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, 2017	Mar. 31, 2016
Numerator [Abstract]
Net income (in dollars)	$ 80,930	$ 74,858
Denominator [Abstract]
Shares used for basic net income per share	173,158	176,403
Effect of dilutive securities:
Convertible senior notes (in shares)	0	0
Warrants related to issuance of convertible senior notes (in shares)	0	0
Shares used for diluted net income per share	175,171	177,539
Basic net income per share (in dollars per share)	$ 0.47	$ 0.42
Diluted net income per share (in dollars per share)	$ 0.46	$ 0.42
Stock options
Effect of dilutive securities:
Dilutive securities (in shares)	360	403
RSUs and deferred stock units
Effect of dilutive securities:
Dilutive securities (in shares)	1,653	733