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, 2015		Mar. 31, 2014
Numerator:
Net income used for calculating basic and diluted earnings per common share	$ 28,351		$ 37,736
Denominator:
Weighted average number of common shares used in the calculation of basic earnings per share	86,539		91,669
Common stock equivalents associated with stock-based compensation plans	1,234	[1]	1,540	[1]
Shares used in the calculation of diluted earnings per share	87,773		93,209
Basic earnings per share (in Dollars per share)	$ 0.33		$ 0.41
Diluted earnings per share (in Dollars per share)	$ 0.32		$ 0.40

[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 common share equivalents totaled less than 0.2 million in each of the periods presented.