Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA - Continuing Operations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
EBITDA - Continuing Operations:
EBITDA - Continuing operations	$ 441.5	$ 150.0	$ 403.7
Reportable Segments [Member] | Communications [Member]
EBITDA - Continuing Operations:
EBITDA - Continuing operations	244.6	194.8	204.0
Reportable Segments [Member] | Oil and Gas [Member]
EBITDA - Continuing Operations:
EBITDA - Continuing operations	297.3	157.0	195.1
Reportable Segments [Member] | Electrical Transmission [Member]
EBITDA - Continuing Operations:
EBITDA - Continuing operations	(42.9)	(71.3)	45.0
Reportable Segments [Member] | Power Generation and Industrial [Member]
EBITDA - Continuing Operations:
EBITDA - Continuing operations	18.3	8.8	14.2
Reportable Segments [Member] | Other [Member]
EBITDA - Continuing Operations:
EBITDA - Continuing operations	(2.6)	(18.8)	(1.2)
Corporate [Member]
EBITDA - Continuing Operations:
EBITDA - Continuing operations	$ (73.1)	$ (120.5)	$ (53.4)