Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Consolidated Statements of Income (Unaudited) [Abstract]
Revenue	$ 543,332	$ 671,061
Cost of sales	105,055	106,644
Gross profit	438,277	564,417
Operating expenses:
Selling expenses	234,005	313,101
General and administrative expenses	135,626	150,119
Total operating expenses	369,631	463,220
Operating income	68,646	101,197
Other income (expense), net	(12,268)	(17,508)
Income before provision for income taxes	56,378	83,689
Provision for income taxes	20,096	28,835
Net income	$ 36,282	$ 54,854
Net income per share (Note 2):
Basic (in dollars per share)	$ 0.62	$ 0.93
Diluted (in dollars per share)	$ 0.60	$ 0.90
Weighted-average common shares outstanding (000s):
Basic (in shares)	58,991,000	58,869,000
Diluted (in shares)	60,261,000,000	61,227,000,000