v2.4.0.8
Segment and geographic information (Details 2) (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
Revenue and Assets          
Project Revenue $ 141.8 $ 106.3 $ 421.0 $ 326.4  
Property, plant, and equipment, net 1,873.9   1,873.9   2,055.5
United States
         
Revenue and Assets          
Project Revenue 98.0 61.0 264.7 171.9  
Property, plant, and equipment, net 1,368.0   1,368.0   1,504.8
Canada
         
Revenue and Assets          
Project Revenue 43.8 45.3 156.3 154.5  
Property, plant, and equipment, net $ 505.9   $ 505.9   $ 550.7