Annual report pursuant to Section 13 and 15(d)

Revenue from Contracts with Customers - Additional Information (Details)

v3.10.0.1
Revenue from Contracts with Customers - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Jan. 01, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]    
Contract with customer, liability, noncurrent $ 6,342,000  
Contract with customer, asset, reclassified to receivable 510,470,000  
Contract with customer, asset, revenue recognized 485,143,000  
Contract with customer, liability, revenue recognized 95,318,000  
Contract with customer, liability, billings 80,007,000  
Revenue, remaining performance obligation $ 1,660,800,000  
Revenue, remaining performance obligation, percentage 25.00%  
Capitalized commission costs $ 927,000 $ 927,000
Impairment charges in connection with the the Company's commissionn costs or project development costs 0  
Capitalized contract cost, project development costs $ 15,672,000  
Minimum    
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]    
Contract receivable retainage percentage 5.00%  
Maximum    
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]    
Contract receivable retainage percentage 10.00%  
Accounting Standards Update 2014-09    
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]    
Increase (decrease) in retained earnings   $ 4,454,000