CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 11,641	$ 12,575
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,705	18,256
Losses on sales and/or abandonment of property and equipment	44	53
Write-off of patents and intangible assets	90	14
Acquired in-process research and development	100	0
Amortization of deferred credits	(85)	(85)
Amortization of long-term debt issuance costs	521	494
Deferred income taxes	141	383
Excess tax benefits from stock-based compensation	12	(1,420)
Stock-based compensation expense	1,410	1,085
Changes in operating assets and liabilities, net of effects from acquisitions:
Trade receivables	(6,459)	(2,793)
Employee receivables	51	20
Other receivables	2,126	942
Inventories	(1,403)	166
Prepaid expenses	(2,226)	(631)
Prepaid income taxes	(118)	(43)
Income tax refund receivables	872	(78)
Other assets	(762)	(2,887)
Trade payables	(5,147)	5,222
Accrued expenses	3,039	4,475
Advances from employees	(119)	262
Income taxes payable	1,620	2,909
Deferred compensation payable	603	822
Other long-term obligations	(212)	641
Total adjustments	13,803	27,807
Net cash provided by operating activities	25,444	40,382
Capital expenditures for:
Property and equipment	(21,222)	(25,366)
Intangible assets	(989)	(875)
Proceeds from sale-leaseback transactions	0	2,017
Proceeds from the sale of property and equipment	0	6
Proceeds from sale of cost method investment	1,089	0
Cash paid in acquisitions, net of cash acquired	(22,800)	(2,250)
Net cash used in investing activities	(43,922)	(26,468)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	791	5,144
Proceeds from issuance of long-term debt	93,812	65,339
Payments on long-term debt	(69,687)	(80,056)
Excess tax benefits from stock-based compensation	(12)	1,421
Contingent payments related to acquisitions	(183)	(180)
Payment of taxes related to an exchange of common stock	0	(660)
Net cash provided by (used in) financing activities	24,721	(8,992)
EFFECT OF EXCHANGE RATES ON CASH	67	(175)
NET INCREASE IN CASH AND CASH EQUIVALENTS	6,310	4,747
CASH AND CASH EQUIVALENTS:
Beginning of period	4,177	7,355
End of period	10,487	12,102
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Interest (net of capitalized interest of $194 and $185, respectively)	2,912	3,279
Income taxes	1,580	2,209
Property and equipment purchases in accounts payable	1,497	2,352
Contingent receivable received in exchange for sale of cost method investment	681	0
Acquisition purchases in accrued expenses	0	1,500
Merit common stock surrendered (0 and 166 shares, respectively) in exchange for exercise of stock options	$ 0	$ 3,317