Segments and Related Information (Schedule of Financial Information by Reportable Segment - Capital Expenditures) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2014	Jun. 30, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Capital Expenditures:
Capital expenditures	$ 35,554	$ 67,566	$ 90,962	$ 109,254	$ 126,288	$ 79,686
Continuing Operations [Member]
Capital Expenditures:
Capital expenditures				109,300	126,100	79,400
Reportable Segments [Member] | Communications [Member]
Capital Expenditures:
Capital expenditures				23,400	25,100	19,200
Reportable Segments [Member] | Oil and Gas [Member]
Capital Expenditures:
Capital expenditures				44,200	67,400	40,300
Reportable Segments [Member] | Electrical Transmission [Member]
Capital Expenditures:
Capital expenditures				25,800	17,600	11,500
Reportable Segments [Member] | Power Generation and Industrial [Member]
Capital Expenditures:
Capital expenditures				6,700	5,700	5,600
Corporate [Member]
Capital Expenditures:
Capital expenditures				$ 9,200	$ 10,300	$ 2,800