Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net sales	$ 796,392	$ 763,520	$ 719,168
Cost of sales	365,351	355,190	337,466
Gross profit	431,041	408,330	381,702
Selling and administrative expense	351,799	338,400	303,091
Research and development expense	32,307	32,254	27,436
Total operating expenses	384,106	370,654	330,527
Income from operations	46,935	37,676	51,175
Other expense	0	2,942	0
Interest expense	18,203	15,359	6,031
Income before income taxes	28,732	19,375	45,144
Provision (benefit) for income taxes	(26,755)	4,711	14,646
Net income	$ 55,487	$ 14,664	$ 30,498
Earnings per share:
Basic (in dollars per share)	$ 1.99	$ 0.53	$ 1.10
Diluted (in dollars per share)	1.97	0.52	1.09
Dividends per share of common stock (in dollars per share)	$ 0.80	$ 0.80	$ 0.80
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments	$ 13,879	$ (4,501)	$ (16,775)
Pension liability	1,023	(755)	7,578
Cash flow hedging gain (loss)	(8,051)	547	(3,291)
Other comprehensive income, before tax	62,338	9,955	18,010
Provision (benefit) for income taxes related to items of other comprehensive income	(2,597)	(77)	1,584
Comprehensive income	$ 64,935	$ 10,032	$ 16,426