v3.26.1
Shareholder Report, Holdings (Details)
Apr. 30, 2026
C000129563 [Member] | Franco Nevada Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
C000129563 [Member] | Barrick Mining Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000129563 [Member] | Newmont Corp CDI [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000129563 [Member] | Dassault Systemes S E [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000129563 [Member] | Kinross Gold Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000129563 [Member] | Evolution A B [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000129563 [Member] | IAMGOLD Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000129563 [Member] | Agnico Eagle Mines Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000129563 [Member] | Novo Nordisk A S ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.40%
C000129563 [Member] | British American Tobacco PLC ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.80%
C000129563 [Member] | JAPAN  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
C000129563 [Member] | AUSTRALIA  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000129563 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000129563 [Member] | DENMARK  
Holdings [Line Items]  
Percent of Net Asset Value 7.40%
C000129563 [Member] | FRANCE  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
C000129563 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
C000129563 [Member] | NETHERLANDS  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000129563 [Member] | NORWAY  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000129563 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000129563 [Member] | SWEDEN  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000129563 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 13.70%
C000129563 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 7.30%
C000129563 [Member] | CHINA  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000129563 [Member] | CANADA  
Holdings [Line Items]  
Percent of Net Asset Value 26.60%
C000129563 [Member] | SWITZERLAND  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000129563 [Member] | IRELAND  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000129563 [Member] | GERMANY  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
C000129563 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000129563 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.90%
C000129563 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
C000086557 [Member] | Franco Nevada Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.40%
C000086557 [Member] | Barrick Mining Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000086557 [Member] | Newmont Corp CDI [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000086557 [Member] | Dassault Systemes S E [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000086557 [Member] | Kinross Gold Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.40%
C000086557 [Member] | Evolution A B [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000086557 [Member] | IAMGOLD Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000086557 [Member] | Agnico Eagle Mines Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000086557 [Member] | Novo Nordisk A S ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.40%
C000086557 [Member] | British American Tobacco PLC ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.80%
C000086557 [Member] | JAPAN  
Holdings [Line Items]  
Percent of Net Asset Value 11.00%
C000086557 [Member] | AUSTRALIA  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000086557 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000086557 [Member] | DENMARK  
Holdings [Line Items]  
Percent of Net Asset Value 7.40%
C000086557 [Member] | FRANCE  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
C000086557 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
C000086557 [Member] | NETHERLANDS  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000086557 [Member] | NORWAY  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000086557 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000086557 [Member] | SWEDEN  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000086557 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 13.70%
C000086557 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 7.30%
C000086557 [Member] | CHINA  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000086557 [Member] | CANADA  
Holdings [Line Items]  
Percent of Net Asset Value 26.60%
C000086557 [Member] | SWITZERLAND  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000086557 [Member] | IRELAND  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000086557 [Member] | GERMANY  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
C000086557 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000086557 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 92.90%
C000086557 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
C000093021 [Member] | Queensland Treasury Corp 1 750 7 20 2034 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000093021 [Member] | Colombia Government International Bond 9 850 6 28 2027 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000093021 [Member] | European Investment Bank 6 950 3 1 2029 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000093021 [Member] | Bonos de la Tesoreria de la Republica en pesos 6 000 4 1 2033 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000093021 [Member] | Republic of Poland Government Bond 5 000 10 25 2035 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000093021 [Member] | Philippine Government International Bond 6 250 1 14 2036 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000093021 [Member] | Malaysia Government Bond 2 632 4 15 2031 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
C000093021 [Member] | Inter American Development Bank 5 100 11 17 2026 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
C000093021 [Member] | Mexican Bonos 7 750 11 23 2034 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
C000093021 [Member] | International Finance Corp 0 000 5 20 2030 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
C000093021 [Member] | ARGENTINA  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000093021 [Member] | AUSTRALIA  
Holdings [Line Items]  
Percent of Net Asset Value 5.30%
C000093021 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000093021 [Member] | CHILE  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000093021 [Member] | COLOMBIA  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000093021 [Member] | DENMARK  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000093021 [Member] | DOMINICAN REPUBLIC  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000093021 [Member] | FRANCE  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000093021 [Member] | LUXEMBOURG  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000093021 [Member] | MALAYSIA  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
C000093021 [Member] | MALTA  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000093021 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
C000093021 [Member] | NETHERLANDS  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000093021 [Member] | NORWAY  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000093021 [Member] | PERU  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
C000093021 [Member] | PHILIPPINES  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
C000093021 [Member] | POLAND  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000093021 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000093021 [Member] | SWEDEN  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000093021 [Member] | THAILAND  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
C000093021 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000093021 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 11.10%
C000093021 [Member] | TÜRKIYE  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
C000093021 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000093021 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000093021 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90%
C000093021 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
C000093021 [Member] | International Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 82.40%
C000129564 [Member] | Queensland Treasury Corp 1 750 7 20 2034 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000129564 [Member] | Colombia Government International Bond 9 850 6 28 2027 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000129564 [Member] | European Investment Bank 6 950 3 1 2029 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000129564 [Member] | Bonos de la Tesoreria de la Republica en pesos 6 000 4 1 2033 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000129564 [Member] | Republic of Poland Government Bond 5 000 10 25 2035 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000129564 [Member] | Philippine Government International Bond 6 250 1 14 2036 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000129564 [Member] | Malaysia Government Bond 2 632 4 15 2031 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
C000129564 [Member] | Inter American Development Bank 5 100 11 17 2026 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
C000129564 [Member] | Mexican Bonos 7 750 11 23 2034 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
C000129564 [Member] | International Finance Corp 0 000 5 20 2030 [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
C000129564 [Member] | ARGENTINA  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000129564 [Member] | AUSTRALIA  
Holdings [Line Items]  
Percent of Net Asset Value 5.30%
C000129564 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000129564 [Member] | CHILE  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000129564 [Member] | COLOMBIA  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000129564 [Member] | DENMARK  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000129564 [Member] | DOMINICAN REPUBLIC  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000129564 [Member] | FRANCE  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000129564 [Member] | LUXEMBOURG  
Holdings [Line Items]  
Percent of Net Asset Value 3.30%
C000129564 [Member] | MALAYSIA  
Holdings [Line Items]  
Percent of Net Asset Value 4.00%
C000129564 [Member] | MALTA  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000129564 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
C000129564 [Member] | NETHERLANDS  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000129564 [Member] | NORWAY  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000129564 [Member] | PERU  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
C000129564 [Member] | PHILIPPINES  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
C000129564 [Member] | POLAND  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000129564 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000129564 [Member] | SWEDEN  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000129564 [Member] | THAILAND  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
C000129564 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 7.00%
C000129564 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 11.10%
C000129564 [Member] | TÜRKIYE  
Holdings [Line Items]  
Percent of Net Asset Value 2.30%
C000129564 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000129564 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.00%
C000129564 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.90%
C000129564 [Member] | Corporate Bond Securities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.50%
C000129564 [Member] | International Bonds [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 82.40%
C000129565 [Member] | Saudi Arabian Oil Co [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000129565 [Member] | Luzhou Laojiao Co Ltd Class A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000129565 [Member] | Vale S A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000129565 [Member] | Alibaba Group Holding Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000129565 [Member] | B3 S A Brasil Bolsa Balcao [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
C000129565 [Member] | Telkom Indonesia Persero Tbk P T [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000129565 [Member] | Astra International Tbk P T [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000129565 [Member] | British American Tobacco PLC [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000129565 [Member] | Taiwan Semiconductor Manufacturing Co Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000129565 [Member] | Samsung Electronics Co Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000129565 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 10.20%
C000129565 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
C000129565 [Member] | PHILIPPINES  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000129565 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
C000129565 [Member] | THAILAND  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000129565 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000129565 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000129565 [Member] | URUGUAY  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000129565 [Member] | TAIWAN  
Holdings [Line Items]  
Percent of Net Asset Value 7.90%
C000129565 [Member] | SOUTH AFRICA  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000129565 [Member] | SAUDI ARABIA  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000129565 [Member] | KOREA, REPUBLIC OF  
Holdings [Line Items]  
Percent of Net Asset Value 14.20%
C000129565 [Member] | KAZAKHSTAN  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000129565 [Member] | INDONESIA  
Holdings [Line Items]  
Percent of Net Asset Value 8.70%
C000129565 [Member] | INDIA  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000129565 [Member] | HUNGARY  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000129565 [Member] | HONG KONG  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
C000129565 [Member] | CHINA  
Holdings [Line Items]  
Percent of Net Asset Value 18.60%
C000129565 [Member] | CANADA  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000129565 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000129565 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.80%
C000129565 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
C000093793 [Member] | Saudi Arabian Oil Co [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000093793 [Member] | Luzhou Laojiao Co Ltd Class A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000093793 [Member] | Vale S A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000093793 [Member] | Alibaba Group Holding Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000093793 [Member] | B3 S A Brasil Bolsa Balcao [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.70%
C000093793 [Member] | Telkom Indonesia Persero Tbk P T [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.90%
C000093793 [Member] | Astra International Tbk P T [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000093793 [Member] | British American Tobacco PLC [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000093793 [Member] | Taiwan Semiconductor Manufacturing Co Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000093793 [Member] | Samsung Electronics Co Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.60%
C000093793 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 10.20%
C000093793 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
C000093793 [Member] | PHILIPPINES  
Holdings [Line Items]  
Percent of Net Asset Value 0.40%
C000093793 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 1.80%
C000093793 [Member] | THAILAND  
Holdings [Line Items]  
Percent of Net Asset Value 2.10%
C000093793 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 3.20%
C000093793 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 1.70%
C000093793 [Member] | URUGUAY  
Holdings [Line Items]  
Percent of Net Asset Value 0.30%
C000093793 [Member] | TAIWAN  
Holdings [Line Items]  
Percent of Net Asset Value 7.90%
C000093793 [Member] | SOUTH AFRICA  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000093793 [Member] | SAUDI ARABIA  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000093793 [Member] | KOREA, REPUBLIC OF  
Holdings [Line Items]  
Percent of Net Asset Value 14.20%
C000093793 [Member] | KAZAKHSTAN  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000093793 [Member] | INDONESIA  
Holdings [Line Items]  
Percent of Net Asset Value 8.70%
C000093793 [Member] | INDIA  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000093793 [Member] | HUNGARY  
Holdings [Line Items]  
Percent of Net Asset Value 1.60%
C000093793 [Member] | HONG KONG  
Holdings [Line Items]  
Percent of Net Asset Value 1.20%
C000093793 [Member] | CHINA  
Holdings [Line Items]  
Percent of Net Asset Value 18.60%
C000093793 [Member] | CANADA  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000093793 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.50%
C000093793 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 91.80%
C000093793 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.70%
C000129046 [Member] | Franco Nevada Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
C000129046 [Member] | Barrick Mining Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000129046 [Member] | Agnico Eagle Mines Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10%
C000129046 [Member] | Pan American Silver Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000129046 [Member] | Fortuna Silver Mines Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.80%
C000129046 [Member] | Royal Gold Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000129046 [Member] | Wheaton Precious Metals Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
C000129046 [Member] | Heliostar Metals Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000129046 [Member] | AngloGold Ashanti Ltd ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000129046 [Member] | Aurion Resources Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000129046 [Member] | Gold mining [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.70%
C000129046 [Member] | Royalty Companies [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.70%
C000129046 [Member] | Gold Exploration [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10%
C000129046 [Member] | Diversified Exploration and Mining [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60%
C000129046 [Member] | Precious Metals Exploration [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000129046 [Member] | Silver Exploration and Mining [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000129046 [Member] | Precious Metals Developmental [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000129046 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000129046 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.60%
C000129046 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000129046 [Member] | Warrant [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000206106 [Member] | Franco Nevada Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.90%
C000206106 [Member] | Barrick Mining Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.00%
C000206106 [Member] | Agnico Eagle Mines Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 7.10%
C000206106 [Member] | Pan American Silver Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 6.30%
C000206106 [Member] | Fortuna Silver Mines Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.80%
C000206106 [Member] | Royal Gold Inc [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.80%
C000206106 [Member] | Wheaton Precious Metals Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.30%
C000206106 [Member] | Heliostar Metals Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.20%
C000206106 [Member] | AngloGold Ashanti Ltd ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000206106 [Member] | Aurion Resources Ltd [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000206106 [Member] | Gold mining [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 46.70%
C000206106 [Member] | Royalty Companies [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 35.70%
C000206106 [Member] | Gold Exploration [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 10.10%
C000206106 [Member] | Diversified Exploration and Mining [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 4.60%
C000206106 [Member] | Precious Metals Exploration [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000206106 [Member] | Silver Exploration and Mining [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000206106 [Member] | Precious Metals Developmental [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000206106 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.20%
C000206106 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 99.60%
C000206106 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000206106 [Member] | Warrant [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.10%
C000134866 [Member] | Barrick Mining Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000134866 [Member] | IAMGOLD Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134866 [Member] | British American Tobacco PLC ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000134866 [Member] | Eni S p A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000134866 [Member] | Engie S A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134866 [Member] | Nokia Oyj [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134866 [Member] | TotalEnergies S E ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000134866 [Member] | Samsung Electronics Co Ltd GDR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000134866 [Member] | SK Telecom Co Ltd ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000134866 [Member] | Vodafone Group PLC [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000134866 [Member] | AUSTRALIA  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
C000134866 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 6.80%
C000134866 [Member] | DENMARK  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000134866 [Member] | FRANCE  
Holdings [Line Items]  
Percent of Net Asset Value 8.30%
C000134866 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134866 [Member] | NETHERLANDS  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000134866 [Member] | NORWAY  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
C000134866 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000134866 [Member] | SWEDEN  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000134866 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 12.40%
C000134866 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000134866 [Member] | KOREA, REPUBLIC OF  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
C000134866 [Member] | INDONESIA  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000134866 [Member] | CHINA  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000134866 [Member] | CANADA  
Holdings [Line Items]  
Percent of Net Asset Value 16.40%
C000134866 [Member] | SWITZERLAND  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
C000134866 [Member] | SPAIN  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
C000134866 [Member] | NEW ZEALAND  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000134866 [Member] | ITALY  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000134866 [Member] | IRELAND  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000134866 [Member] | GERMANY  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000134866 [Member] | FINLAND  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000134866 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000134866 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.40%
C000134866 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%
C000134865 [Member] | Barrick Mining Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.40%
C000134865 [Member] | IAMGOLD Corp [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134865 [Member] | British American Tobacco PLC ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.50%
C000134865 [Member] | Eni S p A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 1.90%
C000134865 [Member] | Engie S A [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134865 [Member] | Nokia Oyj [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134865 [Member] | TotalEnergies S E ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000134865 [Member] | Samsung Electronics Co Ltd GDR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000134865 [Member] | SK Telecom Co Ltd ADR [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.00%
C000134865 [Member] | Vodafone Group PLC [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000134865 [Member] | AUSTRALIA  
Holdings [Line Items]  
Percent of Net Asset Value 4.50%
C000134865 [Member] | BRAZIL  
Holdings [Line Items]  
Percent of Net Asset Value 6.80%
C000134865 [Member] | DENMARK  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000134865 [Member] | FRANCE  
Holdings [Line Items]  
Percent of Net Asset Value 8.30%
C000134865 [Member] | MEXICO  
Holdings [Line Items]  
Percent of Net Asset Value 2.00%
C000134865 [Member] | NETHERLANDS  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000134865 [Member] | NORWAY  
Holdings [Line Items]  
Percent of Net Asset Value 5.70%
C000134865 [Member] | SINGAPORE  
Holdings [Line Items]  
Percent of Net Asset Value 3.90%
C000134865 [Member] | SWEDEN  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000134865 [Member] | UNITED KINGDOM  
Holdings [Line Items]  
Percent of Net Asset Value 12.40%
C000134865 [Member] | UNITED STATES  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000134865 [Member] | KOREA, REPUBLIC OF  
Holdings [Line Items]  
Percent of Net Asset Value 5.20%
C000134865 [Member] | INDONESIA  
Holdings [Line Items]  
Percent of Net Asset Value 0.70%
C000134865 [Member] | CHINA  
Holdings [Line Items]  
Percent of Net Asset Value 1.10%
C000134865 [Member] | CANADA  
Holdings [Line Items]  
Percent of Net Asset Value 16.40%
C000134865 [Member] | SWITZERLAND  
Holdings [Line Items]  
Percent of Net Asset Value 2.80%
C000134865 [Member] | SPAIN  
Holdings [Line Items]  
Percent of Net Asset Value 6.60%
C000134865 [Member] | NEW ZEALAND  
Holdings [Line Items]  
Percent of Net Asset Value 0.60%
C000134865 [Member] | ITALY  
Holdings [Line Items]  
Percent of Net Asset Value 3.80%
C000134865 [Member] | IRELAND  
Holdings [Line Items]  
Percent of Net Asset Value 1.40%
C000134865 [Member] | GERMANY  
Holdings [Line Items]  
Percent of Net Asset Value 2.20%
C000134865 [Member] | FINLAND  
Holdings [Line Items]  
Percent of Net Asset Value 3.60%
C000134865 [Member] | Other Assets in Excess of Liabilities [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 0.50%
C000134865 [Member] | Common Stock [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 94.40%
C000134865 [Member] | Short-Term Investments [Member]  
Holdings [Line Items]  
Percent of Net Asset Value 5.10%