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		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Basic (shares)	80,942	81,437	80,981	81,349
Assumed dilution under stock plans (shares)	566	606	575	610
Diluted (shares)	81,508	82,043	81,556	81,959