Shareholder Report, Average Annual Return (Details) |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
May 31, 2025 |
May 31, 2025 |
May 31, 2025 |
|
| Without Sales Load [Member] | C000126665 | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 2.50% | (2.43%) | 2.38% |
| Bloomberg U.S. Aggregate Bond Index | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 5.46% | (0.90%) | 1.49% |
| Bloomberg U.S. Long Credit Bond Index | |||
| Average Annual Return [Line Items] | |||
| Average Annual Return, Percent | 2.62% | (2.42%) | 2.27% |