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 |
| C000001667 [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 |
6.94%
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1.23%
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2.05%
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| C000001664 [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 |
2.20%
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0.16%
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1.41%
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| C000001668 [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 |
2.75%
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(0.66%)
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1.19%
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| C000001671 [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 |
7.50%
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0.39%
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1.84%
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| C000001675 [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 |
6.92%
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0.07%
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1.69%
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| C000001672 [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 |
2.19%
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(0.98%)
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1.05%
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| C000001676 [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 |
2.45%
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(0.07%)
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1.64%
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| C000001679 [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 |
7.21%
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1.00%
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2.29%
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| C000001683 [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 |
6.50%
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0.67%
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1.94%
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| C000001680 [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 |
1.80%
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(0.38%)
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1.31%
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| C000001684 [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 |
3.49%
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0.11%
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1.65%
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| C000001687 [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 |
8.17%
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1.16%
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2.27%
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| Without Sales Load [Member] | C000137705 [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 |
5.90%
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0.22%
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1.19%
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| Without Sales Load [Member] | C000001664 [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 |
6.71%
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1.03%
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1.85%
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| Without Sales Load [Member] | C000001668 [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 |
7.29%
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0.19%
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1.63%
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| Without Sales Load [Member] | C000137706 [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 |
6.44%
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(0.61%)
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0.98%
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| Without Sales Load [Member] | C000137707 [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 |
5.87%
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(0.92%)
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0.83%
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| Without Sales Load [Member] | C000001672 [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 |
6.71%
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(0.13%)
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1.48%
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| Without Sales Load [Member] | C000001676 [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 |
6.90%
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0.79%
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2.08%
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| Without Sales Load [Member] | C000137708 [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 |
6.06%
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(0.02%)
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1.43%
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| Without Sales Load [Member] | C000137709 [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 |
5.53%
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(0.34%)
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1.08%
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| Without Sales Load [Member] | C000001680 [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 |
6.28%
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0.47%
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1.74%
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| Without Sales Load [Member] | C000001684 [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 |
7.98%
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0.98%
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2.08%
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| Without Sales Load [Member] | C000137710 [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 |
7.12%
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0.17%
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1.44%
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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 Kansas 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 Kansas Index
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| Average Annual Return, Percent |
6.21%
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1.51%
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2.30%
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| S And P Municipal Bond Kentucky 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 Kentucky Index
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| Average Annual Return, Percent |
6.71%
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1.50%
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2.51%
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| S And P Municipal Bond Michigan 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 Michigan Index
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| Average Annual Return, Percent |
6.36%
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1.12%
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2.47%
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| S And P Municipal Bond Missouri 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 Missouri Index
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| Average Annual Return, Percent |
7.30%
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1.37%
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2.43%
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| Lipper Ohio 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 Ohio Municipal Debt Funds Classification Average
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| Average Annual Return, Percent |
6.75%
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0.45%
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1.70%
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| S And P Municipal Bond Ohio 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 Ohio Index
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| Average Annual Return, Percent |
5.96%
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0.90%
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2.46%
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| S And P Municipal Bond Wisconsin 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 Wisconsin Index
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| Average Annual Return, Percent |
6.74%
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1.45%
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2.42%
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