Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Operating activities:
Net income	$ 9,201	$ 5,751
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,202	12,753
Cost of sales of equipment	14	767
Share-based compensation	2,151	2,048
Deferred income taxes	912	(1,043)
Loss on disposal of equipment	862
Changes in operating assets and liabilities:
Accounts receivable	(2,966)	(6,429)
Inventory	(4,331)	(984)
Prepaid expenses and other	(1,185)	(640)
Accounts payable	(668)	1,622
Accrued expenses	(2,096)	5,145
Income taxes	(112)	(1,125)
Deferred revenues	1,882	1,153
Deferred rent	75	(225)
Net cash provided by operating activities	22,941	18,793
Investing activities:
Purchases of property and equipment	(24,964)	(15,987)
Purchases of investments		(999)
Proceeds from sales of investments		10,731
Payments for acquisition	(117)	(82,789)
Net cash used in investing activities	(25,081)	(89,044)
Financing activities:
Proceeds from long-term debt		23,000
Repayment of long-term debt		(2,000)
Proceeds from exercise of stock options	771	215
Stock option income tax benefit	17	29
Repurchase of common stock for treasury	(46)
Net cash provided by financing activities	742	21,244
Effect of exchange rate changes on cash	590	(639)
Net decrease in cash and cash equivalents	(808)	(49,646)
Cash and cash equivalents, beginning of period	30,343	68,979
Cash and cash equivalents, end of period	$ 29,535	$ 19,333