Optimum Large Cap Growth FundOptimum Large Cap Growth FundOptimum Small-Mid Cap Growth FundOptimum Small-Mid Cap Growth FundOptimum Small-Mid Cap Value FundOptimum Small-Mid Cap Value FundOptimum International FundOptimum International FundOptimum Fixed Income FundOptimum Fixed Income FundOptimum Large Cap Value FundOptimum Large Cap Value FundDjulyoptimumpro_2790Optimum Fund Trust Classes A, C, InstitutionalDjulyoptimumsai_2812July - Optimum SAIClass A - C000006451AClass C - C000006453CClass Institutional - C000006454InstitutionalClass A - C000006459AClass C - C000006461CClass Institutional - C000006462InstitutionalClass A - C000006463AClass C - C000006465CClass Institutional - C000006466InstitutionalClass A - C000006447AClass C - C000006449CClass Institutional - C000006450InstitutionalClass A - C000006443AClass C - C000006445CClass Institutional - C000006446InstitutionalClass A - C000006455AClass C - C000006457CClass Institutional - C000006458InstitutionalMarket risk_Market risk_Large-capitalization company risk [Member]Large-capitalization company risk [Member]Equity risk [Member]Equity risk [Member]Investment style risk growth investing [Member]Investment style risk growth investing [Member]Quantitative model risk [Member]Quantitative model risk [Member]Issuer specific risk [Member]Issuer specific risk [Member]Multiple advisor risk [Member]Multiple advisor risk [Member]Portfolio management risk [Member]Portfolio management risk [Member]Industry and sector riskIndustry and sector riskPortfolio concentration risk [Member]Portfolio concentration risk [Member]Liquidity risk_[Member]Liquidity risk_[Member]Russell 1000 Index (reflects no deduction for fees, expenses or taxes)Russell 1000 Index (reflects no deduction for fees, expenses or taxes)Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)Russell 1000 Growth Index (reflects no deduction for fees, expenses, or taxes)Investment style risk value investing [Member]Investment style risk value investing [Member]Liquidity Risk [Member]Liquidity Risk [Member]Russell 1000 Value Index (reflects no deduction for fees, expenses or taxes)Russell 1000 Value Index (reflects no deduction for fees, expenses or taxes)Market Risk [Member]Market Risk [Member]Company size risk [Member]Company size risk [Member]Russell 3000 Index (reflects no deduction for fees, expenses, or taxes)Russell 3000 Index (reflects no deduction for fees, expenses, or taxes)Russell 2500 Growth Index (reflects no deduction for fees, expenses, or taxes)Russell 2500 Growth Index (reflects no deduction for fees, expenses, or taxes)Russell 2500 Value Index (reflects no deduction for fees, expenses, or taxes)Russell 2500 Value Index (reflects no deduction for fees, expenses, or taxes)Foreign and Emerging Markets Risk [Member]Foreign and Emerging Markets Risk [Member]Derivatives Risk [Member]Derivatives Risk [Member]MSCI ACWI (All Country World Index) ex USA Index (net) (reflects no deduction for fees or expenses but reflects the deduction of foreign withholding taxes on dividends)MSCI ACWI (All Country World Index) ex USA Index (net) (reflects no deduction for fees or expenses but reflects the deduction of foreign withholding taxes on dividends)MSCI ACWI (All Country World Index) ex USA Index (gross) (reflects no deduction for fees, expenses, or foreign withholding taxes on dividends)MSCI ACWI (All Country World Index) ex USA Index (gross) (reflects no deduction for fees, expenses, or foreign withholding taxes on dividends)Credit risk [Member]Credit risk [Member]Interest rate risk [Member]Interest rate risk [Member]High Yield (Junk) Bond Risk [Member]High Yield (Junk) Bond Risk [Member]Mortgage-Backed and Asset-Backed Securities Risk [Member]Mortgage-Backed and Asset-Backed Securities Risk [Member]Loans and Other Direct Indebtedness Risk [Member]Loans and Other Direct Indebtedness Risk [Member]Foreign RiskForeign RiskForward foreign currency risk [Member]Forward foreign currency risk [Member]Prepayment Risk [Member]Prepayment Risk [Member]Bloomberg US Aggregate Index (reflects no deduction for fees, expenses, or taxes)Bloomberg US Aggregate Index (reflects no deduction for fees, expenses, or taxes)