
| Expenses Paid, Amount | $ 124 | |
| Expense Ratio, Percent | 0.95% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Focus Equity Fund Class A returned 60.77%, excluding sales load, for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Natera, Inc.; and AppLovin Corp. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Snowflake, Inc.; ASML Holding; Schlumberger Ltd.; EOG Resources, Inc.; and Fluence Energy, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class A shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Focus Equity Fund Class A 52.32 % 17.71 % 15.55 % Alger Focus Equity Fund Class A—excluding sales load 60.77 % 18.99 % 16.17 % Russell 1000 Growth Index 43.77 % 19.00 % 16.18 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 1,791,352,839 | |
| Holdings Count | Holding | 51 | [1] |
| Advisory Fees Paid, Amount | $ 7,683,585 | |
| Investment Company Portfolio Turnover | 92.43% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 51 Portfolio turnover rate as of the end of the reporting period 92.43 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 14.0 % Consumer Discretionary 12.1 % Energy 1.0 % Financials 3.1 % Healthcare 7.4 % Industrials 10.8 % Information Technology 43.7 % Materials 0.3 % Real Estate 0.9 % Utilities 2.3 % Short-Term Investments and Other Net Assets 4.4 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000122072 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Focus Equity Fund | |
| Class Name | Class C | |
| Trading Symbol | ALCFX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Focus Equity Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Focus Equity Fund $ 1.72 % | |
| Expenses Paid, Amount | $ 223 | |
| Expense Ratio, Percent | 1.72% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Focus Equity Fund Class C returned 59.55%, excluding contingent deferred sales charge for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Natera, Inc.; and AppLovin Corp. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Snowflake, Inc.; ASML Holding; Schlumberger Ltd.; EOG Resources, Inc.; and Fluence Energy, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class C shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Focus Equity Fund Class C 58.55 % 18.08 % 15.47 % Alger Focus Equity Fund Class C—excluding contingent deferred sales charges 59.55 % 18.08 % 15.47 % Russell 1000 Growth Index 43.77 % 19.00 % 16.18 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 1,791,352,839 | |
| Holdings Count | Holding | 51 | [2] |
| Advisory Fees Paid, Amount | $ 7,683,585 | |
| Investment Company Portfolio Turnover | 92.43% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 51 Portfolio turnover rate as of the end of the reporting period 92.43 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 14.0 % Consumer Discretionary 12.1 % Energy 1.0 % Financials 3.1 % Healthcare 7.4 % Industrials 10.8 % Information Technology 43.7 % Materials 0.3 % Real Estate 0.9 % Utilities 2.3 % Short-Term Investments and Other Net Assets 4.4 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000024998 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Focus Equity Fund | |
| Class Name | Class I | |
| Trading Symbol | ALGRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Focus Equity Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Focus Equity Fund $ 0.94 % | |
| Expenses Paid, Amount | $ 123 | |
| Expense Ratio, Percent | 0.94% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Focus Equity Fund Class I returned 60.84% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Natera, Inc.; and AppLovin Corp. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Snowflake, Inc.; ASML Holding; Schlumberger Ltd.; EOG Resources, Inc.; and Fluence Energy, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class I shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Focus Equity Fund Class I 60.84 % 19.03 % 16.23 % Russell 1000 Growth Index 43.77 % 19.00 % 16.18 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 1,791,352,839 | |
| Holdings Count | Holding | 51 | [3] |
| Advisory Fees Paid, Amount | $ 7,683,585 | |
| Investment Company Portfolio Turnover | 92.43% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 51 Portfolio turnover rate as of the end of the reporting period 92.43 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 14.0 % Consumer Discretionary 12.1 % Energy 1.0 % Financials 3.1 % Healthcare 7.4 % Industrials 10.8 % Information Technology 43.7 % Materials 0.3 % Real Estate 0.9 % Utilities 2.3 % Short-Term Investments and Other Net Assets 4.4 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000179522 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Focus Equity Fund | |
| Class Name | Class Y | |
| Trading Symbol | ALGYX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Focus Equity Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Focus Equity Fund $ 0.58 % | |
| Expenses Paid, Amount | $ 76 | |
| Expense Ratio, Percent | 0.58% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Focus Equity Fund Class Y returned 61.36% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Natera, Inc.; and AppLovin Corp. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Snowflake, Inc.; ASML Holding; Schlumberger Ltd.; EOG Resources, Inc.; and Fluence Energy, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed annual periods for the life of Class Y shares of the Fund since its inception. The graph assumes a $500,000 initial investment at net asset value at the inception date of the Fund in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $500,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years Since Inception Alger Focus Equity Fund Class Y 61.36 % 19.40 % 18.97 % Russell 1000 Growth Index 43.77 % 19.00 % 18.19 % S&P 500 Index 38.02 % 15.27 % 14.13 % | |
| Performance Inception Date | Feb. 28, 2017 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Mar. 01, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 1,791,352,839 | |
| Holdings Count | Holding | 51 | [4] |
| Advisory Fees Paid, Amount | $ 7,683,585 | |
| Investment Company Portfolio Turnover | 92.43% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 51 Portfolio turnover rate as of the end of the reporting period 92.43 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 14.0 % Consumer Discretionary 12.1 % Energy 1.0 % Financials 3.1 % Healthcare 7.4 % Industrials 10.8 % Information Technology 43.7 % Materials 0.3 % Real Estate 0.9 % Utilities 2.3 % Short-Term Investments and Other Net Assets 4.4 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. Effective March 1, 2024, Alger Management has contractually agreed to waive and/or reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class Y Shares of the Fund to 0.06% of the class’s average daily net assets. On October 22, 2024, the Board approved that any fees incurred as a result of the joint special meeting of shareholders would be excluded from the expense reimbursement. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective March 1, 2024, Alger Management has contractually agreed to waive and/or reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class Y Shares of the Fund to 0.06% of the class’s average daily net assets. On October 22, 2024, the Board approved that any fees incurred as a result of the joint special meeting of shareholders would be excluded from the expense reimbursement. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000122073 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Focus Equity Fund | |
| Class Name | Class Z | |
| Trading Symbol | ALZFX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Focus Equity Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Focus Equity Fund $ 0.63 % | |
| Expenses Paid, Amount | $ 82 | |
| Expense Ratio, Percent | 0.63% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Focus Equity Fund Class Z returned 61.29% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Natera, Inc.; and AppLovin Corp. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Snowflake, Inc.; ASML Holding; Schlumberger Ltd.; EOG Resources, Inc.; and Fluence Energy, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class Z shares of the Fund. The graph assumes a $500,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $500,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Focus Equity Fund Class Z 61.29 % 19.37 % 16.55 % Russell 1000 Growth Index 43.77 % 19.00 % 16.18 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Mar. 01, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 1,791,352,839 | |
| Holdings Count | Holding | 51 | [5] |
| Advisory Fees Paid, Amount | $ 7,683,585 | |
| Investment Company Portfolio Turnover | 92.43% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 51 Portfolio turnover rate as of the end of the reporting period 92.43 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 14.0 % Consumer Discretionary 12.1 % Energy 1.0 % Financials 3.1 % Healthcare 7.4 % Industrials 10.8 % Information Technology 43.7 % Materials 0.3 % Real Estate 0.9 % Utilities 2.3 % Short-Term Investments and Other Net Assets 4.4 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. Effective March 1, 2024, Alger Management has contractually agreed to waive and/or reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class Z Shares of the Fund to 0.11% of the class’s average daily net assets. On October 22, 2024, the Board approved that any fees incurred as a result of the joint special meeting of shareholders would be excluded from the expense reimbursement. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective March 1, 2024, Alger Management has contractually agreed to waive and/or reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class Z Shares of the Fund to 0.11% of the class’s average daily net assets. On October 22, 2024, the Board approved that any fees incurred as a result of the joint special meeting of shareholders would be excluded from the expense reimbursement. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000025000 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Small Cap Growth Institutional Fund | |
| Class Name | Class I | |
| Trading Symbol | ALSRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Small Cap Growth Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Small Cap Growth Institutional Fund $ 1.41 % | |
| Expenses Paid, Amount | $ 159 | |
| Expense Ratio, Percent | 1.41% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Small Cap Growth Institutional Fund Class I returned 25.82% for the fiscal twelve-month period ended October 31, 2024, compared to the 36.49% return of the Russell 2000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Health Care. The largest sector overweight was Consumer Discretionary and the largest sector underweight was Industrials. Contributors to Performance The Consumer Discretionary and Communication Services sectors provided the largest contributions to relative performance. Q2 Holdings, Inc.; Wingstop, Inc.; Shake Shack, Inc.; Guidewire Software, Inc.; and Manhattan Associates, Inc. were the top five contributors to absolute performance. Detractors from Performance The Health Care and Industrials sectors were the largest detractors from relative performance. Cabaletta Bio, Inc.; Structure Therapeutics, Inc.; Capri Holdings Ltd.; DLocal Ltd.; and 908 Devices Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class I shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Small Cap Growth Institutional Fund Class I 25.82 % 4.23 % 7.44 % Russell 2000 Growth Index 36.49 % 7.92 % 8.15 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 89,675,156 | |
| Holdings Count | Holding | 104 | [6] |
| Advisory Fees Paid, Amount | $ 877,483 | |
| Investment Company Portfolio Turnover | 48.95% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 104 Portfolio turnover rate as of the end of the reporting period 48.95 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 0.5 % Consumer Discretionary 18.2 % Consumer Staples 2.1 % Energy 0.7 % Financials 1.4 % Healthcare 29.4 % Industrials 12.2 % Information Technology 34.9 % Materials 0.1 % Short-Term Investments and Other Net Assets 0.5 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000025001 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Small Cap Growth Institutional Fund | |
| Class Name | Class R | |
| Trading Symbol | ASIRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Small Cap Growth Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Small Cap Growth Institutional Fund $ 1.88 % | |
| Expenses Paid, Amount | $ 212 | |
| Expense Ratio, Percent | 1.88% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Small Cap Growth Institutional Fund Class R returned 25.33% for the fiscal twelve-month period ended October 31, 2024, compared to the 36.49% return of the Russell 2000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Health Care. The largest sector overweight was Consumer Discretionary and the largest sector underweight was Industrials. Contributors to Performance The Consumer Discretionary and Communication Services sectors provided the largest contributions to relative performance. Q2 Holdings, Inc.; Wingstop, Inc.; Shake Shack, Inc.; Guidewire Software, Inc.; and Manhattan Associates, Inc. were the top five contributors to absolute performance. Detractors from Performance The Health Care and Industrials sectors were the largest detractors from relative performance. Cabaletta Bio, Inc.; Structure Therapeutics, Inc.; Capri Holdings Ltd.; DLocal Ltd.; and 908 Devices Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class R shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Small Cap Growth Institutional Fund Class R 25.33 % 3.74 % 6.93 % Russell 2000 Growth Index 36.49 % 7.92 % 8.15 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 89,675,156 | |
| Holdings Count | Holding | 104 | [7] |
| Advisory Fees Paid, Amount | $ 877,483 | |
| Investment Company Portfolio Turnover | 48.95% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 104 Portfolio turnover rate as of the end of the reporting period 48.95 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 0.5 % Consumer Discretionary 18.2 % Consumer Staples 2.1 % Energy 0.7 % Financials 1.4 % Healthcare 29.4 % Industrials 12.2 % Information Technology 34.9 % Materials 0.1 % Short-Term Investments and Other Net Assets 0.5 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000172687 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Small Cap Growth Institutional Fund | |
| Class Name | Class Z-2 | |
| Trading Symbol | AISZX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Small Cap Growth Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Small Cap Growth Institutional Fund $ 1.01 % | |
| Expenses Paid, Amount | $ 114 | |
| Expense Ratio, Percent | 1.01% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Small Cap Growth Institutional Fund Class Z-2 returned 26.44% for the fiscal twelve-month period ended October 31, 2024, compared to the 36.49% return of the Russell 2000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Health Care. The largest sector overweight was Consumer Discretionary and the largest sector underweight was Industrials. Contributors to Performance The Consumer Discretionary and Communication Services sectors provided the largest contributions to relative performance. Q2 Holdings, Inc.; Wingstop, Inc.; Shake Shack, Inc.; Guidewire Software, Inc.; and Manhattan Associates, Inc. were the top five contributors to absolute performance. Detractors from Performance The Health Care and Industrials sectors were the largest detractors from relative performance. Cabaletta Bio, Inc.; Structure Therapeutics, Inc.; Capri Holdings Ltd.; DLocal Ltd.; and 908 Devices Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed annual periods for the life of Class Z-2 shares of the Fund since its inception. The graph assumes a $500,000 initial investment at net asset value at the inception date of the Fund in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $500,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years Since Inception Alger Small Cap Growth Institutional Fund Class Z-2 26.44 % 4.60 % 9.45 % Russell 2000 Growth Index 36.49 % 7.92 % 9.01 % S&P 500 Index 38.02 % 15.27 % 14.43 % | |
| Performance Inception Date | Aug. 01, 2016 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 89,675,156 | |
| Holdings Count | Holding | 104 | [8] |
| Advisory Fees Paid, Amount | $ 877,483 | |
| Investment Company Portfolio Turnover | 48.95% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 104 Portfolio turnover rate as of the end of the reporting period 48.95 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 0.5 % Consumer Discretionary 18.2 % Consumer Staples 2.1 % Energy 0.7 % Financials 1.4 % Healthcare 29.4 % Industrials 12.2 % Information Technology 34.9 % Materials 0.1 % Short-Term Investments and Other Net Assets 0.5 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000025002 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Mid Cap Growth Institutional Fund | |
| Class Name | Class I | |
| Trading Symbol | ALMRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Mid Cap Growth Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Mid Cap Growth Institutional Fund $ 1.31 % | |
| Expenses Paid, Amount | $ 154 | |
| Expense Ratio, Percent | 1.31% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Mid Cap Growth Institutional Fund Class I returned 35.83% for the fiscal twelve-month period ended October 31, 2024, compared to the 38.67% return of the Russell Midcap Growth Index. During the reporting period, the largest sector weightings were Information Technology and Industrials. The largest sector overweight was Information Technology and the largest sector underweight was Financials. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. Natera, Inc.; Vertiv Holdings Co.; Spotify Technology; AppLovin Corp.; and Constellation Software Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Discretionary and Financials sectors were the largest detractors from relative performance. Super Micro Computer, Inc.; Lattice Semiconductor Corp.; Wayfair, Inc.; Five Below, Inc.; and Paycom Software, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class I shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Mid Cap Growth Institutional Fund Class I 35.83 % 10.40 % 9.48 % Russell Midcap Growth Index 38.67 % 11.46 % 11.19 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Feb. 29, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 65,737,384 | |
| Holdings Count | Holding | 64 | [9] |
| Advisory Fees Paid, Amount | $ 491,165 | |
| Investment Company Portfolio Turnover | 56.01% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 64 Portfolio turnover rate as of the end of the reporting period 56.01 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 7.8 % Consumer Discretionary 10.8 % Consumer Staples 0.4 % Energy 2.2 % Financials 10.1 % Healthcare 10.8 % Industrials 23.1 % Information Technology 29.9 % Materials 1.8 % Real Estate 3.8 % Short-Term Investments and Other Net Assets (0.7 ) % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. Effective February 29, 2024, Fred Alger Management, LLC has contractually agreed to waive and/or reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class I Shares of the Fund to 0.48% of the class’s average daily net assets. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective February 29, 2024, Fred Alger Management, LLC has contractually agreed to waive and/or reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit other expenses and any other applicable share class-specific expenses of the Class I Shares of the Fund to 0.48% of the class’s average daily net assets. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000025003 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Mid Cap Growth Institutional Fund | |
| Class Name | Class R | |
| Trading Symbol | AGIRX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Mid Cap Growth Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Mid Cap Growth Institutional Fund $ 1.85 % | |
| Expenses Paid, Amount | $ 217 | |
| Expense Ratio, Percent | 1.85% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Mid Cap Growth Institutional Fund Class R returned 35.12% for the fiscal twelve-month period ended October 31, 2024, compared to the 38.67% return of the Russell Midcap Growth Index. During the reporting period, the largest sector weightings were Information Technology and Industrials. The largest sector overweight was Information Technology and the largest sector underweight was Financials. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. Natera, Inc.; Vertiv Holdings Co.; Spotify Technology; AppLovin Corp.; and Constellation Software Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Discretionary and Financials sectors were the largest detractors from relative performance. Super Micro Computer, Inc.; Lattice Semiconductor Corp.; Wayfair, Inc.; Five Below, Inc.; and Paycom Software, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class R shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Mid Cap Growth Institutional Fund Class R 35.12 % 9.86 % 8.93 % Russell Midcap Growth Index 38.67 % 11.46 % 11.19 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 65,737,384 | |
| Holdings Count | Holding | 64 | [10] |
| Advisory Fees Paid, Amount | $ 491,165 | |
| Investment Company Portfolio Turnover | 56.01% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 64 Portfolio turnover rate as of the end of the reporting period 56.01 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 7.8 % Consumer Discretionary 10.8 % Consumer Staples 0.4 % Energy 2.2 % Financials 10.1 % Healthcare 10.8 % Industrials 23.1 % Information Technology 29.9 % Materials 1.8 % Real Estate 3.8 % Short-Term Investments and Other Net Assets (0.7 ) % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000174228 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Mid Cap Growth Institutional Fund | |
| Class Name | Class Z-2 | |
| Trading Symbol | ALMZX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Mid Cap Growth Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Mid Cap Growth Institutional Fund $ 1.00 % | |
| Expenses Paid, Amount | $ 118 | |
| Expense Ratio, Percent | 1% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Mid Cap Growth Institutional Fund Class Z-2 returned 36.22% for the fiscal twelve-month period ended October 31, 2024, compared to the 38.67% return of the Russell Midcap Growth Index. During the reporting period, the largest sector weightings were Information Technology and Industrials. The largest sector overweight was Information Technology and the largest sector underweight was Financials. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. Natera, Inc.; Vertiv Holdings Co.; Spotify Technology; AppLovin Corp.; and Constellation Software Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Discretionary and Financials sectors were the largest detractors from relative performance. Super Micro Computer, Inc.; Lattice Semiconductor Corp.; Wayfair, Inc.; Five Below, Inc.; and Paycom Software, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed annual periods for the life of Class Z-2 shares of the Fund since its inception. The graph assumes a $500,000 initial investment at net asset value at the inception date of the Fund in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $500,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years Since Inception Alger Mid Cap Growth Institutional Fund Class Z-2 36.22 % 10.80 % 12.43 % Russell Midcap Growth Index 38.67 % 11.46 % 13.19 % S&P 500 Index 38.02 % 15.27 % 15.00 % | |
| Performance Inception Date | Oct. 14, 2016 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 65,737,384 | |
| Holdings Count | Holding | 64 | [11] |
| Advisory Fees Paid, Amount | $ 491,165 | |
| Investment Company Portfolio Turnover | 56.01% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 64 Portfolio turnover rate as of the end of the reporting period 56.01 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 7.8 % Consumer Discretionary 10.8 % Consumer Staples 0.4 % Energy 2.2 % Financials 10.1 % Healthcare 10.8 % Industrials 23.1 % Information Technology 29.9 % Materials 1.8 % Real Estate 3.8 % Short-Term Investments and Other Net Assets (0.7 ) % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000025004 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Capital Appreciation Institutional Fund | |
| Class Name | Class I | |
| Trading Symbol | ALARX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Capital Appreciation Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Capital Appreciation Institutional Fund $ 1.24 % | |
| Expenses Paid, Amount | $ 160 | |
| Expense Ratio, Percent | 1.24% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Capital Appreciation Institutional Fund Class I returned 57.90% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Amazon.com, Inc.; and Natera, Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Humana Inc.; Snowflake, Inc.; Schlumberger Ltd.; HubSpot, Inc.; and Snap, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class I shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Capital Appreciation Institutional Fund Class I 57.90 % 17.04 % 14.48 % Russell 1000 Growth Index 43.77 % 19.00 % 16.18 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 2,120,603,780 | |
| Holdings Count | Holding | 70 | [12] |
| Advisory Fees Paid, Amount | $ 17,002,298 | |
| Investment Company Portfolio Turnover | 59.80% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 70 Portfolio turnover rate as of the end of the reporting period 59.80 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 15.2 % Consumer Discretionary 12.8 % Energy 0.5 % Financials 3.9 % Healthcare 9.3 % Industrials 8.4 % Information Technology 47.3 % Materials 0.2 % Real Estate 0.8 % Utilities 1.6 % Short-Term Investments and Other Net Assets 0.0 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000025005 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Capital Appreciation Institutional Fund | |
| Class Name | Class R | |
| Trading Symbol | ACARX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Capital Appreciation Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Capital Appreciation Institutional Fund $ 1.69 % | |
| Expenses Paid, Amount | $ 217 | |
| Expense Ratio, Percent | 1.69% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Capital Appreciation Institutional Fund Class R returned 57.21% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Amazon.com, Inc.; and Natera, Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Humana Inc.; Snowflake, Inc.; Schlumberger Ltd.; HubSpot, Inc.; and Snap, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed ten fiscal years of Class R shares of the Fund. The graph assumes a $10,000 initial investment at the beginning of the first annual period in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years 10 Years Alger Capital Appreciation Institutional Fund Class R 57.21 % 16.53 % 13.96 % Russell 1000 Growth Index 43.77 % 19.00 % 16.18 % S&P 500 Index 38.02 % 15.27 % 13.00 % | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 2,120,603,780 | |
| Holdings Count | Holding | 70 | [13] |
| Advisory Fees Paid, Amount | $ 17,002,298 | |
| Investment Company Portfolio Turnover | 59.80% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 70 Portfolio turnover rate as of the end of the reporting period 59.80 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 15.2 % Consumer Discretionary 12.8 % Energy 0.5 % Financials 3.9 % Healthcare 9.3 % Industrials 8.4 % Information Technology 47.3 % Materials 0.2 % Real Estate 0.8 % Utilities 1.6 % Short-Term Investments and Other Net Assets 0.0 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000179523 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Capital Appreciation Institutional Fund | |
| Class Name | Class Y | |
| Trading Symbol | ACAYX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Capital Appreciation Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Capital Appreciation Institutional Fund $ 0.86 % | |
| Expenses Paid, Amount | $ 111 | |
| Expense Ratio, Percent | 0.86% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Capital Appreciation Institutional Fund Class Y returned 58.48% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Amazon.com, Inc.; and Natera, Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Humana Inc.; Snowflake, Inc.; Schlumberger Ltd.; HubSpot, Inc.; and Snap, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed annual periods for the life of Class Y shares of the Fund since its inception. The graph assumes a $500,000 initial investment at net asset value at the inception date of the Fund in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $500,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years Since Inception Alger Capital Appreciation Institutional Fund Class Y 58.48 % 17.51 % 16.98 % Russell 1000 Growth Index 43.77 % 19.00 % 18.19 % S&P 500 Index 38.02 % 15.27 % 14.13 % | |
| Performance Inception Date | Feb. 28, 2017 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 2,120,603,780 | |
| Holdings Count | Holding | 70 | [14] |
| Advisory Fees Paid, Amount | $ 17,002,298 | |
| Investment Company Portfolio Turnover | 59.80% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 70 Portfolio turnover rate as of the end of the reporting period 59.80 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 15.2 % Consumer Discretionary 12.8 % Energy 0.5 % Financials 3.9 % Healthcare 9.3 % Industrials 8.4 % Information Technology 47.3 % Materials 0.2 % Real Estate 0.8 % Utilities 1.6 % Short-Term Investments and Other Net Assets 0.0 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000174229 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Capital Appreciation Institutional Fund | |
| Class Name | Class Z-2 | |
| Trading Symbol | ACIZX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Alger Capital Appreciation Institutional Fund (“Fund”) for the period of November 1, 2023 to October 31, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Notice [Text Block] | This report describes material changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 992-3863 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last year? (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 Capital Appreciation Institutional Fund $ 0.88 % | |
| Expenses Paid, Amount | $ 114 | |
| Expense Ratio, Percent | 0.88% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Capital Appreciation Institutional Fund Class Z-2 returned 58.44% for the fiscal twelve-month period ended October 31, 2024, compared to the 43.77% return of the Russell 1000 Growth Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Industrials and the largest sector underweight was Consumer Staples. Contributors to Performance The Information Technology and Health Care sectors provided the largest contributions to relative performance. NVIDIA Corp.; Meta Platforms Inc.; Microsoft Corp.; Amazon.com, Inc.; and Natera, Inc. were the top five contributors to absolute performance. Detractors from Performance The Consumer Staples and Financials sectors were the largest detractors from relative performance. Humana Inc.; Snowflake, Inc.; Schlumberger Ltd.; HubSpot, Inc.; and Snap, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Resilient Corporate Earnings Positive Strong corporate earnings were driven by profit margin improvement and robust consumer spending. Themes such as AI proliferation, waning cloud optimization pressure, and profit margin expansion from increased productivity and expense control also supported market sentiment. Federal Reserve Rate Cuts Positive In September 2024, the Federal Reserve initiated a rate-cutting cycle with a 50-basis point reduction, aiming to bolster economic growth amid a strong but softening labor market and easing inflation, creating a favorable backdrop for equities. Rising Geopolitical Tensions Negative Geopolitical conflicts and trade disputes created some uncertainty ahead of the 2024 U.S. presidential election. Weakening U.S. Labor Market Negative In August 2024, equity markets experienced a brief sell-off due to growth concerns following a weaker-than-expected July payrolls report, which raised fears that the Federal Reserve might be slow to respond to slowing economic conditions. The unemployment rate increased to 4.3%, triggering the Sahm rule—a recession indicator that signals a likely recession when the three-month moving average of the unemployment rate rises by at least 50 basis points from its twelve-month low. | |
| Performance Past Does Not Indicate Future [Text] | Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. | |
| Line Graph [Table Text Block] | Fund Performance The following graph compares the initial and subsequent account values at the end of each of the most recently completed annual periods for the life of Class Z-2 shares of the Fund since its inception. The graph assumes a $500,000 initial investment at net asset value at the inception date of the Fund in an appropriate, broad-based securities market index and a more narrowly based index that reflects the market sector in which the Fund invests for the same period. INITIAL INVESTMENT OF $500,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of October 31, 2024) 1 Year 5 Years Since Inception Alger Capital Appreciation Institutional Fund Class Z-2 58.44 % 17.44 % 17.32 % Russell 1000 Growth Index 43.77 % 19.00 % 18.19 % S&P 500 Index 38.02 % 15.27 % 14.13 % | |
| Performance Inception Date | Oct. 14, 2016 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Mar. 01, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 2,120,603,780 | |
| Holdings Count | Holding | 70 | [15] |
| Advisory Fees Paid, Amount | $ 17,002,298 | |
| Investment Company Portfolio Turnover | 59.80% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the fiscal year ended October 31, 2024. Fund net assets $ Total number of portfolio holdings 1 70 Portfolio turnover rate as of the end of the reporting period 59.80 % Total advisory fees paid $ 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 15.2 % Consumer Discretionary 12.8 % Energy 0.5 % Financials 3.9 % Healthcare 9.3 % Industrials 8.4 % Information Technology 47.3 % Materials 0.2 % Real Estate 0.8 % Utilities 1.6 % Short-Term Investments and Other Net Assets 0.0 % 100.0 % † Based on net assets | |
| Material Fund Change [Text Block] | Material and Other Fund Changes Effective January 29, 2024, the Fund's custodian and administrator transitioned from Brown Brothers Harriman & Company to The Bank of New York. On August 16, 2024, at a joint special meeting of shareholders, shareholders of the Fund elected three new trustees and one current trustee to the Board. Effective March 1, 2024, Alger Management has contractually agreed to waive fees or to reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit the Other Expenses of the Class Z-2 Shares of the Fund to 0.05% of the class’s average daily net assets. On October 22, 2024, the Board approved that any fees incurred as a result of the joint special meeting of shareholders would be excluded from the expense reimbursement. This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective March 1, 2024, Alger Management has contractually agreed to waive fees or to reimburse Fund expenses (excluding custody fees, acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through October 31, 2025 to the extent necessary to limit the Other Expenses of the Class Z-2 Shares of the Fund to 0.05% of the class’s average daily net assets. On October 22, 2024, the Board approved that any fees incurred as a result of the joint special meeting of shareholders would be excluded from the expense reimbursement. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since November 1, 2023. For more complete information, you may review the Fund's next prospectus, which we expect to be available by February 28, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 992-3863 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| [1]Excludes Money Market Funds.[2]Excludes Money Market Funds.[3]Excludes Money Market Funds.[4]Excludes Money Market Funds.[5]Excludes Money Market Funds.[6]Excludes Money Market Funds.[7]Excludes Money Market Funds.[8]Excludes Money Market Funds.[9]Excludes Money Market Funds.[10]Excludes Money Market Funds.[11]Excludes Money Market Funds.[12]Excludes Money Market Funds.[13]Excludes Money Market Funds.[14]Excludes Money Market Funds.[15]Excludes Money Market Funds. | ||
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | 60 Months Ended | 92 Months Ended | 97 Months Ended | 99 Months Ended | 120 Months Ended | |||||||||||||
| Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2024 | Oct. 31, 2023 | Oct. 31, 2022 | Oct. 31, 2021 | Oct. 31, 2020 | Oct. 31, 2019 | Oct. 31, 2018 | Oct. 31, 2017 | Feb. 28, 2017 | Oct. 31, 2016 | Oct. 14, 2016 | Aug. 01, 2016 | Oct. 31, 2015 | Oct. 31, 2014 | |
| C000122071 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class A | ||||||||||||||||||
| Account Value | $ 42,427.58 | $ 42,427.58 | $ 42,427.58 | $ 42,427.58 | $ 42,427.58 | $ 42,427.58 | $ 26,389.53 | $ 22,436.74 | $ 33,658.09 | $ 24,681.48 | $ 17,788.9 | $ 15,393.74 | $ 13,815.37 | $ 10,424.64 | $ 10,387.43 | $ 9,474.82 | |||
| Average Annual Return, Percent | 52.32% | 17.71% | 15.55% | ||||||||||||||||
| C000122071 [Member] | Without Sales Load [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class A—excluding sales load | ||||||||||||||||||
| Average Annual Return, Percent | 60.77% | 18.99% | 16.17% | ||||||||||||||||
| C000122072 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class C | ||||||||||||||||||
| Account Value | $ 42,145.84 | $ 42,145.84 | 42,145.84 | 42,145.84 | 42,145.84 | $ 42,145.84 | 26,214.3 | 22,287.74 | 33,694.28 | 24,897.92 | 18,077.17 | 15,763.22 | 14,250.54 | 10,840.47 | 10,879.77 | 10,000 | |||
| Average Annual Return, Percent | 58.55% | 18.08% | 15.47% | ||||||||||||||||
| C000122072 [Member] | Without Sales Load [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class C—excluding contingent deferred sales charges | ||||||||||||||||||
| Average Annual Return, Percent | 59.55% | 18.08% | 15.47% | ||||||||||||||||
| C000024998 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class I | ||||||||||||||||||
| Account Value | $ 44,998.28 | $ 44,998.28 | 44,998.28 | 44,998.28 | 44,998.28 | $ 44,998.28 | 27,978.44 | 23,783.81 | 35,672.31 | 26,145.24 | 18,834.93 | 16,284.82 | 14,604.93 | 11,022.42 | 10,978.71 | 10,000 | |||
| Average Annual Return, Percent | 60.84% | 19.03% | 16.23% | ||||||||||||||||
| C000179522 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class Y | ||||||||||||||||||
| Account Value | $ 1,894,966.12 | $ 1,894,966.12 | $ 1,894,966.12 | 1,894,966.12 | 1,894,966.12 | $ 1,894,966.12 | 1,174,357.47 | 994,794.23 | 1,486,994.46 | 1,086,693.24 | 780,823.73 | 673,317.19 | 601,824.28 | $ 500,000 | |||||
| Average Annual Return, Percent | 61.36% | 19.40% | 18.97% | ||||||||||||||||
| C000122073 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Focus Equity Fund Class Z | ||||||||||||||||||
| Account Value | $ 2,313,131.82 | $ 2,313,131.82 | $ 2,313,131.82 | 2,313,131.82 | 2,313,131.82 | $ 2,313,131.82 | 1,434,187.17 | 1,215,431.36 | 1,817,658.18 | 1,328,605.63 | 954,477.62 | 823,346.79 | 736,010.63 | 554,060.05 | 550,518.73 | 500,000 | |||
| Average Annual Return, Percent | 61.29% | 19.37% | 16.55% | ||||||||||||||||
| C000025000 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Small Cap Growth Institutional Fund Class I | ||||||||||||||||||
| Account Value | $ 20,497.78 | $ 20,497.78 | 20,497.78 | 20,497.78 | 20,497.78 | $ 20,497.78 | 16,290.92 | 18,412.64 | 31,134.41 | 24,015.71 | 16,663.26 | 15,121.19 | 13,386.69 | 9,674.69 | 10,053.17 | 10,000 | |||
| Average Annual Return, Percent | 25.82% | 4.23% | 7.44% | ||||||||||||||||
| C000025001 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Small Cap Growth Institutional Fund Class R | ||||||||||||||||||
| Account Value | $ 19,544.53 | $ 19,544.53 | 19,544.53 | 19,544.53 | 19,544.53 | $ 19,544.53 | 15,595.11 | 17,721.72 | 30,092.18 | 23,323.09 | 16,267.17 | 14,832.51 | 13,186.94 | 9,580.19 | 10,002.17 | 10,000.01 | |||
| Average Annual Return, Percent | 25.33% | 3.74% | 6.93% | ||||||||||||||||
| C000172687 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Small Cap Growth Institutional Fund Class Z-2 | ||||||||||||||||||
| Account Value | $ 1,053,391.24 | $ 1,053,391.24 | 1,053,391.24 | 1,053,391.24 | $ 1,053,391.24 | $ 1,053,391.24 | 833,125.68 | 938,707.52 | 1,581,601.94 | 1,216,135.09 | 841,325.18 | 760,599.96 | 671,009.77 | 483,387.62 | $ 500,000 | ||||
| Average Annual Return, Percent | 26.44% | 4.60% | 9.45% | ||||||||||||||||
| C000025002 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Mid Cap Growth Institutional Fund Class I | ||||||||||||||||||
| Account Value | $ 24,736.96 | $ 24,736.96 | 24,736.96 | 24,736.96 | $ 24,736.96 | $ 24,736.96 | 18,212.11 | 18,244.04 | 30,159.61 | 21,377.97 | 15,085.78 | 13,620.39 | 12,917.05 | 9,734 | 10,162.32 | 10,000 | |||
| Average Annual Return, Percent | 35.83% | 10.40% | 9.48% | ||||||||||||||||
| C000025003 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Mid Cap Growth Institutional Fund Class R | ||||||||||||||||||
| Account Value | $ 23,511.99 | $ 23,511.99 | 23,511.99 | 23,511.99 | 23,511.99 | $ 23,511.99 | 17,401.53 | 17,521.08 | 29,091.94 | 20,718.58 | 14,691.18 | 13,326.9 | 12,704.92 | 9,623.91 | 10,110.9 | 10,000 | |||
| Average Annual Return, Percent | 35.12% | 9.86% | 8.93% | ||||||||||||||||
| C000174228 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Mid Cap Growth Institutional Fund Class Z-2 | ||||||||||||||||||
| Account Value | $ 1,283,109 | $ 1,283,109 | 1,283,109 | $ 1,283,109 | 1,283,109 | $ 1,283,109 | 941,969.14 | 939,324.64 | 1,546,022.65 | 1,092,604.7 | 768,474.61 | 691,799.54 | 654,214.11 | 491,799.54 | $ 500,000 | ||||
| Average Annual Return, Percent | 36.22% | 10.80% | 12.43% | ||||||||||||||||
| C000025004 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Capital Appreciation Institutional Fund Class I | ||||||||||||||||||
| Account Value | $ 38,652.83 | $ 38,652.83 | 38,652.83 | $ 38,652.83 | 38,652.83 | $ 38,652.83 | 24,480.12 | 20,920.89 | 32,143.43 | 23,684.31 | 17,598.72 | 15,276.54 | 14,085.45 | 10,887.33 | 10,895.59 | 10,000 | |||
| Average Annual Return, Percent | 57.90% | 17.04% | 14.48% | ||||||||||||||||
| C000025005 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Capital Appreciation Institutional Fund Class R | ||||||||||||||||||
| Account Value | $ 36,947.58 | $ 36,947.58 | 36,947.58 | 36,947.58 | 36,947.58 | $ 36,947.58 | 23,502.55 | 20,168.63 | 31,125.43 | 23,038.73 | 17,194.09 | 14,991.98 | 13,887.24 | 10,783.75 | 10,846.06 | 10,000 | |||
| Average Annual Return, Percent | 57.21% | 16.53% | 13.96% | ||||||||||||||||
| C000179523 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Capital Appreciation Institutional Fund Class Y | ||||||||||||||||||
| Account Value | $ 1,665,453.32 | $ 1,665,453.32 | $ 1,665,453.32 | 1,665,453.32 | 1,665,453.32 | $ 1,665,453.32 | 1,050,872.35 | 893,982.14 | 1,367,890.65 | 1,004,401.03 | 743,439.69 | 642,633.9 | 590,121.33 | 500,000.01 | |||||
| Average Annual Return, Percent | 58.48% | 17.51% | 16.98% | ||||||||||||||||
| C000174229 [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Alger Capital Appreciation Institutional Fund Class Z-2 | ||||||||||||||||||
| Account Value | $ 1,807,594.27 | $ 1,807,594.27 | $ 1,807,594.27 | $ 1,807,594.27 | 1,807,594.27 | 1,807,594.27 | 1,140,864.1 | 971,153.5 | 1,487,278.47 | 1,092,511.05 | 809,141.56 | 700,182.27 | 643,558.4 | 495,688.05 | 500,000 | ||||
| Average Annual Return, Percent | 58.44% | 17.44% | 17.32% | ||||||||||||||||
| Standard & Poor's 500 Index [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||||||||||||||||
| Account Value | $ 33,950.48 | $ 33,950.48 | $ 33,950.48 | $ 33,950.48 | $ 33,950.48 | $ 33,950.48 | 24,598.75 | 22,333.51 | 26,155.03 | 18,301.25 | 16,681.39 | 14,591.05 | 13,592.51 | 500,000 | 10,994.31 | 500,000 | 500,000 | 10,519.95 | 10,000 |
| Average Annual Return, Percent | 38.02% | 15.27% | 14.13% | 14.13% | 14.43% | 13% | |||||||||||||
| Standard And Poors 500 C000174228 Index [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Average Annual Return, Percent | 15% | ||||||||||||||||||
| Russell 1000 Growth Index [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Russell 1000 Growth Index | ||||||||||||||||||
| Account Value | $ 44,811.68 | $ 44,811.68 | $ 44,811.68 | $ 44,811.68 | $ 44,811.68 | $ 44,811.68 | 31,169.84 | 26,204.02 | 34,751.76 | 24,266.48 | 18,779.47 | 16,036.72 | 14,485.05 | $ 500,000 | 11,167.19 | 500,000 | 10,918.02 | 10,000 | |
| Average Annual Return, Percent | 43.77% | 19% | 18.19% | 18.19% | 16.18% | ||||||||||||||
| Russell 2000 Growth Index [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Russell 2000 Growth Index | ||||||||||||||||||
| Account Value | $ 21,889.58 | $ 21,889.58 | $ 21,889.58 | $ 21,889.58 | $ 21,889.58 | $ 21,889.58 | 16,037.45 | 17,361.82 | 23,469 | 16,950.83 | 14,952.09 | 14,052.58 | 13,494.92 | 10,301.76 | $ 500,000 | 10,352.38 | 10,000 | ||
| Average Annual Return, Percent | 36.49% | 7.92% | 9.01% | 8.15% | |||||||||||||||
| Russell Midcap Growth Index [Member] | |||||||||||||||||||
| Account Value [Line Items] | |||||||||||||||||||
| Line Graph and Table Measure Name | Russell Midcap Growth Index | ||||||||||||||||||
| Account Value | $ 28,880.01 | $ 28,880.01 | $ 28,880.01 | $ 28,880.01 | $ 28,880.01 | $ 28,880.01 | $ 20,826.41 | $ 20,151.35 | $ 28,358.2 | $ 20,339.19 | $ 16,790.25 | $ 14,117.67 | $ 13,301.06 | $ 10,535.85 | $ 500,000 | $ 10,493.56 | $ 10,000 | ||
| Average Annual Return, Percent | 38.67% | 11.46% | 13.19% | 11.19% |
| Shareholder Report, Holdings (Details) | Oct. 31, 2024 | |
| C000122071 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [1] |
| C000122071 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 14% | [1] |
| C000122071 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.10% | [1] |
| C000122071 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1% | [1] |
| C000122071 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [1] |
| C000122071 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.40% | [1] |
| C000122071 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [1] |
| C000122071 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 43.70% | [1] |
| C000122071 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.30% | [1] |
| C000122071 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [1] |
| C000122071 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.30% | [1] |
| C000122071 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.40% | [1] |
| C000122072 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [2] |
| C000122072 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 14% | [2] |
| C000122072 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.10% | [2] |
| C000122072 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1% | [2] |
| C000122072 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [2] |
| C000122072 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.40% | [2] |
| C000122072 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [2] |
| C000122072 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 43.70% | [2] |
| C000122072 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.30% | [2] |
| C000122072 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [2] |
| C000122072 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.30% | [2] |
| C000122072 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.40% | [2] |
| C000024998 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [3] |
| C000024998 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 14% | [3] |
| C000024998 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.10% | [3] |
| C000024998 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1% | [3] |
| C000024998 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [3] |
| C000024998 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.40% | [3] |
| C000024998 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [3] |
| C000024998 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 43.70% | [3] |
| C000024998 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.30% | [3] |
| C000024998 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [3] |
| C000024998 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.30% | [3] |
| C000024998 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.40% | [3] |
| C000179522 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [4] |
| C000179522 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 14% | [4] |
| C000179522 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.10% | [4] |
| C000179522 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1% | [4] |
| C000179522 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [4] |
| C000179522 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.40% | [4] |
| C000179522 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [4] |
| C000179522 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 43.70% | [4] |
| C000179522 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.30% | [4] |
| C000179522 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [4] |
| C000179522 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.30% | [4] |
| C000179522 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.40% | [4] |
| C000122073 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [5] |
| C000122073 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 14% | [5] |
| C000122073 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.10% | [5] |
| C000122073 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1% | [5] |
| C000122073 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [5] |
| C000122073 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.40% | [5] |
| C000122073 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [5] |
| C000122073 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 43.70% | [5] |
| C000122073 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.30% | [5] |
| C000122073 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.90% | [5] |
| C000122073 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.30% | [5] |
| C000122073 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.40% | [5] |
| C000025000 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [6] |
| C000025000 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [6] |
| C000025000 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 18.20% | [6] |
| C000025000 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.70% | [6] |
| C000025000 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.40% | [6] |
| C000025000 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 29.40% | [6] |
| C000025000 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.20% | [6] |
| C000025000 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 34.90% | [6] |
| C000025000 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.10% | [6] |
| C000025000 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.10% | [6] |
| C000025000 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [6] |
| C000025001 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [7] |
| C000025001 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [7] |
| C000025001 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 18.20% | [7] |
| C000025001 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.70% | [7] |
| C000025001 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.40% | [7] |
| C000025001 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 29.40% | [7] |
| C000025001 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.20% | [7] |
| C000025001 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 34.90% | [7] |
| C000025001 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.10% | [7] |
| C000025001 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.10% | [7] |
| C000025001 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [7] |
| C000172687 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [8] |
| C000172687 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [8] |
| C000172687 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 18.20% | [8] |
| C000172687 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.70% | [8] |
| C000172687 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.40% | [8] |
| C000172687 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 29.40% | [8] |
| C000172687 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.20% | [8] |
| C000172687 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 34.90% | [8] |
| C000172687 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.10% | [8] |
| C000172687 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.10% | [8] |
| C000172687 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [8] |
| C000025002 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [9] |
| C000025002 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.80% | [9] |
| C000025002 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [9] |
| C000025002 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.20% | [9] |
| C000025002 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.10% | [9] |
| C000025002 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [9] |
| C000025002 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 23.10% | [9] |
| C000025002 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 29.90% | [9] |
| C000025002 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.80% | [9] |
| C000025002 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.80% | [9] |
| C000025002 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.40% | [9] |
| C000025002 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | (0.70%) | [9] |
| C000025003 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [10] |
| C000025003 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.80% | [10] |
| C000025003 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [10] |
| C000025003 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.20% | [10] |
| C000025003 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.10% | [10] |
| C000025003 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [10] |
| C000025003 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 23.10% | [10] |
| C000025003 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 29.90% | [10] |
| C000025003 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.80% | [10] |
| C000025003 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.80% | [10] |
| C000025003 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.40% | [10] |
| C000025003 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | (0.70%) | [10] |
| C000174228 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [11] |
| C000174228 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 7.80% | [11] |
| C000174228 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [11] |
| C000174228 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.20% | [11] |
| C000174228 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.10% | [11] |
| C000174228 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.80% | [11] |
| C000174228 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 23.10% | [11] |
| C000174228 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 29.90% | [11] |
| C000174228 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.80% | [11] |
| C000174228 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.80% | [11] |
| C000174228 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.40% | [11] |
| C000174228 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | (0.70%) | [11] |
| C000025004 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [12] |
| C000025004 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 15.20% | [12] |
| C000025004 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.80% | [12] |
| C000025004 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [12] |
| C000025004 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.90% | [12] |
| C000025004 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.30% | [12] |
| C000025004 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 8.40% | [12] |
| C000025004 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 47.30% | [12] |
| C000025004 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.20% | [12] |
| C000025004 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [12] |
| C000025004 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.60% | [12] |
| C000025004 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0% | [12] |
| C000025005 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [13] |
| C000025005 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 15.20% | [13] |
| C000025005 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.80% | [13] |
| C000025005 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [13] |
| C000025005 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.90% | [13] |
| C000025005 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.30% | [13] |
| C000025005 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 8.40% | [13] |
| C000025005 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 47.30% | [13] |
| C000025005 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.20% | [13] |
| C000025005 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [13] |
| C000025005 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.60% | [13] |
| C000025005 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0% | [13] |
| C000179523 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [14] |
| C000179523 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 15.20% | [14] |
| C000179523 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.80% | [14] |
| C000179523 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [14] |
| C000179523 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.90% | [14] |
| C000179523 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.30% | [14] |
| C000179523 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 8.40% | [14] |
| C000179523 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 47.30% | [14] |
| C000179523 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.20% | [14] |
| C000179523 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [14] |
| C000179523 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.60% | [14] |
| C000179523 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0% | [14] |
| C000174229 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [15] |
| C000174229 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 15.20% | [15] |
| C000174229 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.80% | [15] |
| C000174229 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [15] |
| C000174229 [Member] | Financial Services Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.90% | [15] |
| C000174229 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.30% | [15] |
| C000174229 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 8.40% | [15] |
| C000174229 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 47.30% | [15] |
| C000174229 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.20% | [15] |
| C000174229 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.80% | [15] |
| C000174229 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.60% | [15] |
| C000174229 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0% | [15] |
| [1]Based on net assets[2]Based on net assets[3]Based on net assets[4]Based on net assets[5]Based on net assets[6]Based on net assets[7]Based on net assets[8]Based on net assets[9]Based on net assets[10]Based on net assets[11]Based on net assets[12]Based on net assets[13]Based on net assets[14]Based on net assets[15]Based on net assets | ||
