| Form N-CSR Cover | 6 Months Ended |
| May 31, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | AB CAP FUND, INC. |
| Entity Central Index Key | 0000081443 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | May 31, 2024 |
| Shareholder Report | 1 Months Ended | 6 Months Ended | 114 Months Ended |
| May 31, 2024 USD ($) Holding | May 31, 2024 USD ($) Holding | May 31, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |||
| Document Type | N-CSRS | ||
| Amendment Flag | false | ||
| Registrant Name | AB CAP FUND, INC. | ||
| Entity Central Index Key | 0000081443 | ||
| Entity Investment Company Type | N-1A | ||
| Document Period End Date | May 31, 2024 | ||
| C000141795 | |||
| Shareholder Report [Line Items] | |||
| Fund Name | AB Small Cap Value Portfolio | ||
| Class Name | Advisor Class | ||
| Trading Symbol | SCYVX | ||
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the AB Small Cap Value Portfolio (the “Fund”) for the period of December 1, 2023 to May 31, 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://www.abfunds.com/link/AB/SCYVX-S | ||
| Additional Information Phone Number | (800) 227 4618 | ||
| Additional Information Website | https://www.abfunds.com/link/AB/SCYVX-S</span>" id="sjs-C19"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left;">https://www.abfunds.com/link/AB/SCYVX-S</span> | ||
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Class Name Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Advisor Class $49 0.92% | ||
| Expenses Paid, Amount | $ 49 | ||
| Expense Ratio, Percent | 0.92% | ||
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left;">The Fund’s past performance is not a good predictor of the Fund’s future performance.</span></p>" id="sjs-C23"><p style="line-height: 15.6px; box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; margin: 0px; overflow: visible; text-align: left;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left;">The Fund’s past performance is not a good predictor of the Fund’s future performance.</span></p> | ||
| Line Graph [Table Text Block] | Advisor Class S&P 500 Index Russell 2000 Value Index 12/14 $10,000 $10,000 $10,000 11/15 $10,693 $10,238 $9,982 11/16 $12,804 $11,063 $11,964 11/17 $14,301 $13,593 $13,563 11/18 $13,628 $14,446 $13,315 11/19 $14,229 $16,773 $13,843 11/20 $13,884 $19,701 $13,891 11/21 $19,474 $25,202 $18,476 11/22 $18,204 $22,881 $17,599 11/23 $16,524 $26,048 $16,766 05/24 $18,873 $30,308 $19,013 | ||
| Average Annual Return [Table Text Block] | 6 Months 1 Year 5 Years Since Inception 12/3/14 Advisor Class (without sales charge) 14.21% 19.89% 8.27% 6.92% Advisor Class (with sales charge) 14.21% 19.89% 8.27% 6.92% S&P 500 Index 16.36% 28.19% 15.80% 12.38% Russell 2000 Value Index 13.40% 21.76% 8.77% 7.00% | ||
| Performance Inception Date | Dec. 03, 2014 | ||
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | ||
| AssetsNet | $ 617,668,887 | $ 617,668,887 | $ 617,668,887 |
| Holdings Count | Holding | 101 | 101 | 101 |
| Advisory Fees Paid, Amount | $ 2,943,035 | ||
| InvestmentCompanyPortfolioTurnover | 32% | ||
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $617,668,887 # of Portfolio Holdings 101 Portfolio Turnover Rate 32% Total Advisory Fees Paid $2,943,035 | ||
| Holdings [Text Block] | Sector Allocation Value Value Industrials 21.8% Financials 21.3% Consumer Discretionary 12.2% Information Technology 11.3% Energy 8.4% Materials 7.8% Real Estate 5.9% Health Care 3.8% Communication Services 2.6% Utilities 2.5% Short-Term Investments 1.5% Consumer Staples 1.2% Others 0.1% Other assets less liabilities -0.4% | ||
| Largest Holdings [Text Block] | 10 Top Holdings Company U.S. $ Value % of Net Assets Blue Bird Corp. $12,778,449 2.1% Matador Resources Co. $10,457,131 1.7% REV Group, Inc. $10,181,993 1.6% Magnolia Oil & Gas Corp. - Class A $10,091,981 1.6% ATI, Inc. $9,450,102 1.5% Northern Oil and Gas, Inc. $8,859,257 1.4% Cactus, Inc. - Class A $8,562,715 1.4% ABM Industries, Inc. $8,559,652 1.4% Criteo SA (Sponsored ADR) $8,383,330 1.4% Avient Corp. $8,237,160 1.3% Total $95,561,770 15.4% | ||
| Material Fund Change [Text Block] | |||
| C000141790 | |||
| Shareholder Report [Line Items] | |||
| Fund Name | AB Small Cap Value Portfolio | ||
| Class Name | Class A | ||
| Trading Symbol | SCAVX | ||
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the AB Small Cap Value Portfolio (the Fund) for the period of December 1, 2023 to May 31, 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://www.abfunds.com/link/AB/SCAVX-S | ||
| Additional Information Phone Number | (800) 227 4618 | ||
| Additional Information Website | https://www.abfunds.com/link/AB/SCAVX-S</span>" id="sjs-C45"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left; height: auto; max-height: none; min-height: 0px;">https://www.abfunds.com/link/AB/SCAVX-S</span> | ||
| Expenses [Text Block] | What were the Fund costs for last six months? (Based on a hypothetical $10,000 investment) Class Name Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class A $63 1.17% | ||
| Expenses Paid, Amount | $ 63 | ||
| Expense Ratio, Percent | 1.17% | ||
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left; height: auto; max-height: none; min-height: 0px;">The Funds past performance is not a good predictor of the Funds future performance.</span></p>" id="sjs-C49"><p style="line-height: 15.6px; box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; margin: 0px; overflow: visible; text-align: left; height: 15.5938px; max-height: none; min-height: 0px;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left; height: auto; max-height: none; min-height: 0px;">The Funds past performance is not a good predictor of the Funds future performance.</span></p> | ||
| Line Graph [Table Text Block] | Class A S&P 500 Index Russell 2000 Value Index 12/14 $10,000 $10,000 $10,000 11/15 $10,662 $10,238 $9,982 11/16 $12,744 $11,063 $11,964 11/17 $14,190 $13,593 $13,563 11/18 $13,485 $14,446 $13,315 11/19 $14,054 $16,773 $13,843 11/20 $13,673 $19,701 $13,891 11/21 $19,132 $25,202 $18,476 11/22 $17,847 $22,881 $17,599 11/23 $16,148 $26,048 $16,766 05/24 $18,430 $30,308 $19,013 | ||
| Average Annual Return [Table Text Block] | 6 Months 1 Year 5 Years Since Inception 12/3/14 Class A (without sales charge) 14.13% 19.58% 7.99% 6.65% Class A (with sales charge) 9.25% 14.51% 7.06% 6.17% S&P 500 Index 16.36% 28.19% 15.80% 12.38% Russell 2000 Value Index 13.40% 21.76% 8.77% 7.00% | ||
| Performance Inception Date | Dec. 03, 2014 | ||
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | ||
| AssetsNet | $ 617,668,887 | $ 617,668,887 | $ 617,668,887 |
| Holdings Count | Holding | 101 | 101 | 101 |
| Advisory Fees Paid, Amount | $ 2,943,035 | ||
| InvestmentCompanyPortfolioTurnover | 32% | ||
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $617,668,887 # of Portfolio Holdings 101 Portfolio Turnover Rate 32% Total Advisory Fees Paid $2,943,035 | ||
| Holdings [Text Block] | Sector Allocation Value Value Industrials 21.8% Financials 21.3% Consumer Discretionary 12.2% Information Technology 11.3% Energy 8.4% Materials 7.8% Real Estate 5.9% Health Care 3.8% Communication Services 2.6% Utilities 2.5% Short-Term Investments 1.5% Consumer Staples 1.2% Others 0.1% Other assets less liabilities -0.4% | ||
| Largest Holdings [Text Block] | 10 Top Holdings Company U.S. $ Value % of Net Assets Blue Bird Corp. $12,778,449 2.1% Matador Resources Co. $10,457,131 1.7% REV Group, Inc. $10,181,993 1.6% Magnolia Oil & Gas Corp. - Class A $10,091,981 1.6% ATI, Inc. $9,450,102 1.5% Northern Oil and Gas, Inc. $8,859,257 1.4% Cactus, Inc. - Class A $8,562,715 1.4% ABM Industries, Inc. $8,559,652 1.4% Criteo SA (Sponsored ADR) $8,383,330 1.4% Avient Corp. $8,237,160 1.3% Total $95,561,770 15.4% | ||
| Material Fund Change [Text Block] | |||
| C000141791 | |||
| Shareholder Report [Line Items] | |||
| Fund Name | AB Small Cap Value Portfolio | ||
| Class Name | Class C | ||
| Trading Symbol | SCCVX | ||
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the AB Small Cap Value Portfolio (the Fund) for the period of December 1, 2023 to May 31, 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://www.abfunds.com/link/AB/SCCVX-S | ||
| Additional Information Phone Number | (800) 227 4618 | ||
| Additional Information Website | https://www.abfunds.com/link/AB/SCCVX-S</span>" id="sjs-C71"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left; height: auto; max-height: none; min-height: 0px;">https://www.abfunds.com/link/AB/SCCVX-S</span> | ||
| Expenses [Text Block] | What were the Fund costs for last six months? (Based on a hypothetical $10,000 investment) Class Name Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class C $103 1.92% | ||
| Expenses Paid, Amount | $ 103 | ||
| Expense Ratio, Percent | 1.92% | ||
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left; height: auto; max-height: none; min-height: 0px;">The Funds past performance is not a good predictor of the Funds future performance.</span></p>" id="sjs-C75"><p style="line-height: 15.6px; box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; margin: 0px; overflow: visible; text-align: left; height: 15.5938px; max-height: none; min-height: 0px;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left; height: auto; max-height: none; min-height: 0px;">The Funds past performance is not a good predictor of the Funds future performance.</span></p> | ||
| Line Graph [Table Text Block] | Class C S&P 500 Index Russell 2000 Value Index 12/14 $10,000 $10,000 $10,000 11/15 $10,578 $10,238 $9,982 11/16 $12,547 $11,063 $11,964 11/17 $13,869 $13,593 $13,563 11/18 $13,090 $14,446 $13,315 11/19 $13,536 $16,773 $13,843 11/20 $13,075 $19,701 $13,891 11/21 $18,151 $25,202 $18,476 11/22 $16,817 $22,881 $17,599 11/23 $15,109 $26,048 $16,766 05/24 $17,174 $30,308 $19,013 | ||
| Average Annual Return [Table Text Block] | 6 Months 1 Year 5 Years Since Inception 12/3/14 Class C (without sales charge) 13.67% 18.59% 7.22% 5.86% Class C (with sales charge) 12.67% 17.59% 7.22% 5.86% S&P 500 Index 16.36% 28.19% 15.80% 12.38% Russell 2000 Value Index 13.40% 21.76% 8.77% 7.00% | ||
| Performance Inception Date | Dec. 03, 2014 | ||
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | ||
| AssetsNet | $ 617,668,887 | $ 617,668,887 | $ 617,668,887 |
| Holdings Count | Holding | 101 | 101 | 101 |
| Advisory Fees Paid, Amount | $ 2,943,035 | ||
| InvestmentCompanyPortfolioTurnover | 32% | ||
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $617,668,887 # of Portfolio Holdings 101 Portfolio Turnover Rate 32% Total Advisory Fees Paid $2,943,035 | ||
| Holdings [Text Block] | Sector Allocation Value Value Industrials 21.8% Financials 21.3% Consumer Discretionary 12.2% Information Technology 11.3% Energy 8.4% Materials 7.8% Real Estate 5.9% Health Care 3.8% Communication Services 2.6% Utilities 2.5% Short-Term Investments 1.5% Consumer Staples 1.2% Others 0.1% Other assets less liabilities -0.4% | ||
| Largest Holdings [Text Block] | 10 Top Holdings Company U.S. $ Value % of Net Assets Blue Bird Corp. $12,778,449 2.1% Matador Resources Co. $10,457,131 1.7% REV Group, Inc. $10,181,993 1.6% Magnolia Oil & Gas Corp. - Class A $10,091,981 1.6% ATI, Inc. $9,450,102 1.5% Northern Oil and Gas, Inc. $8,859,257 1.4% Cactus, Inc. - Class A $8,562,715 1.4% ABM Industries, Inc. $8,559,652 1.4% Criteo SA (Sponsored ADR) $8,383,330 1.4% Avient Corp. $8,237,160 1.3% Total $95,561,770 15.4% | ||
| Material Fund Change [Text Block] | |||
| C000249214 | |||
| Shareholder Report [Line Items] | |||
| Fund Name | AB Mid Cap Value Portfolio | ||
| Class Name | Class Z | ||
| Trading Symbol | ABMVX | ||
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the AB Mid Cap Value Portfolio (the “Fund”) for the period of April 30, 2024 to May 31, 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://www.abfunds.com/link/AB/ABMVX-S | ||
| Additional Information Phone Number | (800) 227 4618 | ||
| Additional Information Website | https://www.abfunds.com/link/AB/ABMVX-S</span>" id="sjs-B97"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left;">https://www.abfunds.com/link/AB/ABMVX-S</span> | ||
| Expenses [Text Block] | What were the Fund costs for the last six months? (Based on a hypothetical $10,000 investment) Class Name Cost of a $10,000 investment Costs paid as a percentage of a $10,000 investment Class Z $10 0.67% | ||
| Expenses Paid, Amount | $ 10 | ||
| Expense Ratio, Percent | 0.67% | ||
| Performance Past Does Not Indicate Future [Text] | <span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left;">The Fund’s past performance is not a good predictor of the Fund’s future performance.</span></p>" id="sjs-B101"><p style="line-height: 15.6px; box-sizing: border-box; color: rgb(0, 0, 0); display: block; flex-wrap: nowrap; font-size: 12px; font-weight: 400; grid-area: auto; margin: 0px; overflow: visible; text-align: left;"><span style="font-weight: 700; box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 12px; grid-area: auto; line-height: 15.6px; margin: 0px; overflow: visible; text-align: left;">The Fund’s past performance is not a good predictor of the Fund’s future performance.</span></p> | ||
| Line Graph [Table Text Block] | Class Z Russell Midcap Value Index S&P 500 Index 04/24 $10,000 $10,000 $10,000 05/24 $10,330 $10,188 $10,331 | ||
| Average Annual Return [Table Text Block] | Since Inception 4/30/24 Class Z (without sales charge) 3.30% Class Z (with sales charge) 3.30% Russell Midcap Value Index 1.88% S&P 500 Index 3.31% | ||
| Performance Inception Date | Apr. 30, 2024 | ||
| No Deduction of Taxes [Text Block] | The graph and table do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | ||
| AssetsNet | $ 2,066,217 | $ 2,066,217 | $ 2,066,217 |
| Holdings Count | Holding | 56 | 56 | 56 |
| Advisory Fees Paid, Amount | $ (55,105) | ||
| InvestmentCompanyPortfolioTurnover | 15% | ||
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $2,066,217 # of Portfolio Holdings 56 Portfolio Turnover Rate 15% Total Advisory Fees Paid $(55,105) | ||
| Holdings [Text Block] | Sector Allocation Value Value Industrials 18.8% Consumer Discretionary 13.0% Financials 12.8% Information Technology 9.7% Health Care 9.5% Energy 7.6% Real Estate 7.3% Utilities 6.6% Materials 6.4% Consumer Staples 4.9% Communication Services 2.2% Short-Term Investments 1.1% Other assets less liabilities 0.1% | ||
| Largest Holdings [Text Block] | 10 Top Holdings Company U.S. $ Value % of Net Assets Humana, Inc. $60,164 2.9% Corteva, Inc. $53,814 2.6% CenterPoint Energy, Inc. $52,294 2.5% Cameco Corp. $51,680 2.5% First Citizens BancShares, Inc./NC - Class A $50,953 2.5% Fluor Corp. $50,214 2.4% NXP Semiconductors NV $48,434 2.3% EOG Resources, Inc. $47,329 2.3% Tapestry, Inc. $46,056 2.2% American Financial Group, Inc./OH $45,988 2.2% Total $506,926 24.4% | ||
| Material Fund Change [Text Block] |
| Shareholder Report, Line Graph (Details) - USD ($) | 1 Months Ended | 6 Months Ended | |||||||||||
| May 31, 2024 | May 31, 2024 | Apr. 29, 2024 | Nov. 30, 2023 | Nov. 30, 2022 | Nov. 30, 2021 | Nov. 30, 2020 | Nov. 30, 2019 | Nov. 30, 2018 | Nov. 30, 2017 | Nov. 30, 2016 | Nov. 30, 2015 | Dec. 02, 2014 | |
| C000141795 | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Advisor Class | ||||||||||||
| Account Value | $ 18,873 | $ 18,873 | $ 16,524 | $ 18,204 | $ 19,474 | $ 13,884 | $ 14,229 | $ 13,628 | $ 14,301 | $ 12,804 | $ 10,693 | $ 10,000 | |
| C000141790 | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Class A | ||||||||||||
| Account Value | 18,430 | $ 18,430 | 16,148 | 17,847 | 19,132 | 13,673 | 14,054 | 13,485 | 14,190 | 12,744 | 10,662 | 10,000 | |
| C000141791 | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Class C | ||||||||||||
| Account Value | $ 17,174 | $ 17,174 | 15,109 | 16,817 | 18,151 | 13,075 | 13,536 | 13,090 | 13,869 | 12,547 | 10,578 | 10,000 | |
| C000249214 | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Class Z | ||||||||||||
| AllianceBernstein Index: S&P 500 Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||||||||||
| Account Value | $ 30,308 | $ 30,308 | 26,048 | 22,881 | 25,202 | 19,701 | 16,773 | 14,446 | 13,593 | 11,063 | 10,238 | 10,000 | |
| AllianceBernstein Index: S&P 500 Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||||||||||
| Account Value | 30,308 | $ 30,308 | 26,048 | 22,881 | 25,202 | 19,701 | 16,773 | 14,446 | 13,593 | 11,063 | 10,238 | 10,000 | |
| AllianceBernstein Index: S&P 500 Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||||||||||
| Account Value | $ 30,308 | $ 30,308 | 26,048 | 22,881 | 25,202 | 19,701 | 16,773 | 14,446 | 13,593 | 11,063 | 10,238 | 10,000 | |
| Alliance Bernstein Index:Russell Midcap Value Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell Midcap Value Index | ||||||||||||
| Account Value | $ 10,188 | $ 10,188 | $ 10,000 | ||||||||||
| AllianceBernstein Index: Russell 2000 Value Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell 2000 Value Index | ||||||||||||
| Account Value | 19,013 | $ 19,013 | 16,766 | 17,599 | 18,476 | 13,891 | 13,843 | 13,315 | 13,563 | 11,964 | 9,982 | 10,000 | |
| AllianceBernstein Index: Russell 2000 Value Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell 2000 Value Index | ||||||||||||
| Account Value | 19,013 | $ 19,013 | 16,766 | 17,599 | 18,476 | 13,891 | 13,843 | 13,315 | 13,563 | 11,964 | 9,982 | 10,000 | |
| AllianceBernstein Index: Russell 2000 Value Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Russell 2000 Value Index | ||||||||||||
| Account Value | $ 19,013 | $ 19,013 | $ 16,766 | $ 17,599 | $ 18,476 | $ 13,891 | $ 13,843 | $ 13,315 | $ 13,563 | $ 11,964 | $ 9,982 | $ 10,000 | |
| AllianceBernstein Index: S&P 500 Index | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||||||||||
| Account Value | $ 10,331 | $ 10,331 | $ 10,000 |
| Shareholder Report, Average Annual Return (Details) | 1 Months Ended | 6 Months Ended | 12 Months Ended | 60 Months Ended | 114 Months Ended |
| May 31, 2024 | May 31, 2024 | May 31, 2024 | May 31, 2024 | May 31, 2024 | |
| C000141795 | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Advisor Class | ||||
| C000141790 | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Class A | ||||
| C000141791 | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Class C | ||||
| C000249214 | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Class Z | ||||
| Without Sales Load [Member] | C000141795 | |||||
| Average Annual Return [Line Items] | |||||
| Average Annual Return, Percent | 14.21% | 19.89% | 8.27% | 6.92% | |
| Without Sales Load [Member] | C000141790 | |||||
| Average Annual Return [Line Items] | |||||
| Average Annual Return, Percent | 14.13% | 19.58% | 7.99% | 6.65% | |
| Without Sales Load [Member] | C000141791 | |||||
| Average Annual Return [Line Items] | |||||
| Average Annual Return, Percent | 13.67% | 18.59% | 7.22% | 5.86% | |
| Without Sales Load [Member] | C000249214 | |||||
| Average Annual Return [Line Items] | |||||
| Average Annual Return, Percent | 3.30% | ||||
| AllianceBernstein Index: S&P 500 Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||
| Average Annual Return, Percent | 16.36% | 28.19% | 15.80% | 12.38% | |
| AllianceBernstein Index: S&P 500 Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||
| Average Annual Return, Percent | 16.36% | 28.19% | 15.80% | 12.38% | |
| AllianceBernstein Index: S&P 500 Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | S&P 500 Index | ||||
| Average Annual Return, Percent | 16.36% | 28.19% | 15.80% | 12.38% | |
| Alliance Bernstein Index:Russell Midcap Value Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Russell Midcap Value Index | ||||
| Average Annual Return, Percent | 1.88% | ||||
| AllianceBernstein Index: Russell 2000 Value Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Russell 2000 Value Index | ||||
| AllianceBernstein Index: Russell 2000 Value Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Russell 2000 Value Index | ||||
| AllianceBernstein Index: Russell 2000 Value Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | Russell 2000 Value Index | ||||
| AllianceBernstein Index: S&P 500 Index | |||||
| Average Annual Return [Line Items] | |||||
| Line Graph and Table Measure Name | S&P 500 Index |
| Shareholder Report, Holdings (Details) | May 31, 2024 |
| C000141795 | Blue Bird Corp.FR_095306106 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| C000141795 | Matador Resources Co.FR_576485205 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| C000141795 | REV Group, Inc.FR_749527107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| C000141795 | Magnolia Oil & Gas Corp.FR_559663109 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| C000141795 | ATI, Inc.FR_01741R102 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| C000141795 | Northern Oil and Gas, Inc.FR_665531307 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141795 | Cactus, Inc.FR_127203107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141795 | ABM Industries, Inc.FR_000957100 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141795 | Criteo SA (Sponsored ADR)FR_226718104 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141795 | Avient Corp.FR_05368V106 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.30% |
| C000141795 | Industrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.80% |
| C000141795 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.30% |
| C000141795 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.20% |
| C000141795 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.30% |
| C000141795 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.40% |
| C000141795 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.80% |
| C000141795 | Real Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000141795 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000141795 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000141795 | Utilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000141795 | Short-Term Investments | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| C000141795 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| C000141795 | Others | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| C000141790 | Blue Bird Corp.FR_095306106 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| C000141790 | Matador Resources Co.FR_576485205 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| C000141790 | REV Group, Inc.FR_749527107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| C000141790 | Magnolia Oil & Gas Corp.FR_559663109 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| C000141790 | ATI, Inc.FR_01741R102 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| C000141790 | Northern Oil and Gas, Inc.FR_665531307 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141790 | Cactus, Inc.FR_127203107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141790 | ABM Industries, Inc.FR_000957100 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141790 | Criteo SA (Sponsored ADR)FR_226718104 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141790 | Avient Corp.FR_05368V106 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.30% |
| C000141790 | Industrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.80% |
| C000141790 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.30% |
| C000141790 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.20% |
| C000141790 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.30% |
| C000141790 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.40% |
| C000141790 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.80% |
| C000141790 | Real Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000141790 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000141790 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000141790 | Utilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000141790 | Short-Term Investments | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| C000141790 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| C000141790 | Others | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| C000141791 | Blue Bird Corp.FR_095306106 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.10% |
| C000141791 | Matador Resources Co.FR_576485205 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.70% |
| C000141791 | REV Group, Inc.FR_749527107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| C000141791 | Magnolia Oil & Gas Corp.FR_559663109 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.60% |
| C000141791 | ATI, Inc.FR_01741R102 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| C000141791 | Northern Oil and Gas, Inc.FR_665531307 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141791 | Cactus, Inc.FR_127203107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141791 | ABM Industries, Inc.FR_000957100 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141791 | Criteo SA (Sponsored ADR)FR_226718104 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.40% |
| C000141791 | Avient Corp.FR_05368V106 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.30% |
| C000141791 | Industrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.80% |
| C000141791 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 21.30% |
| C000141791 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.20% |
| C000141791 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.30% |
| C000141791 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.40% |
| C000141791 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.80% |
| C000141791 | Real Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000141791 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000141791 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000141791 | Utilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000141791 | Short-Term Investments | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.50% |
| C000141791 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.20% |
| C000141791 | Others | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.10% |
| C000249214 | Humana, Inc.FR_444859102 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.90% |
| C000249214 | Corteva, Inc.FR_22052L104 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.60% |
| C000249214 | CenterPoint Energy, Inc.FR_15189T107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000249214 | Cameco Corp.FR_13321L108 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000249214 | First Citizens BancShares, Inc./NCFR_31946M103 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.50% |
| C000249214 | Fluor Corp.FR_343412102 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.40% |
| C000249214 | NXP Semiconductors NVFR_N6596X109 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000249214 | EOG Resources, Inc.FR_26875P101 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| C000249214 | Tapestry, Inc.FR_876030107 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000249214 | American Financial Group, Inc./OHFR_025932104 | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000249214 | Industrials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 18.80% |
| C000249214 | Financials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.80% |
| C000249214 | Consumer Discretionary | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13% |
| C000249214 | Information Technology | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.70% |
| C000249214 | Energy | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.60% |
| C000249214 | Materials | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.40% |
| C000249214 | Real Estate | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.30% |
| C000249214 | Health Care | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.50% |
| C000249214 | Communication Services | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.20% |
| C000249214 | Utilities | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.60% |
| C000249214 | Short-Term Investments | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 1.10% |
| C000249214 | Consumer Staples | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.90% |
