Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Contract with Customer, Asset and Liability (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Contract with Customer, Asset and Liability (Details) - USD ($)
$ in Thousands
Jun. 30, 2018
Dec. 31, 2017
Accounting Policies [Abstract]    
Contract assets $ 551,505 $ 497,292
Contract liabilities $ 496,083 $ 433,387