Earnings Per Share - Details of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 96,564	$ 46,064	$ 109,750	$ 86,230	$ 142,628	$ 195,980
Weighted average shares outstanding - basic	85,651		83,978		85,724	83,871
Dilutive effect of stock plans	1,283		1,505		1,428	1,617
Weighted average shares outstanding - diluted	86,934		85,483		87,152	85,488
Basic earnings per share	$ 1.13		$ 1.31		$ 1.66	$ 2.34
Diluted earnings per share	$ 1.11		$ 1.28		$ 1.64	$ 2.29
Anti-dilutive shares	26		0		27	0