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 |
|
| C000009551 [Member] | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Selected American Shares (Class S) | |||
| Average Annual Return, Percent | 26.15% | 10.90% | 13.53% | |
| C000009552 [Member] | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Selected American Shares (Class D) | |||
| Average Annual Return, Percent | 26.56% | 11.26% | 13.89% | |
| 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% | |
| Russell 1000 Value Index [Member] | ||||
| Average Annual Return [Line Items] | ||||
| Line Graph and Table Measure Name | Russell 1000 Value Index | |||
| Average Annual Return, Percent | 27.12% | 11.17% | 11.52% |