Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies- Project Assets (Details)

v2.4.1.9
Summary of Significant Accounting Policies- Project Assets (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Accounting Policies [Abstract]      
Interest costs capitalized $ 114us-gaap_InterestCostsCapitalized $ 395us-gaap_InterestCostsCapitalized  
Minimum qualifying operating period for prorated repayments of grants 5 years    
Deferred grant income $ 8,704us-gaap_OtherDeferredCreditsNoncurrent   $ 8,842us-gaap_OtherDeferredCreditsNoncurrent