Segments and Related Information (Schedule of Segment Reporting Information, by Segment - Revenue) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Revenue	$ 964,029	$ 918,648
Operating Segments [Member] | Communications [Member]
Segment Reporting Information [Line Items]
Revenue	447,100	424,900
Operating Segments [Member] | Oil and Gas [Member]
Segment Reporting Information [Line Items]
Revenue	379,800	318,800
Operating Segments [Member] | Electrical Transmission [Member]
Segment Reporting Information [Line Items]
Revenue	80,100	84,600
Operating Segments [Member] | Power Generation and Industrial [Member]
Segment Reporting Information [Line Items]
Revenue	54,200	88,900
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Revenue	2,800	2,300
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue	$ 0	$ (900)