Computation of Earnings Per Share (Detail) - Calculations Of Basic And Diluted Earnings Per Share (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Numerator:
Net income used for calculating basic and diluted earnings per common share (in Dollars)	$ 165,903		$ 136,902		$ 96,285
Denominator: (1)
Weighted average number of common shares used in the calculation of basic earnings per share	93,444	[1]	96,019	[1]	95,747	[1]
Common share equivalents associated with stock-based compensation plans	2,398	[1]	2,827	[1]	4,087	[1]
Shares used in the calculation of diluted earnings per share	95,842	[1]	98,846	[1]	99,834	[1]
Earnings per share:
Basic (in Dollars per share)	$ 1.78		$ 1.43		$ 1.01
Diluted (in Dollars per share)	$ 1.73		$ 1.39		$ 0.96

[1] During 2012, 2011 and 2010, the Company repurchased 2.7 million, 5.9 million, and 3.9 million shares of its Common Stock, respectively.