Net Income per Share (Tables)

6 Months Ended

Jun. 30, 2014

Earnings Per Share [Abstract]

Schedule of calculation of numerator and denominator in earnings per share

	Three Months Ended				Six Months Ended
	June 30,				June 30,
Net Income per Basic and Diluted Share:	2014		2013		2014		2013
(in thousands except per share amounts)
Numerator
Net income used to compute net income per basic share	$	92,055	$	93,742	$	164,938	$	147,213
Add back interest expense for convertible notes, net of estimated tax of approximately $0 and $3 for the three months ended June 30, 2014 and 2013, respectively, and $0 and $7 for the six months ended June 30, 2014 and 2013, respectively.	—		6		—		13
Net income used to compute net income per diluted share	$	92,055	$	93,748	$	164,938	$	147,226
Denominator
Weighted-average shares used to compute net income per basic share	160,256		139,825		155,752		139,821
Restricted stock outstanding	115		75		90		71
Effect of dilutive stock options	22		19		21		19
Assumed conversion of February 2018 Notes	1,872		—		1,484		—
Assumed conversion of Series 2012 Notes	4,487		8,304		7,570		8,693
Assumed conversion of May 2015 Notes	10,476		3,825		10,894		4,004
Assumed conversion of February 2015 Notes	—		176		—		176
Weighted-average shares used to compute net income per diluted share	177,228		152,224		175,811		152,784
Net income per share - basic	$	0.57	$	0.67	$	1.06	$	1.05
Net income per share - diluted	$	0.52	$	0.62	$	0.94	$	0.96