Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 194,599	$ 171,403
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment and amortization of other intangible assets	32,115	30,526
Stock-based compensation	19,365	16,429
Excess tax benefit associated with stock-based compensation	(15,309)	(17,642)
Deferred Income Taxes	(22,613)	16,055
Unrealized Gain (Loss) on Derivatives	(10,515)	4,437
Other, net	5,169	5,627
Changes in operating assets and liabilities
Accounts receivable	(233)	(2,263)
Prepaid expenses and other assets	26,414	(991)
Accounts payable and accrued liabilities	(869)	30,090
Deferred revenues	34,615	43,802
Net cash provided by operating activities	262,738	297,473
Cash flows from investing activities:
Proceeds from maturities and sales of marketable securities	2,118,861	1,564,459
Purchases of marketable securities	(2,042,657)	(1,557,724)
Purchases of property and equipment	(18,747)	(37,550)
Other investing activities	74	(3,221)
Net cash used in investing activities	57,531	(34,036)
Cash flows from financing activities:
Proceeds from issuance of common stock from option exercises and employee stock purchase plans	8,970	9,396
Repurchases of common stock	(446,676)	(478,148)
Repayments of Long-term Lines of Credit	0	(100,000)
Proceeds from Issuance of Senior Long-term Debt	0	738,731
Excess tax benefit associated with stock-based compensation	15,309	17,642
Net cash used in financing activities	(422,397)	187,621
Effect of exchange rate changes on cash and cash equivalents	266	(3,493)
Net decrease in cash and cash equivalents	(101,862)	447,565
Cash and cash equivalents at beginning of period	339,223	130,736
Cash and cash equivalents at end of period	237,361	578,301
Supplemental cash flow disclosures:
Cash paid for interest, net of capitalized interest	37,507	20,495
Cash paid for income taxes, net of refunds received	$ 34,464	$ 17,531