Net Income Per Share - Reconciliation of Shares Used in Computation of Basic and Diluted Net Income Per Share (Detail) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Basic (shares)	80,949	81,309	81,003	81,300
Assumed dilution under stock plans (shares)	481	732	580	718
Diluted (shares)	81,430	82,041	81,583	82,018