Segments and Related Information (Schedule of Financial Information by Reportable Segment - Depreciation and Amortization) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Depreciation and Amortization:
Depreciation and amortization	$ 82.6	$ 55.2	$ 210.6	$ 174.2
Reportable Segments [Member] | Communications [Member]
Depreciation and Amortization:
Depreciation and amortization	21.1	15.7	62.1	45.7
Reportable Segments [Member] | Oil and Gas [Member]
Depreciation and Amortization:
Depreciation and amortization	47.5	28.8	107.7	97.7
Reportable Segments [Member] | Electrical Transmission [Member]
Depreciation and Amortization:
Depreciation and amortization	6.2	5.1	18.6	14.8
Reportable Segments [Member] | Clean Energy and Infrastructure [Member]
Depreciation and Amortization:
Depreciation and amortization	5.0	3.3	13.7	9.7
Reportable Segments [Member] | Other [Member]
Depreciation and Amortization:
Depreciation and amortization	0.0	0.0	0.0	0.1
Corporate [Member]
Depreciation and Amortization:
Depreciation and amortization	$ 2.8	$ 2.3	$ 8.5	$ 6.2