Shareholder Report, Holdings (Details)	Nov. 30, 2024
C000015134 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	5.20%	[1]
C000015134 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	16.00%	[1]
C000015134 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	17.30%	[1]
C000015134 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	33.20%	[1]
C000015134 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	19.60%	[1]
C000015134 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	8.70%	[1]
C000015134 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000137678 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	5.20%	[2]
C000137678 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	16.00%	[2]
C000137678 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	17.30%	[2]
C000137678 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	33.20%	[2]
C000137678 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	19.60%	[2]
C000137678 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	8.70%	[2]
C000137678 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015135 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	5.20%	[3]
C000015135 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	16.00%	[3]
C000015135 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	17.30%	[3]
C000015135 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	33.20%	[3]
C000015135 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	19.60%	[3]
C000015135 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	8.70%	[3]
C000015135 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015136 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	6.30%	[4]
C000015136 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	14.10%	[4]
C000015136 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	18.50%	[4]
C000015136 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	31.30%	[4]
C000015136 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	25.30%	[4]
C000015136 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	4.50%	[4]
C000015136 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000137679 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	6.30%	[5]
C000137679 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	14.10%	[5]
C000137679 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	18.50%	[5]
C000137679 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	31.30%	[5]
C000137679 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	25.30%	[5]
C000137679 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	4.50%	[5]
C000137679 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015138 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	6.30%	[6]
C000015138 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	14.10%	[6]
C000015138 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	18.50%	[6]
C000015138 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	31.30%	[6]
C000015138 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	25.30%	[6]
C000015138 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	4.50%	[6]
C000015138 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015139 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	1.20%	[7]
C000015139 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	7.30%	[7]
C000015139 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	2.20%	[7]
C000015139 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	66.30%	[7]
C000015139 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	20.70%	[7]
C000015139 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	2.30%	[7]
C000015139 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000137680 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	1.20%	[8]
C000137680 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	7.30%	[8]
C000137680 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	2.20%	[8]
C000137680 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	66.30%	[8]
C000137680 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	20.70%	[8]
C000137680 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	2.30%	[8]
C000137680 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015141 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	1.20%	[9]
C000015141 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	7.30%	[9]
C000015141 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	2.20%	[9]
C000015141 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	66.30%	[9]
C000015141 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	20.70%	[9]
C000015141 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	2.30%	[9]
C000015141 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015145 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	2.70%	[10]
C000015145 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	7.40%	[10]
C000015145 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	3.30%	[10]
C000015145 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	66.10%	[10]
C000015145 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	11.90%	[10]
C000015145 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	8.60%	[10]
C000015145 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000137681 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	2.70%	[11]
C000137681 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	7.40%	[11]
C000137681 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	3.30%	[11]
C000137681 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	66.10%	[11]
C000137681 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	11.90%	[11]
C000137681 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	8.60%	[11]
C000137681 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%
C000015146 [Member] | BB or Lower [Member]
Holdings [Line Items]
Percent of Total Investments	2.70%	[12]
C000015146 [Member] | N R not rated [Member]
Holdings [Line Items]
Percent of Total Investments	7.40%	[12]
C000015146 [Member] | Standard & Poor's, AAA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	3.30%	[12]
C000015146 [Member] | Standard & Poor's, AA Rating [Member]
Holdings [Line Items]
Percent of Total Investments	66.10%	[12]
C000015146 [Member] | Standard & Poor's, A Rating [Member]
Holdings [Line Items]
Percent of Total Investments	11.90%	[12]
C000015146 [Member] | Standard & Poor's, BBB Rating [Member]
Holdings [Line Items]
Percent of Total Investments	8.60%	[12]
C000015146 [Member] | Municipal Bonds [Member]
Holdings [Line Items]
Percent of Total Investments	100.00%

[1] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[2] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[3] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[4] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[5] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[6] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[7] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[8] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[9] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[10] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[11] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.

[12] The ratings disclosed are the highest rating given by one of the following national rating agencies: Standard & Poor’s (S&P), Moody’s Investors Service, Inc. (Moody’s) or Fitch, Inc (Fitch). This treatment of split-rated securities may differ from that used for other purposes, such as for Fund investment policies. Credit ratings are subject to change. AAA, AA, A, and BBB are investment grade ratings; BB, B, CCC, CC, C and D are below-investment grade ratings. Holdings designated N/R are not rated by these national ratings agencies.