Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Statement of Cash Flows [Abstract]
Net income	$ 55,939		$ 59,688
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of intangible assets	36,760	[1]	35,127	[1]
Depreciation and amortization of property and equipment	33,271		29,409
Stock-based compensation expense	40,701		43,556
Loss (gain) on investments	5,133		(85)
Provision for doubtful accounts	610		407
Provision for product returns	584		1,619
Provision for inventory reserves	453		331
Tax effect of stock-based compensation	(3,967)		14,846
Excess tax benefit from stock-based compensation	(2,332)		(9,476)
Deferred income tax benefit	(2,474)		(18,189)
Effects of exchange rate changes on monetary assets and liabilities denominated in foreign currencies	(850)		(909)
Other non-cash items	39		175
Total adjustments to reconcile net income to net cash provided by operating activities	107,928		96,811
Changes in operating assets and liabilities, net of the effects of acquisitions:
Accounts receivable	142,974		183,892
Inventories	1,117		(1,140)
Prepaid expenses and other current assets	(28,276)		(35,158)
Other assets	2,101		811
Income taxes, net	(3,707)		(32,536)
Accounts payable	(1,312)		(11,312)
Accrued expenses and other current liabilities	10,598		(21,338)
Deferred revenues	(938)		21,448
Other liabilities	1,452		5,632
Total changes in operating assets and liabilities, net of the effects of acquisitions	124,009		110,299
Net cash provided by operating activities	287,876		266,798
Investing Activities
Purchases of available-for-sale investments	(607,892)		(636,792)
Proceeds from sales of available-for-sale investments	266,421		231,782
Proceeds from maturities of available-for-sale investments	121,757		131,101
Purchases of property and equipment	(30,469)		(28,297)
Proceeds from the sales of cost method investments	803		0
Purchases of cost method investments	(766)		(1,102)
Cash paid for acquisitions, net of cash acquired	(24,154)		(324,049)
Cash paid for licensing agreements and product related intangible assets	(711)		(2,236)
Net cash used in investing activities	(275,011)		(629,593)
Financing Activities
Proceeds from issuance of common stock under stock-based compensation plans	7,958		25,251
Repayment of acquired debt	(3,766)		0
Excess tax benefit from stock-based compensation	2,332		9,476
Stock repurchases, net	0		(61,364)
Cash paid for tax withholding on vested stock awards	(2,316)		(2,254)
Net cash provided by (used in) financing activities	4,208		(28,891)
Effect of exchange rate changes on cash and cash equivalents	706		(458)
Change in cash and cash equivalents	17,779		(392,144)
Cash and cash equivalents at beginning of period	280,740		643,609
Cash and cash equivalents at end of period	$ 298,519		$ 251,465

[1] Represents expenses presented to management on a consolidated basis only and not allocated to the operating segments.