Net Income per Share (Net Income Per Basic and Diluted Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator
Income used to compute net income per diluted share	$ 60,439	$ 4,148	$ 67,680	$ 60,035
Denominator
Total weighted-average shares used to compute net income per basic share (in Shares)	155,654	163,791	159,677	163,729
Diluted (in Shares)	156,394	164,029	160,168	163,920
Basic (in Dollars per Share)	$ 0.39	$ 0.03	$ 0.42	$ 0.37
Net income per diluted share (in Dollars per Share)	$ 0.39	$ 0.03	$ 0.42	$ 0.37
Restricted Stock [Member]
Debt Instrument [Line Items]
Additional shares included in the calculation of diluted EPS (in Shares)	740	238	491	191