v3.25.1
Shareholder Report, Holdings (Details)
Mar. 31, 2025
C000174035 | Banco Santander S.A., 4.75, 2173-08-12  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000174035 | Liberty Mutual Group, Inc., 7.8, 2037-03-15  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000174035 | Comerica, Inc., 5.625, 2168-10-01  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000174035 | Provident Financing Trust I, 7.405, 2038-03-15  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000174035 | New York Community Bancorp, Inc., 6.375, 2027-03-17  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000174035 | KeyCorporation, 5, 2049-12-29  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000174035 | Athene Holding Ltd., 6.35, 2029-06-30  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000174035 | Wells Fargo & Company, 6.85, 2174-07-15  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174035 | Bank of Nova Scotia (The), 4.9, 2168-09-04  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174035 | Synovus Financial Corporation, 8.397, 2029-07-01  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
C000174035 | Money Market Funds  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000174035 | Corporate Debt Securities  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000174035 | Contingent Capital Securities  
Holdings [Line Items]  
Percent of Net Asset Value 25.30%
C000174035 | Preferred Securities  
Holdings [Line Items]  
Percent of Net Asset Value 72.90%
C000174035 | Materials  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000174035 | Health Care  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000174035 | Consumer Discretionary  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174035 | Consumer Staples  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174035 | Communications  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000174035 | Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000174035 | Utilities  
Holdings [Line Items]  
Percent of Net Asset Value 13.70%
C000174035 | Financials  
Holdings [Line Items]  
Percent of Net Asset Value 77.40%
C000174036 | Banco Santander S.A., 4.75, 2173-08-12  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000174036 | Liberty Mutual Group, Inc., 7.8, 2037-03-15  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000174036 | Comerica, Inc., 5.625, 2168-10-01  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000174036 | Provident Financing Trust I, 7.405, 2038-03-15  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000174036 | New York Community Bancorp, Inc., 6.375, 2027-03-17  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000174036 | KeyCorporation, 5, 2049-12-29  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000174036 | Athene Holding Ltd., 6.35, 2029-06-30  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000174036 | Wells Fargo & Company, 6.85, 2174-07-15  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174036 | Bank of Nova Scotia (The), 4.9, 2168-09-04  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174036 | Synovus Financial Corporation, 8.397, 2029-07-01  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
C000174036 | Money Market Funds  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000174036 | Corporate Debt Securities  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000174036 | Contingent Capital Securities  
Holdings [Line Items]  
Percent of Net Asset Value 25.30%
C000174036 | Preferred Securities  
Holdings [Line Items]  
Percent of Net Asset Value 72.90%
C000174036 | Materials  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000174036 | Health Care  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000174036 | Consumer Discretionary  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174036 | Consumer Staples  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174036 | Communications  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000174036 | Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000174036 | Utilities  
Holdings [Line Items]  
Percent of Net Asset Value 13.70%
C000174036 | Financials  
Holdings [Line Items]  
Percent of Net Asset Value 77.40%
C000174037 | Banco Santander S.A., 4.75, 2173-08-12  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000174037 | Liberty Mutual Group, Inc., 7.8, 2037-03-15  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000174037 | Comerica, Inc., 5.625, 2168-10-01  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000174037 | Provident Financing Trust I, 7.405, 2038-03-15  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000174037 | New York Community Bancorp, Inc., 6.375, 2027-03-17  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000174037 | KeyCorporation, 5, 2049-12-29  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000174037 | Athene Holding Ltd., 6.35, 2029-06-30  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000174037 | Wells Fargo & Company, 6.85, 2174-07-15  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174037 | Bank of Nova Scotia (The), 4.9, 2168-09-04  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174037 | Synovus Financial Corporation, 8.397, 2029-07-01  
Holdings [Line Items]  
Percent of Net Asset Value 1.30%
C000174037 | Money Market Funds  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000174037 | Corporate Debt Securities  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000174037 | Contingent Capital Securities  
Holdings [Line Items]  
Percent of Net Asset Value 25.30%
C000174037 | Preferred Securities  
Holdings [Line Items]  
Percent of Net Asset Value 72.90%
C000174037 | Materials  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000174037 | Health Care  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000174037 | Consumer Discretionary  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000174037 | Consumer Staples  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000174037 | Communications  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000174037 | Energy  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000174037 | Utilities  
Holdings [Line Items]  
Percent of Net Asset Value 13.70%
C000174037 | Financials  
Holdings [Line Items]  
Percent of Net Asset Value 77.40%