Share-Based Compensation - Summary of Company's Share-Based Compensation Activity and Related Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Beginning Balance, Shares	5,100
Granted, Shares	900
Exercised, Shares	(1,335)
Forfeited, Shares	(85)
Ending Balance, Shares	4,580
Exercisable at end of year, Shares	2,601
Shares available for future grants	2,743
Weighted-Average Exercise price, Beginning Balance	$ 50
Weighted-Average Exercise price, Granted	$ 77
Weighted-Average Exercise price, Exercised	$ 45
Weighted-Average Exercise price, Forfeited	$ 63
Weighted-Average Exercise price, Ending Balance	$ 56
Exercisable at end of year	$ 48