v2.4.0.6
Assets Held for Development (Summary) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Assets Held for Development [Line Items]    
Total assets held for development, net of impairment $ 331,770 $ 1,089,819
Land | Echelon Infrastructure
   
Assets Held for Development [Line Items]    
Assets held for development 453,013 215,969
Construction and Development Costs | Echelon Infrastructure
   
Assets Held for Development [Line Items]    
Assets held for development 499,842 500,787
Construction and Development Costs | Echelon Central Energy Facility
   
Assets Held for Development [Line Items]    
Assets held for development 163,519 163,806
Project Management and Other Costs | Echelon Infrastructure
   
Assets Held for Development [Line Items]    
Assets held for development 115,712 115,712
Professional and Design Fees | Echelon Infrastructure
   
Assets Held for Development [Line Items]    
Assets held for development 93,545 93,545
Echelon Development
   
Assets Held for Development [Line Items]    
Assets held for development 1,325,631 1,089,819
Impairment 993,861 0
Total assets held for development, net of impairment $ 331,770 $ 1,089,819