Debt (Secured Tower Revenue Securities) (Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended	12 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended		12 Months Ended		0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended		12 Months Ended		0 Months Ended		1 Months Ended	12 Months Ended		0 Months Ended			12 Months Ended	0 Months Ended	12 Months Ended			12 Months Ended		12 Months Ended
	Dec. 31, 2013 item	Dec. 31, 2012	Dec. 31, 2011	Apr. 16, 2010 4.254% 2010-1 Tower Securities [Member]	Dec. 31, 2013 4.254% 2010-1 Tower Securities [Member]	Dec. 31, 2012 4.254% 2010-1 Tower Securities [Member]	Apr. 16, 2010 5.101% 2010-2 Tower Securities [Member]	Dec. 31, 2013 5.101% 2010-2 Tower Securities [Member]	Dec. 31, 2012 5.101% 2010-2 Tower Securities [Member]	Apr. 16, 2010 2010 Secured Tower Revenue Securities [Member]	Aug. 09, 2012 2.933% 2012-1 Tower Securities [Member]	Dec. 31, 2013 2.933% 2012-1 Tower Securities [Member]	Dec. 31, 2012 2.933% 2012-1 Tower Securities [Member]	Apr. 18, 2013 2.240% 2013-1C Tower Securities [Member]	Dec. 31, 2013 2.240% 2013-1C Tower Securities [Member]	Apr. 18, 2013 3.722% 2013-2C Tower Securities [Member]	Dec. 31, 2013 3.722% 2013-2C Tower Securities [Member]	Apr. 18, 2013 3.598% 2013-1D Tower Securities [Member]	Dec. 31, 2013 3.598% 2013-1D Tower Securities [Member]	Apr. 18, 2013 2013 Secured Tower Revenue Securities [Member]	Apr. 18, 2013 Revolving Credit Facility [Member]	Dec. 31, 2013 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member]	Feb. 07, 2014 2011 Term Loan [Member]	Apr. 18, 2013 2011 Term Loan [Member]	Apr. 24, 2013 2011 Term Loan [Member]	Dec. 31, 2013 2011 Term Loan [Member]	Jun. 30, 2011 2011 Term Loan [Member]	Feb. 07, 2014 2012-2 Term Loan B [Member]	Apr. 24, 2013 2012-2 Term Loan B [Member]	Apr. 18, 2013 2012-2 Term Loan B [Member]	Dec. 31, 2013 2012-2 Term Loan B [Member]	May 16, 2008 1.875% Convertible Senior Notes [Member]	Dec. 31, 2013 1.875% Convertible Senior Notes [Member]	Apr. 18, 2013 1.875% Convertible Senior Notes [Member]	Dec. 31, 2012 1.875% Convertible Senior Notes [Member]	Dec. 31, 2013 Tower Securities [Member] site	Apr. 18, 2013 2010 Tower Securities, 2012-1 Tower Securities, and 2013 Tower Securities [Member]	Dec. 31, 2013 Minimum [Member] Tower Securities [Member]	Dec. 31, 2013 Excess Cash Flow Reserve Minimum [Member] Tower Securities [Member]	Dec. 31, 2013 Amortization Period Prepay Maximum [Member] Tower Securities [Member]
Debt Instrument [Line Items]
Debt instrument, face amount	$ 5,910,041,000	$ 5,440,073,000		$ 680,000,000	$ 680,000,000	$ 680,000,000	$ 550,000,000	$ 550,000,000	$ 550,000,000		$ 610,000,000	$ 610,000,000	$ 610,000,000	$ 425,000,000	$ 425,000,000	$ 575,000,000	$ 575,000,000	$ 330,000,000	$ 330,000,000	$ 1,330,000,000		$ 215,000,000	$ 100,000,000				$ 500,000,000	$ 500,000,000				$ 300,000,000				$ 468,836,000
Debt instrument, interest rate, stated percentage				4.254%	4.254%		5.101%	5.101%			2.933%	2.933%		2.24%	2.24%	3.722%	3.722%	3.598%	3.598%														1.875%	1.875%	1.875%
Debt instrument, weighted average interest rate										4.70%										3.218%
Repayment date of debt instrument				April 15, 2015			April 17, 2017				December 15, 2017			April 2018		April 2023		April 2018
Debt instrument, maturity date				Apr. 16, 2040	Apr. 15, 2015		Apr. 15, 2042	Apr. 17, 2017			Dec. 15, 2042	Dec. 15, 2017		Apr. 01, 2043	Apr. 17, 2018	Apr. 01, 2048	Apr. 17, 2023	Apr. 01, 2043	Apr. 17, 2018			May 09, 2017					Jun. 30, 2018					Sep. 28, 2019	May 01, 2013	May 01, 2013
Amortized deferred financing fees	15,560,000	12,870,000	9,188,000							18,000,000	14,900,000									25,300,000				1,100,000		2,300,000			1,000,000			2,000,000
Weighted average life of debt instrument through the anticipated repayment date																				7 years 2 months 12 days
Repayments of long-term debt																					100,000,000			180,500,000	310,700,000	310,700,000	312,000,000		110,000,000	189,300,000	189,300,000	190,000,000
Company Owned Tower Sites	20,079
Aggregate debt	$ 5,876,607,000	$ 5,356,103,000			$ 680,000,000	$ 680,000,000		$ 550,000,000	$ 550,000,000			$ 610,000,000	$ 610,000,000		$ 425,000,000		$ 575,000,000		$ 330,000,000			$ 215,000,000	$ 100,000,000				$ 180,500,000					$ 110,000,000				$ 457,351,000		$ 3,170,000,000
Aggregate number of tower sites owned by Borrowers																																					8,932
Property management fee percentage																																					7.50%
Additional interest rate for non-compliance																																							5.00%
U.S. Treasury rate term																																					10 years
Interest added to Treasury rate and credit-based spread for non-compliance																																					5.00%
Debt service coverage ratio																																								1.30	1.15