v3.25.2
Shareholder Report, Holdings (Details)
Jun. 30, 2025
C000037571 [Member] | Multifamily [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10%
C000037571 [Member] | Electric And Gas [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10%
C000037571 [Member] | Prepaid Gas Utility [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.10%
C000037571 [Member] | Hospital [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000037571 [Member] | Toll Road [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000037571 [Member] | Water And Sewer [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
C000037571 [Member] | Public Power [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000037571 [Member] | Industrial Development Bond Pollution Control Revenue [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000037571 [Member] | General Obligation Local [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.90%
C000037571 [Member] | General Obligation State [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000037571 [Member] | General Obligation State Appropriation [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000024677 [Member] | Multifamily [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10%
C000024677 [Member] | Electric And Gas [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10%
C000024677 [Member] | Prepaid Gas Utility [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.10%
C000024677 [Member] | Hospital [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000024677 [Member] | Toll Road [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000024677 [Member] | Water And Sewer [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
C000024677 [Member] | Public Power [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000024677 [Member] | Industrial Development Bond Pollution Control Revenue [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000024677 [Member] | General Obligation Local [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.90%
C000024677 [Member] | General Obligation State [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000024677 [Member] | General Obligation State Appropriation [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000024678 [Member] | Multifamily [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 15.10%
C000024678 [Member] | Electric And Gas [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 14.10%
C000024678 [Member] | Prepaid Gas Utility [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 12.10%
C000024678 [Member] | Hospital [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000024678 [Member] | Toll Road [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000024678 [Member] | Water And Sewer [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
C000024678 [Member] | Public Power [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000024678 [Member] | Industrial Development Bond Pollution Control Revenue [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000024678 [Member] | General Obligation Local [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.90%
C000024678 [Member] | General Obligation State [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000024678 [Member] | General Obligation State Appropriation [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%