v3.25.2
Shareholder Report, Holdings (Details)
Jul. 31, 2025
C000016770 | NR  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000016770 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016770 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016770 | A  
Holdings [Line Items]  
Percent of Net Asset Value 16.00%
C000016770 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 29.00%
C000016770 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
C000016770 | B  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000016770 | AssetCorporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016770 | AssetMortgage-Backed Securities Pass-Throughs  
Holdings [Line Items]  
Percent of Net Asset Value 23.00%
C000016770 | AssetAsset-Backed  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
C000016770 | AssetCommercial Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 10.00%
C000016770 | AssetCollateralized Mortgage Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 8.00%
C000016770 | AssetGovernment & Agency Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016770 | AssetWarrants  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016770 | Asset Other Net Line  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016773 | NR  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000016773 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016773 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016773 | A  
Holdings [Line Items]  
Percent of Net Asset Value 16.00%
C000016773 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 29.00%
C000016773 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
C000016773 | B  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000016773 | AssetCorporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016773 | AssetMortgage-Backed Securities Pass-Throughs  
Holdings [Line Items]  
Percent of Net Asset Value 23.00%
C000016773 | AssetAsset-Backed  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
C000016773 | AssetCommercial Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 10.00%
C000016773 | AssetCollateralized Mortgage Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 8.00%
C000016773 | AssetGovernment & Agency Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016773 | AssetWarrants  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016773 | Asset Other Net Line  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016774 | NR  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000016774 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016774 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016774 | A  
Holdings [Line Items]  
Percent of Net Asset Value 16.00%
C000016774 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 29.00%
C000016774 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
C000016774 | B  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000016774 | AssetCorporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016774 | AssetMortgage-Backed Securities Pass-Throughs  
Holdings [Line Items]  
Percent of Net Asset Value 23.00%
C000016774 | AssetAsset-Backed  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
C000016774 | AssetCommercial Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 10.00%
C000016774 | AssetCollateralized Mortgage Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 8.00%
C000016774 | AssetGovernment & Agency Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016774 | AssetWarrants  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016774 | Asset Other Net Line  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016775 | NR  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000016775 | AAA  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016775 | AA  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016775 | A  
Holdings [Line Items]  
Percent of Net Asset Value 16.00%
C000016775 | BBB  
Holdings [Line Items]  
Percent of Net Asset Value 29.00%
C000016775 | BB  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
C000016775 | B  
Holdings [Line Items]  
Percent of Net Asset Value 1.00%
C000016775 | AssetCorporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 41.00%
C000016775 | AssetMortgage-Backed Securities Pass-Throughs  
Holdings [Line Items]  
Percent of Net Asset Value 23.00%
C000016775 | AssetAsset-Backed  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
C000016775 | AssetCommercial Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 10.00%
C000016775 | AssetCollateralized Mortgage Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 8.00%
C000016775 | AssetGovernment & Agency Obligations  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000016775 | AssetWarrants  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000016775 | Asset Other Net Line  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%