Label	Element	Value
Class C | Transportation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	15.70%
Class C | Local General Obligation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	11.70%
Class C | Utilities [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	11.40%
Class C | Health Care [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	11.10%
Class C | Education [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	10.50%
Class C | State General Obligation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	7.20%
Class C | Housing [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	7.00%
Class C | Special Tax [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	5.70%
Class C | Tobacco [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	4.30%
Class C | Financials [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	4.20%
Class C | Land [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	1.70%
Class C | Prerefunded [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	1.70%
Class C | Other [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	0.70%
Class C | Cash and Equivalents [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	7.10%