Shareholder Report, Average Annual Return (Details)
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12 Months Ended |
60 Months Ended |
120 Months Ended |
May 31, 2026 |
May 31, 2026 |
May 31, 2026 |
| C000001477 [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 |
7.27%
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0.63%
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2.06%
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| C000001474 [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 |
2.61%
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(0.42%)
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1.43%
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| C000001478 [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 |
2.06%
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(0.42%)
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1.52%
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| C000001481 [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 |
6.78%
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0.63%
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2.14%
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| C000001489 [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 |
7.75%
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0.81%
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2.14%
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| C000001486 [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 |
3.00%
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(0.24%)
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1.51%
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| C000001490 [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 |
2.83%
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(0.14%)
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1.43%
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| C000001493 [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 |
7.60%
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0.91%
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2.07%
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| C000001497 [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 |
8.33%
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0.81%
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2.17%
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| C000001494 [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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(0.24%)
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1.53%
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| C000001498 [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 |
2.71%
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(0.45%)
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1.39%
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| C000001501 [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 |
7.49%
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0.62%
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2.02%
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| Without Sales Load [Member] | C000137693 [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 |
6.31%
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(0.36%)
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1.23%
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| Without Sales Load [Member] | C000001474 [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 |
7.13%
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0.44%
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1.87%
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| Without Sales Load [Member] | C000001478 [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 |
6.58%
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0.44%
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1.95%
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| Without Sales Load [Member] | C000137694 [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 |
5.76%
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(0.37%)
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1.29%
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| Without Sales Load [Member] | C000137695 [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 |
6.72%
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(0.17%)
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1.30%
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| Without Sales Load [Member] | C000001486 [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 |
7.55%
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0.63%
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1.95%
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| Without Sales Load [Member] | C000001490 [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 |
7.36%
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0.72%
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1.87%
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| Without Sales Load [Member] | C000137696 [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 |
6.55%
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(0.06%)
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1.23%
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| Without Sales Load [Member] | C000137697 [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 |
7.26%
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(0.18%)
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1.32%
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| Without Sales Load [Member] | C000001494 [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 |
8.12%
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0.62%
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1.97%
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| Without Sales Load [Member] | C000001498 [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 |
7.18%
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0.41%
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1.82%
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| Without Sales Load [Member] | C000137698 [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 |
6.33%
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(0.39%)
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1.17%
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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 |
6.57%
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1.14%
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2.30%
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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 |
7.08%
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0.43%
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1.54%
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| S And P Municipal Bond Arizona 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 Arizona Index
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| Average Annual Return, Percent |
6.51%
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1.26%
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2.25%
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| S And P Municipal Bond Colorado 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 Colorado Index
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| Average Annual Return, Percent |
7.30%
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1.47%
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2.69%
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| Lipper Maryland 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 Maryland Municipal Debt Funds Classification Average
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| Average Annual Return, Percent |
7.16%
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0.69%
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1.74%
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| S And P Municipal Bond Maryland 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 Maryland Index
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| Average Annual Return, Percent |
6.10%
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1.06%
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2.02%
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| S And P Municipal Bond New Mexico 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 New Mexico Index
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| Average Annual Return, Percent |
5.64%
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1.33%
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2.05%
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| Lipper Pennsylvania 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 Pennsylvania Municipal Debt Funds Classification Average
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| Average Annual Return, Percent |
7.19%
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0.56%
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1.93%
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| S And P Municipal Bond Pennsylvania 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 Pennsylvania Index
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| Average Annual Return, Percent |
6.74%
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1.15%
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2.42%
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| S And P Municipal Bond Virginia 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 Virginia Index
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| Average Annual Return, Percent |
6.53%
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1.10%
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2.15%
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| Lipper Virginia 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 Virginia Municipal Debt Funds Classification Average
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| Average Annual Return, Percent |
7.18%
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0.39%
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1.52%
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