Share-Based Compensation - Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding Beginning Balance	5,711	6,059	5,836
Number of Shares, Granted	1,453	930	831
Number of Shares, Exercised	(1,443)	(1,218)	(582)
Number of Shares, Forfeited	(1)	(60)	(26)
Number of Shares, Outstanding Ending Balance	5,720	5,711	6,059
Weighted Average Exercise Price, Outstanding	$ 20.86	$ 15.31	$ 12.74
Number of Shares, Exercisable at December 31, 2013	1,971
Weighted Average Exercise Price, Granted	$ 67.08	$ 43.53	$ 26.83
Weighted Average Exercise Price, Exercised	$ 12.68	$ 10.22	$ 6.10
Weighted Average Exercise Price, Forfeited	$ 68.17	$ 28.07	$ 15.78
Weighted Average Exercise Price, Outstanding	$ 34.66	$ 20.86	$ 15.31
Weighted Average Exercise Price, Exercisable at December 31, 2013	$ 15.41
Weighted Average Remaining Contractual Life (Years), Outstanding at December 31, 2013	7 years
Weighted Average Remaining Contractual Life (Years), Exercisable at December 31, 2013	5 years
Aggregate Intrinsic Value, Outstanding at December 31, 2013	$ 385,868
Aggregate Intrinsic Value, Exercisable at December 31, 2013	$ 170,956