Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Disaggregation of Revenue (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2018
Disaggregation of Revenue [Line Items]    
Total revenues $ 2,656,348 $ 5,073,924
Unit-price contracts    
Disaggregation of Revenue [Line Items]    
Total revenues 1,018,145 1,631,583
Fixed price contracts    
Disaggregation of Revenue [Line Items]    
Total revenues 1,032,991 2,258,080
Cost-plus contracts    
Disaggregation of Revenue [Line Items]    
Total revenues 605,212 1,184,261
United States    
Disaggregation of Revenue [Line Items]    
Total revenues 2,193,437 3,905,864
Canada    
Disaggregation of Revenue [Line Items]    
Total revenues 315,173 853,531
Australia    
Disaggregation of Revenue [Line Items]    
Total revenues 113,880 233,337
Latin America and Other    
Disaggregation of Revenue [Line Items]    
Total revenues $ 33,858 $ 81,192