S000000853 [Member] Average Annual Total Returns |
12 Months Ended | 60 Months Ended | 120 Months Ended |
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2025 |
Dec. 31, 2025 |
|
| Russell Midcap® Index (reflects no deduction for fees, expenses or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 10.60% | 8.67% | 11.01% |
| Russell 1000® Index (reflects no deduction for fees, expenses or taxes) | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 17.37% | 13.59% | 14.59% |
| Investor Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 12.85% | 5.01% | 9.01% |
| Investor Shares | After Taxes on Distributions | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 10.11% | 3.34% | 7.69% |
| Investor Shares | After Taxes on Distributions and Sales | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 9.20% | 3.62% | 7.04% |
| Institutional Shares | |||
| Prospectus [Line Items] | |||
| Average Annual Return, Percent | 13.08% | 5.22% | 9.24% |