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