Condensed Consolidated Statements of Earnings (unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Condensed Consolidated Statements of Earnings (unaudited) [Abstract]
Net sales	$ 160,490	$ 87,593	$ 378,715	$ 255,540
Cost of sales	116,003	63,071	278,678	181,901
Gross margin	44,487	24,522	100,037	73,639
Operating expenses:
Selling expenses	11,458	3,679	24,199	12,012
Research and development expenses	1,445	876	3,337	2,661
General and administrative expenses	6,300	2,991	17,353	9,509
Operating expenses	19,203	7,546	44,889	24,182
Earnings from operations	25,284	16,976	55,148	49,457
Other expenses (income):
Interest income	(3)	(65)	(62)	(178)
Interest expense	2,052	2	3,368	5
Other, net	26	(21)	(30)	25
Earnings before income tax expense	23,209	17,060	51,872	49,605
Income tax expense	8,031	5,403	18,068	15,478
Net earnings	$ 15,178	$ 11,657	$ 33,804	$ 34,127
Net earnings per common share - basic (in dollars per share)	$ 0.50	$ 0.39	$ 1.12	$ 1.16
Net earnings per common share - diluted (in dollars per share)	$ 0.49	$ 0.38	$ 1.09	$ 1.11