S000010792 [Member] Average Annual Total Returns	12 Months Ended	15 Months Ended	60 Months Ended	120 Months Ended	158 Months Ended	198 Months Ended	239 Months Ended	289 Months Ended
S000010792 [Member] Average Annual Total Returns	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025	Dec. 31, 2025
Russell Midcap® Value Index (reflects no deductions for fees, expenses or taxes)
Prospectus [Line Items]
Average Annual Return, Percent	11.05%		9.83%	9.78%
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)
Prospectus [Line Items]
Average Annual Return, Percent	17.15%		13.15%	14.29%
C000122577 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	13.95%		11.43%	10.59%
Performance Inception Date					Nov. 08, 2012
C000253704 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	13.90%		11.13%	10.23%
Performance Inception Date		Oct. 02, 2024
C000029850 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	7.06%		9.74%	9.54%
Performance Inception Date								Nov. 20, 2001
C000029850 [Member] \| After Taxes on Distributions
Prospectus [Line Items]
Average Annual Return, Percent	5.41%		8.19%	7.20%
Performance Inception Date								Nov. 20, 2001
C000029850 [Member] \| After Taxes on Distributions and Sales
Prospectus [Line Items]
Average Annual Return, Percent	5.25%		7.44%	7.00%
Performance Inception Date								Nov. 20, 2001
C000029852 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	11.67%		10.20%	9.37%
Performance Inception Date								Nov. 20, 2001
C000029853 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	13.26%		10.76%	9.92%
Performance Inception Date							Jan. 23, 2006
C000029854 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	13.84%		11.32%	10.47%
Performance Inception Date								Nov. 20, 2001
C000079026 [Member]
Prospectus [Line Items]
Average Annual Return, Percent	13.99%		11.47%	10.63%
Performance Inception Date						Jul. 15, 2009