Label	Element	Value
Class C | Housing [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	17.20%
Class C | Health Care [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	16.80%
Class C | Transportation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	14.70%
Class C | Education [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	11.00%
Class C | Industrial Development Revenue and Pollution Control [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	9.50%
Class C | Other Revenue Bonds [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	7.70%
Class C | Lease [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	7.10%
Class C | Special Tax [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	5.80%
Class C | Utilities [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	4.20%
Class C | Local General Obligation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	2.80%
Class C | State General Obligation [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	2.50%
Class C | Refunded [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	0.40%
Class C | Not Available [Member]
Holdings [Line Items]	oef_HoldingsLineItems
Percent of Net Asset Value	oef_PctOfNav	0.30%