v3.19.3.a.u2
Equity method investments in unconsolidated affiliates - Op Results (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Operating results      
Revenue $ 144.0 $ 125.7 $ 124.0
Project expenses 96.5 80.9 91.8
Project other expenses (50.5) (1.6) (87.0)
Net income (loss) (3.0) 43.2 (54.8)
Frederickson      
Operating results      
Revenue 36.0 21.0 21.6
Project expenses 26.9 14.1 21.0
Project other expenses     (28.4)
Net income (loss) 9.1 6.9 (27.8)
Orlando Cogen, LP      
Operating results      
Revenue 61.5 60.2 55.0
Project expenses 28.5 30.1 29.4
Net income (loss) 33.0 30.1 25.6
Koma Kulshan Associates      
Operating results      
Revenue   1.2 1.8
Project expenses   0.6 1.1
Net income (loss)   0.6 0.7
Chambers Cogen, LP      
Operating results      
Revenue 39.4 43.3 43.8
Project expenses 34.6 36.1 37.5
Project other expenses (50.9) (1.6) (48.9)
Net income (loss) (46.1) $ 5.6 (42.6)
Selkirk Cogen Partners, LP      
Operating results      
Revenue     1.8
Project expenses     2.8
Project other expenses     (9.7)
Net income (loss)     $ (10.7)
Craven County Wood Energy, LP      
Operating results      
Revenue 4.9    
Project expenses 4.7    
Net income (loss) 0.2    
Grayling Generating Station, LP      
Operating results      
Revenue 2.2    
Project expenses 1.8    
Project other expenses 0.4    
Net income (loss) $ 0.8