v2.4.0.8
Segment and geographic information (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Segment and geographic information          
Project revenues $ 141.8 $ 106.3 $ 421.0 $ 326.4  
Segment assets 3,496.7 3,644.0 3,496.7 3,644.0 4,002.7
Project Adjusted EBITDA 76.2 57.4 213.3 170.7  
Change in fair value of derivative instruments 3.5 (10.8) (34.8) 48.9  
Depreciation and amortization 51.4 41.8 154.5 123.0  
Interest, net 10.6 5.8 30.5 18.1  
Other project (income) expense 5.9 0.9 5.8 4.4  
Project income (loss) 4.8 19.7 57.3 (23.7)  
Administration 8.4 6.3 28.5 22.0  
Interest, net 27.5 25.8 78.7 69.3  
Foreign exchange gain (loss) 9.1 7.7 (12.9) 4.4  
Other expense, net   0.3 (9.5) (5.7)  
Loss from continuing operations before income taxes (40.2) (20.4) (27.5) (113.7)  
Income tax benefit   3.1 (1.9) (19.1)  
Net income (loss) from continuing operations (40.2) (23.5) (25.6) (94.6)  
Income (loss) from discontinued operations (0.4) 19.0 (6.1) 48.8  
Net income (loss) (40.6) (4.5) (31.7) (45.8)  
Rollcast
          
Segment and geographic information          
Ownership interest (as a percent)     60.00%    
Operating Segments | Northeast
          
Segment and geographic information          
Project revenues 47.3 43.8 167.9 156.6  
Segment assets 1,134.8 1,157.9 1,134.8 1,157.9  
Project Adjusted EBITDA 24.9 20.3 96.8 85.2  
Change in fair value of derivative instruments 3.5 (10.2) (12.9) 46.3  
Depreciation and amortization 17.8 20.4 55.7 58.0  
Interest, net 4.1 4.5 12.8 13.9  
Other project (income) expense 31.4 0.3 32.3 0.8  
Project income (loss) (31.9) 5.3 8.9 (33.8)  
Loss from continuing operations before income taxes (31.9) 5.3 8.9 (33.8)  
Net income (loss) from continuing operations (31.9) 5.3 8.9 (33.8)  
Net income (loss) (31.9) 5.3 8.9 (33.8)  
Operating Segments | Southeast
          
Segment and geographic information          
Project revenues 10.6   16.8    
Segment assets 177.4 446.3 177.4 446.3  
Project Adjusted EBITDA 5.9 2.3 10.4 6.5  
Change in fair value of derivative instruments 0.5 (0.6) (3.1) 2.6  
Depreciation and amortization 3.4 1.4 7.9 4.3  
Interest, net 1.4   2.6    
Other project (income) expense     0.1    
Project income (loss) 0.6 1.5 2.9 (0.4)  
Loss from continuing operations before income taxes 0.6 1.5 2.9 (0.4)  
Net income (loss) from continuing operations 0.6 1.5 2.9 (0.4)  
Income (loss) from discontinued operations   19.3 (1.1) 49.5  
Net income (loss) 0.6 20.8 1.8 49.1  
Operating Segments | Northwest
          
Segment and geographic information          
Project revenues 23.5 15.0 69.5 46.9  
Segment assets 1,113.3 852.0 1,113.3 852.0  
Project Adjusted EBITDA 19.4 12.6 53.0 38.5  
Change in fair value of derivative instruments (0.5)   (18.8)    
Depreciation and amortization 15.1 10.7 45.7 31.7  
Interest, net 4.8 1.2 14.2 3.8  
Project income (loss) 0 0.7 11.9 3.0  
Loss from continuing operations before income taxes 0 0.7 11.9 3.0  
Net income (loss) from continuing operations 0 0.7 11.9 3.0  
Net income (loss) 0 0.7 11.9 3.0  
Operating Segments | Southwest
          
Segment and geographic information          
Project revenues 61.0 47.7 167.7 121.7  
Segment assets 913.9 1,162.6 913.9 1,162.6  
Project Adjusted EBITDA 29.5 23.4 64.5 48.0  
Depreciation and amortization 14.9 9.3 44.7 28.9  
Interest, net 0.4 0.1 0.9 0.4  
Other project (income) expense (26.3) 0.2 (26.6) 2.9  
Project income (loss) 40.5 13.8 45.5 15.8  
Loss from continuing operations before income taxes 40.5 13.8 45.5 15.8  
Net income (loss) from continuing operations 40.5 13.8 45.5 15.8  
Income (loss) from discontinued operations   0.8 1.3 1.5  
Net income (loss) 40.5 14.6 46.8 17.3  
Un-allocated Corporate
          
Segment and geographic information          
Project revenues (0.6) (0.2) (0.9) 1.2  
Segment assets 157.3 25.2 157.3 25.2  
Project Adjusted EBITDA (3.5) (1.2) (11.4) (7.5)  
Depreciation and amortization 0.2   0.5 0.1  
Interest, net (0.1)        
Other project (income) expense 0.8 0.4   0.7  
Project income (loss) (4.4) (1.6) (11.9) (8.3)  
Administration 8.4 6.3 28.5 22.0  
Interest, net 27.5 25.8 78.7 69.3  
Foreign exchange gain (loss) 9.1 7.7 (12.9) 4.4  
Other expense, net   0.3 (9.5) (5.7)  
Loss from continuing operations before income taxes (49.4) (41.7) (96.7) (98.3)  
Income tax benefit (4.1) 3.1 (1.9) (19.1)  
Net income (loss) from continuing operations (45.3) (44.8) (94.8) (79.2)  
Income (loss) from discontinued operations (0.4) (1.1) (6.3) (2.2)  
Net income (loss) $ (45.7) $ (45.9) $ (101.1) $ (81.4)