Quarterly Information (Unaudited) (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2014	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information [Line Items]
Quarterly financial information, explanatory disclosure				During the years ended December 31, 2014 and 2013, the Company acquired and disposed of certain businesses. As a result, the quarterly results of 2014 may not be comparable with those of 2013. Other transactions affecting comparisons of the Company’s quarterly results include: (i) $5.3 million of WesTower acquisition integration costs recorded in the fourth quarter of 2014; (ii) $5.6 million of debt extinguishment charges recorded in the first quarter of 2013; and (iii) $2.8 million of Sintel legal settlement charges recorded in the second quarter of 2013.
Loss on extinguishment of debt				$ 0	$ 5,624	$ 0
Sintel [Member] | Resolved Litigation [Member]
Quarterly Financial Information [Line Items]
Legal settlement charges		$ 2,800
7.625% Senior Notes [Member] | Senior Notes [Member]
Quarterly Financial Information [Line Items]
Loss on extinguishment of debt			$ 5,600		$ 5,600
Communications [Member]
Quarterly Financial Information [Line Items]
Business combinations, acquisition integration costs	$ 5,300