Revenue - Schedule of Marine Segment Revenue (Details) - Marine Services $ in Millions	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 377.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 158.6
Remaining performance obligation period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 178.2
Remaining performance obligation period	5 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 40.6
Remaining performance obligation period
Telecommunication - Installation
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 277.8
Telecommunication - Installation | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 76.4
Remaining performance obligation period	1 year
Telecommunication - Installation | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 160.8
Remaining performance obligation period	5 years
Telecommunication - Installation | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 40.6
Remaining performance obligation period
Telecommunication - Maintenance
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 13.8
Telecommunication - Maintenance | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 13.8
Remaining performance obligation period	1 year
Telecommunication - Maintenance | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 0.0
Remaining performance obligation period	5 years
Telecommunication - Maintenance | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 0.0
Remaining performance obligation period
Power - Operations, Maintenance & Construction Support
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 29.0
Power - Operations, Maintenance & Construction Support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 11.6
Remaining performance obligation period	1 year
Power - Operations, Maintenance & Construction Support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 17.4
Remaining performance obligation period	5 years
Power - Operations, Maintenance & Construction Support | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 0.0
Remaining performance obligation period
Power - Cable Installation & Repair
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 56.8
Power - Cable Installation & Repair | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 56.8
Remaining performance obligation period	1 year
Power - Cable Installation & Repair | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 0.0
Remaining performance obligation period	5 years
Power - Cable Installation & Repair | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Segment Reporting Information [Line Items]
Remaining performance obligations	$ 0.0
Remaining performance obligation period