Schedule II - Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Provision for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of the Period	$ 0	$ 0	$ 0
Charged to Revenue, Cost or Expense	4,280	0	0
Deduction	0	0	0
Balance at the End of the Period	4,280	0	0
Reserve for losses on uncompleted contracts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at the Beginning of the Period	0	0	0
Charged to Revenue, Cost or Expense	22,770	0	0
Deduction	0	0	0
Balance at the End of the Period	$ 22,770	$ 0	$ 0