Statements Of Changes In Shareholders' Equity (Deficit) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Shareholders' equity (deficit) - beginning of period	$ (1,846,637)	$ (1,748,981)
Net income	127,568	258,847
Adjustment of redeemable capital Shares to redemption value	(1,392,290)	(356,503)
Shareholders' equity (deficit) - end of period	$ (3,111,359)	$ (1,846,637)