Segments and Related Information (Schedule of Financial Information by Reportable Segment - Revenue) (Details) - USD ($) $ in Thousands		3 Months Ended									6 Months Ended	9 Months Ended	12 Months Ended
		Dec. 31, 2014	[1]	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2014	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue:
Revenue (in dollars)		$ 1,231,300		$ 1,315,488	$ 1,107,232	$ 957,818	$ 1,159,100	$ 1,269,400	$ 977,600	$ 918,600	$ 2,065,050	$ 3,380,538	$ 4,611,803	$ 4,324,787	$ 3,726,789
Communications [Member] | Customer Concentration Risk [Member] | Revenue [Member] | Utilities [Member]
Revenue:
Utilities customers, percentage of Communications segment revenue													6.80%	6.90%	10.90%
Electrical Transmission [Member]
Revenue:
Revenue (in dollars)				$ 138,000	$ 117,000	$ 74,000					$ 191,000	$ 329,000
Reportable Segments [Member] | Communications [Member]
Revenue:
Revenue (in dollars)	[2]												$ 2,041,000	$ 1,962,600	$ 1,772,700
Reportable Segments [Member] | Oil and Gas [Member]
Revenue:
Revenue (in dollars)													1,731,400	1,628,800	959,000
Reportable Segments [Member] | Electrical Transmission [Member]
Revenue:
Revenue (in dollars)													471,900	428,800	312,200
Reportable Segments [Member] | Power Generation and Industrial [Member]
Revenue:
Revenue (in dollars)													357,000	294,300	668,100
Reportable Segments [Member] | Other [Member]
Revenue:
Revenue (in dollars)													14,700	12,300	16,700
Eliminations [Member]
Revenue:
Revenue (in dollars)													$ (4,200)	$ (2,000)	$ (1,900)

[1] Preliminary, unaudited fourth quarter and full year 2014 results were previously issued pursuant to a press release dated February 26, 2015 and not previously filed in a report under the Securities Exchange Act of 1934, as amended. The unaudited quarterly information for the three month period ended December 31, 2014 in the table above includes the effect of adjustments determined by management following the review process described in Note 2 - Independent Investigation of the Audit Committee and Related Restatements.

[2] Revenue generated by utilities customers represented 6.8%, 6.9% and 10.9% of Communications segment revenue in 2014, 2013 and 2012, respectively.