Medium-Term Investments (Details) (USD $)	1 Months Ended
	Jan. 31, 2011	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Medium-Term Investments (Textuals)
Medium-term investments principal balance		$ 0	$ 5,531,000	$ 5,532,000
Medium term investment reclassified to cash equivalents			3,630,000
Medium-term investments		0	0	3,910,000	[1]
Redemption of medium-term investments	$ 3,630,000

[1] As Restated, See Note 1