v3.26.3
Shareholder Report, Holdings (Details)
Aug. 31, 2026
C000135926 [Member] | NEW HAMPSHIRE  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000135926 [Member] | CALIFORNIA  
Holdings [Line Items]  
Percent of Net Asset Value 83.33%
C000135926 [Member] | VIRGIN ISLANDS, US  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000135926 [Member] | PUERTO RICO  
Holdings [Line Items]  
Percent of Net Asset Value 14.39%
C000135926 [Member] | GUAM  
Holdings [Line Items]  
Percent of Net Asset Value 0.39%
C000135926 [Member] | Water And Sewer Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.34%
C000135926 [Member] | Lease Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.88%
C000135926 [Member] | Housing Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.04%
C000135926 [Member] | Electric Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.04%
C000135926 [Member] | State General Obligation Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.77%
C000135926 [Member] | Special Tax Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.48%
C000135926 [Member] | Industrial Development Revenue Pollution Control Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.00%
C000135926 [Member] | Healthcare Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.37%
C000135926 [Member] | Transportation Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.88%
C000135926 [Member] | Education Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.32%
C000006417 [Member] | NEW HAMPSHIRE  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000006417 [Member] | CALIFORNIA  
Holdings [Line Items]  
Percent of Net Asset Value 83.33%
C000006417 [Member] | VIRGIN ISLANDS, US  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000006417 [Member] | PUERTO RICO  
Holdings [Line Items]  
Percent of Net Asset Value 14.39%
C000006417 [Member] | GUAM  
Holdings [Line Items]  
Percent of Net Asset Value 0.39%
C000006417 [Member] | Water And Sewer Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.34%
C000006417 [Member] | Lease Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.88%
C000006417 [Member] | Housing Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.04%
C000006417 [Member] | Electric Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.04%
C000006417 [Member] | State General Obligation Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.77%
C000006417 [Member] | Special Tax Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.48%
C000006417 [Member] | Industrial Development Revenue Pollution Control Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.00%
C000006417 [Member] | Healthcare Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.37%
C000006417 [Member] | Transportation Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.88%
C000006417 [Member] | Education Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.32%
C000006415 [Member] | NEW HAMPSHIRE  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000006415 [Member] | CALIFORNIA  
Holdings [Line Items]  
Percent of Net Asset Value 83.33%
C000006415 [Member] | VIRGIN ISLANDS, US  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000006415 [Member] | PUERTO RICO  
Holdings [Line Items]  
Percent of Net Asset Value 14.39%
C000006415 [Member] | GUAM  
Holdings [Line Items]  
Percent of Net Asset Value 0.39%
C000006415 [Member] | Water And Sewer Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.34%
C000006415 [Member] | Lease Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.88%
C000006415 [Member] | Housing Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.04%
C000006415 [Member] | Electric Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.04%
C000006415 [Member] | State General Obligation Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.77%
C000006415 [Member] | Special Tax Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.48%
C000006415 [Member] | Industrial Development Revenue Pollution Control Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.00%
C000006415 [Member] | Healthcare Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 13.37%
C000006415 [Member] | Transportation Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.88%
C000006415 [Member] | Education Revenue Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 23.32%