| Form N-CSR Cover | 12 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | RBB FUND, INC. |
| Entity Central Index Key | 0000831114 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 12 Months Ended | |
| Jun. 30, 2024 USD ($) $ / shares | ||
| Shareholder Report [Line Items] | ||
| Document Type | N-CSR | |
| Amendment Flag | false | |
| Registrant Name | RBB FUND, INC. | |
| Entity Central Index Key | 0000831114 | |
| Entity Investment Company Type | N-1A | |
| Document Period End Date | Jun. 30, 2024 | |
| Investor Class | ||
| Shareholder Report [Line Items] | ||
| Fund Name | F/m Investments Large Cap Focused Fund | |
| Class Name | Investor Class | |
| Trading Symbol | IAFMX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the F/m Investments Large Cap Focused Fund (the “Fund”) for the period of July 1, 2023, to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://www.fminvest.com/mutual-funds/iafmx-iaflx . You can also request this information by contacting us at 1-800-292-6775 . | |
| Additional Information Phone Number | 1-800-292-6775 | |
| Additional Information Website | https://www.fminvest.com/mutual-funds/iafmx-iaflx | |
| Expenses [Text Block] | WHAT WERE THE FUND COSTS FOR THE PAST YEAR? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Investor Class $129 1.15% | |
| Expenses Paid, Amount | $ 129 | |
| Expense Ratio, Percent | 1.15% | |
| Factors Affecting Performance [Text Block] | HOW DID THE FUND PERFORM LAST YEAR AND WHAT AFFECTED ITS PERFORMANCE? Over the last 12-months ended 06/30/2024, the Fund underperformed its benchmark. This short-term relative underperformance was driven by our quantActive investment process which has long-term capital appreciation as a goal. We expect that some short-term periods will deviate from this long-term objective. In terms of the drivers for the relative underperformance, we believe that our investment process led us to be overexposed to information technology stocks that were not the best performers over the forestated period. These information technology stocks corrected over the Spring of 2024. Furthermore, we were underexposed to the utilities, financials and healthcare sectors. These are traditionally more defensive sectors and performed well during the period. Going forward, we believe the Fund is positioned to take advantage of the artificial intelligence revolution. We hold companies such as NVDA and AMD which we believe are at the forefront of this inflection point in the evolution of the internet. | |
| Performance Past Does Not Indicate Future [Text] | The Fund’s past performance is not a good predictor of the Fund’s future performance. | |
| Line Graph [Table Text Block] | ||
| Average Annual Return [Table Text Block] | ANNUAL AVERAGE TOTAL RETURN (%) 1 Year 5 Year Since Inception (10/03/2016) Investor Class a 24.24 17.30 17.31 S&P 500 Total Return Index 24.56 15.05 14.74 Russell 1000 Growth Total Return Index 33.48 19.34 18.91 | [1] |
| No Deduction of Taxes [Text Block] | The returns do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | |
| Updated Performance Information Location [Text Block] | Visit https://www.fminvest.com/mutual-funds/iafmx-iaflx for more recent performance information. | |
| Net Assets | $ 66,139,555 | |
| Holdings Count | $ / shares | 24 | |
| Advisory Fees Paid, Amount | $ 241,533 | |
| Investment Company Portfolio Turnover | 59% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of June 30, 2024) Net Assets $66,139,555 Number of Holdings 24 Net Advisory Fee $241,533 Portfolio Turnover 59% | |
| Holdings [Text Block] | Sector Allocation (% of Net Assets) Information Technology 54.3% Communication Services 17.4% Consumer Discretionary 15.1% Industrials 4.9% Health Care 2.3% Financials 2.0% Energy 2.0% Cash & Other 2.0% Top 10 Securities (% of Net Assets) Apple, Inc. 12.1% NVIDIA Corp. 11.8% Amazon.com, Inc. 8.4% Microsoft Corp. 8.2% Meta Platforms, Inc. 7.2% Netflix, Inc. 5.3% Alphabet, Inc. 4.9% Advanced Micro Devices, Inc. 4.7% Adobe, Inc. 3.1% First Solar, Inc. 2.7% | |
| Updated Prospectus Web Address | https://www.fminvest.com/mutual-funds/iafmx-iaflx | |
| Institutional Class | ||
| Shareholder Report [Line Items] | ||
| Fund Name | F/m Investments Large Cap Focused Fund | |
| Class Name | Institutional Class | |
| Trading Symbol | IAFLX | |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the F/m Investments Large Cap Focused Fund (the “Fund”) for the period of July 1, 2023, to June 30, 2024. | |
| Shareholder Report Annual or Semi-Annual | annual shareholder report | |
| Additional Information [Text Block] | You can find additional information about the Fund at https://www.fminvest.com/mutual-funds/iafmx-iaflx . You can also request this information by contacting us at 1-800-292-6775 . | |
| Additional Information Phone Number | 1-800-292-6775 | |
| Additional Information Website | https://www.fminvest.com/mutual-funds/iafmx-iaflx | |
| Expenses [Text Block] | WHAT WERE THE FUND COSTS FOR THE PAST YEAR? (based on a hypothetical $10,000 investment) Class Name Costs of a $10,000 investment Costs paid as a percentage of a $10,000 investment Institutional Class $101 0.90% | |
| Expenses Paid, Amount | $ 101 | |
| Expense Ratio, Percent | 0.90% | |
| Factors Affecting Performance [Text Block] | HOW DID THE FUND PERFORM LAST YEAR AND WHAT AFFECTED ITS PERFORMANCE? Over the last 12-months ended 06/30/2024, the Fund underperformed its benchmark. This short-term relative underperformance was driven by our quantActive investment process which has long-term capital appreciation as a goal. We expect that some short-term periods will deviate from this long-term objective. In terms of the drivers for the relative underperformance, we believe that our investment process led us to be overexposed to information technology stocks that were not the best performers over the forestated period. These information technology stocks corrected over the Spring of 2024. Furthermore, we were underexposed to the utilities, financials and healthcare sectors. These are traditionally more defensive sectors and performed well during the period. Going forward, we believe the Fund is positioned to take advantage of the artificial intelligence revolution. We hold companies such as NVDA and AMD which we believe are at the forefront of this inflection point in the evolution of the internet. | |
| Performance Past Does Not Indicate Future [Text] | The Fund’s past performance is not a good predictor of the Fund’s future performance. | |
| Line Graph [Table Text Block] | ||
| Average Annual Return [Table Text Block] | ANNUAL AVERAGE TOTAL RETURN (%) 1 Year 5 Year Since Inception (10/03/2016) Institutional Class a 24.47 17.59 17.60 S&P 500 Total Return Index 24.56 15.05 14.74 Russell 1000 Growth Total Return Index 33.48 19.34 18.91 | [2] |
| No Deduction of Taxes [Text Block] | The returns do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or redemption of Fund shares. | |
| Updated Performance Information Location [Text Block] | Visit https://www.fminvest.com/mutual-funds/iafmx-iaflx for more recent performance information. | |
| Net Assets | $ 66,139,555 | |
| Holdings Count | $ / shares | 24 | |
| Advisory Fees Paid, Amount | $ 241,533 | |
| Investment Company Portfolio Turnover | 59% | |
| Additional Fund Statistics [Text Block] | KEY FUND STATISTICS (as of June 30, 2024) Net Assets $66,139,555 Number of Holdings 24 Net Advisory Fee $241,533 Portfolio Turnover 59% | |
| Holdings [Text Block] | Sector Allocation (% of Net Assets) Information Technology 54.3% Communication Services 17.4% Consumer Discretionary 15.1% Industrials 4.9% Health Care 2.3% Financials 2.0% Energy 2.0% Cash & Other 2.0% Top 10 Securities (% of Net Assets) Apple, Inc. 12.1% NVIDIA Corp. 11.8% Amazon.com, Inc. 8.4% Microsoft Corp. 8.2% Meta Platforms, Inc. 7.2% Netflix, Inc. 5.3% Alphabet, Inc. 4.9% Advanced Micro Devices, Inc. 4.7% Adobe, Inc. 3.1% First Solar, Inc. 2.7% | |
| Updated Prospectus Web Address | https://www.fminvest.com/mutual-funds/iafmx-iaflx | |
| [1] a The Fund commenced operations on October 3, 2016 as a separate series (the “Predecessor Fund”) of F/m Funds Trust. Effective as of the close of business on October 27, 2023, the Predecessor Fund was reorganized as a new series of The RBB Fund, Inc. The performance shown for periods prior to October 30, 2023 represents the performance of the Predecessor Fund. a The Fund commenced operations on October 3, 2016 as a separate series (the “Predecessor Fund”) of F/m Funds Trust. Effective as of the close of business on October 27, 2023, the Predecessor Fund was reorganized as a new series of The RBB Fund, Inc. The performance shown for periods prior to October 30, 2023 represents the performance of the Predecessor Fund. | ||
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | ||||||||
| Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2017 | ||
| Investor Class | |||||||||
| Account Value [Line Items] | |||||||||
| Line Graph and Table Measure Name | [1] | Investor Classa | |||||||
| Account Value | $ 34,415 | $ 27,700 | $ 21,488 | $ 27,315 | $ 19,151 | $ 15,499 | $ 14,165 | $ 11,198 | |
| Institutional Class | |||||||||
| Account Value [Line Items] | |||||||||
| Line Graph and Table Measure Name | [2] | Institutional Classa | |||||||
| Account Value | $ 350,643 | 281,717 | 217,860 | 276,175 | 193,130 | 155,950 | 142,241 | 112,143 | |
| S&P 500 Total Return Index [Member] | |||||||||
| Account Value [Line Items] | |||||||||
| Line Graph and Table Measure Name | S&P 500 Total Return Index | ||||||||
| Account Value | $ 28,984 | 23,270 | 19,458 | 21,768 | 15,461 | 14,382 | 13,025 | 11,388 | |
| Russell 1000 Growth Total Return Index | |||||||||
| Account Value [Line Items] | |||||||||
| Line Graph and Table Measure Name | Russell 1000 Growth Total Return Index | ||||||||
| Account Value | $ 38,198 | 28,617 | 22,514 | 27,718 | 19,451 | 15,778 | 14,143 | 11,544 | |
| S&P 500 Total Return Index [Member] | |||||||||
| Account Value [Line Items] | |||||||||
| Line Graph and Table Measure Name | S&P 500 Total Return Index | ||||||||
| Account Value | $ 289,843 | 232,701 | 194,576 | 217,685 | 154,612 | 143,818 | 130,250 | 113,880 | |
| Russell 1000 Growth Total Return Index | |||||||||
| Account Value [Line Items] | |||||||||
| Line Graph and Table Measure Name | Russell 1000 Growth Total Return Index | ||||||||
| Account Value | $ 381,983 | $ 286,168 | $ 225,140 | $ 277,176 | $ 194,513 | $ 157,777 | $ 141,431 | $ 115,443 | |
| [1] a The Fund commenced operations on October 3, 2016 as a separate series (the “Predecessor Fund”) of F/m Funds Trust. Effective as of the close of business on October 27, 2023, the Predecessor Fund was reorganized as a new series of The RBB Fund, Inc. The performance shown for periods prior to October 30, 2023 represents the performance of the Predecessor Fund. a The Fund commenced operations on October 3, 2016 as a separate series (the “Predecessor Fund”) of F/m Funds Trust. Effective as of the close of business on October 27, 2023, the Predecessor Fund was reorganized as a new series of The RBB Fund, Inc. The performance shown for periods prior to October 30, 2023 represents the performance of the Predecessor Fund. | |||||||||
| Shareholder Report, Average Annual Return (Details) | 12 Months Ended | 60 Months Ended | 93 Months Ended | |||
| Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | ||
| Investor Class | ||||||
| Average Annual Return [Line Items] | ||||||
| Line Graph and Table Measure Name | [1] | Investor Classa | ||||
| Average Annual Return, Percent | [1] | 24.24% | 17.30% | 17.31% | ||
| Institutional Class | ||||||
| Average Annual Return [Line Items] | ||||||
| Line Graph and Table Measure Name | [2] | Institutional Classa | ||||
| Average Annual Return, Percent | [2] | 24.47% | 17.59% | 17.60% | ||
| S&P 500 Total Return Index [Member] | ||||||
| Average Annual Return [Line Items] | ||||||
| Line Graph and Table Measure Name | S&P 500 Total Return Index | |||||
| Average Annual Return, Percent | 24.56% | 15.05% | 14.74% | |||
| Russell 1000 Growth Total Return Index | ||||||
| Average Annual Return [Line Items] | ||||||
| Line Graph and Table Measure Name | Russell 1000 Growth Total Return Index | |||||
| Average Annual Return, Percent | 33.48% | 19.34% | 18.91% | |||
| S&P 500 Total Return Index [Member] | ||||||
| Average Annual Return [Line Items] | ||||||
| Line Graph and Table Measure Name | S&P 500 Total Return Index | |||||
| Average Annual Return, Percent | 24.56% | 15.05% | 14.74% | |||
| Russell 1000 Growth Total Return Index | ||||||
| Average Annual Return [Line Items] | ||||||
| Line Graph and Table Measure Name | Russell 1000 Growth Total Return Index | |||||
| Average Annual Return, Percent | 33.48% | 19.34% | 18.91% | |||
| [1] a The Fund commenced operations on October 3, 2016 as a separate series (the “Predecessor Fund”) of F/m Funds Trust. Effective as of the close of business on October 27, 2023, the Predecessor Fund was reorganized as a new series of The RBB Fund, Inc. The performance shown for periods prior to October 30, 2023 represents the performance of the Predecessor Fund. a The Fund commenced operations on October 3, 2016 as a separate series (the “Predecessor Fund”) of F/m Funds Trust. Effective as of the close of business on October 27, 2023, the Predecessor Fund was reorganized as a new series of The RBB Fund, Inc. The performance shown for periods prior to October 30, 2023 represents the performance of the Predecessor Fund. | ||||||
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| Investor Class | Apple, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.10% |
| Investor Class | NVIDIA Corp. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.80% |
| Investor Class | Amazon.com, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.40% |
| Investor Class | Microsoft Corp. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.20% |
| Investor Class | Meta Platforms, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.20% |
| Investor Class | Netflix, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.30% |
| Investor Class | Alphabet, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.90% |
| Investor Class | Advanced Micro Devices, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| Investor Class | Adobe, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.10% |
| Investor Class | First Solar, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| Investor Class | Information Technology [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 54.30% |
| Investor Class | Communications Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.40% |
| Investor Class | Consumer Discretionary [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.10% |
| Investor Class | Industrial Sector [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.90% |
| Investor Class | Health Care [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| Investor Class | Financials [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| Investor Class | Energy [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| Investor Class | Cash & Other [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| Institutional Class | Apple, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.10% |
| Institutional Class | NVIDIA Corp. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.80% |
| Institutional Class | Amazon.com, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.40% |
| Institutional Class | Microsoft Corp. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.20% |
| Institutional Class | Meta Platforms, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7.20% |
| Institutional Class | Netflix, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.30% |
| Institutional Class | Alphabet, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.90% |
| Institutional Class | Advanced Micro Devices, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.70% |
| Institutional Class | Adobe, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.10% |
| Institutional Class | First Solar, Inc. [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.70% |
| Institutional Class | Information Technology [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 54.30% |
| Institutional Class | Communication Services [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 17.40% |
| Institutional Class | Consumer Discretionary [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 15.10% |
| Institutional Class | Industrials [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.90% |
| Institutional Class | Health Care [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.30% |
| Institutional Class | Financials [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| Institutional Class | Energy [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
| Institutional Class | Cash & Other [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2% |
