Shareholder Report, Average Annual Return (Details) |
6 Months Ended | 12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2026 |
Jun. 30, 2026 |
Jun. 30, 2026 |
|
| C000009559 [Member] | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Davis Real Estate Portfolio | |||
| Average Annual Return, Percent | 7.97% | 0.97% | 3.89% | |
| Standard & Poor's 500 Index [Member] | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | S&P 500 Index | |||
| Average Annual Return, Percent | 22.32% | 13.40% | 15.50% | |
| Wilshire U S Real Estate Securities Index [Member] | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Wilshire U.S. Real Estate Securities Index | |||
| Average Annual Return, Percent | 14.27% | 5.17% | 5.81% |