Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 17,566	$ 11,968
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	9,052	8,602
Provision for doubtful accounts	437	97
Stock compensation	1,979	1,668
Loss (gain) on disposal of property and equipment	(56)	49
Bond premium amortization	399	947
Cash provided (used) by changes in operating assets and liabilities
Accounts receivable	3,908	(1,970)
Inventories	(4,025)	(1,423)
Prepaid expenses and other assets	(1,373)	(1,784)
Accounts payable	1,286	(1,140)
Accrued liabilities	(599)	1,387
Deferred revenue	(254)	(2,283)
Prepaid and deferred income taxes	(2,857)	1,421
Net cash provided by operating activities	25,463	17,539
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property and equipment	(9,755)	(11,285)
Proceeds from sale of asset	0	893
Proceeds from insurance	2,781	0
Purchases of investment securities	(32,236)	(13,698)
Proceeds from sale of investment securities	12,900	44,166
Net cash provided (used) by investing activities	(26,310)	20,076
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options	4,572	103
Proceeds from employee stock purchase plan	909	747
Tax benefits from exercise of stock options	2,717	58
Purchase of treasury stock	0	(28,648)
Net cash provided (used) by financing activities	8,198	(27,740)
Effect of exchange rate changes on cash	1,167	(3,521)
NET INCREASE IN CASH AND CASH EQUIVALENTS	8,518	6,354
CASH AND CASH EQUIVALENTS, beginning of period	78,850	51,248
CASH AND CASH EQUIVALENTS, end of period	87,368	57,602
NON-CASH INVESTING ACTIVITIES
Accrued liabilities for property and equipment	$ 262	$ 354