Stock-Based Compensation Plans - Stock Option Activity (Detail) (USD $) In Thousands, except 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, Beginning balance	1,429,822	2,927,737	4,403,562
Number of Shares, Granted	51,597	13,292	340,771
Number of Shares, Canceled	(4,348)		(211,323)
Number of Shares, Exercised	(256,622)	(1,511,207)	(1,605,273)
Number of Shares, Ending Balance	1,220,449	1,429,822	2,927,737
Weighted Average Exercise Price, Beginning Balance	$ 13.62	$ 9.42	$ 9.09
Number of Shares, Exercisable	1,023,337
Weighted Average Exercise Price, Granted	$ 41.75	$ 32.45	$ 21.60
Weighted Average Exercise Price, Canceled	$ 33.84		$ 16.16
Weighted Average Exercise Price, Exercised	$ 12.33	$ 5.64	$ 10.21
Weighted Average Exercise Price, Ending Balance	$ 15.01	$ 13.62	$ 9.42
Remaining contractual term, Outstanding at December 31, 2013	4 years
Weighted Average Exercise Price, Exercisable	$ 12.68
Remaining contractual term, Exercisable at December 31, 2013	3 years 4 months 24 days
Intrinsic Value, Exercised	$ 10,723
Intrinsic Value, Ending Balance	63,369
Intrinsic Value, Exercisable	$ 55,515