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Euro Deposits - Additional Information (Detail)
9 Months Ended 12 Months Ended
Jul. 31, 2017
USD ($)
Jul. 31, 2017
EUR (€)
Jul. 31, 2016
USD ($)
Oct. 31, 2016
EUR (€)
Jul. 31, 2017
EUR (€)
Oct. 31, 2016
USD ($)
Oct. 31, 2016
EUR (€)
Cash and Cash Equivalents [Abstract]              
Annual nominal rate (0.40%) (0.40%)          
Principal deposits $ 832,272,473 € 765,589,618 $ 1,050,948,694 € 1,080,489,764      
Principal redemptions 779,828,591 741,516,852 1,072,721,397 1,158,683,985      
Withdrawals (to pay expenses) 1,407,108 € 1,294,369 $ 1,704,848 € 2,026,744      
Deposits, interest bearing $ 313,706,062       € 266,077,953 $ 266,705,058 € 243,299,556