v2.4.0.8
Basis of presentation and summary of significant accounting policies (Details)
9 Months Ended
Sep. 30, 2013
MW
state
province
project
Dec. 31, 2012
Delta-Person
Basis of presentation and summary of significant accounting policies    
Percentage of ownership interest   40.00%
Gross generating capacity of project (in MW) 3,018  
Ownership interest in operational power generation projects (in MW) 2,098  
Number of operational power generation projects 29  
Number of states in which power generation projects operate 11  
Number of provinces in which power generation projects operate 2  
Number of projects Which are wholly owned subsidiaries 23