v3.25.2
Shareholder Report, Holdings (Details)
May 31, 2025
C000174964 | U.S. Treasury Notes  
Holdings [Line Items]  
Percent of Net Asset Value 16.10%
C000174964 | U.S. Treasury Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 12.40%
C000174964 | Federal National Mortgage Assn.  
Holdings [Line Items]  
Percent of Net Asset Value 9.40%
C000174964 | Federal Home Loan Mortgage  
Holdings [Line Items]  
Percent of Net Asset Value 5.40%
C000174964 | Government National Mortgage Assn.  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000174964 | Carvana Auto Receivables Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174964 | CarMax Auto Owner Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174964 | Cross Mortgage Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174964 | Santander Drive Auto Receivables Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174964 | Octagon Investment Partners 47  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174964 | U.S. Government Agency Obligations (Excluding Mortgage-Backed)  
Holdings [Line Items]  
Percent of Net Asset Value 28.50%
C000174964 | U.S. Government & Agency Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 20.10%
C000174964 | Corporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 18.60%
C000174964 | Asset-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 13.50%
C000174964 | Bank Loans  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000174964 | Non-U.S. Government Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000174964 | Foreign Government Obligations & Municipalities  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
C000174964 | Municipal Securities  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174964 | Other Holdings Grouping  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
C000174965 | U.S. Treasury Notes  
Holdings [Line Items]  
Percent of Net Asset Value 16.10%
C000174965 | U.S. Treasury Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 12.40%
C000174965 | Federal National Mortgage Assn.  
Holdings [Line Items]  
Percent of Net Asset Value 9.40%
C000174965 | Federal Home Loan Mortgage  
Holdings [Line Items]  
Percent of Net Asset Value 5.40%
C000174965 | Government National Mortgage Assn.  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000174965 | Carvana Auto Receivables Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174965 | CarMax Auto Owner Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174965 | Cross Mortgage Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174965 | Santander Drive Auto Receivables Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174965 | Octagon Investment Partners 47  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174965 | U.S. Government Agency Obligations (Excluding Mortgage-Backed)  
Holdings [Line Items]  
Percent of Net Asset Value 28.50%
C000174965 | U.S. Government & Agency Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 20.10%
C000174965 | Corporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 18.60%
C000174965 | Asset-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 13.50%
C000174965 | Bank Loans  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000174965 | Non-U.S. Government Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000174965 | Foreign Government Obligations & Municipalities  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
C000174965 | Municipal Securities  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174965 | Other Holdings Grouping  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
C000174966 | U.S. Treasury Notes  
Holdings [Line Items]  
Percent of Net Asset Value 16.10%
C000174966 | U.S. Treasury Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 12.40%
C000174966 | Federal National Mortgage Assn.  
Holdings [Line Items]  
Percent of Net Asset Value 9.40%
C000174966 | Federal Home Loan Mortgage  
Holdings [Line Items]  
Percent of Net Asset Value 5.40%
C000174966 | Government National Mortgage Assn.  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000174966 | Carvana Auto Receivables Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174966 | CarMax Auto Owner Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174966 | Cross Mortgage Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174966 | Santander Drive Auto Receivables Trust  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174966 | Octagon Investment Partners 47  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174966 | U.S. Government Agency Obligations (Excluding Mortgage-Backed)  
Holdings [Line Items]  
Percent of Net Asset Value 28.50%
C000174966 | U.S. Government & Agency Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 20.10%
C000174966 | Corporate Bonds  
Holdings [Line Items]  
Percent of Net Asset Value 18.60%
C000174966 | Asset-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 13.50%
C000174966 | Bank Loans  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000174966 | Non-U.S. Government Mortgage-Backed Securities  
Holdings [Line Items]  
Percent of Net Asset Value 7.50%
C000174966 | Foreign Government Obligations & Municipalities  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
C000174966 | Municipal Securities  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000174966 | Other Holdings Grouping  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%