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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net income	$ 156,497	$ 161,915	$ 312,192	$ 285,061
Denominator:
Shares used for basic net income per share	163,074	162,413	163,067	162,203
Effect of dilutive securities:
Stock options (in shares)	48	62	27	37
RSUs and DSU (in shares)	1,359	1,640	1,513	1,659
Convertible senior notes (in shares)	1,782	653	1,369	327
Warrants related to issuance of convertible senior notes	0	0	0	0
Weighted Average Number of Shares Outstanding, Diluted, Total (in shares)	166,263	164,768	165,976	164,226
Basic net income per share (in dollars per share)	$ 0.96	$ 1.00	$ 1.91	$ 1.76
Diluted net income per share (in dollars per share)	$ 0.94	$ 0.98	$ 1.88	$ 1.74