S000005559 [Member] Average Annual Total Returns

12 Months Ended

60 Months Ended

120 Months Ended

131 Months Ended

329 Months Ended

438 Months Ended

Dec. 31, 2024

Dec. 31, 2024

Dec. 31, 2024

Dec. 31, 2024

Dec. 31, 2024

Dec. 31, 2024

S&P Municipal Bond Index (reflects no deduction for fees, expenses or taxes)

Prospectus [Line Items]

Average Annual Return, Percent

^[1]

1.90%

1.20%

2.34%

S&P Municipal Bond Minnesota Index (reflects no deduction for fees, expenses or taxes)

Prospectus [Line Items]

Average Annual Return, Percent

^[2]

1.77%

1.01%

2.11%

Lipper Minnesota Municipal Debt Funds Classification Average (reflects no deduction for taxes or sales loads)

Prospectus [Line Items]

Average Annual Return, Percent

^[3]

2.04%

0.45%

1.62%

Class A

Prospectus [Line Items]

Average Annual Return, Percent

(1.74%)

(0.28%)

1.62%

Performance Inception Date

Jul. 11, 1988

Class A | After Taxes on Distributions

Prospectus [Line Items]

Average Annual Return, Percent

(1.74%)

(0.28%)

1.61%

Performance Inception Date

Jul. 11, 1988

Class A | After Taxes on Distributions and Sales

Prospectus [Line Items]

Average Annual Return, Percent

0.35%

0.40%

1.91%

Performance Inception Date

Jul. 11, 1988

Class I

Prospectus [Line Items]

Average Annual Return, Percent

2.87%

0.77%

2.26%

Performance Inception Date

Aug. 01, 1997

Class C

Prospectus [Line Items]

Average Annual Return, Percent

1.76%

(0.24%)

1.40%

Performance Inception Date

Feb. 10, 2014

[1]	An index designed to measure the performance of the tax-exempt U.S. municipal bond market.
[2]	An index designed to measure the performance of the tax-exempt Minnesota municipal bond market.
[3]	Represents the average annualized total return for all reporting funds in the Lipper Minnesota Municipal Debt Funds Classification.