Shareholder Report, Average Annual Return (Details)
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12 Months Ended |
60 Months Ended |
120 Months Ended |
May 31, 2025 |
May 31, 2025 |
May 31, 2025 |
| C000001556 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A Shares at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
(3.59%)
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(1.42%)
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0.83%
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| C000001559 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
0.83%
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(0.38%)
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1.47%
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| C000001551 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
0.91%
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(0.25%)
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1.37%
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| C000001548 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A Shares at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
(3.58%)
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(1.32%)
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0.73%
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| C000001552 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A Shares at maximum sales charge (Offering Price)
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| Average Annual Return, Percent |
(4.78%)
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(0.02%)
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1.49%
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| C000001555 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class I Shares at NAV
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| Average Annual Return, Percent |
(0.41%)
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1.07%
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2.13%
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| Without Sales Load [Member] | C000001556 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
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| Average Annual Return, Percent |
0.59%
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(0.57%)
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1.27%
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| Without Sales Load [Member] | C000137685 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class C Shares at NAV (excluding maximum sales charge)
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| Average Annual Return, Percent |
(0.19%)
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(1.37%)
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0.62%
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| Without Sales Load [Member] | C000001548 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
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| Average Annual Return, Percent |
0.62%
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(0.47%)
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1.16%
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| Without Sales Load [Member] | C000137683 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class C Shares at NAV (excluding maximum sales charge)
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| Average Annual Return, Percent |
(0.12%)
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(1.25%)
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0.52%
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| Without Sales Load [Member] | C000001552 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class A Shares at NAV (excluding maximum sales charge)
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| Average Annual Return, Percent |
(0.64%)
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0.85%
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1.92%
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| Without Sales Load [Member] | C000137684 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Class C Shares at NAV (excluding maximum sales charge)
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| Average Annual Return, Percent |
(1.43%)
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0.06%
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1.27%
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| S And P Municipal Bond Index [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
S&P Municipal Bond Index
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| Average Annual Return, Percent |
2.44%
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0.78%
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2.22%
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| Lipper Other States Municipal Debt Funds Classification Average [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Lipper Other States Municipal Debt Funds Classification Average
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| Average Annual Return, Percent |
0.90%
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(0.12%)
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1.32%
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| S And P Municipal Bond North Carolina Index [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
S&P Municipal Bond North Carolina Index
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| Average Annual Return, Percent |
2.99%
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0.38%
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1.83%
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| S And P Municipal Bond Louisiana Index [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
S&P Municipal Bond Louisiana Index
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| Average Annual Return, Percent |
2.50%
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1.35%
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2.35%
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| S And P Municipal Bond Georgia Index [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
S&P Municipal Bond Georgia Index
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| Average Annual Return, Percent |
3.16%
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0.78%
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2.03%
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