v3.26.1
Shareholder Report, Holdings (Details)
May 31, 2026
C000142693 [Member] | ONEOK Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [1]
C000142693 [Member] | Pembina Pipeline Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [1]
C000142693 [Member] | TC Energy Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [1]
C000142693 [Member] | MPLX LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [1]
C000142693 [Member] | Keyera Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [1]
C000142693 [Member] | Plains GP Holdings LP Class A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [1]
C000142693 [Member] | DT Midstream Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [1]
C000142693 [Member] | Williams Cos Inc The [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.80% [1]
C000142693 [Member] | Energy Transfer LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [1]
C000142693 [Member] | Targa Resources Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.80% [1]
C000142693 [Member] | Water Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000142693 [Member] | Oil Field Services [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000142693 [Member] | Upstream Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000142693 [Member] | Crude Oil And Refined Products [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
C000142693 [Member] | Refiners [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000142693 [Member] | Canadian Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000142693 [Member] | Natural Gas Transportation And Storage [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000142693 [Member] | Natural Gas Gatherers And Processors [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.30%
C000142693 [Member] | Large Cap MLP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
C000142693 [Member] | Large Cap Diversified C Corps [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 39.50%
C000142693 [Member] | Unclassified Sector [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000142692 [Member] | ONEOK Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [2]
C000142692 [Member] | Pembina Pipeline Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [2]
C000142692 [Member] | TC Energy Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [2]
C000142692 [Member] | MPLX LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [2]
C000142692 [Member] | Keyera Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [2]
C000142692 [Member] | Plains GP Holdings LP Class A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [2]
C000142692 [Member] | DT Midstream Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [2]
C000142692 [Member] | Williams Cos Inc The [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.80% [2]
C000142692 [Member] | Energy Transfer LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [2]
C000142692 [Member] | Targa Resources Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.80% [2]
C000142692 [Member] | Water Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000142692 [Member] | Oil Field Services [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000142692 [Member] | Upstream Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000142692 [Member] | Crude Oil And Refined Products [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
C000142692 [Member] | Refiners [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000142692 [Member] | Canadian Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000142692 [Member] | Natural Gas Transportation And Storage [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000142692 [Member] | Natural Gas Gatherers And Processors [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.30%
C000142692 [Member] | Large Cap MLP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
C000142692 [Member] | Large Cap Diversified C Corps [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 39.50%
C000142692 [Member] | Unclassified Sector [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000142691 [Member] | ONEOK Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [3]
C000142691 [Member] | Pembina Pipeline Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [3]
C000142691 [Member] | TC Energy Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [3]
C000142691 [Member] | MPLX LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [3]
C000142691 [Member] | Keyera Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [3]
C000142691 [Member] | Plains GP Holdings LP Class A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [3]
C000142691 [Member] | DT Midstream Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [3]
C000142691 [Member] | Williams Cos Inc The [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.80% [3]
C000142691 [Member] | Energy Transfer LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [3]
C000142691 [Member] | Targa Resources Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.80% [3]
C000142691 [Member] | Water Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000142691 [Member] | Oil Field Services [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000142691 [Member] | Upstream Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000142691 [Member] | Crude Oil And Refined Products [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
C000142691 [Member] | Refiners [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000142691 [Member] | Canadian Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000142691 [Member] | Natural Gas Transportation And Storage [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000142691 [Member] | Natural Gas Gatherers And Processors [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.30%
C000142691 [Member] | Large Cap MLP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
C000142691 [Member] | Large Cap Diversified C Corps [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 39.50%
C000142691 [Member] | Unclassified Sector [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000142690 [Member] | ONEOK Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60% [4]
C000142690 [Member] | Pembina Pipeline Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [4]
C000142690 [Member] | TC Energy Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90% [4]
C000142690 [Member] | MPLX LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [4]
C000142690 [Member] | Keyera Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10% [4]
C000142690 [Member] | Plains GP Holdings LP Class A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.70% [4]
C000142690 [Member] | DT Midstream Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.00% [4]
C000142690 [Member] | Williams Cos Inc The [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.80% [4]
C000142690 [Member] | Energy Transfer LP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 8.90% [4]
C000142690 [Member] | Targa Resources Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 9.80% [4]
C000142690 [Member] | Water Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000142690 [Member] | Oil Field Services [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000142690 [Member] | Upstream Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000142690 [Member] | Crude Oil And Refined Products [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.60%
C000142690 [Member] | Refiners [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.10%
C000142690 [Member] | Canadian Midstream [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000142690 [Member] | Natural Gas Transportation And Storage [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.90%
C000142690 [Member] | Natural Gas Gatherers And Processors [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 17.30%
C000142690 [Member] | Large Cap MLP [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 18.30%
C000142690 [Member] | Large Cap Diversified C Corps [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 39.50%
C000142690 [Member] | Unclassified Sector [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
[1] Excluding short-term investments
[2] Excluding short-term investments
[3] Excluding short-term investments
[4] Excluding short-term investments