Quarterly report pursuant to Section 13 or 15(d)

Revenue and Contract Costs - Narrative (Details)

v3.7.0.1
Revenue and Contract Costs - Narrative (Details) - USD ($)
 3 Months Ended
Mar. 31, 2017
Dec. 31, 2016
Long-term Contracts or Programs Disclosure [Line Items]    
Contracts in progress $ 30,380,000 $ 26,829,000
Advance billings on contracts 4,762,000 $ 3,977,000
Loss related to disputed change orders 488,000  
Project, Approved Scope, Unapproved Price    
Long-term Contracts or Programs Disclosure [Line Items]    
Revenue 0  
One Major Customer | Customer Concentration Risk | Costs in Excess of Billings    
Long-term Contracts or Programs Disclosure [Line Items]    
Contracts in progress 22,900,000  
Two Major Customers | Customer Concentration Risk | Billings in Excess of Costs    
Long-term Contracts or Programs Disclosure [Line Items]    
Customer advances $ 3,800,000