Investments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Available-for-sale Securities
Prior Period Reclassification Adjustment	$ 605	$ 0	$ 605	$ 0
Investment in Marketable Securities (Textual) [Abstract]
Other comprehensive unrealized gain	6,026
Marketable Securities, Unrealized Gain (Loss)		(2,789)	774	(4,176)
Short term investments	657		657		20,254
Marketable securities [Member]
Available-for-sale Securities
Available-for-sale Securities, Amortized Cost	34,839		34,839		24,819
Available-for-sales Securities, Gross Unrealized Losses	(7,982)		(7,982)		(4,975)
Available-for-sale Securities, Gross Unrealized Gains	(4,386)		(4,386)		0
Available-for-sale Securities, Estimated Fair Value	$ 31,243		$ 31,243		$ 19,844