Condensed Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating activities
Net income	$ 164,437	$ 144,347
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	46,533	40,627
Deferred income tax provision (benefit)	7,301	(1,659)
Loss on disposal of assets	2,739	2,725
Bad debt allowance	39	185
Stock-based compensation expense	34,333	37,677
Excess tax benefit on stock-based compensation	(4,251)	(73,652)
Other	262	207
Changes in operating assets and liabilities:
Accounts receivable	1,795	(2,147)
Inventory	(181)	(1,593)
Prepaid expenses and other current assets	(7,596)	(6,893)
Other assets	(3,365)	(10,213)
Accounts payable	6,078	4,899
Accrued liabilities	(12,551)	(12,705)
Income tax payable/receivable	17,688	34,964
Deferred rent	11,794	11,446
Other long-term liabilities	2,698	2,660
Net cash provided by operating activities	267,753	170,875
Investing activities
Purchases of leasehold improvements, property and equipment	(80,130)	(90,332)
Purchases of investments	(230,397)	(110,870)
Maturities of investments	78,750
Net cash used in investing activities	(231,777)	(201,202)
Financing activities
Acquisition of treasury stock	(81,065)	(39,597)
Proceeds from employee stock plan transactions	261	167
Excess tax benefit on stock-based compensation	4,251	73,652
Other financing payments	(70)	(65)
Net cash provided by (used in) financing activities	(76,623)	34,157
Effect of exchange rate changes on cash and cash equivalents	(274)	(276)
Net change in cash and cash equivalents	(40,921)	3,554
Cash and cash equivalents at beginning of period	322,553	401,243
Cash and cash equivalents at end of period	281,632	404,797
Supplemental disclosures of cash flow information
Increase (decrease) in purchases of leasehold improvements, property and equipment accrued in accounts payable	$ (1,432)	$ 4,687