CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 342,029	$ 341,159	$ 324,705
Cost of sales	(91,037)	(90,937)	(85,345)
Gross profit	250,992	250,222	239,360
Operating expenses:
Volume incentives	119,970	119,910	117,786
Selling, general and administrative	129,635	120,273	107,702
Operating income	1,387	10,039	13,872
Other income (expense):
Interest and other income, net	144	591	1,486
Interest expense	(289)	(16)	(130)
Foreign exchange gains (losses), net	1,980	(1,348)	(1,948)
Other income (expense), net	1,835	(773)	(592)
Income from continuing operations before provision for income taxes	3,222	9,266	13,280
Provision for income taxes	17,039	8,591	1,740
Net income (loss) from continuing operations	(13,817)	675	11,540
Income from discontinued operations	0	0	2,116
Net income (loss)	(13,817)	675	13,656
Net loss attributable to noncontrolling interests	(875)	(1,464)	(1,031)
Net income (loss) attributable to common shareholders	$ (12,942)	$ 2,139	$ 14,687
Basic earnings (loss) per share attributable to common shareholders:
Net income (loss) from continuing operations (in dollars per share)	$ (0.69)	$ 0.11	$ 0.67
Income from discontinued operations (in dollars per share)	0.00	0.00	0.11
Net Income (loss) per common share attributable to shareholders (in dollars per share)	(0.69)	0.11	0.79
Diluted earnings (loss) per share attributable to common shareholders:
Net income (loss) from continuing operations (in dollars per share)	(0.69)	0.11	0.66
Income from discontinued operations (in dollars per share)	0.00	0.00	0.11
Net Income (loss) per common share attributable to shareholders (in dollars per share)	$ (0.69)	$ 0.11	$ 0.77
Weighted average basic common shares outstanding (in shares)	18,882	18,731	18,656
Weighted average diluted common shares outstanding (in shares)	18,882	19,056	19,177
Dividends declared per common share (in dollars per share)	$ 0.10	$ 0.4	$ 0.4