Nomura Healthcare FundNomura Healthcare FundDjulycombopro_2793DELAWARE GROUP EQUITY FUNDS IV - A, C, R, and InstitutionalClass A - C000052257AClass C - C000052258CClass R - C000052259RClass Institutional - C000052260InstitutionalForeign and Emerging Markets Risk [Member]Foreign and Emerging Markets Risk [Member]Active management and selection risk [Member]Active management and selection risk [Member]Company size risk [Member]Company size risk [Member]Market risk_Market risk_Healthcare sector risk [Member]Healthcare sector risk [Member]Liquidity risk_[Member]Liquidity risk_[Member]Russell 3000 Index (reflects no deduction for fees, expenses, or taxes)Russell 3000 Index (reflects no deduction for fees, expenses, or taxes)Concentration riskConcentration riskGovernment and Regulatory Risk [Member]Government and Regulatory Risk [Member]Russell 3000 Healthcare Index (reflects no deduction for fees, expenses, or taxes)Russell 3000 Healthcare Index (reflects no deduction for fees, expenses, or taxes)