Subsequent Events (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	May 02, 2014 Four and Seven Eigths Percent Secured Notes [Member]	May 02, 2014 Fixed Rate Securitized Debt January 2010 Tower Revenue Notes First Tranche [Member]	May 02, 2014 Fixed Rate - High Yield Bonds, 7.125% Senior Notes [Member]
Subsequent Event [Line Items]
Debt instrument, face amount			$ 850,000,000	$ 300,000,000
Gains (losses) on retirement of long-term obligations	0	(35,909,000)		4,000,000	41,000,000
Proceeds from issuance of long-term debt			$ 839,000,000
Stated interest rate			4.875%