v3.19.3.a.u2
Segment and geographic information - EBITDA (Detail)
$ in Millions
 3 Months Ended 12 Months Ended
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Sep. 30, 2018
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2019
USD ($)
segment
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Segment and geographic information                      
Number of reportable segments | segment                 4    
Project revenues $ 66.2 $ 71.1 $ 71.3 $ 73.0 $ 70.7 $ 65.4 $ 66.2 $ 80.0 $ 281.6 $ 282.3 $ 431.0
Segment assets 935.6       1,031.5       935.6 1,031.5 1,158.8
Goodwill 21.3       21.3       21.3 21.3 21.3
Capital expenditures                 7.3 1.8 5.5
Project Adjusted EBITDA                 196.1 185.1 288.8
Change in fair value of derivative instruments                 8.9 (2.2) (2.1)
Depreciation and amortization                 80.7 99.7 133.2
Interest, net                 2.5 3.4 19.2
Insurance loss                 1.0    
Impairment                 55.0   187.1
Other project (income) expense                 1.2 (4.0) (1.2)
Project income (loss) (33.4) $ 27.9 $ 21.7 $ 30.6 20.1 $ 26.2 $ 13.6 $ 28.3 46.8 88.2 (47.4)
Administration                 23.9 23.9 23.6
Interest expense, net                 44.0 52.7 64.2
Foreign exchange loss (gain)                 11.9 (22.8) 16.3
Other income (expenses), net                 1.0 (3.0) (0.4)
(Loss) income from operations before income taxes                 (34.0) 37.4 (151.1)
Income tax expense (benefit)                 9.8 0.2 (58.1)
Net income (loss)                 (43.8) 37.2 (93.0)
Solid Fuel                      
Segment and geographic information                      
Project revenues                 80.0 83.8 93.7
Segment assets 222.7       258.3       222.7 258.3 284.2
Capital expenditures                 6.8 1.3 4.7
Project Adjusted EBITDA                 32.7 46.7 54.9
Change in fair value of derivative instruments                     (8.1)
Depreciation and amortization                 23.9 23.7 30.4
Interest, net                 2.6 3.3 19.1
Insurance loss                 1.0    
Impairment                 55.0   76.2
Other project (income) expense                     (0.1)
Project income (loss)                 (49.8) 19.7 (62.6)
(Loss) income from operations before income taxes                 (49.8) 19.7 (62.6)
Net income (loss)                 (49.8) 19.7 (62.6)
Natural Gas                      
Segment and geographic information                      
Project revenues                 131.8 139.2 276.8
Segment assets 241.0       280.8       241.0 280.8 369.0
Goodwill 6.9       6.9       6.9 6.9 6.9
Capital expenditures                 0.1    
Project Adjusted EBITDA                 108.2 90.4 185.3
Change in fair value of derivative instruments                 1.4 (3.2) 7.9
Depreciation and amortization                 37.2 57.0 84.5
Interest, net                 (0.1) 0.1 0.1
Impairment                     96.2
Other project (income) expense                 1.2 3.2 (1.0)
Project income (loss)                 68.5 33.3 (2.4)
(Loss) income from operations before income taxes                 68.5 33.3 (2.4)
Net income (loss)                 68.5 33.3 (2.4)
Hydroelectric                      
Segment and geographic information                      
Project revenues                 68.8 58.3 59.5
Segment assets 388.3       404.5       388.3 404.5 408.8
Goodwill 14.4       14.4       14.4 14.4 14.4
Capital expenditures                 0.4 0.2 0.8
Project Adjusted EBITDA                 55.5 47.5 47.2
Depreciation and amortization                 19.5 18.9 17.7
Impairment                     14.7
Other project (income) expense                   (7.2)  
Project income (loss)                 36.0 35.8 14.8
(Loss) income from operations before income taxes                 36.0 35.8 14.8
Net income (loss)                 36.0 35.8 14.8
Corporate                      
Segment and geographic information                      
Project revenues                 1.0 1.0 1.0
Segment assets $ 83.6       $ 87.9       83.6 87.9 96.8
Capital expenditures                   0.3  
Project Adjusted EBITDA                 (0.3) 0.5 1.4
Change in fair value of derivative instruments                 7.5 1.0 (1.9)
Depreciation and amortization                 0.1 0.1 0.6
Other project (income) expense                     (0.1)
Project income (loss)                 (7.9) (0.6) 2.8
Administration                 23.9 23.9 23.6
Interest expense, net                 44.0 52.7 64.2
Foreign exchange loss (gain)                 11.9 (22.8) 16.3
Other income (expenses), net                 1.0 (3.0) (0.4)
(Loss) income from operations before income taxes                 (88.7) (51.4) (100.9)
Income tax expense (benefit)                 9.8 0.2 (58.1)
Net income (loss)                 $ (98.5) $ (51.6) $ (42.8)