Condensed Consolidated Statements of Earnings (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Consolidated Statements of Earnings (unaudited) [Abstract]
Net sales	$ 134,773	$ 132,230	$ 279,635	$ 218,225
Cost of sales	92,906	99,895	194,638	162,675
Gross margin	41,867	32,335	84,997	55,550
Operating expenses:
Selling expenses	11,367	8,552	23,153	12,741
Research and development expenses	1,492	1,119	2,940	1,892
General and administrative expenses	5,234	6,155	10,092	11,053
Operating expenses	18,093	15,826	36,185	25,686
Earnings from operations	23,774	16,509	48,812	29,864
Other expenses (income):
Interest income	(3)	(13)	(5)	(59)
Interest expense	1,594	1,315	3,475	1,316
Other, net	16	(84)	90	(56)
Earnings before income tax expense	22,167	15,291	45,252	28,663
Income tax expense	7,251	5,559	15,164	10,037
Net earnings	$ 14,916	$ 9,732	$ 30,088	$ 18,626
Net earnings per common share - basic (in dollars per share)	$ 0.48	$ 0.32	$ 0.97	$ 0.62
Net earnings per common share - diluted (in dollars per share)	$ 0.47	$ 0.31	$ 0.95	$ 0.60