Statements of Cash Flows (USD $)
12 Months Ended
Oct. 31, 2012
Oct. 31, 2011
Oct. 31, 2010
Cash flows from operating activities      
Cash received for accrued income $ 27,212,810 $ 32,885,342 $ 23,645,519
Cash paid for expenses (2,854,155) (3,054,668) (2,662,853)
Net cash provided by operating activities 24,358,655 29,830,674 20,982,666
Cash flows from financing activities      
Cash received to purchase redeemable shares 423,131,548 748,290,041 294,995,478
Cash paid to redeem redeemable shares (676,167,642) (609,007,896) (431,197,241)
Cash paid for distributions (23,954,507) (30,011,685) (20,831,349)
Net cash (used in) / provided by financing activities (276,990,601) 109,270,460 (157,033,112)
Adjustment to period cash flows due to currency (21,000,038) 58,717,633 52,113,166
(Decrease)/Increase in cash (273,631,984) 197,818,767 (83,937,280)
Cash at beginning of year 859,493,792 661,675,025 745,612,305
Cash at end of year 585,861,808 859,493,792 661,675,025
Reconciliation of net income to net cash provided by operating activities      
Net Income 22,792,149 30,565,349 21,506,266
Adjustments to reconcile net income to net cash provided by operating activities:      
Receivable from accrued interest (1,422,297) (3,148,620) (2,210,983)
Prior period receivable from accrued interest 3,148,620 2,210,983 1,533,470
Currency translation adjustment (80,418) 143,137 161,484
Accrued sponsor fee 201,151 280,550 220,725
Prior period accrued sponsor fee (280,550) (220,725) (228,296)
Net cash provided by operating activities $ 24,358,655 $ 29,830,674 $ 20,982,666