S000018524 [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 1-5 Year Blend Municipal Bond Index (reflects no deduction for fees, expenses, or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.35% | 1.31% | 1.73% |
| LIMITED TERM TAX-EXEMPT FUND | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.05% | 1.21% | 1.58% |
| LIMITED TERM TAX-EXEMPT FUND | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 4.04% | 1.12% | 1.45% |
| LIMITED TERM TAX-EXEMPT FUND | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 3.45% | 1.30% | 1.53% |