Shareholder Report, Holdings (Details)
|
Jul. 31, 2025 |
Kansas Municipal Fund | Class A [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
0.36%
|
[1] |
Kansas Municipal Fund | Class A [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
74.75%
|
[1] |
Kansas Municipal Fund | Class A [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.17%
|
[1] |
Kansas Municipal Fund | Class A [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.07%
|
[1] |
Kansas Municipal Fund | Class A [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.65%
|
[1] |
Kansas Municipal Fund | Class A [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
48.90%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.20%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.10%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.00%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
8.70%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.40%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.30%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Pre-Refunded [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.40%
|
[2] |
Kansas Municipal Fund | Class A [Member] | Transportation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.00%
|
[2] |
Kansas Municipal Fund | Class I [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
0.36%
|
[3] |
Kansas Municipal Fund | Class I [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
74.75%
|
|
Kansas Municipal Fund | Class I [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.17%
|
|
Kansas Municipal Fund | Class I [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.07%
|
|
Kansas Municipal Fund | Class I [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.65%
|
[3] |
Kansas Municipal Fund | Class I [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
48.90%
|
[4] |
Kansas Municipal Fund | Class I [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.20%
|
|
Kansas Municipal Fund | Class I [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.10%
|
|
Kansas Municipal Fund | Class I [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.00%
|
|
Kansas Municipal Fund | Class I [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
8.70%
|
[4] |
Kansas Municipal Fund | Class I [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.40%
|
|
Kansas Municipal Fund | Class I [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.30%
|
[4] |
Kansas Municipal Fund | Class I [Member] | Pre-Refunded [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.40%
|
[4] |
Kansas Municipal Fund | Class I [Member] | Transportation Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.00%
|
|
Maine Municipal Fund | Class A [Member] | AAA [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
8.67%
|
[5] |
Maine Municipal Fund | Class A [Member] | AA [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
84.27%
|
[5] |
Maine Municipal Fund | Class A [Member] | A [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
7.06%
|
[5] |
Maine Municipal Fund | Class A [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
27.60%
|
[6] |
Maine Municipal Fund | Class A [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
17.50%
|
[6] |
Maine Municipal Fund | Class A [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
22.00%
|
[6] |
Maine Municipal Fund | Class A [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
17.30%
|
[6] |
Maine Municipal Fund | Class A [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.40%
|
[6] |
Maine Municipal Fund | Class A [Member] | Transportation Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.20%
|
[6] |
Maine Municipal Fund | Class I [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
8.67%
|
[7] |
Maine Municipal Fund | Class I [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
84.27%
|
[7] |
Maine Municipal Fund | Class I [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
7.06%
|
[7] |
Maine Municipal Fund | Class I [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
27.60%
|
[8] |
Maine Municipal Fund | Class I [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
17.50%
|
[8] |
Maine Municipal Fund | Class I [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
22.00%
|
[8] |
Maine Municipal Fund | Class I [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
17.30%
|
[8] |
Maine Municipal Fund | Class I [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.40%
|
[8] |
Maine Municipal Fund | Class I [Member] | Transportation Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.20%
|
[8] |
Nebraska Municipal Fund | Class A [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.09%
|
[9] |
Nebraska Municipal Fund | Class A [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
58.55%
|
[9] |
Nebraska Municipal Fund | Class A [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.09%
|
[9] |
Nebraska Municipal Fund | Class A [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
19.27%
|
[9] |
Nebraska Municipal Fund | Class A [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
58.00%
|
[10] |
Nebraska Municipal Fund | Class A [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.10%
|
[10] |
Nebraska Municipal Fund | Class A [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.50%
|
[10] |
Nebraska Municipal Fund | Class A [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.00%
|
[10] |
Nebraska Municipal Fund | Class A [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.80%
|
[10] |
Nebraska Municipal Fund | Class A [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.60%
|
[10] |
Nebraska Municipal Fund | Class I [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.09%
|
[11] |
Nebraska Municipal Fund | Class I [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
58.55%
|
[11] |
Nebraska Municipal Fund | Class I [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.09%
|
[11] |
Nebraska Municipal Fund | Class I [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
19.27%
|
[11] |
Nebraska Municipal Fund | Class I [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
58.00%
|
[12] |
Nebraska Municipal Fund | Class I [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.10%
|
[12] |
Nebraska Municipal Fund | Class I [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.50%
|
[12] |
Nebraska Municipal Fund | Class I [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.00%
|
[12] |
Nebraska Municipal Fund | Class I [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.80%
|
[12] |
Nebraska Municipal Fund | Class I [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.60%
|
[12] |
Oklahoma Municipal Fund | Class A [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.78%
|
[13] |
Oklahoma Municipal Fund | Class A [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
24.16%
|
[13] |
Oklahoma Municipal Fund | Class A [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
25.75%
|
[13] |
Oklahoma Municipal Fund | Class A [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
16.30%
|
[13] |
Oklahoma Municipal Fund | Class A [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
22.01%
|
|
Oklahoma Municipal Fund | Class A [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.00%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
68.50%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.40%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
4.90%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.60%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
1.10%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.50%
|
[14] |
Oklahoma Municipal Fund | Class A [Member] | Transportation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.00%
|
[14] |
Oklahoma Municipal Fund | Class I [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.78%
|
[15] |
Oklahoma Municipal Fund | Class I [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
24.16%
|
[15] |
Oklahoma Municipal Fund | Class I [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
25.75%
|
[15] |
Oklahoma Municipal Fund | Class I [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
16.30%
|
[15] |
Oklahoma Municipal Fund | Class I [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
22.01%
|
[15] |
Oklahoma Municipal Fund | Class I [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.00%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
68.50%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
3.40%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
4.90%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.60%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
1.10%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.50%
|
[16] |
Oklahoma Municipal Fund | Class I [Member] | Transportation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.00%
|
[16] |
Viking Tax-Free Fund for Montana | Class A [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
72.57%
|
[17] |
Viking Tax-Free Fund for Montana | Class A [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
19.54%
|
[17] |
Viking Tax-Free Fund for Montana | Class A [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
0.62%
|
[17] |
Viking Tax-Free Fund for Montana | Class A [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
7.27%
|
[17] |
Viking Tax-Free Fund for Montana | Class A [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
47.10%
|
[18] |
Viking Tax-Free Fund for Montana | Class A [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
13.60%
|
[18] |
Viking Tax-Free Fund for Montana | Class A [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.50%
|
[18] |
Viking Tax-Free Fund for Montana | Class A [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
19.30%
|
[18] |
Viking Tax-Free Fund for Montana | Class A [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.50%
|
[18] |
Viking Tax-Free Fund for Montana | Class A [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.40%
|
[18] |
Viking Tax-Free Fund for Montana | Class A [Member] | Transportation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
1.60%
|
[18] |
Viking Tax-Free Fund for Montana | Class I [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
72.57%
|
[19] |
Viking Tax-Free Fund for Montana | Class I [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
19.54%
|
[19] |
Viking Tax-Free Fund for Montana | Class I [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
0.62%
|
[19] |
Viking Tax-Free Fund for Montana | Class I [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
7.27%
|
[19] |
Viking Tax-Free Fund for Montana | Class I [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
47.10%
|
[20] |
Viking Tax-Free Fund for Montana | Class I [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
13.60%
|
[20] |
Viking Tax-Free Fund for Montana | Class I [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.50%
|
[20] |
Viking Tax-Free Fund for Montana | Class I [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
19.30%
|
[20] |
Viking Tax-Free Fund for Montana | Class I [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.50%
|
[20] |
Viking Tax-Free Fund for Montana | Class I [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
2.40%
|
[20] |
Viking Tax-Free Fund for Montana | Class I [Member] | Transportation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
1.60%
|
[20] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
1.92%
|
[21] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
52.02%
|
[21] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.85%
|
[21] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.91%
|
[21] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
24.30%
|
[21] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
35.50%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.40%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.40%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.40%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
14.90%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.50%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class A [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.90%
|
[22] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Standard & Poor's, AAA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
1.92%
|
[23] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Standard & Poor's, AA Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
52.02%
|
[23] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Standard & Poor's, A Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.85%
|
[23] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Standard & Poor's, BBB Rating [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.91%
|
[23] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | NR [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
24.30%
|
[23] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | General Obligation [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
35.50%
|
[24] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Other Revenue [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
5.40%
|
[24] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Utilities Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
11.40%
|
[24] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Education [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
10.40%
|
[24] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Housing [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
14.90%
|
[24] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Healthcare Sector [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
12.50%
|
[24] |
Viking Tax-Free Fund for North Dakota | Class I [Member] | Cash Equivalents and Other [Member] |
|
|
Holdings [Line Items] |
|
|
Percent of Net Asset Value |
9.90%
|
[24] |
|
|