Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net income from continuing operations	$ 48,769	$ 41,132	$ 50,744	$ 177,043
Net income from discontinued operations, net of tax	2,681	0	14,306	0
Net income	$ 51,450	$ 41,132	$ 65,050	$ 177,043
Weighted-average shares used to calculate basic EPS	71,190	57,082	69,689	56,894
Effect of dilutive securities:
Employee equity awards (in shares)	718	626	700	627
Weighted-average shares used to calculate diluted EPS	71,908	57,708	70,389	57,521
Basic EPS from continuing operations (in dollars per share)	$ 0.69	$ 0.72	$ 0.73	$ 3.11
Basic EPS from discontinued operations (in dollars per share)	0.04	0.00	0.21	0.00
Basic EPS (in dollars per share)	0.73	0.72	0.94	3.11
Diluted EPS from continuing operations (in dollars per share)	0.68	0.71	0.72	3.08
Diluted EPS from discontinued operations (in dollars per share)	0.04	0.00	0.20	0.00
Diluted EPS (in dollars per share)	$ 0.72	$ 0.71	$ 0.92	$ 3.08