Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Measurements [Abstract]

Summary Of Fair Values, Principal Balances, And Carrying Values Of Company's Debt Instruments

	As of December 31, 2013						As of December 31, 2012
	Fair Value		Principal Balance		Carrying Value		Fair Value		Principal Balance		Carrying Value
	(in thousands)
1.875% Convertible Senior Notes due 2013	$	—	$	—	$	—	$	714,096	$	468,836	$	457,351
4.000% Convertible Senior Notes due 2014		1,479,859		499,944		468,394		1,060,622		499,987		430,751
8.250% Senior Notes due 2019		262,031		243,750		242,387		272,391		243,750		242,205
5.625% Senior Notes due 2019		514,375		500,000		500,000		523,750		500,000		500,000
5.750% Senior Notes due 2020		832,000		800,000		800,000		848,000		800,000		800,000
4.254% 2010-1 Tower Securities		689,717		680,000		680,000		713,619		680,000		680,000
5.101% 2010-2 Tower Securities		586,586		550,000		550,000		621,379		550,000		550,000
2.933% 2012-1Tower Securities		604,736		610,000		610,000		635,614		610,000		610,000
2.240% 2013-1C Tower Securities		408,442		425,000		425,000		—		—		—
3.722% 2013-2C Tower Securities		530,098		575,000		575,000		—		—		—
3.598% 2013-1D Tower Securities		318,856		330,000		330,000		—		—		—
Revolving Credit Facility		215,000		215,000		215,000		100,000		100,000		100,000
2011 Term Loan B		180,980		180,529		180,234		493,731		492,500		491,518
2012-1 Term Loan A		184,538		185,000		185,000		194,513		195,000		195,000
2012-2 Term Loan B		110,383		109,971		109,745		300,750		300,000		299,278
BNDES Loans		5,847		5,847		5,847		—		—		—
Totals	$	6,923,448	$	5,910,041	$	5,876,607	$	6,478,465	$	5,440,073	$	5,356,103