Quarterly report pursuant to Section 13 or 15(d)

Revenue from Contracts with Customers - Additional Information (Details)

v3.19.2
Revenue from Contracts with Customers - Additional Information (Details) - USD ($)
 6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Contract with customer, liability, noncurrent $ 5,829,000   $ 6,343,000
Contract with customer, asset, reclassified to receivable 220,062,000 $ 285,321,000  
Contract with customer, asset, revenue recognized 201,908,000 236,327,000  
Contract with customer, liability, revenue recognized 38,854,000 60,492,000  
Contract with customer, liability, billings 35,172,000 50,119,000  
Revenue, remaining performance obligation $ 1,695,300,000    
Revenue, remaining performance obligation, percentage 29.00%    
Capitalized project development costs, noncurrent $ 211,000   $ 639,000
Capitalized contract cost, project development costs 11,033,000 6,010,000  
Capitalized contract cost, impairment loss $ 0 $ 0  
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%