Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statements of Income [Abstract]
Revenue	$ 3,176,718	$ 2,132,257	$ 1,719,588
Cost of sales	505,806	353,152	322,624
Gross profit	2,670,912	1,779,105	1,396,964
Operating expenses:
Selling expenses	1,476,772	932,812	727,045
General and administrative expenses	640,028	505,449	436,177
Total operating expenses	2,116,800	1,438,261	1,163,222
Operating income	554,112	340,844	233,742
Other income (expense), net (Note 23)	2,828	4,398	(6,973)
Income before provision for income taxes	556,940	345,242	226,769
Provision for income taxes	192,052	123,597	73,439
Net income	$ 364,888	$ 221,645	$ 153,330
Net income per share:
Basic (in dollars per share)	$ 6.23	$ 3.66	$ 2.47
Diluted (in dollars per share)	$ 5.94	$ 3.52	$ 2.38
Weighted-average common shares outstanding (000s):
Basic (in shares)	58,606	60,600	62,066
Diluted (in shares)	61,448	63,025	64,546