v3.26.3
Shareholder Report, Holdings (Details)
Aug. 31, 2026
C000135933 [Member] | PENNSYLVANIA  
Holdings [Line Items]  
Percent of Net Asset Value 81.46%
C000135933 [Member] | VIRGIN ISLANDS, US  
Holdings [Line Items]  
Percent of Net Asset Value 0.67%
C000135933 [Member] | PUERTO RICO  
Holdings [Line Items]  
Percent of Net Asset Value 15.02%
C000135933 [Member] | Local General Obligation Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.06%
C000135933 [Member] | Water And Sewer Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.24%
C000135933 [Member] | Lease Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.31%
C000135933 [Member] | Electric Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.51%
C000135933 [Member] | Housing Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.21%
C000135933 [Member] | Industrial Development Revenue Pollution Control Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.35%
C000135933 [Member] | Education Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.55%
C000135933 [Member] | Special Tax Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30%
C000135933 [Member] | Transportation Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.32%
C000135933 [Member] | Healthcare Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 27.08%
C000006344 [Member] | PENNSYLVANIA  
Holdings [Line Items]  
Percent of Net Asset Value 81.46%
C000006344 [Member] | VIRGIN ISLANDS, US  
Holdings [Line Items]  
Percent of Net Asset Value 0.67%
C000006344 [Member] | PUERTO RICO  
Holdings [Line Items]  
Percent of Net Asset Value 15.02%
C000006344 [Member] | Local General Obligation Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.06%
C000006344 [Member] | Water And Sewer Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.24%
C000006344 [Member] | Lease Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.31%
C000006344 [Member] | Electric Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.51%
C000006344 [Member] | Housing Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.21%
C000006344 [Member] | Industrial Development Revenue Pollution Control Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.35%
C000006344 [Member] | Education Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.55%
C000006344 [Member] | Special Tax Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30%
C000006344 [Member] | Transportation Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.32%
C000006344 [Member] | Healthcare Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 27.08%
C000006342 [Member] | PENNSYLVANIA  
Holdings [Line Items]  
Percent of Net Asset Value 81.46%
C000006342 [Member] | VIRGIN ISLANDS, US  
Holdings [Line Items]  
Percent of Net Asset Value 0.67%
C000006342 [Member] | PUERTO RICO  
Holdings [Line Items]  
Percent of Net Asset Value 15.02%
C000006342 [Member] | Local General Obligation Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.06%
C000006342 [Member] | Water And Sewer Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.24%
C000006342 [Member] | Lease Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.31%
C000006342 [Member] | Electric Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.51%
C000006342 [Member] | Housing Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.21%
C000006342 [Member] | Industrial Development Revenue Pollution Control Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.35%
C000006342 [Member] | Education Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.55%
C000006342 [Member] | Special Tax Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.30%
C000006342 [Member] | Transportation Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.32%
C000006342 [Member] | Healthcare Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 27.08%