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		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income	$ 178,916	$ 158,623	$ 491,108	$ 443,684
Denominator:
Shares used for basic net income per share	162,767	162,757	162,967	162,387
Effect of dilutive securities:
Stock options (in shares)	3	6	19	27
RSUs and DSU (in shares)	1,520	2,024	1,515	1,781
Convertible senior notes (in shares)	2,028	1,732	1,589	795
Warrants related to issuance of convertible senior notes	0	0	0	0
Shares used for diluted net income per share	166,318	166,519	166,090	164,990
Basic net income per share (in dollars per share)	$ 1.10	$ 0.97	$ 3.01	$ 2.73
Diluted net income per share (in dollars per share)	$ 1.08	$ 0.95	$ 2.96	$ 2.69