v2.4.0.8
Acquisitions and divestments (Details) (USD $)
6 Months Ended 0 Months Ended 1 Months Ended 0 Months Ended 1 Months Ended 1 Months Ended 0 Months Ended 3 Months Ended
Jun. 30, 2012
May 02, 2013
Canadian Hills
Jul. 31, 2012
Canadian Hills
Mar. 30, 2012
Canadian Hills
Dec. 31, 2012
Canadian Hills
item
Jun. 30, 2013
Canadian Hills
Jan. 31, 2012
Canadian Hills
MW
Apr. 12, 2013
Auburndale, Lake and Pasco
Jan. 30, 2013
Auburndale, Lake and Pasco
Apr. 30, 2013
Auburndale, Lake and Pasco
Apr. 30, 2013
Path 15
Jun. 30, 2013
Path 15
May 31, 2012
Primary Energy Recycling Corporation
Feb. 29, 2012
Primary Energy Recycling Corporation
Feb. 16, 2012
Primary Energy Recycling Corporation
Apr. 02, 2013
Gregory
Jun. 30, 2013
Gregory
Sep. 30, 2013
Gregory
Subsequent event
Acquisition and divestments                                    
Percentage acquired in entity       48.00%     51.00%                      
Wind power project capacity (in MW)             300                      
Percentage of ownership interest       99.00%                     14.30%   17.10%  
Percentage of retained interest       1.00%                            
Project-level construction financing facility       $ 310,000,000               $ 137,200,000            
Construction loan       290,000,000                            
Letter of credit facility       20,000,000                            
Letter of credit facility, term       5 years                            
Investment in equity     190,000,000                              
Tax equity investments received         225,000,000                          
Number of institutional tax equity investors by whom tax equity investments received         4                          
Own tax equity investment   44,000,000     44,000,000                          
Interest sold (as a percent)   100.00%                                
Tax equity interests   269,000,000                                
Short-term debt         265,000,000 0                        
Proceeds from sale of remaining tax equity ownership   42,100,000           92,000,000   25,000,000                
Total price                 140,000,000   56,000,000     30,200,000   274,200,000    
Expected proceeds from sale                               34,600,000    
Proceeds from sale to be held in escrow account                               5,000,000    
Term Of Escrow Account                               1 year    
Net cash proceeds from sale 24,200,000             117,000,000     52,000,000              
Management termination fee                     4,000,000     6,000,000        
Outstanding balance of senior credit facility               64,100,000                    
Price of entity's common membership interest in equity method investee                           24,200,000        
Gain on sale of equity method investment                         $ 600,000         $ 31,000,000
Entity's common membership interest to be purchased in equity method investee (in shares)                           7,462,830.33