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Summary of Significant Accounting Policies (Additional Information) (Details)	Mar. 31, 2016 $ / Units
Significant Accounting Policies [Line Items]
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets	350
Creation Baskets
Significant Accounting Policies [Line Items]
Number of Shares per basket	50,000
Prior to July 1, 2011
Significant Accounting Policies [Line Items]
Fee paid by Authorized Purchasers for each order placed to create one or more Creation Baskets or to redeem one or more baskets	350