Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Income [Abstract]
Revenue	$ 2,420,416	$ 2,679,008	$ 2,279,099
Cost of sales	581,420	634,140	502,078
Gross profit	1,838,996	2,044,868	1,777,021
Operating expenses:
Selling expenses	955,600	1,071,020	938,024
General and administrative expenses	615,970	662,302	564,514
Restructuring and impairment expenses	0	70,686	0
Total operating expenses	1,571,570	1,804,008	1,502,538
Operating income	267,426	240,860	274,483
Other income (expense), net (Note 20)	(12,254)	(21,194)	(8,916)
Income before provision for income taxes	255,172	219,666	265,567
Provision for income taxes	81,619	97,779	136,130
Net income	$ 173,553	$ 121,887	$ 129,437
Net income per share:
Basic (in dollars per share)	$ 3.13	$ 2.21	$ 2.45
Diluted (in dollars per share)	$ 3.10	$ 2.16	$ 2.36
Weighted-average common shares outstanding:
Basic (in shares)	55,518	55,170	52,806
Diluted (in shares)	55,927	56,476	54,852