Net Income per Share - Schedule of Components Used in Diluted and Basic Income Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Numerator [Abstract]
Net income (in dollars)	$ 74,858	$ 77,746
Denominator [Abstract]
Shares used for basic net income per share	176,403	178,545
Effect of dilutive securities:
Convertible senior notes	0	0
Warrants related to issuance of convertible senior notes	0	0
Shares used for diluted net income per share	177,539	180,825
Basic net income per share (in dollars per share)	$ 0.42	$ 0.44
Diluted net income per share (in dollars per share)	$ 0.42	$ 0.43
Stock options
Effect of dilutive securities:
Dilutive securities	403	996
RSUs and deferred stock units
Effect of dilutive securities:
Dilutive securities	733	1,284