Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accretion expense related to liabilities for contingent retirement obligations	$ 8,100,000	$ 6,500,000	$ 5,600,000
Asset retirement obligation	118,400,000	95,000,000
Asset retirement obligation future outlay	1,200,000,000
Sprint [Member]
Taxes, Other	27,700,000
Estimated future property tax commitment	43,700,000
ATT, TMO, WCP, and NextG Acquisitions [Member]
Increase (Decrease) in Asset Retirement Obligations	$ 16,300,000	$ 21,100,000