S000001258 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Bloomberg U.S. Municipal Bond Index (reflects no deduction for fees, expenses, or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.25% | 0.80% | 2.34% |
| Bloomberg Municipal 1 – 15 Year Index (reflects no deduction for fees, expenses, or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 5.18% | 1.16% | 2.27% |
| INTERMEDIATE TAX-EXEMPT FUND | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.83% | 0.67% | 1.90% |
| INTERMEDIATE TAX-EXEMPT FUND | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.80% | 0.61% | 1.76% |
| INTERMEDIATE TAX-EXEMPT FUND | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.16% | 1.06% | 1.93% |