Consolidated Statements of Operations (USD $)
In Thousands, except Share data, unless otherwise specified
 3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Revenue:    
Electricity sales $ 53,871 $ 45,232
Energy derivative settlements 2,735 5,408
Unrealized loss on energy derivative (7,733) (6,803)
Related party revenue 445  
Other revenue 231  
Total revenue 49,549 43,837
Cost of revenue:    
Project expense 16,074 12,977
Depreciation and accretion 21,177 22,566
Total cost of revenue 37,251 35,543
Gross profit 12,298 8,294
Operating expenses:    
General and administrative 3,903 144
Related party general and administrative 1,280 2,662
Total operating expenses 5,183 2,806
Operating income 7,115 5,488
Other income (expense):    
Interest expense (14,621) (16,642)
Equity in losses in unconsolidated investments (12,548) (10,025)
Interest rate derivative settlements (1,017)  
Unrealized (loss) gain on derivatives (3,723) 1,931
Related party income 696  
Other income, net 167 758
Total other expense (31,046) (23,978)
Net loss before income tax (23,931) (18,490)
Tax (benefit) provision (2,032) 294
Net loss (21,899) (18,784)
Net loss attributable to noncontrolling interest (7,010) (3,579)
Net loss attributable to controlling interest (14,889) (15,205)
Unaudited pro forma net loss after tax:    
Net loss before income tax   (18,490)
Pro forma tax provision   279
Pro forma net loss   $ (18,769)
Class A Common Stock [Member]
    
Weighted average number of shares:    
Basic and diluted common stock 35,533,166  
Earnings per share    
Basic and diluted loss per share $ (0.20)  
Cash dividends declared per common share $ 0.31  
Class B Common Stock [Member]
    
Weighted average number of shares:    
Basic and diluted common stock 15,555,000  
Earnings per share    
Basic and diluted loss per share $ (0.51)  
Cash dividends declared per common share