Segments and Related Information (Schedule of Financial Information by Reportable Segment - Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue:
Revenue	$ 1,962,658	$ 1,569,297	$ 3,738,082	$ 2,985,901
Communications | Customer Concentration Risk | Revenue | Utilities
Revenue:
Utilities customers, percentage of communications segment revenue	20.60%	14.90%	20.40%	15.00%
Reportable Segments | Communications
Revenue:
Revenue	$ 630,400	$ 654,300	$ 1,199,000	$ 1,298,400
Reportable Segments | Clean Energy and Infrastructure
Revenue:
Revenue	481,500	426,100	831,900	712,400
Reportable Segments | Oil and Gas
Revenue:
Revenue	621,400	368,500	1,346,900	727,600
Reportable Segments | Electrical Transmission
Revenue:
Revenue	232,500	124,100	366,000	252,200
Reportable Segments | Other
Revenue:
Revenue	0	100	0	100
Eliminations
Revenue:
Revenue	$ (3,100)	$ (3,800)	$ (5,700)	$ (4,800)