Statements Of Changes In Shareholders' Equity (Deficit) (USD $) In Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Statements Of Changes In Shareholders' Equity (Deficit) [Abstract]
Shareholders' equity (deficit) - beginning of period	$ (1,748,981)	$ (878,372)
Net income	241,212	32,297
Adjustment of redeemable capital Shares to redemption value	(889,933)	(902,906)
Shareholders' equity (deficit) - end of period	$ (2,397,702)	$ (1,748,981)