Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
EBITDA:
EBITDA	$ 114.0	$ 136.4
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	50.8	45.3
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	74.4	107.4
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	8.3	3.8
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	5.0	3.2
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	7.4	6.2
Corporate [Member]
EBITDA:
EBITDA	$ (31.9)	$ (29.5)