Segments and Related Information (Schedule of Segment Reporting Information, by Segment - Capital Expenditures) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Capital expenditures	$ 126,288	$ 79,686	$ 71,710
Continuing Operations [Member]
Segment Reporting Information [Line Items]
Capital expenditures	126,100	79,400	71,000
Continuing Operations [Member] | Operating Segments [Member] | Communications [Member]
Segment Reporting Information [Line Items]
Capital expenditures	25,100	19,200	23,000
Continuing Operations [Member] | Operating Segments [Member] | Oil and Gas [Member]
Segment Reporting Information [Line Items]
Capital expenditures	67,400	40,300	25,700
Continuing Operations [Member] | Operating Segments [Member] | Electrical Transmission [Member]
Segment Reporting Information [Line Items]
Capital expenditures	17,600	11,500	9,300
Continuing Operations [Member] | Operating Segments [Member] | Power Generation and Industrial [Member]
Segment Reporting Information [Line Items]
Capital expenditures	5,700	5,600	4,600
Continuing Operations [Member] | Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Capital expenditures	0	0	0
Continuing Operations [Member] | Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Capital expenditures	$ 10,300	$ 2,800	$ 8,400