Quarterly Results of Operations (UNAUDITED) (Results of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 173,000	$ 165,259	$ 157,489	$ 160,566	$ 152,928	$ 160,366	$ 163,098	$ 165,051	$ 656,314	[1]	$ 641,443	[1]	$ 610,911	[1]
Gross margin	66,849	61,929	60,199	60,508	52,604	59,672	60,661	62,425	$ 249,485		$ 235,362		$ 234,753
Income (loss) from continuing operations	$ 11,913	$ 16,065	$ 5,377	$ 14,928	$ 6,577	$ 12,546	$ 13,554	$ 13,643
Net income per share:
Basic income from continuing operations (in dollars per share)	$ 0.66	$ 0.89	$ 0.30	$ 0.83	$ 0.37	$ 0.68	$ 0.73	$ 0.74
Diluted income from continuing operations (in dollars per share)	$ 0.65	$ 0.88	$ 0.29	$ 0.82	$ 0.37	$ 0.67	$ 0.71	$ 0.72

[1] Net sales are allocated to countries based on the location of the customer.