CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS (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
Income Statement [Abstract]
NET SALES	$ 233,777	$ 224,510	$ 666,980	$ 615,853
COST OF GOODS SOLD	159,045	154,951	460,363	438,818
Gross profit	74,732	69,559	206,617	177,035
OPERATING EXPENSES
Selling, general and administrative	33,897	33,810	99,518	99,266
Research and development	13,864	13,611	39,565	35,836
Other operating expenses	1,967	1,876	5,044	7,657
Total operating expenses	49,728	49,297	144,127	142,759
Income from operations	25,004	20,262	62,490	34,276
OTHER INCOME (EXPENSES)	1,300	(2,768)	309	(1,970)
Income before income taxes and noncontrolling interest	26,304	17,494	62,799	32,306
INCOME TAX PROVISION	6,172	3,604	14,370	11,653
NET INCOME	20,132	13,890	48,429	20,653
Less: NET INCOME attributable to noncontrolling interest	(705)	(271)	(1,415)	(325)
NET INCOME attributable to common stockholders	$ 19,427	$ 13,619	$ 47,014	$ 20,328
EARNINGS PER SHARE attributable to common stockholders
Basic	$ 0.41	$ 0.29	$ 1.00	$ 0.44
Diluted	$ 0.40	$ 0.28	$ 0.97	$ 0.43
Number of shares used in computation
Basic	47,548	46,605	47,047	46,260
Diluted	48,736	48,023	48,385	47,584