Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
EBITDA:
EBITDA	$ 136.4	$ 104.6
Reportable Segments [Member] | Communications [Member]
EBITDA:
EBITDA	45.3	82.1
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA:
EBITDA	107.4	33.0
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA:
EBITDA	3.8	4.6
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA:
EBITDA	3.2	4.8
Reportable Segments [Member] | Other [Member]
EBITDA:
EBITDA	6.2	5.9
Corporate [Member]
EBITDA:
EBITDA	$ (29.5)	$ (25.8)