v3.26.3
Shareholder Report, Holdings (Details)
Aug. 31, 2026
C000015521 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000015521 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000015521 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000015521 [Member] | Warrants [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000015521 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000087984 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000087984 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000087984 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000087984 [Member] | Warrants [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000087984 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000189669 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000189669 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000189669 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000189669 [Member] | Warrants [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000189669 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000015522 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000015522 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000015522 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000015522 [Member] | Warrants [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000015522 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000015524 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.20%
C000015524 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000015524 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000015524 [Member] | Warrants [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000015524 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000015525 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 101.40%
C000015525 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000015525 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000015525 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.10%)
C000087985 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 101.40%
C000087985 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000087985 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000087985 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.10%)
C000189670 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 101.40%
C000189670 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000189670 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000189670 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.10%)
C000087986 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 101.40%
C000087986 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000087986 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000087986 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.10%)
C000087987 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 101.40%
C000087987 [Member] | Affiliated Funds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000087987 [Member] | U.S. Treasury Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000087987 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value (2.10%)
C000015528 [Member] | Municipal Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 98.50%
C000015528 [Member] | Other Assets and Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%