v2.4.1.9

Creation and Redemption of Creation Units - Additional Information (Detail) | 3 Months Ended
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Mar. 31, 2015
Creation And Redemption Of Creation Units [Line Items] |
Creation Unit, block Shares of a Fund | 50,000 ck0001415311_CreationUnitBlockSharesOfFund
Fixed transaction fee per Creation Unit | 500 ck0001415311_FixedTransactionFeePerCreationUnit
Variable transaction fee, percent of the value of the Creation Unit, maximum | 0.10%ck0001415311_VariableTransactionFeePercentOfValueOfCreationUnitMaximum
Managed Futures Fund [Member] |
Creation And Redemption Of Creation Units [Line Items] |
Creation Unit, block Shares of a Fund | 50,000 ck0001415311_CreationUnitBlockSharesOfFund / us-gaap_InvestmentTypeAxis = ck0001415311_ManagedFuturesFundMember
Volatility Index Fund [Member] |
Creation And Redemption Of Creation Units [Line Items] |
Creation Unit, block Shares of a Fund | 25,000 ck0001415311_CreationUnitBlockSharesOfFund / us-gaap_CapitalUnitsByClassAxis = ck0001415311_VolatilityIndexFundMember
Variable transaction fee, percent of the value of the Creation Unit, maximum | 0.05%ck0001415311_VariableTransactionFeePercentOfValueOfCreationUnitMaximum / us-gaap_CapitalUnitsByClassAxis = ck0001415311_VolatilityIndexFundMember

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- Details
Name: | ck0001415311_CreationAndRedemptionOfCreationUnitsLineItems
Namespace Prefix: | ck0001415311_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Creation unit, block shares of a fund. + References No definition available. + Details
Name: | ck0001415311_CreationUnitBlockSharesOfFund
Namespace Prefix: | ck0001415311_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fixed transaction fee per creation unit. + References No definition available. + Details
Name: | ck0001415311_FixedTransactionFeePerCreationUnit
Namespace Prefix: | ck0001415311_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Variable transaction fee, percent of the value of the creation unit, maximum. + References No definition available. + Details
Name: | ck0001415311_VariableTransactionFeePercentOfValueOfCreationUnitMaximum
Namespace Prefix: | ck0001415311_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CapitalUnitsByClassAxis=ck0001415311_VolatilityIndexFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=ck0001415311_ManagedFuturesFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |