Net Income per Common Share - Summary of Calculation of Basic And Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net income	$ 66,604	$ 35,708	$ 56,622	$ 23,220	$ 102,312	$ 79,842
Weighted average common shares:
Basic	115,757		114,636		115,592	114,365
Dilutive effect of options and RSUs	1,162		2,057		1,134	2,330
Weighted average shares outstanding, diluted	116,919		116,693		116,726	116,695
Net income per share:
Basic	$ 0.58		$ 0.49		$ 0.89	$ 0.70
Diluted	$ 0.57		$ 0.49		$ 0.88	$ 0.68
Antidilutive and contingent options and RSUs excluded from diluted EPS	325		588		659	345