Shareholder Report, Average Annual Return (Details)
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12 Months Ended |
60 Months Ended |
120 Months Ended |
Aug. 31, 2026 |
Aug. 31, 2026 |
Aug. 31, 2026 |
| C000074146 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Fund (Institutional Class) – including sales charge
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| Average Annual Return, Percent |
6.03%
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(0.29%)
|
2.20%
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| C000006387 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Fund (Class C) – including sales charge
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| Average Annual Return, Percent |
3.99%
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(1.26%)
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1.19%
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| C000006385 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Fund (Class A) – including sales charge
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| Average Annual Return, Percent |
1.03%
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(1.44%)
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1.47%
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| C000006388 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Intermediate Fund (Class A) – including sales charge
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| Average Annual Return, Percent |
1.38%
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(0.61%)
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1.37%
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| C000006390 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Intermediate Fund (Class C) – including sales charge
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| Average Annual Return, Percent |
2.48%
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(0.81%)
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0.84%
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| C000074147 [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Intermediate Fund (Institutional Class) – including sales charge
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| Average Annual Return, Percent |
4.52%
|
0.19%
|
1.86%
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| Without Sales Load [Member] | C000074146 [Member] |
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| Average Annual Return [Line Items] |
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|
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Fund (Institutional Class) – excluding sales charge
|
|
|
| Average Annual Return, Percent |
6.03%
|
(0.29%)
|
2.20%
|
| Without Sales Load [Member] | C000006387 [Member] |
|
|
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| Average Annual Return [Line Items] |
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|
|
| Line Graph and Table Measure Name |
Nomura Tax-Free USA Fund (Class C) – excluding sales charge
|
|
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| Average Annual Return, Percent |
4.99%
|
(1.26%)
|
1.19%
|
| Without Sales Load [Member] | C000006385 [Member] |
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| Average Annual Return [Line Items] |
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|
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Fund (Class A) – excluding sales charge
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| Average Annual Return, Percent |
5.78%
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(0.53%)
|
1.94%
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| Without Sales Load [Member] | C000006388 [Member] |
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| Average Annual Return [Line Items] |
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|
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Intermediate Fund (Class A) – excluding sales charge
|
|
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| Average Annual Return, Percent |
4.26%
|
(0.05%)
|
1.66%
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| Without Sales Load [Member] | C000006390 [Member] |
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| Average Annual Return [Line Items] |
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|
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| Line Graph and Table Measure Name |
Nomura Tax-Free USA Intermediate Fund (Class C) – excluding sales charge
|
|
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| Average Annual Return, Percent |
3.48%
|
(0.81%)
|
0.84%
|
| Without Sales Load [Member] | C000074147 [Member] |
|
|
|
| Average Annual Return [Line Items] |
|
|
|
| Line Graph and Table Measure Name |
Nomura Tax-Free USA Intermediate Fund (Institutional Class) – excluding sales charge
|
|
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| Average Annual Return, Percent |
4.52%
|
0.19%
|
1.86%
|
| Bloomberg Municipal Bond Index [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Bloomberg Municipal Bond Index
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| Average Annual Return, Percent |
4.12%
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0.54%
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1.91%
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| Bloomberg 3 15 Year Blend Municipal Bond Index [Member] |
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| Average Annual Return [Line Items] |
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| Line Graph and Table Measure Name |
Bloomberg 3–15 Year Blend Municipal Bond Index
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| Average Annual Return, Percent |
2.93%
|
0.83%
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1.93%
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