Earnings per Share (Detail) - Calculations Of Basic And Diluted Earnings Per Share (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Numerator:
Net income used for calculating basic and diluted earnings per share	$ 37,736		$ 36,675
Denominator:
Weighted average number of common shares used in the calculation of basic earnings per share	91,669		93,595
Common stock equivalents associated with stock-based compensation plans	1,540	[1]	1,942	[1]
Shares used in the calculation of diluted earnings per share	93,209		95,537
Basic earnings per share (in Dollars per share)	$ 0.41		$ 0.39
Diluted earnings per share (in Dollars per share)	$ 0.40		$ 0.38

[1] Certain common stock equivalents were not included in the computation of diluted earnings per share because the effect would have been anti-dilutive. These shares totaled 0.2 million for both the three months ended March 31, 2014 and 2013.