CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 19,710,000	$ 23,044,000	$ 12,460,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,534,000	19,194,000	14,856,000
Losses on sales and/or abandonment of property and equipment	204,000	31,000	533,000
Write-off of patents and license agreement	55,000	103,000	134,000
Goodwill impairment charge	0	0	8,344,000
Impairment of cost-method investment	2,368,000	0	0
Acquired in-process research and development	2,450,000	5,838,000	0
Amortization of deferred credits	(174,000)	(106,000)	(111,000)
Purchase of trading investments	0	0	(644,000)
Unrealized gains on trading investments	0	0	(382,000)
Realized gain on sale of marketable securities	(745,000)	0	0
Deferred income taxes	549,000	1,677,000	(554,000)
Excess tax benefits from stock-based compensation	(877,000)	(3,122,000)	(399,000)
Stock-based compensation expense	1,917,000	1,644,000	1,294,000
Changes in operating assets and liabilities, net of effects from acquisitions:
Trade receivables	(6,576,000)	(3,323,000)	(2,088,000)
Employee receivables	(11,000)	(62,000)	29,000
Other receivables	(760,000)	(245,000)	223,000
Inventories	(8,965,000)	(9,314,000)	(7,614,000)
Prepaid expenses	736,000	(1,726,000)	(192,000)
Prepaid income taxes	(367,000)	(431,000)	(60,000)
Income tax refund receivable	452,000	(733,000)	(1,573,000)
Other assets	(1,178,000)	(283,000)	(43,000)
Trade payables	7,721,000	(2,129,000)	5,643,000
Accrued expenses	4,448,000	1,334,000	3,090,000
Advances from employees	317,000	(65,000)	99,000
Income taxes payable	2,057,000	2,658,000	1,037,000
Liabilities related to unrecognized tax benefits	(209,000)	(226,000)	(372,000)
Deferred compensation payable	1,371,000	327,000	876,000
Other long-term obligations	(89,000)	(70,000)	174,000
Total adjustments	27,228,000	10,971,000	22,300,000
Net cash provided by operating activities	46,938,000	34,015,000	34,760,000
Capital expenditures for:
Property and equipment	(64,643,000)	(59,195,000)	(23,648,000)
Intangible assets	(1,460,000)	(2,077,000)	(1,083,000)
Purchase of marketable securities	0	(2,503,000)	0
Proceeds from the sale of marketable securities	3,248,000	0	9,673,000
Proceeds from the sale of property and equipment	43,000	5,000	17,000
Cash paid in acquisitions, net of cash acquired	(192,762,000)	(10,250,000)	(97,785,000)
Net cash used in investing activities	(255,574,000)	(74,020,000)	(112,826,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	3,755,000	95,454,000	1,708,000
Payment of offering costs related to issuance of common stock	0	(127,000)	0
Proceeds from issuance of long-term debt	330,630,000	104,585,000	108,491,000
Payments on long-term debt	(123,801,000)	(155,386,000)	(26,953,000)
Borrowings on line of credit	0	0	1,500,000
Payments on line of credit	0	0	(8,500,000)
Proceeds from industrial assistant grants	1,029,000	0	0
Excess tax benefits from stock-based compensation	877,000	3,122,000	399,000
Long-term debt issuance costs	(3,706,000)	0	(522,000)
Contingent payments related to acquisitions	(57,000)	0	0
Payment of taxes related to an exchange of common stock	(439,000)	(953,000)	0
Net cash provided by financing activities	208,288,000	46,695,000	76,123,000
EFFECT OF EXCHANGE RATES ON CASH	(61,000)	(297,000)	(455,000)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(409,000)	6,393,000	(2,398,000)
CASH AND CASH EQUIVALENTS:
Beginning of year	10,128,000	3,735,000	6,133,000
End of year	9,719,000	10,128,000	3,735,000
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Interest (net of capitalized interest of $456, $299 and $13, respectively)	434,000	509,000	512,000
Income taxes	5,277,000	7,023,000	6,050,000
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES
Property and equipment purchases in accounts payable	12,372,000	8,849,000	3,778,000
Acquisition of customer list in exchange for a settlement of trade receivables	377,000	0	0
Acquisition purchases in accrued expenses and other long-term obligations	5,149,000	1,270,000	250,000
Merit common stock surrendered (131, 78 and 0 shares, respectively) in exchange for exercise of stock options	$ (1,831,000)	$ (1,252,000)	$ 0