v2.4.0.6
Segment and geographic information (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Dec. 31, 2012
Segment and related information      
Project revenues $ 140.2 $ 118.7  
Segment assets 3,939.4 3,475.7 4,002.7
Project Adjusted EBITDA 80.6 66.6  
Change in fair value of derivative instruments (11.5) 57.5  
Depreciation and amortization 52.4 39.9  
Interest, net 9.5 6.0  
Other project (income) expense (0.9) 0.2  
Project income (loss) 31.1 (37.0)  
Administration 8.3 7.7  
Interest, net 25.9 22.0  
Foreign exchange loss (gain) (7.5) 1.0  
Income (loss) from continuing operations before income taxes 4.4 (67.7)  
Income tax benefit (2.5) (16.9)  
Net income (loss) from continuing operations 6.9 (50.8)  
Income from discontinued operations 0.9 11.6  
Net income (loss) 7.8 (39.2)  
Rollcast
      
Segment and related information      
Ownership interest (as a percent) 60.00%    
Northeast
      
Segment and related information      
Project revenues 67.8 67.2  
Segment assets 1,147.1 1,198.7  
Project Adjusted EBITDA 45.9 42.4  
Change in fair value of derivative instruments (8.1) 58.0  
Depreciation and amortization 20.1 17.4  
Interest, net 4.4 4.7  
Other project (income) expense 0.4 0.2  
Project income (loss) 29.1 (37.9)  
Income (loss) from continuing operations before income taxes 29.1 (37.9)  
Net income (loss) from continuing operations 29.1 (37.9)  
Net income (loss) 29.1 (37.9)  
Southeast
      
Segment and related information      
Segment assets 372.6 431.0  
Project Adjusted EBITDA 2.1 2.1  
Change in fair value of derivative instruments (1.3) (0.5)  
Depreciation and amortization 1.5 1.4  
Project income (loss) 1.9 1.2  
Income (loss) from continuing operations before income taxes 1.9 1.2  
Net income (loss) from continuing operations 1.9 1.2  
Income from discontinued operations 0.3 10.6  
Net income (loss) 2.2 11.8  
Northwest
      
Segment and related information      
Project revenues 24.7 15.3  
Segment assets 1,192.6 825.0  
Project Adjusted EBITDA 21.3 13.4  
Change in fair value of derivative instruments (3.0)    
Depreciation and amortization 15.8 10.4  
Interest, net 4.7 1.1  
Project income (loss) 3.8 1.9  
Income (loss) from continuing operations before income taxes 3.8 1.9  
Net income (loss) from continuing operations 3.8 1.9  
Net income (loss) 3.8 1.9  
Southwest
      
Segment and related information      
Project revenues 48.0 35.5  
Segment assets 1,143.8 940.7  
Project Adjusted EBITDA 16.0 12.1  
Depreciation and amortization 15.0 10.6  
Interest, net 0.2    
Other project (income) expense   0.1  
Project income (loss) 0.8 1.4  
Income (loss) from continuing operations before income taxes 0.8 1.4  
Net income (loss) from continuing operations 0.8 1.4  
Income from discontinued operations 0.6 1.0  
Net income (loss) 1.4 2.4  
Un-allocated Corporate
      
Segment and related information      
Project revenues (0.3) 0.7  
Segment assets 83.3 80.3  
Project Adjusted EBITDA (4.7) (3.4)  
Change in fair value of derivative instruments 0.9    
Depreciation and amortization   0.1  
Interest, net 0.2 0.2  
Other project (income) expense (1.3) (0.1)  
Project income (loss) (4.5) (3.6)  
Administration 8.3 7.7  
Interest, net 25.9 22.0  
Foreign exchange loss (gain) (7.5) 1.0  
Income (loss) from continuing operations before income taxes (31.2) (34.3)  
Income tax benefit (2.5) (16.9)  
Net income (loss) from continuing operations (28.7) (17.4)  
Net income (loss) $ (28.7) $ (17.4)