Note 2 - Summary of Significant Accounting Policies (Details) - Share Activity (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share Activity [Abstract]
Shares issued	74,950	85,750	82,150
Shares issued	$ 1,361,917	$ 2,096,484	$ 2,496,406
Shares redeemed	(63,450)	(88,250)	(64,650)
Shares redeemed	(1,108,223)	(2,031,644)	(1,943,269)
Net increase	11,500
Net increase	$ 253,694	$ 3,530,747	$ (454,637)