Equity Investment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summarized financial information of CEP
Revenues	$ 13,938	$ 25,524	$ 31,687	$ 50,290
Net income (loss)	(18,508)	7,531	(11,161)	3,670
CEP [Member]
Summarized financial information of CEP
Revenues	11,812		35,372
Gross profit (loss) (1)	(3,569)		3,838
Net income (loss) from continuing operations	(5,010)		875
Net income (loss)	$ (5,010)		$ 875