Mid Cap Strategic Growth Fund Performance Management - Mid Cap Strategic Growth Fund |
May 31, 2026 |
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| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | <span style="color:#000000;font-family:Arial;font-size:12pt;font-weight:bold;">Performance Information</span> |
| Performance Narrative [Text Block] | The below bar chart and table illustrate the risks of investing in the Fund by showing changes in the Fund’s performance from calendar year to calendar year and comparing the Fund’s average annual returns to those of the Russell 3000® Index (a broad-based securities market index) and the Russell Midcap® Growth Index, which is relevant to the Fund because it has characteristics similar to the Fund’s investment strategies. Fees and expenses incurred at the contract level are not reflected in the bar chart or table. If these amounts were reflected, returns would be less than those shown. Of course, past performance of the Fund is not necessarily an indication of how the Fund will perform in the future.Janus Henderson Investors US LLC (“Janus”) assumed sub-advisory duties of the Fund effective December 7, 2015. Allianz Global Investors U.S. LLC (“AllianzGI”) served as a subadviser from March 22, 2011 through July 25, 2022. Voya Investment Management Co. LLC (“Voya IM”) assumed sub-advisory duties of the Fund from AllianzGI effective July 25, 2022. The percentage of the Fund’s assets that each subadviser manages may, at the adviser’s discretion, change from time to time. |
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:Arial;font-size:10pt;">Of course, past </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">performance of the Fund is not necessarily an indication </span><span style="font-family:Arial;font-size:10pt;">of how the Fund will perform in the future.</span> |
| Performance Information Illustrates Variability of Returns [Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0%;">The below bar chart and table illustrate the risks of investing in the Fund by showing changes in the Fund’s performance from calendar year to calendar year and comparing the Fund’s average annual returns to those of the Russell 3000</span><span style="font-family:Arial;font-size:6.5pt;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:10pt;"> Index (a broad-based securities market </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">index) and the Russell Midcap</span><span style="font-family:Arial;font-size:6.5pt;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:10pt;"> Growth Index, which is </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">relevant to the Fund because it has characteristics similar to the Fund’s investment strategies. </span> |
| Bar Chart Does Not Reflect Sales Loads [Text] | <span style="font-family:Arial;font-size:10pt;"> Fees and expenses </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">incurred at the contract level are not reflected in the bar chart or table. If these amounts were reflected, returns would be less than those shown. </span> |
| Bar Chart Closing [Text Block] | During the period shown in the bar chart:Highest Quarterly Return:June 30, 202027.28%Lowest Quarterly Return:March 31, 2020-21.73%Year to Date Most Recent Quarter:June 30, 202614.56% |
| Performance Table Heading | <span style="font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Average Annual Total Returns</span><span style="font-family:Arial;font-size:10pt;"> (For the periods ended December 31, 2025)</span> |
| None | |
| Prospectus [Line Items] | |
| Year to Date Return, Label [Optional Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Year to Date Most </span><span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Recent Quarter:</span> |
| Bar Chart, Year to Date Return | 14.56% |
| Bar Chart, Year to Date Return, Date | Jun. 30, 2026 |
| Highest Quarterly Return, Label [Optional Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Highest Quarterly </span><span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Return:</span> |
| Highest Quarterly Return | 27.28% |
| Highest Quarterly Return, Date | Jun. 30, 2020 |
| Lowest Quarterly Return, Label [Optional Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Lowest Quarterly </span><span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Return:</span> |
| Lowest Quarterly Return | (21.73%) |
| Lowest Quarterly Return, Date | Mar. 31, 2020 |