Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 84,513	$ 68,009
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment and amortization of other intangible assets	15,118	12,741
Stock-based compensation	7,594	8,130
Excess tax benefit associated with stock-based compensation	(11,808)	(3,567)
Deferred Income Taxes	4,787	10,560
Other, net	10,742	1,006
Changes in operating assets and liabilities
Accounts receivable	(2,280)	1,392
Prepaid expenses and other assets	3,210	9,822
Accounts payable and accrued liabilities	4,549	(52,534)
Deferred revenues	34,212	54,719
Net cash provided by operating activities	150,637	110,278
Cash flows from investing activities:
Proceeds from maturities and sales of marketable securities	706,244	5,060
Purchases of marketable securities	(764,268)	(5,082)
Purchases of property and equipment	(17,115)	(12,917)
Other investing activities	(3,426)	0
Net cash used in investing activities	(78,565)	(12,939)
Cash flows from financing activities:
Proceeds from issuance of common stock from option exercises and employee stock purchase plans	8,733	11,390
Repurchases of common stock	(142,892)	(75,149)
Excess tax benefit associated with stock-based compensation	11,808	3,567
Other financing activities	0	189
Net cash used in financing activities	(122,351)	(60,003)
Effect of exchange rate changes on cash and cash equivalents	(1,837)	2,355
Net decrease in cash and cash equivalents	(52,116)	39,691
Cash and cash equivalents at beginning of period	130,736	1,313,349
Cash and cash equivalents at end of period	78,620	1,353,040
Supplemental cash flow disclosures:
Cash paid for interest, net of capitalized interest	20,393	20,036
Cash paid for income taxes, net of refunds received	$ 729	$ 13,186