Summary Of Major Accounting Policies - Property, Plant and Equipment and Long-Lived Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Interest Costs Capitalized		$ 3,400
Remotely Operated Vehicles [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Operating Lease Term	8 years
Marine Services Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Operating Lease Term	25 years
Marine Services Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Operating Lease Term	3 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Operating Lease Term	25 years
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Operating Leases, Operating Lease Term	3 years