Quarterly Results of Operations (UNAUDITED) (Results of Operations) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 147,724	$ 163,052	$ 153,495	$ 146,640	$ 136,231	$ 142,820	$ 132,452	$ 125,979	$ 610,911	[1]	$ 537,482	[1]	$ 498,761	[1]
Gross margin	58,335	64,548	57,138	53,919	50,796	51,186	44,429	41,289	233,939		187,700		158,746
Income (loss) from continuing operations	$ 7,013	$ 20,388	$ 10,902	$ 14,580	$ 11,528	$ 13,572	$ 5,583	$ 6,976	$ 52,883		$ 37,659		$ 69,134
Net income per basic share (in dollars per share)	$ 0.38	$ 1.12	$ 0.60	$ 0.81	$ 0.66	$ 0.79	$ 0.33	$ 0.41	$ 2.91		$ 2.19		$ 4.21
Net income per diluted share (in dollars per share)	$ 0.37	$ 1.09	$ 0.58	$ 0.79	$ 0.64	$ 0.76	$ 0.32	$ 0.39	$ 2.83		$ 2.12		$ 4.07

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