CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net sales	$ 385,205	$ 362,215
Cost of sales	(101,276)	(93,940)
Gross profit	283,929	268,275
Operating expenses:
Volume incentives	131,150	123,410
Selling, general and administrative	131,297	128,740
Operating income	21,482	16,125
Other income (expense):
Interest and other income, net	171	262
Interest expense	(102)	(43)
Foreign exchange gains (losses), net	1,270	(702)
Other income (expense), net	1,339	(483)
Income from operations before provision for income taxes	22,821	15,642
Provision (benefit) for income taxes	(137)	8,713
Net income	22,958	6,929
Net income attributable to noncontrolling interests	1,621	164
Net income attributable to common shareholders	$ 21,337	$ 6,765
Basic and diluted net income per common share
Basic earnings per share attributable to common shareholders (in dollars per share)	$ 1.09	$ 0.35
Diluted earnings per share attributable to common shareholders (in dollars per share)	$ 1.07	$ 0.34
Weighted average basic common shares outstanding (in shares)	19,537	19,314
Weighted average diluted common shares outstanding (in shares)	19,968	19,663