Fair Value Measurements - Summary of Fair Values, Principal Balances, and Carrying Values of Company's Debt Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Fair Value [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	$ 6,444,851	$ 6,478,465
Fair Value [Member] | 1.875% Convertible Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument		714,096
Fair Value [Member] | 4.000% Convertible Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	1,227,459	1,060,622
Fair Value [Member] | 8.250% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	263,250	272,391
Fair Value [Member] | 5.625% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	495,000	523,750
Fair Value [Member] | 5.750% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	796,000	848,000
Fair Value [Member] | 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	699,149	713,619
Fair Value [Member] | 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	593,868	621,379
Fair Value [Member] | 2.933% Secured Tower Revenue Securities Series 2012-1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	613,983	635,614
Fair Value [Member] | 2.240% Secured Tower Revenue Securities Series 2013-1C [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	413,865
Fair Value [Member] | 3.722% Secured Tower Revenue Securities Series 2013-2C [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	542,254
Fair Value [Member] | 3.598% Secured Tower Revenue Securities Series 2013-1D [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	319,285
Fair Value [Member] | Revolving Credit Facility [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument		100,000
Fair Value [Member] | 2011 Term Loan B [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	180,529	493,731
Fair Value [Member] | 2012-1 Term Loan A [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	190,238	194,513
Fair Value [Member] | 2012-2 Term Loan B [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	109,971	300,750
Principal Balance [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	5,694,223	5,440,073
Principal Balance [Member] | 1.875% Convertible Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument		468,836
Principal Balance [Member] | 4.000% Convertible Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	499,973	499,987
Principal Balance [Member] | 8.250% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	243,750	243,750
Principal Balance [Member] | 5.625% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	500,000	500,000
Principal Balance [Member] | 5.750% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	800,000	800,000
Principal Balance [Member] | 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	680,000	680,000
Principal Balance [Member] | 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	550,000	550,000
Principal Balance [Member] | 2.933% Secured Tower Revenue Securities Series 2012-1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	610,000	610,000
Principal Balance [Member] | 2.240% Secured Tower Revenue Securities Series 2013-1C [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	425,000
Principal Balance [Member] | 3.722% Secured Tower Revenue Securities Series 2013-2C [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	575,000
Principal Balance [Member] | 3.598% Secured Tower Revenue Securities Series 2013-1D [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	330,000
Principal Balance [Member] | Revolving Credit Facility [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument		100,000
Principal Balance [Member] | 2011 Term Loan B [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	180,529	492,500
Principal Balance [Member] | 2012-1 Term Loan A [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	190,000	195,000
Principal Balance [Member] | 2012-2 Term Loan B [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	109,971	300,000
Carrying Value [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	5,641,209	5,356,103
Carrying Value [Member] | 1.875% Convertible Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument		457,351
Carrying Value [Member] | 4.000% Convertible Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	448,988	430,751
Carrying Value [Member] | 8.250% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	242,295	242,205
Carrying Value [Member] | 5.625% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	500,000	500,000
Carrying Value [Member] | 5.750% Senior Notes [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	800,000	800,000
Carrying Value [Member] | 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	680,000	680,000
Carrying Value [Member] | 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	550,000	550,000
Carrying Value [Member] | 2.933% Secured Tower Revenue Securities Series 2012-1 [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	610,000	610,000
Carrying Value [Member] | 2.240% Secured Tower Revenue Securities Series 2013-1C [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	425,000
Carrying Value [Member] | 3.722% Secured Tower Revenue Securities Series 2013-2C [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	575,000
Carrying Value [Member] | 3.598% Secured Tower Revenue Securities Series 2013-1D [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	330,000
Carrying Value [Member] | Revolving Credit Facility [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument		100,000
Carrying Value [Member] | 2011 Term Loan B [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	180,201	491,518
Carrying Value [Member] | 2012-1 Term Loan A [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	190,000	195,000
Carrying Value [Member] | 2012-2 Term Loan B [Member]
Fair Value Inputs Assets Liabilities Quantitative Information [Line Items]
Debt instrument	$ 109,725	$ 299,278