Common and Common Equivalent Shares - Schedule of Calculation of Shares Used in Basic and Diluted Net Income Per Common Share (Detail)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Earnings Per Share [Abstract]    
Weighted average number of common shares outstanding 94,231 99,076
Weighted average number of dilutive common share equivalents 1,094 1,620
Weighted average number of common and common equivalent shares outstanding 95,325 100,696
Antidilutive securities not included in the diluted net income per common share calculation   1