v3.26.1
S000010796 [Member] Expense Example - S000010796 [Member]
Jan. 31, 2026
USD ($)
C000029869 [Member]  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year $ 664
Expense Example, with Redemption, 3 Years 854
Expense Example, with Redemption, 5 Years 1,060
Expense Example, with Redemption, 10 Years 1,652
C000029871 [Member]  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 271
Expense Example, with Redemption, 3 Years 530
Expense Example, with Redemption, 5 Years 913
Expense Example, with Redemption, 10 Years 1,788
C000029872 [Member]  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 120
Expense Example, with Redemption, 3 Years 375
Expense Example, with Redemption, 5 Years 649
Expense Example, with Redemption, 10 Years 1,432
C000029873 [Member]  
Prospectus [Line Items]  
Expense Example, with Redemption, 1 Year 69
Expense Example, with Redemption, 3 Years 218
Expense Example, with Redemption, 5 Years 379
Expense Example, with Redemption, 10 Years $ 847