Summary Of Major Accounting Policies Summary of Major Accounting Policies - Inventory (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Inventory [Line Items]
Inventory Write-down	$ 0	$ 0	$ 30,490
Subsea Products Member
Inventory [Line Items]
Inventory Write-down			5,300
ROVs [Member]
Inventory [Line Items]
Inventory Write-down			$ 25,200