v3.25.2
S000012102 [Member] Average Annual Total Returns
 3 Months Ended 12 Months Ended 60 Months Ended 120 Months Ended 146 Months Ended 171 Months Ended 186 Months Ended 348 Months Ended 353 Months Ended 461 Months Ended
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Dec. 31, 2024
Russell 2000® Value Index (reflects no deductions for fees, expenses or taxes)                    
Prospectus [Line Items]                    
Average Annual Return, Percent   8.05% 7.29% 7.14%            
Russell 3000® Index (reflects no deductions for fees, expenses or taxes)                    
Prospectus [Line Items]                    
Average Annual Return, Percent   23.81% 13.86% 12.55%            
C000122683 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   9.02% 11.17% 9.20%            
Performance Inception Date         Nov. 08, 2012          
C000255093 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   8.71% 10.80% 8.81%            
Performance Inception Date Oct. 02, 2024                  
C000033005 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   2.39% 9.48% 8.16%            
Performance Inception Date                   Jul. 25, 1986
C000033005 [Member] | After Taxes on Distributions                    
Prospectus [Line Items]                    
Average Annual Return, Percent   0.78% 7.72% 6.10%            
Performance Inception Date                   Jul. 25, 1986
C000033005 [Member] | After Taxes on Distributions and Sales                    
Prospectus [Line Items]                    
Average Annual Return, Percent   2.47% 7.24% 6.04%            
Performance Inception Date                   Jul. 25, 1986
C000033007 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   6.88% 9.96% 7.98%            
Performance Inception Date               Jan. 15, 1996    
C000033008 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   8.91% 11.06% 9.07%            
Performance Inception Date                 Jul. 31, 1995  
C000078991 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   9.07% 11.23% 9.26%            
Performance Inception Date             Jul. 15, 2009      
C000094701 [Member]                    
Prospectus [Line Items]                    
Average Annual Return, Percent   8.37% 10.51% 8.53%            
Performance Inception Date           Sep. 27, 2010