Investments (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Aug. 06, 2012	Dec. 31, 2011
Available-for-sale Securities
Available-for-sale Securities, Estimated Fair Value					$ 2.0
Investment in Marketable Securities (Textual) [Abstract]
Other comprehensive unrealized gain	(5,700,000)	(1,400,000)	(5,300,000)	(1,400,000)
Short term investments	907,000		907,000			20,254,000
Marketable securities [Member]
Available-for-sale Securities
Available-for-sale Securities, Amortized Cost	31,377,000		31,377,000			24,819,000
Available-for-sales Securities, Gross Unrealized Losses	(11,544,000)		(11,544,000)			(4,975,000)
Available-for-sale Securities, Gross Unrealized Gains	(1,317,000)		(1,317,000)			0
Available-for-sale Securities, Estimated Fair Value	$ 21,150,000		$ 21,150,000			$ 19,844,000