v3.26.3
Average Annual Total Returns
 12 Months Ended 60 Months Ended 102 Months Ended 120 Months Ended
Aug. 31, 2026
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Bloomberg Municipal Bond Index[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent   4.25% 0.80% 2.31% [1] 2.34%
Bloomberg Municipal High Yield Bond Index[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent   2.46% 2.18% 4.04% [1] 4.35%
Bloomberg Municipal Bond Index (50%)/Bloomberg Municipal High Yield Bond Index (50%)[Member]          
Prospectus [Line Items]          
Average Annual Return, Percent   3.35% 1.50% 3.19% [1] 3.36%
A          
Prospectus [Line Items]          
Average Annual Return, Percent   (0.29%) 0.39%   2.45%
C          
Prospectus [Line Items]          
Average Annual Return, Percent   1.21% 0.25%   2.00%
Z          
Prospectus [Line Items]          
Average Annual Return, Percent   3.30% 1.29%   3.02%
Z | After Taxes on Distributions          
Prospectus [Line Items]          
Average Annual Return, Percent   3.18% 1.25%   3.00%
Z | After Taxes on Distributions and Sales          
Prospectus [Line Items]          
Average Annual Return, Percent   3.56% 1.79%   3.20%
R6          
Prospectus [Line Items]          
Average Annual Return, Percent   3.39% 1.38% 2.95%
Performance Inception Date Jun. 27, 2017        
[1] Since Inception returns for the Indexes are measured from the month-end closest to the inception date for Class R6 shares.