Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flow from operating activities:
Net income	$ 94,072	$ 109,116	$ 17,085
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	49,897	37,872	38,365
Stock-based compensation	23,219	18,795	20,299
Tax expense (benefit) from deferred income taxes	(8,581)	3,668	17,196
Tax expense (benefit) from stock option plans	(5,151)	(96)	1,450
Changes in operating assets and liabilities:
Accounts receivable	(21,957)	(22,923)	17,591
Inventories	(11,817)	(30,930)	20,843
Prepaid expenses and other assets	(1,350)	(20,411)	12,740
Accounts payable	5,573	9,630	(7,374)
Deferred revenue	16,953	14,408	11,728
Taxes and other liabilities	29,041	25,929	(14,272)
Net cash provided by operating activities	169,899	145,058	135,651
Cash flow from investing activities:
Capital expenditures	(54,830)	(28,397)	(20,847)
Capitalization of internally developed software	(12,065)	(15,759)	(12,583)
Additions to other intangibles	(5,035)	(4,151)	(4,602)
Acquisitions, net of cash received	(73,558)	(4,218)	0
Purchases of short-term investments	(257,449)	(126,691)	(93,087)
Sales and maturities of short-term investments	166,104	82,672	19,204
Net cash (used by) investing activities	(236,833)	(96,544)	(111,915)
Cash flow from financing activities:
Proceeds from issuance of common stock	32,905	51,852	21,672
Repurchase of common stock	0	(41,862)	(34,585)
Dividends paid	(47,961)	(40,618)	(37,308)
Tax (expense) benefit from stock option plans	5,151	96	(1,450)
Net cash (used by) financing activities	(9,905)	(30,532)	(51,671)
Net change in cash and cash equivalents	(76,839)	17,982	(27,935)
Cash and cash equivalents at beginning of period	219,447	201,465	229,400
Cash and cash equivalents at end of period	142,608	219,447	201,465
Cash paid for interest and income taxes:
Interest	14	82	23
Income taxes	$ 2,393	$ 14,807	$ 14,608