Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net income	$ 407,728	$ 324,140
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	96,228	80,724
Deferred income tax (benefit) provision	(12,542)	(19,045)
Loss on disposal of assets	7,744	4,767
Bad debt allowance	(27)	(10)
Stock-based compensation expense	59,725	82,156
Excess tax benefit on stock-based compensation	(74,861)	(12,971)
Other	273	9
Changes in operating assets and liabilities:
Accounts receivable	10,637	5,250
Inventory	(2,212)	(2,851)
Prepaid expenses and other current assets	(3,028)	547
Other assets	(3,967)	(3,723)
Accounts payable	7,101	14,706
Accrued liabilities	(7,434)	11,462
Income tax payable/receivable	77,858	41,274
Deferred rent	21,532	19,380
Other long-term liabilities	3,808	3,941
Net cash provided by operating activities	588,563	549,756
Investing activities
Purchases of leasehold improvements, property and equipment	(181,840)	(160,400)
Purchases of investments	(433,829)	(390,632)
Maturities of investments	287,450	171,250
Net cash used in investing activities	(328,219)	(379,782)
Financing activities
Acquisition of treasury stock	(147,122)	(63,405)
Excess tax benefit on stock-based compensation	74,862	12,971
Stock plan transactions and other financing activities	(225)	(69)
Net cash used in financing activities	(72,485)	(50,503)
Effect of exchange rate changes on cash and cash equivalents	(3,162)	(56)
Net change in cash and cash equivalents	184,697	119,415
Cash and cash equivalents at beginning of period	419,465	323,203
Cash and cash equivalents at end of period	604,162	442,618
Supplemental disclosures of cash flow information
Increase (decrease) in purchases of leasehold improvements, property and equipment accrued in accounts payable and accrued liabilities	$ (1,032)	$ 13,804