Federated Short-intermediate Duration Municipal Trust
Company Profile
| Form N-CSR Cover | 12 Months Ended |
| Jun. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Federated Hermes Short-Intermediate Duration Municipal Trust |
| Entity Central Index Key | 0000353101 |
| Document Period End Date | Jun. 30, 2024 |
| Shareholder Report | 12 Months Ended |
| Jun. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSR |
| Amendment Flag | false |
| Registrant Name | Federated Hermes Short-Intermediate Duration Municipal Trust |
| Entity Central Index Key | 0000353101 |
| Document Period End Date | Jun. 30, 2024 |
| C000037571 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Short-Intermediate Municipal Fund |
| Class Name | Class A Shares |
| Trading Symbol | FMTAX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Short-Intermediate Municipal 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 FederatedHermes.com/us/FundInformation |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1‑800‑341‑7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last 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 Class A Shares $ 0.72 % |
| Expenses Paid, Amount | $ 73 |
| Expense Ratio, Percent | 0.72% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the S&P Municipal Bond Short Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the S&P Municipal Bond Index, which represents the overall U.S. municipal fixed-income market. The Fund seeks to provide dividend income which is exempt from federal regular income tax by investing its assets so that normally distributions of annual interest income are exempt from federal regular income tax and a majority of its assets are invested in securities rated investment-grade. Top Contributors to Performance Credit allocation contributed positively with significant overweight positions relative to the Index in A-rated and BBB-rated securities, both of which outperformed the Index. Sector allocation contributed positively with a significant overweight in Senior Care and Industrial Development/Pollution Control inclusive of pre-paid gas utility and electric and gas utility bonds. An underweight in general obligation and pre-refunded sectors also contributed positively. Yield curve allocations contributed positively, namely a barbell strategy of variable and floating-rate notes combined with tactical longer duration allocations to pre-paid gas utility bonds and 15-year high grade callable bonds when the municipal market was attractive. Security selection contributed favorably as the Fund outperformed the Index after accounting for duration, yield curve, sector and credit allocation contributions. Noteworthy positive contributors included low coupon discount bonds with maturities inside of five years, a significant allocation to floating-rate notes (excluded in the Index) in a rising interest rate environment and various A-rated and BBB-rated and lower quality bonds that experienced larger price movements relative to comparable quality securities. The Fund had less than a 5% allocation to non-investment grade securities over the period and did not use derivatives. Top Detractors from Performance Duration management modestly detracted from relative performance. The Fund held a long duration position and extended duration at various points over the period relative to the Index during a volatile year for rates. The 5-year AAA-rated Bloomberg Evaluation Service municipal yield fluctuated over a wide range from 2.22% to 3.56% and ended the period higher by 35 basis points at 2.96%. |
| 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 Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. Cumulative Performance: June 30, 2014 through June 30, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year Class A Shares — including sales load 2.35 % 0.42 % 0.61 % Class A Shares — excluding sales load 3.39 % 0.62 % 0.72 % S&P Municipal Bond Index 3.60 % 1.29 % 2.47 % S&P Municipal Bond Short Index 2.98 % 1.13 % 1.22 % S&P Municipal Bond 1-5 Years Investment Grade 5% Pre-Refunded Index 2.74 % 0.97 % 1.26 % Morningstar US Fund Muni National Short Funds Average 3.28 % 1.11 % 1.13 % |
| 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. |
| Updated Performance Information Location [Text Block] | Visit FederatedHermes.com/us/FundInformation |
| Net Assets | $ 378,847,335 |
| Holdings Count | Holding | 178 |
| Advisory Fees Paid, Amount | $ 1,099,711 |
| Investment Company Portfolio Turnover | 37% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $ % Number of Investments $ % Portfolio Turnover Rate $ % Total Advisory Fees Paid $ % |
| Holdings [Text Block] | Fund Holdings Top Sectors |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of certain changes made to the Fund. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation On August 11, 2023, the Fund’s Board of Trustees approved a tax-free conversion of the Fund’s Class A2 Shares into the Fund’s Class A Shares. This conversion was effective as of October 27, 2023, resulting in the closure and termination of the Fund’s Class A2 Shares. Effective September 1, 2024, total annual fund operating expenses (as shown in the financial highlights, excluding interest expense, extraordinary expenses and proxy-related expenses, if any) paid by the Fund’s Class A Shares (after the voluntary waivers and reimbursements) will not exceed 0.65%. Prior to September 1, 2024, the Fee Limit for the Class A Shares was 0.72%. |
| Updated Prospectus Phone Number | 1-800-341-7400 |
| Updated Prospectus Web Address | FederatedHermes.com/us/FundInformation |
| C000024677 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Short-Intermediate Municipal Fund |
| Class Name | Institutional Shares |
| Trading Symbol | FSHIX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Short-Intermediate Municipal 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 FederatedHermes.com/us/FundInformation |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1‑800‑341‑7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last 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 Shares $ 0.47 % |
| Expenses Paid, Amount | $ 48 |
| Expense Ratio, Percent | 0.47% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the S&P Municipal Bond Short Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the S&P Municipal Bond Index, which represents the overall U.S. municipal fixed-income market. The Fund seeks to provide dividend income which is exempt from federal regular income tax by investing its assets so that normally distributions of annual interest income are exempt from federal regular income tax and a majority of its assets are invested in securities rated investment-grade. Top Contributors to Performance Credit allocation contributed positively with significant overweight positions relative to the Index in A-rated and BBB-rated securities, both of which outperformed the Index. Sector allocation contributed positively with a significant overweight in Senior Care and Industrial Development/Pollution Control inclusive of pre-paid gas utility and electric and gas utility bonds. An underweight in general obligation and pre-refunded sectors also contributed positively. Yield curve allocations contributed positively, namely a barbell strategy of variable and floating-rate notes combined with tactical longer duration allocations to pre-paid gas utility bonds and 15-year high grade callable bonds when the municipal market was attractive. Security selection contributed favorably as the Fund outperformed the Index after accounting for duration, yield curve, sector and credit allocation contributions. Noteworthy positive contributors included low coupon discount bonds with maturities inside of five years, a significant allocation to floating-rate notes (excluded in the Index) in a rising interest rate environment and various A-rated and BBB-rated and lower quality bonds that experienced larger price movements relative to comparable quality securities. The Fund had less than a 5% allocation to non-investment grade securities over the period and did not use derivatives. Top Detractors from Performance Duration management modestly detracted from relative performance. The Fund held a long duration position and extended duration at various points over the period relative to the Index during a volatile year for rates. The 5-year AAA-rated Bloomberg Evaluation Service municipal yield fluctuated over a wide range from 2.22% to 3.56% and ended the period higher by 35 basis points at 2.96%. |
| 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 Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. Cumulative Performance: June 30, 2014 through June 30, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year Institutional Shares 3.76 % 0.91 % 1.12 % S&P Municipal Bond Index 3.60 % 1.29 % 2.47 % S&P Municipal Bond Short Index 2.98 % 1.13 % 1.22 % S&P Municipal Bond 1-5 Years Investment Grade 5% Pre-Refunded Index 2.74 % 0.97 % 1.26 % Morningstar US Fund Muni National Short Funds Average 3.28 % 1.11 % 1.13 % |
| 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. |
| Updated Performance Information Location [Text Block] | Visit FederatedHermes.com/us/FundInformation |
| Net Assets | $ 378,847,335 |
| Holdings Count | Holding | 178 |
| Advisory Fees Paid, Amount | $ 1,099,711 |
| Investment Company Portfolio Turnover | 37% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $ % Number of Investments $ % Portfolio Turnover Rate $ % Total Advisory Fees Paid $ % |
| Holdings [Text Block] | Fund Holdings Top Sectors |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of certain changes made to the Fund. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective September 1, 2024, total annual fund operating expenses (as shown in the financial highlights, excluding interest expense, extraordinary expenses and proxy-related expenses, if any) paid by the Fund’s Institutional Shares (after the voluntary waivers and reimbursements) will not exceed 0.40%. Prior to September 1, 2024, the Fee Limit for the Institutional Shares was 0.47%. |
| Updated Prospectus Phone Number | 1-800-341-7400 |
| Updated Prospectus Web Address | FederatedHermes.com/us/FundInformation |
| C000024678 [Member] | |
| Shareholder Report [Line Items] | |
| Fund Name | Federated Hermes Short-Intermediate Municipal Fund |
| Class Name | Service Shares |
| Trading Symbol | FSHSX |
| Annual or Semi-Annual Statement [Text Block] | This annual shareholder report contains important information about the Federated Hermes Short-Intermediate Municipal 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 FederatedHermes.com/us/FundInformation |
| Material Fund Change Notice [Text Block] | This report describes changes to the Fund that occurred during the reporting period. |
| Additional Information Phone Number | 1‑800‑341‑7400 |
| Additional Information Website | FederatedHermes.com/us/FundInformation |
| Expenses [Text Block] | What were the Fund costs for the last 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 Service Shares $ 0.70 % |
| Expenses Paid, Amount | $ 71 |
| Expense Ratio, Percent | 0.70% |
| Factors Affecting Performance [Text Block] | Management's Discussion of Fund Performance The following discussion compares the performance of the Fund to the S&P Municipal Bond Short Index (the “Index”) to show how the Fund’s performance compares to the returns of similar investments for the reporting period. See the Average Annual Total Returns table below for the returns of the Fund and related indexes, including the S&P Municipal Bond Index, which represents the overall U.S. municipal fixed-income market. The Fund seeks to provide dividend income which is exempt from federal regular income tax by investing its assets so that normally distributions of annual interest income are exempt from federal regular income tax and a majority of its assets are invested in securities rated investment-grade. Top Contributors to Performance Credit allocation contributed positively with significant overweight positions relative to the Index in A-rated and BBB-rated securities, both of which outperformed the Index. Sector allocation contributed positively with a significant overweight in Senior Care and Industrial Development/Pollution Control inclusive of pre-paid gas utility and electric and gas utility bonds. An underweight in general obligation and pre-refunded sectors also contributed positively. Yield curve allocations contributed positively, namely a barbell strategy of variable and floating-rate notes combined with tactical longer duration allocations to pre-paid gas utility bonds and 15-year high grade callable bonds when the municipal market was attractive. Security selection contributed favorably as the Fund outperformed the Index after accounting for duration, yield curve, sector and credit allocation contributions. Noteworthy positive contributors included low coupon discount bonds with maturities inside of five years, a significant allocation to floating-rate notes (excluded in the Index) in a rising interest rate environment and various A-rated and BBB-rated and lower quality bonds that experienced larger price movements relative to comparable quality securities. The Fund had less than a 5% allocation to non-investment grade securities over the period and did not use derivatives. Top Detractors from Performance Duration management modestly detracted from relative performance. The Fund held a long duration position and extended duration at various points over the period relative to the Index during a volatile year for rates. The 5-year AAA-rated Bloomberg Evaluation Service municipal yield fluctuated over a wide range from 2.22% to 3.56% and ended the period higher by 35 basis points at 2.96%. |
| 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 Keep in mind that the Fund’s past performance is not a good predictor of how the Fund will perform in the future. The graph and table do not reflect the deduction of taxes that a shareholder would pay on fund distributions or redemption of fund shares. Cumulative Performance: June 30, 2014 through June 30, 2024 Initial Investment of $10,000 |
| Average Annual Return [Table Text Block] | Average Annual Total Returns 1 Year 5 Year 10 Year Service Shares 3.51 % 0.67 % 0.88 % S&P Municipal Bond Index 3.60 % 1.29 % 2.47 % S&P Municipal Bond Short Index 2.98 % 1.13 % 1.22 % S&P Municipal Bond 1-5 Years Investment Grade 5% Pre-Refunded Index 2.74 % 0.97 % 1.26 % Morningstar US Fund Muni National Short Funds Average 3.28 % 1.11 % 1.13 % |
| 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. |
| Updated Performance Information Location [Text Block] | Visit FederatedHermes.com/us/FundInformation |
| Net Assets | $ 378,847,335 |
| Holdings Count | Holding | 178 |
| Advisory Fees Paid, Amount | $ 1,099,711 |
| Investment Company Portfolio Turnover | 37% |
| Additional Fund Statistics [Text Block] | Key Fund Statistics Net Assets $ % Number of Investments $ % Portfolio Turnover Rate $ % Total Advisory Fees Paid $ % |
| Holdings [Text Block] | Fund Holdings Top Sectors |
| Material Fund Change [Text Block] | Material Fund Changes Following is a summary of certain changes made to the Fund. For more complete and current information, you may review the Fund’s disclosure documents on its webpage at FederatedHermes.com/us/FundInformation Effective September 1, 2024, total annual fund operating expenses (as shown in the financial highlights, excluding interest expense, extraordinary expenses and proxy-related expenses, if any) paid by the Fund’s Service Shares (after the voluntary waivers and reimbursements) will not exceed 0.65%. Prior to September 1, 2024, the Fee Limit for the Service Shares was 0.72%. |
| Updated Prospectus Phone Number | 1-800-341-7400 |
| Updated Prospectus Web Address | FederatedHermes.com/us/FundInformation |
| Shareholder Report, Line Graph (Details) - USD ($) | 12 Months Ended | 60 Months Ended | 120 Months Ended | ||||||||||
| Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2015 | Jun. 30, 2014 | |
| C000037571 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Class A Shares — including sales load | ||||||||||||
| Account Value | $ 10,631 | $ 10,631 | $ 10,631 | $ 10,282 | $ 10,104 | $ 10,599 | $ 10,393 | $ 10,309 | $ 10,087 | $ 10,027 | $ 10,019 | $ 9,908 | $ 9,900 |
| Average Annual Return, Percent | 2.35% | 0.42% | 0.61% | ||||||||||
| C000037571 [Member] | Without Sales Load [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Class A Shares — excluding sales load | ||||||||||||
| Average Annual Return, Percent | 3.39% | 0.62% | 0.72% | ||||||||||
| C000024677 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Institutional Shares | ||||||||||||
| Account Value | $ 11,177 | $ 11,177 | $ 11,177 | 10,772 | 10,570 | 11,049 | 10,796 | 10,682 | 10,390 | 10,276 | 10,227 | 10,063 | 10,000 |
| Average Annual Return, Percent | 3.76% | 0.91% | 1.12% | ||||||||||
| C000024678 [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Service Shares | ||||||||||||
| Account Value | $ 10,911 | $ 10,911 | $ 10,911 | 10,541 | 10,368 | 10,863 | 10,650 | 10,553 | 10,299 | 10,202 | 10,177 | 10,038 | 10,000 |
| Average Annual Return, Percent | 3.51% | 0.67% | 0.88% | ||||||||||
| S And P Municipal Bond Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P Municipal Bond Index | ||||||||||||
| Account Value | $ 12,763 | $ 12,763 | $ 12,763 | 12,320 | 11,972 | 13,000 | 12,476 | 11,970 | 11,251 | 11,073 | 11,104 | 10,300 | 10,000 |
| Average Annual Return, Percent | 3.60% | 1.29% | 2.47% | ||||||||||
| S And P Municipal Bond Short Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P Municipal Bond Short Index | ||||||||||||
| Account Value | $ 11,284 | $ 11,284 | $ 11,284 | 10,958 | 10,828 | 11,069 | 10,950 | 10,666 | 10,355 | 10,284 | 10,229 | 10,053 | 10,000 |
| Average Annual Return, Percent | 2.98% | 1.13% | 1.22% | ||||||||||
| S And P Municipal Bond 1 5 Years Investment Grade 5 Pre Refunded Index [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | S&P Municipal Bond 1-5 Years Investment Grade 5% Pre-Refunded Index | ||||||||||||
| Account Value | $ 11,331 | $ 11,331 | $ 11,331 | 11,028 | 10,908 | 11,285 | 11,126 | 10,797 | 10,422 | 10,369 | 10,324 | 10,077 | 10,000 |
| Average Annual Return, Percent | 2.74% | 0.97% | 1.26% | ||||||||||
| Morningstar US Fund Muni National Short Funds Average [Member] | |||||||||||||
| Account Value [Line Items] | |||||||||||||
| Line Graph and Table Measure Name | Morningstar US Fund Muni National Short Funds Average | ||||||||||||
| Account Value | $ 11,170 | $ 11,170 | $ 11,170 | $ 10,819 | $ 10,640 | $ 10,978 | $ 10,794 | $ 10,582 | $ 10,290 | $ 10,224 | $ 10,210 | $ 10,015 | $ 10,000 |
| Average Annual Return, Percent | 3.28% | 1.11% | 1.13% |
| Shareholder Report, Holdings (Details) | Jun. 30, 2024 |
| C000037571 [Member] | Electric And Gas [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.40% |
| C000037571 [Member] | Prepaid Gas Utility [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000037571 [Member] | Hospital [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.40% |
| C000037571 [Member] | Multi Family Housing [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.70% |
| C000037571 [Member] | Senior Care [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.20% |
| C000037571 [Member] | Public Power [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000037571 [Member] | Airport [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000037571 [Member] | Industrial Development Bond Pollution Control Revenue [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.30% |
| C000037571 [Member] | General Obligation Local [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| C000037571 [Member] | General Obligation State [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000037571 [Member] | General Obligation State Appropriation [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.80% |
| C000024677 [Member] | Electric And Gas [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.40% |
| C000024677 [Member] | Prepaid Gas Utility [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000024677 [Member] | Hospital [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.40% |
| C000024677 [Member] | Multi Family Housing [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.70% |
| C000024677 [Member] | Senior Care [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.20% |
| C000024677 [Member] | Public Power [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000024677 [Member] | Airport [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000024677 [Member] | Industrial Development Bond Pollution Control Revenue [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.30% |
| C000024677 [Member] | General Obligation Local [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| C000024677 [Member] | General Obligation State [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000024677 [Member] | General Obligation State Appropriation [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.80% |
| C000024678 [Member] | Electric And Gas [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.40% |
| C000024678 [Member] | Prepaid Gas Utility [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000024678 [Member] | Hospital [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.40% |
| C000024678 [Member] | Multi Family Housing [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.70% |
| C000024678 [Member] | Senior Care [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.20% |
| C000024678 [Member] | Public Power [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000024678 [Member] | Airport [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.60% |
| C000024678 [Member] | Industrial Development Bond Pollution Control Revenue [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.30% |
| C000024678 [Member] | General Obligation Local [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.70% |
| C000024678 [Member] | General Obligation State [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.30% |
| C000024678 [Member] | General Obligation State Appropriation [Member] | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.80% |