Acquisition (Details Textuals) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012 facilities
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Number of Businesses Acquired		14
Business Combination, Consideration Transferred		$ 294,000,000
Business Combination, Payments to Acquire Businesses, Gross		220,000,000
Business Acquisition, Consideration Transferred, Other		74,000,000
Number of Project Companies Acquired Deemed VIEs that assumed Debt Relates		2
Exposure Loss Related to the Debt Assumed		0
Business Combination, Intangible assets		75,000,000
Amortization Years for Intangible Assets Acquired in a Business Combination		8 years
Revenues of Acquired Business Included in the Company's Consolidated Statement of Operations		30,000,000
Earnings of Acquired Business Included in the Company's Consolidated Statements of Operations		$ 2,000,000
The Period of the Acquired Project Companies Following the Closing included in Results of Operations	3 months
Minimum [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Equity Method Investment, Ownership Percentage		46.00%
Maximum [Member]
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Equity Method Investment, Ownership Percentage		100.00%