| Form N-CSR Cover | 6 Months Ended |
| Sep. 30, 2024 | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | EATON VANCE INVESTMENT TRUST |
| Entity Central Index Key | 0000779991 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Sep. 30, 2024 |
| Shareholder Report | 6 Months Ended |
| Sep. 30, 2024 USD ($) Holding | |
| Shareholder Report [Line Items] | |
| Document Type | N-CSRS |
| Amendment Flag | false |
| Registrant Name | EATON VANCE INVESTMENT TRUST |
| Entity Central Index Key | 0000779991 |
| Entity Investment Company Type | N-1A |
| Document Period End Date | Sep. 30, 2024 |
| C000013057 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance New York Municipal Opportunities Fund |
| Class Name | Class A |
| Trading Symbol | EXNYX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance New York Municipal Opportunities Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B19"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 $41 0.80% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 41 |
| Expense Ratio, Percent | 0.80% |
| AssetsNet | $ 61,004,123 |
| Holdings Count | Holding | 77 |
| InvestmentCompanyPortfolioTurnover | 61% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $61,004,123 # of Portfolio Holdings 77 Portfolio Turnover Rate 61% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 3.0% Lease Rev./Cert. of Participation 3.2% Senior Living/Life Care 3.2% Education 4.0% Industrial Development Revenue 5.2% Electric Utilities 8.5% Housing 8.6% Hospital 9.5% General Obligations 10.7% Water and Sewer 11.1% Transportation 11.9% Special Tax Revenue 21.1% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 6.0% B 2.8% BB 4.6% BBB 10.9% A 5.4% AA 58.8% AAA 11.5% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013059 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance New York Municipal Opportunities Fund |
| Class Name | Class C |
| Trading Symbol | EZNYX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance New York Municipal Opportunities Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B39"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 C $78 1.54% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 78 |
| Expense Ratio, Percent | 1.54% |
| AssetsNet | $ 61,004,123 |
| Holdings Count | Holding | 77 |
| InvestmentCompanyPortfolioTurnover | 61% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $61,004,123 # of Portfolio Holdings 77 Portfolio Turnover Rate 61% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 3.0% Lease Rev./Cert. of Participation 3.2% Senior Living/Life Care 3.2% Education 4.0% Industrial Development Revenue 5.2% Electric Utilities 8.5% Housing 8.6% Hospital 9.5% General Obligations 10.7% Water and Sewer 11.1% Transportation 11.9% Special Tax Revenue 21.1% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 6.0% B 2.8% BB 4.6% BBB 10.9% A 5.4% AA 58.8% AAA 11.5% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000091012 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance New York Municipal Opportunities Fund |
| Class Name | Class I |
| Trading Symbol | ENYIX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance New York Municipal Opportunities Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B59"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 I $33 0.64% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 33 |
| Expense Ratio, Percent | 0.64% |
| AssetsNet | $ 61,004,123 |
| Holdings Count | Holding | 77 |
| InvestmentCompanyPortfolioTurnover | 61% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $61,004,123 # of Portfolio Holdings 77 Portfolio Turnover Rate 61% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 3.0% Lease Rev./Cert. of Participation 3.2% Senior Living/Life Care 3.2% Education 4.0% Industrial Development Revenue 5.2% Electric Utilities 8.5% Housing 8.6% Hospital 9.5% General Obligations 10.7% Water and Sewer 11.1% Transportation 11.9% Special Tax Revenue 21.1% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 6.0% B 2.8% BB 4.6% BBB 10.9% A 5.4% AA 58.8% AAA 11.5% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013049 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Short Duration Municipal Opportunities Fund |
| Class Name | Class A |
| Trading Symbol | EXMAX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance Short Duration Municipal Opportunities Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B79"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 $34 0.66% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 34 |
| Expense Ratio, Percent | 0.66% |
| AssetsNet | $ 729,818,414 |
| Holdings Count | Holding | 414 |
| InvestmentCompanyPortfolioTurnover | 46% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $729,818,414 # of Portfolio Holdings 414 Portfolio Turnover Rate 46% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 4.6% Special Tax Revenue 5.0% Water and Sewer 5.4% Education 5.9% Electric Utilities 6.0% Other Revenue 6.1% Senior Living/Life Care 6.8% Housing 7.7% Industrial Development Revenue 9.6% Hospital 9.9% Transportation 13.2% General Obligations 19.8% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 6.6% B 0.7% BB 8.2% BBB 9.8% A 23.6% AA 35.0% AAA 16.1% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013051 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Short Duration Municipal Opportunities Fund |
| Class Name | Class C |
| Trading Symbol | EZMAX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance Short Duration Municipal Opportunities Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B99"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 C $72 1.41% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 72 |
| Expense Ratio, Percent | 1.41% |
| AssetsNet | $ 729,818,414 |
| Holdings Count | Holding | 414 |
| InvestmentCompanyPortfolioTurnover | 46% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $729,818,414 # of Portfolio Holdings 414 Portfolio Turnover Rate 46% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 4.6% Special Tax Revenue 5.0% Water and Sewer 5.4% Education 5.9% Electric Utilities 6.0% Other Revenue 6.1% Senior Living/Life Care 6.8% Housing 7.7% Industrial Development Revenue 9.6% Hospital 9.9% Transportation 13.2% General Obligations 19.8% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 6.6% B 0.7% BB 8.2% BBB 9.8% A 23.6% AA 35.0% AAA 16.1% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000091010 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance Short Duration Municipal Opportunities Fund |
| Class Name | Class I |
| Trading Symbol | EMAIX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance Short Duration Municipal Opportunities Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B119"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 I $26 0.51% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 26 |
| Expense Ratio, Percent | 0.51% |
| AssetsNet | $ 729,818,414 |
| Holdings Count | Holding | 414 |
| InvestmentCompanyPortfolioTurnover | 46% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $729,818,414 # of Portfolio Holdings 414 Portfolio Turnover Rate 46% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 4.6% Special Tax Revenue 5.0% Water and Sewer 5.4% Education 5.9% Electric Utilities 6.0% Other Revenue 6.1% Senior Living/Life Care 6.8% Housing 7.7% Industrial Development Revenue 9.6% Hospital 9.9% Transportation 13.2% General Obligations 19.8% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 6.6% B 0.7% BB 8.2% BBB 9.8% A 23.6% AA 35.0% AAA 16.1% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013046 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance National Ultra-Short Municipal Income Fund |
| Class Name | Class A |
| Trading Symbol | EXFLX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance National Ultra-Short Municipal Income Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B139"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 $25 0.50% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 25 |
| Expense Ratio, Percent | 0.50% |
| AssetsNet | $ 328,179,957 |
| Holdings Count | Holding | 158 |
| InvestmentCompanyPortfolioTurnover | 74% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $328,179,957 # of Portfolio Holdings 158 Portfolio Turnover Rate 74% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 7.7% Housing 3.1% Electric Utilities 3.3% Lease Rev./Cert. of Participation 5.6% Special Tax Revenue 6.2% Water and Sewer 7.2% Industrial Development Revenue 8.2% Other Revenue 9.1% Hospital 12.4% Transportation 13.9% General Obligations 23.3% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 10.5% BB 3.4% BBB 7.0% A 24.8% AA 41.7% AAA 12.6% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000225142 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance National Ultra-Short Municipal Income Fund |
| Class Name | Advisers Class |
| Trading Symbol | EAMLX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance National Ultra-Short Municipal Income Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B159"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 Advisers Class $25 0.50% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 25 |
| Expense Ratio, Percent | 0.50% |
| AssetsNet | $ 328,179,957 |
| Holdings Count | Holding | 158 |
| InvestmentCompanyPortfolioTurnover | 74% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $328,179,957 # of Portfolio Holdings 158 Portfolio Turnover Rate 74% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 7.7% Housing 3.1% Electric Utilities 3.3% Lease Rev./Cert. of Participation 5.6% Special Tax Revenue 6.2% Water and Sewer 7.2% Industrial Development Revenue 8.2% Other Revenue 9.1% Hospital 12.4% Transportation 13.9% General Obligations 23.3% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 10.5% BB 3.4% BBB 7.0% A 24.8% AA 41.7% AAA 12.6% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000091009 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance National Ultra-Short Municipal Income Fund |
| Class Name | Class I |
| Trading Symbol | EILMX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance National Ultra-Short Municipal Income Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B179"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 I $18 0.35% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 18 |
| Expense Ratio, Percent | 0.35% |
| AssetsNet | $ 328,179,957 |
| Holdings Count | Holding | 158 |
| InvestmentCompanyPortfolioTurnover | 74% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $328,179,957 # of Portfolio Holdings 158 Portfolio Turnover Rate 74% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 7.7% Housing 3.1% Electric Utilities 3.3% Lease Rev./Cert. of Participation 5.6% Special Tax Revenue 6.2% Water and Sewer 7.2% Industrial Development Revenue 8.2% Other Revenue 9.1% Hospital 12.4% Transportation 13.9% General Obligations 23.3% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 10.5% BB 3.4% BBB 7.0% A 24.8% AA 41.7% AAA 12.6% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013052 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance National Limited Maturity Municipal Income Fund |
| Class Name | Class A |
| Trading Symbol | EXNAX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance National Limited Maturity Municipal Income Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B199"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 $35 0.69% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 35 |
| Expense Ratio, Percent | 0.69% |
| AssetsNet | $ 464,970,250 |
| Holdings Count | Holding | 211 |
| InvestmentCompanyPortfolioTurnover | 43% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $464,970,250 # of Portfolio Holdings 211 Portfolio Turnover Rate 43% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 7.3% Water and Sewer 5.5% Electric Utilities 5.8% Other Revenue 7.2% Industrial Development Revenue 7.8% Education 7.9% Housing 8.3% Special Tax Revenue 9.3% Hospital 9.6% General Obligations 14.1% Transportation 17.2% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 5.9% B 0.6% BB 3.0% BBB 3.8% A 26.1% AA 46.8% AAA 13.8% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000013054 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance National Limited Maturity Municipal Income Fund |
| Class Name | Class C |
| Trading Symbol | EZNAX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance National Limited Maturity Municipal Income Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B219"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 C $73 1.44% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 73 |
| Expense Ratio, Percent | 1.44% |
| AssetsNet | $ 464,970,250 |
| Holdings Count | Holding | 211 |
| InvestmentCompanyPortfolioTurnover | 43% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $464,970,250 # of Portfolio Holdings 211 Portfolio Turnover Rate 43% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 7.3% Water and Sewer 5.5% Electric Utilities 5.8% Other Revenue 7.2% Industrial Development Revenue 7.8% Education 7.9% Housing 8.3% Special Tax Revenue 9.3% Hospital 9.6% General Obligations 14.1% Transportation 17.2% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 5.9% B 0.6% BB 3.0% BBB 3.8% A 26.1% AA 46.8% AAA 13.8% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| C000081647 | |
| Shareholder Report [Line Items] | |
| Fund Name | Eaton Vance National Limited Maturity Municipal Income Fund |
| Class Name | Class I |
| Trading Symbol | EINAX |
| Annual or Semi-Annual Statement [Text Block] | This semi-annual shareholder report contains important information about the Eaton Vance National Limited Maturity Municipal Income Fund for the period of April 1, 2024 to September 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 www.eatonvance.com/open-end-mutual-fund-documents.php |
| Additional Information Phone Number | 1-800-262-1122 |
| Additional Information Website | www.eatonvance.com/open-end-mutual-fund-documents.php</span>" id="sjs-B239"><span style="box-sizing: border-box; color: rgb(0, 0, 0); display: inline; flex-wrap: nowrap; font-size: 10.6667px; font-weight: 400; grid-area: auto; line-height: 16px; margin: 0px; overflow: visible; text-align: left;">www.eatonvance.com/open-end-mutual-fund-documents.php</span> |
| Expenses [Text Block] | What were the Fund costs for the last six months? (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 I $27 0.54% Footnote Reference Footnote Description Footnote 1 Annualized |
| Expenses Paid, Amount | $ 27 |
| Expense Ratio, Percent | 0.54% |
| AssetsNet | $ 464,970,250 |
| Holdings Count | Holding | 211 |
| InvestmentCompanyPortfolioTurnover | 43% |
| Additional Fund Statistics Significance or Limits [Text Block] | Key Fund Statistics Total Net Assets $464,970,250 # of Portfolio Holdings 211 Portfolio Turnover Rate 43% |
| Holdings [Text Block] | Sector Allocation (% of total investments) Value Value Other Footnote Reference 7.3% Water and Sewer 5.5% Electric Utilities 5.8% Other Revenue 7.2% Industrial Development Revenue 7.8% Education 7.9% Housing 8.3% Special Tax Revenue 9.3% Hospital 9.6% General Obligations 14.1% Transportation 17.2% Footnote Description Footnote * Sectors less than 3% each Credit Quality (% of total investments) Footnote Reference Value Value Not Rated 5.9% B 0.6% BB 3.0% BBB 3.8% A 26.1% AA 46.8% AAA 13.8% Footnote Description Footnote a Ratings are based on Moody’s Investors Service, Inc. (“Moody’s”), S&P Global Ratings (“S&P”) or Fitch Ratings (“Fitch”). If securities are rated differently by the ratings agencies, the highest rating is applied. Moody's ratings are converted to the S&P and Fitch scale with ratings ranging from AAA, being the highest, to D, being the lowest. Ratings of BBB or higher are considered to be investment-grade quality. Holdings designated as “Not Rated” (if any) are not rated by the national ratings agencies stated above. |
| Material Fund Change [Text Block] | |
| Updated Prospectus Phone Number | 1-800-262-1122 |
| Shareholder Report, Holdings (Details) | Sep. 30, 2024 |
| C000013057 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| C000013057 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| C000013057 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.60% |
| C000013057 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.90% |
| C000013057 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| C000013057 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 58.80% |
| C000013057 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000013057 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3% |
| C000013057 | Lease Rev./Cert. of Participation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.20% |
| C000013057 | Senior Living/Life Care | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.20% |
| C000013057 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4% |
| C000013057 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.20% |
| C000013057 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.50% |
| C000013057 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.60% |
| C000013057 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.50% |
| C000013057 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 10.70% |
| C000013057 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.10% |
| C000013057 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.90% |
| C000013057 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 21.10% |
| C000013059 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| C000013059 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| C000013059 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.60% |
| C000013059 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.90% |
| C000013059 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| C000013059 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 58.80% |
| C000013059 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000013059 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3% |
| C000013059 | Lease Rev./Cert. of Participation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.20% |
| C000013059 | Senior Living/Life Care | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.20% |
| C000013059 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4% |
| C000013059 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.20% |
| C000013059 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.50% |
| C000013059 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.60% |
| C000013059 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.50% |
| C000013059 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 10.70% |
| C000013059 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.10% |
| C000013059 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.90% |
| C000013059 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 21.10% |
| C000091012 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6% |
| C000091012 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 2.80% |
| C000091012 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 4.60% |
| C000091012 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.90% |
| C000091012 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.40% |
| C000091012 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 58.80% |
| C000091012 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 11.50% |
| C000091012 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3% |
| C000091012 | Lease Rev./Cert. of Participation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.20% |
| C000091012 | Senior Living/Life Care | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.20% |
| C000091012 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4% |
| C000091012 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.20% |
| C000091012 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.50% |
| C000091012 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.60% |
| C000091012 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.50% |
| C000091012 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 10.70% |
| C000091012 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.10% |
| C000091012 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 11.90% |
| C000091012 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 21.10% |
| C000013049 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.60% |
| C000013049 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| C000013049 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.20% |
| C000013049 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.80% |
| C000013049 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.60% |
| C000013049 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 35% |
| C000013049 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.10% |
| C000013049 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.60% |
| C000013049 | Senior Living/Life Care | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.80% |
| C000013049 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.90% |
| C000013049 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.60% |
| C000013049 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6% |
| C000013049 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| C000013049 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.90% |
| C000013049 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 19.80% |
| C000013049 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| C000013049 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.20% |
| C000013049 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5% |
| C000013049 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.10% |
| C000013051 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.60% |
| C000013051 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| C000013051 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.20% |
| C000013051 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.80% |
| C000013051 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.60% |
| C000013051 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 35% |
| C000013051 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.10% |
| C000013051 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.60% |
| C000013051 | Senior Living/Life Care | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.80% |
| C000013051 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.90% |
| C000013051 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.60% |
| C000013051 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6% |
| C000013051 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| C000013051 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.90% |
| C000013051 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 19.80% |
| C000013051 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| C000013051 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.20% |
| C000013051 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5% |
| C000013051 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.10% |
| C000091010 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 6.60% |
| C000091010 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.70% |
| C000091010 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 8.20% |
| C000091010 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 9.80% |
| C000091010 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 23.60% |
| C000091010 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 35% |
| C000091010 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 16.10% |
| C000091010 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 4.60% |
| C000091010 | Senior Living/Life Care | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.80% |
| C000091010 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.90% |
| C000091010 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.60% |
| C000091010 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6% |
| C000091010 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| C000091010 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.90% |
| C000091010 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 19.80% |
| C000091010 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.40% |
| C000091010 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.20% |
| C000091010 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5% |
| C000091010 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.10% |
| C000013046 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.50% |
| C000013046 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| C000013046 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000013046 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.80% |
| C000013046 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 41.70% |
| C000013046 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.60% |
| C000013046 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| C000013046 | Lease Rev./Cert. of Participation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.60% |
| C000013046 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.20% |
| C000013046 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.30% |
| C000013046 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.10% |
| C000013046 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 12.40% |
| C000013046 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 23.30% |
| C000013046 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| C000013046 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.90% |
| C000013046 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.20% |
| C000013046 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.10% |
| C000225142 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.50% |
| C000225142 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| C000225142 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000225142 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.80% |
| C000225142 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 41.70% |
| C000225142 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.60% |
| C000225142 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| C000225142 | Lease Rev./Cert. of Participation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.60% |
| C000225142 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.20% |
| C000225142 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.30% |
| C000225142 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.10% |
| C000225142 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 12.40% |
| C000225142 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 23.30% |
| C000225142 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| C000225142 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.90% |
| C000225142 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.20% |
| C000225142 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.10% |
| C000091009 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 10.50% |
| C000091009 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.40% |
| C000091009 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 7% |
| C000091009 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 24.80% |
| C000091009 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 41.70% |
| C000091009 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 12.60% |
| C000091009 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.70% |
| C000091009 | Lease Rev./Cert. of Participation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.60% |
| C000091009 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.20% |
| C000091009 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.30% |
| C000091009 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 3.10% |
| C000091009 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 12.40% |
| C000091009 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 23.30% |
| C000091009 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| C000091009 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 13.90% |
| C000091009 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 6.20% |
| C000091009 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.10% |
| C000013052 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000013052 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| C000013052 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000013052 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000013052 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 26.10% |
| C000013052 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 46.80% |
| C000013052 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.80% |
| C000013052 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.30% |
| C000013052 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000013052 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.80% |
| C000013052 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.80% |
| C000013052 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.30% |
| C000013052 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.60% |
| C000013052 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.10% |
| C000013052 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.50% |
| C000013052 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.20% |
| C000013052 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.30% |
| C000013052 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| C000013054 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000013054 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| C000013054 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000013054 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000013054 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 26.10% |
| C000013054 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 46.80% |
| C000013054 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.80% |
| C000013054 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.30% |
| C000013054 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000013054 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.80% |
| C000013054 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.80% |
| C000013054 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.30% |
| C000013054 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.60% |
| C000013054 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.10% |
| C000013054 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.50% |
| C000013054 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.20% |
| C000013054 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.30% |
| C000013054 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
| C000081647 | Not Rated | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 5.90% |
| C000081647 | B | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 0.60% |
| C000081647 | BB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3% |
| C000081647 | BBB | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 3.80% |
| C000081647 | A | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 26.10% |
| C000081647 | AA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 46.80% |
| C000081647 | AAA | |
| Holdings [Line Items] | |
| Percent of Net Asset Value | 13.80% |
| C000081647 | Industry Other Line | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.30% |
| C000081647 | Education | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.90% |
| C000081647 | Industrial Development Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.80% |
| C000081647 | Electric Utilities | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.80% |
| C000081647 | Housing | |
| Holdings [Line Items] | |
| Percent of Total Investments | 8.30% |
| C000081647 | Hospital | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.60% |
| C000081647 | General Obligations | |
| Holdings [Line Items] | |
| Percent of Total Investments | 14.10% |
| C000081647 | Water and Sewer | |
| Holdings [Line Items] | |
| Percent of Total Investments | 5.50% |
| C000081647 | Transportation | |
| Holdings [Line Items] | |
| Percent of Total Investments | 17.20% |
| C000081647 | Special Tax Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 9.30% |
| C000081647 | Other Revenue | |
| Holdings [Line Items] | |
| Percent of Total Investments | 7.20% |
