CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net income	$ 27,499	$ 26,167
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	18,804	18,740
Provision for doubtful accounts receivable, product returns, and inventory valuation	1,582	5,399
Non-cash stock compensation expense	5,023	5,761
Deferred taxes	6,165	9,824
Gain on sale of assets held for sale	(2,177)
Other	345	(1,553)
Changes in operating assets and liabilities, net of assets acquired and liabilities assumed in business combinations:
Change in operating assets	5,370	12,726
Change in operating liabilities	7,143	(13,428)
Net cash provided by operating activities	69,754	63,636
Cash flows from investing activities:
Purchases of property and equipment	(9,306)	(8,816)
Proceeds from sale of assets held for sale	5,500
Proceeds from repayment of loan	2,275
Other	14	124
Net cash used in investing activities	(1,517)	(8,692)
Cash flows from financing activities:
Proceeds from exercise of stock options and issuance of common stock	6,669	1,100
Net cash provided by financing activities	6,669	1,100
Effect of exchange rate changes on cash and cash equivalents	232	(393)
Net increase in cash and cash equivalents	75,138	55,651
Cash and cash equivalents, beginning of period	132,536	57,386
Cash and cash equivalents, end of period	$ 207,674	$ 113,037