Statements of Changes in Shareholders’ Equity (Deficit) (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Shareholders’ equity (deficit) – beginning of period	$ (2,332,728)	$ (1,846,637)
Net income	67,050	136,332
Adjustment of redeemable capital Shares to redemption value	2,265,678	(622,423)
Shareholders’ equity (deficit) – end of period	$ 0	$ (2,332,728)