Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities
Net income	$ 336,262	$ 188,087
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other	219,155	295,810
Stock-based compensation expense	136,202	103,674
Excess tax benefit from stock-based compensation	(12,374)	(2,236)
Deferred income tax benefit	(23,912)	(31,873)
Effects of exchange rate changes on monetary assets and liabilities denominated in foreign currencies	(3,489)	13,382
Other non-cash items	9,247	11,155
Total adjustments to reconcile net income to net cash provided by operating activities	324,829	389,912
Changes in operating assets and liabilities, net of the effects of acquisitions:
Accounts receivable	193,023	198,075
Inventories	(5,354)	1,084
Prepaid expenses and other current assets	14,306	(7,375)
Other assets	(8,341)	(1,460)
Income taxes, net	51,967	21,088
Accounts payable	(17,778)	6,658
Accrued expenses and other current liabilities	484	(674)
Deferred revenues	(47,128)	(47,982)
Other liabilities	14,513	5,400
Total changes in operating assets and liabilities, net of the effects of acquisitions	195,692	174,814
Net cash provided by operating activities	856,783	752,813
Investing Activities
Purchases of available-for-sale investments	(1,411,077)	(1,806,781)
Proceeds from sales of available-for-sale investments	1,156,168	1,552,983
Proceeds from maturities of available-for-sale investments	511,023	518,755
Purchases of property and equipment	(105,339)	(119,591)
Cash paid for acquisitions, net of cash acquired	(11,455)	(250,986)
Cash paid for licensing agreements and technology	(26,079)	(10,666)
Other	464	(3,400)
Net cash provided by (used in) investing activities	113,705	(119,686)
Financing Activities
Proceeds from issuance of common stock under stock-based compensation plans	39,438	79,338
Proceeds from credit facility	0	95,000
Repayment of credit facility	0	(95,000)
Repayment of acquired debt	0	(7,569)
Excess tax benefit from stock-based compensation	12,374	2,236
Stock repurchases, net	(28,689)	(398,070)
Cash paid for tax withholding on vested stock awards	(55,402)	(32,351)
Net cash used in financing activities	(32,279)	(356,416)
Effect of exchange rate changes on cash and cash equivalents	1,956	(9,266)
Change in cash and cash equivalents	940,165	267,445
Cash and cash equivalents at beginning of period	368,518	260,149
Cash and cash equivalents at end of period	$ 1,308,683	$ 527,594