v3.26.1
S000010027 [Member] Average Annual Total Returns
 12 Months Ended 60 Months Ended 120 Months Ended
Dec. 31, 2025
Dec. 31, 2025
Dec. 31, 2025
Russell 1000® Index      
Prospectus [Line Items]      
Average Annual Return, Percent [1] 17.37% 13.59% 14.59%
Russell Midcap® Growth Index      
Prospectus [Line Items]      
Average Annual Return, Percent [2] 8.66% 6.65% 12.49%
Shares      
Prospectus [Line Items]      
Average Annual Return, Percent 1.51% 4.91% 10.70%
Shares | After Taxes on Distributions      
Prospectus [Line Items]      
Average Annual Return, Percent (3.23%) 2.02% 8.29%
Shares | After Taxes on Distributions and Sales      
Prospectus [Line Items]      
Average Annual Return, Percent 4.40% 3.57% 8.36%
[1] The Russell 1000® Index is an unmanaged market capitalization weighted index of the 1000 largest U.S. companies. The Index figures do not reflect any deduction for fees, taxes or expenses.
[2] The Russell Midcap® Growth Index, an unmanaged index, measures the performance of the mid‑cap growth segment of the U.S. equity universe. It includes those Russell Midcap Index companies with higher price‑to‑book ratios and higher forecasted growth values. The Index figures do not reflect any deduction for fees, taxes or expenses.