Schedule Of Stock Compensation Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense recognized	$ 21,605	[1]	$ 14,954	[1]	$ 11,848	[1]
Tax benefit recognized	7,562		5,234		4,147
Weighted-average grant-date fair value of options granted	$ 15.70		$ 15.48		$ 10.35
Intrinsic value of options exercised	80,781		40,991		12,102
Cash received from options exercised	181,022		162,613		37,863
Actual tax benefit received from exercises	$ 28,086		$ 14,347		$ 4,236

[1] No stock-based compensation expense was capitalized in any period.