| Form N-CSR Cover | 6 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | Alger ETF Trust |
| Entity Central Index Key | 0001807486 |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 6 Months Ended | |
| Jun. 30, 2024 USD ($) Holding | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSRS | |
| Amendment Flag | false | |
| Registrant Name | Alger ETF Trust | |
| Entity Central Index Key | 0001807486 | |
| Document Period End Date | Jun. 30, 2024 | |
| C000222789 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger 35 ETF | |
| Class Name | Alger 35 ETF | |
| Trading Symbol | ATFV | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Alger 35 ETF (“Fund”) for the period of January 1, 2024 to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | semi-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 changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 223-3810 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Fund Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Alger 35 ETF $ 0.55 % | |
| Expenses Paid, Amount | $ 31 | |
| Expense Ratio, Percent | 0.55% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger 35 ETF generated a 23.53% return for the fiscal six-month period ended June 30, 2024, compared to the 15.29% return of the S&P 500 Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Information Technology and the largest sector underweight was Financials. Contributors to Performance The Information Technology and Communication Services sectors provided the largest contributions to relative performance. Regarding individual positions, NVIDIA Corporation; Spotify Technology SA; Amazon.com, Inc.; Natera, Inc.; and Microsoft Corporation were the top five contributors to absolute performance. Detractors from Performance The Financials and Consumer Staples sectors were the largest detractors from relative performance. Regarding individual positions, Cabaletta Bio, Inc.; 908 Devices Inc.; Autolus Therapeutics; Snap, Inc.; and Joby Aviation, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Soft-landing Narrative Positive During the period, the soft-landing scenario—an economic slowdown without a recession—drove equity markets higher as U.S. GDP for the fourth quarter of 2023 grew 3.4%, exceeding the initial 2.0% consensus, driven by robust consumer spending. AI Enthusiasm Positive Continued anticipation about artificial intelligence drove strong gains for related companies, supported by robust operating results and upward earnings revisions. Elevated Inflation Negative Inflation concerns resurfaced during the first quarter of 2024, with Consumer Price Index (CPI) and Personal Consumption Expenditure Price Index (PCE) readings coming in higher-than-expected. Revised Federal Reserve Rate Cut Expectations Negative Elevated inflation readings during the first quarter of 2024 led to the Federal Reserve postponing an anticipated March rate cut. The revision of the market’s rate cut expectations, initially from a projected six cuts at the beginning of the period down to just one for the year, led to some market volatility in April. | |
| 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 and chart compares the initial and subsequent account values at the end of each of the most recently completed semi-annual periods of the Fund since its inception. The graph assumes a $10,000 initial investment at Net Asset Value at the INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of June 30, 2024) 1 Year Since Inception Alger 35 ETF 36.91 % 2.14 % S&P 500 Index 24.56 % 10.44 % Russell 3000 Growth Index 32.22 % 11.47 % | |
| Performance Inception Date | May 03, 2021 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Apr. 30, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 19,498,948 | |
| Holdings Count | Holding | 31 | [1] |
| Investment Company Portfolio Turnover | 152.51% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the reporting date. Fund net assets $ % Total number of portfolio holdings 1 $ % Portfolio turnover rate as of the end of the reporting period $ % 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 16.4 % Consumer Discretionary 14.0 % Energy 1.9 % Healthcare 9.0 % Industrials 4.9 % Information Technology 47.0 % Materials 2.0 % Utilities 2.0 % Short-Term Investments and Other Net Assets 2.8 % 100.0 % † Based on net assets of the Fund. | |
| Material Fund Change [Text Block] | Material and Other Fund Changes In January 2024, George Ortega was added as a portfolio manager of the Fund. On May 23, 2023, the Board of Trustees of the Fund (the “Board”) approved the transition of the Fund’s custodian, administrator, and transfer agent from Brown Brothers Harriman & Company to The Bank of New York. This change was implemented on March 18, 2024. 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 April 30, 2024, Alger Management contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through December 31, 2025 to the extent necessary to limit other expenses of the Fund to 0.10% of the Fund’s average daily net assets. This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective April 30, 2024, Alger Management contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through December 31, 2025 to the extent necessary to limit other expenses of the Fund to 0.10% of the Fund’s average daily net assets. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 223-3810 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000248577 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Concentrated Equity ETF | |
| Class Name | Alger Concentrated Equity ETF | |
| Trading Symbol | CNEQ | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Alger Concentrated Equity ETF (“Fund”) for the period of April 4, 2024 (commencement of operations) to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | semi-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 changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 223-3810 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs since inception? (Based on a hypothetical $10,000 investment) Fund Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Alger Concentrated Equity ETF $ 1 0.55 % 1 The Fund commenced investment operations on April 4, 2024. Had the Fund been in operation for a complete fiscal year, the cost of a $10,000 investment would have been higher. | |
| Expenses Paid, Amount | $ 14 | [2] |
| Expense Ratio, Percent | 0.55% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Concentrated Equity ETF generated a 11.65% return from its April 4, 2024, inception date to June 30, 2024, compared to the 10.63% 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 Industrials sectors provided the largest contributions to relative performance. Regarding individual positions, NVIDIA Corporation; Apple Inc.; Microsoft Corporation; Taiwan Semiconductor Manufacturing Co., Ltd.; and Amazon.com, Inc. were the top five contributors to absolute performance. Detractors from Performance The Communication Services and Consumer Discretionary sectors were the largest detractors from relative performance. Regarding individual positions, Mobileye Global, Inc.; Meta Platforms Inc; Advanced Micro Devices, Inc.; Visa Inc.; and Broadcom Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY AI Enthusiasm Positive Continued anticipation about artificial intelligence drove strong gains for related companies, supported by robust operating results and upward earnings revisions. Revised Federal Reserve Rate Cut Expectations Negative Elevated inflation readings during the first quarter of 2024 led to the Federal Reserve postponing an anticipated March rate cut. The revision of the market’s rate cut expectations, initially from a projected six cuts at the beginning of the period down to just one for the year, led to some market volatility in April. | |
| 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. | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of June 30, 2024) Since Inception Alger Concentrated Equity ETF 11.65 % Russell 1000 Growth Index 10.63 % S&P 500 Index 6.43 % | |
| Performance Inception Date | Apr. 04, 2024 | |
| No Deduction of Taxes [Text Block] | The table does | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 5,235,743 | |
| Holdings Count | Holding | 30 | [3] |
| Investment Company Portfolio Turnover | 17.31% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the reporting date. Fund net assets $ % Total number of portfolio holdings 1 $ % Portfolio turnover rate as of the end of the reporting period $ % 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 13.0 % Consumer Discretionary 11.1 % Energy 1.0 % Financials 4.1 % Healthcare 8.0 % Industrials 9.1 % Information Technology 49.2 % Utilities 1.4 % Short-Term Investments and Other Net Assets 3.1 % 100.0 % † Based on net assets of the Fund. | |
| Material Fund Change [Text Block] | Material and Other Fund Changes 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 of the Fund. This is a summary of certain changes to the Fund since April 4, 2024 (commencement of operations). For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since April 4, 2024 (commencement of operations). For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 223-3810 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000248578 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger AI Enablers & Adopters ETF | |
| Class Name | Alger AI Enablers & Adopters ETF | |
| Trading Symbol | ALAI | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Alger AI Enablers & Adopters ETF (“Fund”) for the period of April 4, 2024 (commencement of operations) to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | semi-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 changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 223-3810 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs since inception? (Based on a hypothetical $10,000 investment) Fund Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Alger AI Enablers & Adopters ETF $ 1 0.55 % 1 The Fund commenced investment operations on April 4, 2024. Had the Fund been in operation for a complete fiscal year, the cost of a $10,000 investment would have been higher. | |
| Expenses Paid, Amount | $ 14 | [4] |
| Expense Ratio, Percent | 0.55% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger AI Enablers & Adopters ETF generated a 11.76% return from its April 4, 2024, inception date to June 30, 2024, compared to the 6.43% return of the S&P 500 Index. During the reporting period, the largest sector weightings were Information Technology and Communication Services. The largest sector overweight was Information Technology and the largest sector underweight was Financials. Contributors to Performance The Information Technology and Communication Services sectors provided the largest contributions to relative performance. Regarding individual positions, NVIDIA Corporation; Apple Inc.; Microsoft Corporation; Alphabet Inc.; and Broadcom Inc. were the top five contributors to absolute performance. Detractors from Performance The Real Estate and Consumer Staples sectors were the largest detractors from relative performance. Regarding individual positions, Meta Platforms Inc; DraftKings, Inc.; Mobileye Global, Inc.; International Business Machines Corporation; and Salesforce, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY AI Enthusiasm Positive Continued anticipation about artificial intelligence drove strong gains for related companies, supported by robust operating results and upward earnings revisions. Revised Federal Reserve Rate Cut Expectations Negative Elevated inflation readings during the first quarter of 2024 led to the Federal Reserve postponing an anticipated March rate cut. The revision of the market’s rate cut expectations, initially from a projected six cuts at the beginning of the period down to just one for the year, led to some market volatility in April. | |
| 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. | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of June 30, 2024) Since Inception Alger AI Enablers & Adopters ETF 11.76 % S&P 500 Index 6.43 % | |
| Performance Inception Date | Apr. 04, 2024 | |
| No Deduction of Taxes [Text Block] | The table does | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 7,166,844 | |
| Holdings Count | Holding | 46 | [5] |
| Investment Company Portfolio Turnover | 28.28% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the reporting date. Fund net assets $ % Total number of portfolio holdings 1 $ % Portfolio turnover rate as of the end of the reporting period $ % 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 15.9 % Consumer Discretionary 13.5 % Consumer Staples 0.5 % Financials 3.6 % Healthcare 4.3 % Industrials 2.1 % Information Technology 52.3 % Real Estate 1.9 % Utilities 2.8 % Short-Term Investments and Other Net Assets 3.1 % 100.0 % † Based on net assets of the Fund. | |
| Material Fund Change [Text Block] | Material and Other Fund Changes 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 of the Fund. This is a summary of certain changes to the Fund since April 4, 2024 (commencement of operations). For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since April 4, 2024 (commencement of operations). For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 223-3810 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000222788 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Mid Cap 40 ETF | |
| Class Name | Alger Mid Cap 40 ETF | |
| Trading Symbol | FRTY | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Alger Mid Cap 40 ETF (“Fund”) for the period of January 1, 2024 to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | semi-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 changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 223-3810 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Fund Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Alger Mid Cap 40 ETF $ 0.60 % | |
| Expenses Paid, Amount | $ 33 | |
| Expense Ratio, Percent | 0.60% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Mid Cap 40 ETF generated a 18.31% return for the fiscal six-month period ended June 30, 2024, compared to the 5.98% return of 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 Industrials sectors provided the largest contributions to relative performance. Regarding individual positions, Super Micro Computer, Inc.; Vertiv Holdings Co.; Natera, Inc.; Micron Technology, Inc.; and AppFolio Inc were the top five contributors to absolute performance. Detractors from Performance The Energy and Financials sectors were the largest detractors from relative performance. Regarding individual positions, Exact Sciences Corporation; Cabaletta Bio, Inc.; Akero Therapeutics, Inc.; Snowflake, Inc.; and indie Semiconductor, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Soft-landing Narrative Positive During the period, the soft-landing scenario—an economic slowdown without a recession—drove equity markets higher as U.S. GDP for the fourth of 2023 quarter grew 3.4%, exceeding the initial 2.0% consensus, driven by robust consumer spending. AI Enthusiasm Positive Continued anticipation about artificial intelligence drove strong gains for related companies, supported by robust operating results and upward earnings revisions. Elevated Inflation Negative Inflation concerns resurfaced during the first quarter of 2024, with Consumer Price Index (CPI) and Personal Consumption Expenditure Price Index (PCE) readings coming in higher-than-expected. Revised Federal Reserve Rate Cut Expectations Negative Elevated inflation readings during the first quarter of 2024 led to the Federal Reserve postponing an anticipated March rate cut. The revision of the market’s rate cut expectations, initially from a projected six cuts at the beginning of the period down to just one for the year, led to some market volatility in April. | |
| 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 and chart compares the initial and subsequent account values at the end of each of the most recently completed semi-annual periods of the Fund since its inception. The graph assumes a $10,000 initial investment at Net Asset Value at the INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of June 30, 2024) 1 Year Since Inception Alger Mid Cap 40 ETF 26.30 % (4.75 ) % Russell Midcap Growth Index 15.05 % 2.53 ) % S&P 500 Index 24.56 % 13.10 ) % | |
| Performance Inception Date | Feb. 26, 2021 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Apr. 30, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 37,002,601 | |
| Holdings Count | Holding | 40 | [6] |
| Investment Company Portfolio Turnover | 91.35% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the reporting date. Fund net assets $ % Total number of portfolio holdings 1 $ % Portfolio turnover rate as of the end of the reporting period $ % 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 8.1 % Consumer Discretionary 10.4 % Consumer Staples 1.6 % Energy 2.5 % Financials 2.1 % Healthcare 12.2 % Industrials 23.8 % Information Technology 26.2 % Utilities 2.8 % Short-Term Investments and Other Net Assets 10.3 % 100.0 % † Based on net assets of the Fund. | |
| Material Fund Change [Text Block] | Material and Other Fund Changes On May 23, 2023, the Board of Trustees of the Fund (the “Board”) approved the transition of the Fund’s custodian, administrator, and transfer agent from Brown Brothers Harriman & Company to The Bank of New York. This change was implemented on March 18, 2024. 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 April 30, 2024, Alger Management contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through December 31, 2025 to the extent necessary to limit other expenses of the Fund to 0.10% of the Fund’s average daily net assets. This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective April 30, 2024, Alger Management contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through December 31, 2025 to the extent necessary to limit other expenses of the Fund to 0.10% of the Fund’s average daily net assets. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 223-3810 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| C000240821 [Member] | ||
| Shareholder Report [Line Items] | ||
| Fund Name | Alger Weatherbie Enduring Growth ETF | |
| Class Name | Alger Weatherbie Enduring Growth ETF | |
| Trading Symbol | AWEG | |
| Security Exchange Name | NYSEArca | |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Alger Weatherbie Enduring Growth ETF (“Fund”) for the period of January 1, 2024 to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | semi-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 changes to the Fund that occurred during the reporting period | |
| Additional Information Phone Number | (800) 223-3810 | |
| Additional Information Website | https://connect.rightprospectus.com/Alger | |
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Fund Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Alger Weatherbie Enduring Growth ETF $ 0.65 % | |
| Expenses Paid, Amount | $ 34 | |
| Expense Ratio, Percent | 0.65% | |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance What impacted Fund performance over the reporting period? The Alger Weatherbie Enduring Growth ETF returned 6.80% during the fiscal six-month period ended June 30, 2024, compared to the 5.98% 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 Consumer Staples and the largest sector underweight was Communication Services. Contributors to Performance The Industrials and Information Technology sectors provided the largest contributions to relative performance. Regarding individual positions, TransDigm Group Incorporated; Glaukos Corp; Impinj, Inc.; StepStone Group, Inc.; and Vertex, Inc. were the top five contributors to absolute performance. Detractors from Performance The Health Care and Real Estate sectors were the largest detractors from relative performance. Regarding individual positions, Nevro Corp.; ACADIA Pharmaceuticals Inc.; Paylocity Holding Corp.; SiteOne Landscape Supply, Inc.; and Progyny, Inc. were the top five detractors from absolute performance. U.S. FACTOR IMPACT SUMMARY Soft-landing Narrative Positive During the period, the soft-landing scenario—an economic slowdown without a recession—drove equity markets higher as U.S. GDP for the fourth quarter grew 3.4%, exceeding the initial 2.0% consensus, driven by robust consumer spending. AI Enthusiasm Positive Continued anticipation about artificial intelligence drove strong gains for related companies, supported by robust operating results and upward earnings revisions. Elevated Inflation Negative Inflation concerns resurfaced during the first quarter of 2024, with Consumer Price Index (CPI) and Personal Consumption Expenditure Price Index (PCE) readings coming in higher-than-expected. Revised Federal Reserve Rate Cut Expectations Negative Elevated inflation readings during the first quarter of 2024 led to the Federal Reserve postponing an anticipated March rate cut. The revision of the market’s rate cut expectations, initially from a projected six cuts at the beginning of the period down to just one for the year, led to some market volatility in April. | |
| 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 and chart compares the initial and subsequent account values at the end of each of the most recently completed semi-annual periods of the Fund since its inception. The graph assumes a $10,000 initial investment at Net Asset Value at the INITIAL INVESTMENT OF $10,000 | |
| Average Annual Return [Table Text Block] | Average Annual Total Returns (As of June 30, 2024) 1 Year Since Inception Alger Weatherbie Enduring Growth ETF 12.89 % 13.92 % Russell Midcap Growth Index 15.05 % 15.92 % S&P 500 Index 24.56 % 27.45 % | |
| Performance Inception Date | Mar. 06, 2023 | |
| No Deduction of Taxes [Text Block] | The graph and table do | |
| Material Change Date | Apr. 30, 2024 | |
| Updated Performance Information Location [Text Block] | Visit https://www.alger.com/Pages/StrategyFinder.aspx?vehicle=mf | |
| Net Assets | $ 4,714,365 | |
| Holdings Count | Holding | 25 | [7] |
| Investment Company Portfolio Turnover | 22.44% | |
| Additional Fund Statistics [Text Block] | Key Fund Statistics The following table outlines key fund statistics as of the reporting date. Fund net assets $ % Total number of portfolio holdings 1 $ % Portfolio turnover rate as of the end of the reporting period $ % 1 Excludes Money Market Funds. | |
| Holdings [Text Block] | Sector Allocation † Communication Services 1.4 % Consumer Discretionary 3.3 % Financials 4.8 % Healthcare 16.6 % Industrials 44.4 % Information Technology 16.3 % Real Estate 6.7 % Short-Term Investments and Other Net Assets 6.5 % 100.0 % † Based on net assets of the Fund. | |
| Material Fund Change [Text Block] | Material and Other Fund Changes On May 23, 2023, the Board of Trustees of the Fund (the “Board”) approved the transition of the Fund’s custodian, administrator, and transfer agent from Brown Brothers Harriman & Company to The Bank of New York. This change was implemented on March 18, 2024. 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 April 30, 2024, Alger Management contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through December 31, 2025 to the extent necessary to limit other expenses of the Fund to 0.10% of the Fund’s average daily net assets. This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Material Fund Change Expenses [Text Block] | Effective April 30, 2024, Alger Management contractually agreed to waive and/or reimburse Fund expenses (excluding acquired fund fees and expenses, dividend expense on short sales, net borrowing costs, interest, taxes, brokerage and extraordinary expenses, to the extent applicable) through December 31, 2025 to the extent necessary to limit other expenses of the Fund to 0.10% of the Fund’s average daily net assets. | |
| Summary of Change Legend [Text Block] | This is a summary of certain changes to the Fund since January 1, 2024. For more complete information, you may review the Fund's next prospectus, which we expect to be available by May 1, 2025 at https://connect.rightprospectus.com/Alger | |
| Updated Prospectus Phone Number | (800) 223-3810 | |
| Updated Prospectus Web Address | https://connect.rightprospectus.com/Alger | |
| [1]Excludes Money Market Funds.[2]The Fund commenced investment operations on April 4, 2024. Had the Fund been in operation for a complete fiscal year, the cost of a $10,000 investment would have been higher.[3]Excludes Money Market Funds.[4]The Fund commenced investment operations on April 4, 2024. Had the Fund been in operation for a complete fiscal year, the cost of a $10,000 investment would have been higher.[5]Excludes Money Market Funds.[6]Excludes Money Market Funds.[7]Excludes Money Market Funds. | ||
| Shareholder Report, Line Graph (Details) - USD ($) | 3 Months Ended | 6 Months Ended | 12 Months Ended | 16 Months Ended | 38 Months Ended | 40 Months Ended | |||||||
| Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2023 | Mar. 06, 2023 | Jun. 30, 2022 | Jun. 30, 2021 | May 03, 2021 | Feb. 26, 2021 | |
| C000222789 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Alger 35 ETF | ||||||||||||
| Account Value | $ 10,691.90 | $ 10,691.90 | $ 10,691.90 | $ 10,691.90 | $ 10,691.90 | $ 10,691.90 | $ 10,691.90 | $ 7,809.34 | $ 7,060 | $ 10,600 | $ 10,000 | ||
| Average Annual Return, Percent | 36.91% | 2.14% | |||||||||||
| C000248577 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Alger Concentrated Equity ETF | ||||||||||||
| Average Annual Return, Percent | 11.65% | ||||||||||||
| C000248578 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Alger AI Enablers & Adopters ETF | ||||||||||||
| Average Annual Return, Percent | 11.76% | ||||||||||||
| C000222788 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Alger Mid Cap 40 ETF | ||||||||||||
| Account Value | $ 8,499.67 | $ 8,499.67 | 8,499.67 | $ 8,499.67 | 8,499.67 | $ 8,499.67 | $ 8,499.67 | 6,730.01 | 6,798.68 | 10,330 | $ 10,000 | ||
| Average Annual Return, Percent | 26.30% | (4.75%) | |||||||||||
| C000240821 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Alger Weatherbie Enduring Growth ETF | ||||||||||||
| Account Value | 11,873.74 | $ 11,873.74 | 11,873.74 | $ 11,873.74 | $ 11,873.74 | 11,873.74 | $ 11,873.74 | 10,517.60 | $ 10,000 | ||||
| Average Annual Return, Percent | 12.89% | 13.92% | |||||||||||
| Russell 3000 Growth Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell 3000 Growth Index | ||||||||||||
| Account Value | 14,090.07124 | $ 14,090.07124 | $ 14,090.07124 | $ 14,090.07124 | $ 14,090.07124 | $ 14,090.07124 | 14,090.07124 | 10,656.5355 | 8,417.4846 | 10,493 | 10,000 | ||
| Average Annual Return, Percent | 32.22% | 11.47% | |||||||||||
| Standard & Poor's 500 Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||||||||||
| Account Value | $ 13,682.96362 | $ 13,682.96362 | $ 13,682.96362 | $ 13,682.96362 | $ 13,682.96362 | $ 13,682.96362 | $ 13,682.96362 | 10,985.03823 | 10,000 | 9,185.5826 | 10,277 | $ 10,000 | 10,000 |
| Average Annual Return, Percent | 6.43% | 24.56% | 27.45% | 10.44% | 13.10% | ||||||||
| Russell Midcap Growth Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell Midcap Growth Index | ||||||||||||
| Account Value | $ 10,870.15 | $ 10,870.15 | $ 10,870.15 | $ 10,870.15 | $ 10,870.15 | $ 10,870.15 | $ 10,870.15 | $ 9,448.19 | $ 10,000 | $ 7,673.35 | $ 10,895 | $ 10,000 | |
| Average Annual Return, Percent | 15.05% | 15.92% | 2.53% | ||||||||||
| Russell 1000 Growth Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell 1000 Growth Index | ||||||||||||
| Average Annual Return, Percent | 10.63% | ||||||||||||
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 | |
| C000222789 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [1] |
| C000222789 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 14% | [1] |
| C000222789 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2% | [1] |
| C000222789 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 16.40% | [1] |
| C000222789 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.90% | [1] |
| C000222789 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9% | [1] |
| C000222789 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.90% | [1] |
| C000222789 [Member] | Materials Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2% | [1] |
| C000222789 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 47% | [1] |
| C000222789 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.80% | [1] |
| C000248577 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [2] |
| C000248577 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 11.10% | [2] |
| C000248577 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.40% | [2] |
| C000248577 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 13% | [2] |
| C000248577 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1% | [2] |
| C000248577 [Member] | Financials [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.10% | [2] |
| C000248577 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 8% | [2] |
| C000248577 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 9.10% | [2] |
| C000248577 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 49.20% | [2] |
| C000248577 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [2] |
| C000248578 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [3] |
| C000248578 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 13.50% | [3] |
| C000248578 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.80% | [3] |
| C000248578 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.90% | [3] |
| C000248578 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 15.90% | [3] |
| C000248578 [Member] | Financials [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.60% | [3] |
| C000248578 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.30% | [3] |
| C000248578 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 0.50% | [3] |
| C000248578 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.10% | [3] |
| C000248578 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 52.30% | [3] |
| C000248578 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.10% | [3] |
| C000222788 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [4] |
| C000222788 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.40% | [4] |
| C000222788 [Member] | Utilities Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.80% | [4] |
| C000222788 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 8.10% | [4] |
| C000222788 [Member] | Energy Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.50% | [4] |
| C000222788 [Member] | Financials [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 2.10% | [4] |
| C000222788 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 12.20% | [4] |
| C000222788 [Member] | Consumer Staples Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.60% | [4] |
| C000222788 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 23.80% | [4] |
| C000222788 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 26.20% | [4] |
| C000222788 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 10.30% | [4] |
| C000240821 [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 100% | [5] |
| C000240821 [Member] | Consumer Discretionary Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 3.30% | [5] |
| C000240821 [Member] | Real Estate Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.70% | [5] |
| C000240821 [Member] | Communications Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 1.40% | [5] |
| C000240821 [Member] | Financials [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 4.80% | [5] |
| C000240821 [Member] | Healthcare Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 16.60% | [5] |
| C000240821 [Member] | Industrial Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 44.40% | [5] |
| C000240821 [Member] | Information Technology Sector [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 16.30% | [5] |
| C000240821 [Member] | Short Term Investments and Other Net Assets [Member] | ||
| Holdings [Line Items] | ||
| Percent of Net Asset Value | 6.50% | [5] |
| [1]Based on net assets of the Fund.[2]Based on net assets of the Fund.[3]Based on net assets of the Fund.[4]Based on net assets of the Fund.[5]Based on net assets of the Fund. | ||
