Segments and Related Information (Schedule of Financial Information by Reportable Segment - Revenue) (Details) - USD ($) $ in Thousands		3 Months Ended											12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	[1]	Jun. 30, 2014	[1]	Mar. 31, 2014	[1]	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Revenue (in dollars)		$ 1,027,400	$ 1,111,000	$ 1,066,600	$ 1,003,300	$ 1,231,300	$ 1,315,500		$ 1,107,200		$ 957,800		$ 4,208,330	$ 4,611,803	$ 4,324,787
Communications [Member] | Customer Concentration Risk [Member] | Revenue [Member] | Utilities [Member]
Revenue:
Utilities customers, percentage of Communications segment revenue													10.60%	6.80%	6.90%
Reportable Segments [Member] | Communications [Member]
Revenue:
Revenue (in dollars)	[2]												$ 1,973,200	$ 2,041,000	$ 1,962,600
Reportable Segments [Member] | Oil and Gas [Member]
Revenue:
Revenue (in dollars)													1,495,100	1,731,400	1,628,800
Reportable Segments [Member] | Electrical Transmission [Member]
Revenue:
Revenue (in dollars)													341,500	471,900	428,800
Reportable Segments [Member] | Power Generation and Industrial [Member]
Revenue:
Revenue (in dollars)													381,600	357,000	294,300
Reportable Segments [Member] | Other [Member]
Revenue:
Revenue (in dollars)													24,100	14,700	12,300
Eliminations [Member]
Revenue:
Revenue (in dollars)													$ (7,200)	$ (4,200)	$ (2,000)

[1] Reflects restated data as previously presented in the Company’s 2014 10-K. See Independent Investigation of the Audit Committee and Related Restatements in Note 1 - Business, Basis of Presentation and Significant Accounting Policies.

[2] Revenue generated primarily by utilities customers represented 10.6%, 6.8% and 6.9% of Communications segment revenue for the years ended December 31, 2015, 2014 and 2013, respectively.