Shareholder Report, Line Graph (Details) - USD ($) |
6 Months Ended | 12 Months Ended | 24 Months Ended | 36 Months Ended | 48 Months Ended | 60 Months Ended | 72 Months Ended | 84 Months Ended | 96 Months Ended | 108 Months Ended | 120 Months Ended | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Aug. 31, 2016 |
Aug. 31, 2026 |
Aug. 31, 2017 |
Aug. 31, 2018 |
Aug. 31, 2019 |
Aug. 31, 2020 |
Aug. 31, 2021 |
Aug. 31, 2022 |
Aug. 31, 2023 |
Aug. 31, 2024 |
Aug. 31, 2025 |
Aug. 31, 2026 |
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| C000029067 | ||||||||||||
| Account Value [Line Items] | ||||||||||||
| Line Graph and Table Measure Name | CM Advisors Fixed Income Fund | |||||||||||
| Accumulated Value | $ 10,000 | $ 10,321 | $ 10,357 | $ 10,386 | $ 10,580 | $ 10,822 | $ 10,625 | $ 10,948 | $ 12,201 | $ 13,119 | $ 13,529 | |
| Bloomberg U.S. Aggregate Bond Index | ||||||||||||
| Account Value [Line Items] | ||||||||||||
| Line Graph and Table Measure Name | Bloomberg U.S. Aggregate Bond Index | |||||||||||
| Accumulated Value | $ 10,000 | $ 10,049 | $ 9,944 | $ 10,955 | $ 11,664 | $ 11,655 | $ 10,313 | $ 10,189 | $ 10,933 | $ 11,276 | $ 11,489 |