Annual report pursuant to Section 13 and 15(d)

Contract Receivable - Additional Information (Detail)

v2.4.0.6
Contract Receivable - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Long-term Contracts or Programs Disclosure [Line Items]    
Contract receivable $ 60,535 $ 72,474
Contracts In Progress
   
Long-term Contracts or Programs Disclosure [Line Items]    
Contract receivable 71,723 60,977
Cheviot Project
   
Long-term Contracts or Programs Disclosure [Line Items]    
Contract receivable 31,300  
Cheviot Project | Contracts In Progress
   
Long-term Contracts or Programs Disclosure [Line Items]    
Contract receivable $ 31,300