Segments and Related Information (Schedule of Financial Information by Reportable Segment - Depreciation and Amortization) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Depreciation and Amortization:
Depreciation and amortization	$ 60.5	$ 59.0
Reportable Segments [Member] | Communications [Member]
Depreciation and Amortization:
Depreciation and amortization	19.7	14.7
Reportable Segments [Member] | Oil and Gas [Member]
Depreciation and Amortization:
Depreciation and amortization	28.1	34.6
Reportable Segments [Member] | Electrical Transmission [Member]
Depreciation and Amortization:
Depreciation and amortization	5.9	4.5
Reportable Segments [Member] | Power Generation and Industrial [Member]
Depreciation and Amortization:
Depreciation and amortization	4.0	3.1
Reportable Segments [Member] | Other [Member]
Depreciation and Amortization:
Depreciation and amortization	0.0	0.0
Corporate [Member]
Depreciation and Amortization:
Depreciation and amortization	$ 2.8	$ 2.1