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				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Numerator:
Net income used for calculating basic and diluted earnings per share	$ 33,846		$ 38,194		$ 124,622		$ 121,383
Denominator:
Weighted average number of common shares used in the calculation of basic earnings per share	88,513		92,689		89,901		93,286
Common stock equivalents associated with stock-based compensation plans	1,195	[1]	1,666	[1]	1,372	[1]	1,814	[1]
Shares used in the calculation of diluted earnings per share	89,708		94,355		91,273		95,100
Basic earnings per share (in Dollars per share)	$ 0.38		$ 0.41		$ 1.39		$ 1.30
Diluted earnings per share (in Dollars per share)	$ 0.38		$ 0.40		$ 1.37		$ 1.28

[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 less than 0.4 million in each of the periods presented.