{"cik":"0001746967","entityName":"RiverNorth Opportunistic Municipal Income Fund, Inc.","facts":{"cef":{"AcquiredFundFeesAndExpensesPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.016,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"DividendExpenseOnPreferredSharesPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"DividendReinvestmentAndCashPurchaseFees":{"label":"","description":"","units":{"USD":[{"start":"2025-07-01","end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ExpenseExampleYear01":{"label":"","description":"","units":{"USD":[{"start":"2025-07-01","end":"2026-06-30","val":60,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ExpenseExampleYears1to10":{"label":"","description":"","units":{"USD":[{"start":"2025-07-01","end":"2026-06-30","val":573,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ExpenseExampleYears1to3":{"label":"","description":"","units":{"USD":[{"start":"2025-07-01","end":"2026-06-30","val":178,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ExpenseExampleYears1to5":{"label":"","description":"","units":{"USD":[{"start":"2025-07-01","end":"2026-06-30","val":294,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"InterestExpensesOnBorrowingsPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.0198,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ManagementFeesPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.0172,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"OtherAnnualExpensesPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.0073,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"OtherTransactionExpense1Percent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"OtherTransactionExpense2Percent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ReturnAtMinusFivePercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":-0.1031,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ReturnAtMinusTenPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":-0.1863,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ReturnAtPlusFivePercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.0633,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ReturnAtPlusTenPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.1465,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"ReturnAtZeroPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":-0.0199,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"SalesLoadPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}},"SeniorSecuritiesAmt":{"label":"","description":"","units":{"USD":[{"end":"2019-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2019Q2I"},{"end":"2020-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2020Q2I"},{"end":"2021-06-30","val":10000000,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2021Q2I"},{"end":"2022-06-30","val":13000000,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2022Q2I"},{"end":"2023-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2023Q2I"},{"end":"2024-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2024Q2I"},{"end":"2025-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2025Q2I"},{"end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026Q2I"}]}},"SeniorSecuritiesCvgPerUnit":{"label":"","description":"","units":{"USD/shares":[{"end":"2019-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2019Q2I"},{"end":"2020-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2020Q2I"},{"end":"2021-06-30","val":16523,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2021Q2I"},{"end":"2022-06-30","val":9711,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2022Q2I"},{"end":"2023-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2023Q2I"},{"end":"2024-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2024Q2I"},{"end":"2025-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2025Q2I"},{"end":"2026-06-30","val":0,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026Q2I"}]}},"TotalAnnualExpensesPercent":{"label":"","description":"","units":{"pure":[{"start":"2025-07-01","end":"2026-06-30","val":0.0603,"accn":"0001398344-26-016682","fy":null,"fp":null,"form":"N-CSR","filed":"2026-09-04","frame":"CY2026"}]}}}}}