Investments in Equity Method Affiliates (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Schedule of Equity Method Investment Net Income
Net income / (loss)	$ 5,767	$ 17,783	$ (10,119)	$ 1,952
Net income / (loss) attributable to the investees	$ 5,730	$ 18,207	$ (9,841)	$ 2,666