Shareholders' Equity - Summary of Information about Stock Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years
Number of shares
Outstanding Beginning Balance	16,293,671
Options granted	2,998,390
Options exercised	(1,605,342)
Options forfeited	(409,163)
Options cancelled	(25,327)
Outstanding Ending Balance	17,252,229
Exercisable at December 31, 2011	8,422,318
Weighted average exercise price per share
Outstanding Beginning Balance	$ 34.11
Options granted	$ 52.80
Options exercised	$ 20.20
Options forfeited	$ 42.59
Options cancelled	$ 38.76
Outstanding Ending Balance	$ 38.45
Exercisable at December 31, 2011	$ 32.07
Weighted average remaining contractual life
Outstanding at December 31, 2011	5.85
Exercisable at December 31, 2011	3.48
Aggregate intrinsic value
Outstanding at December 31, 2011	$ 98,668
Exercisable at December 31, 2011	$ 89,452