Condensed Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net income	$ 22,938	$ 475,602	$ 445,374
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	146,368	130,368	110,474
Deferred income tax (benefit) provision	(14,207)	11,666	(20,671)
Loss on disposal and impairment of assets	23,877	13,194	6,976
Bad debt allowance	(262)	(23)	9
Stock-based compensation expense	64,166	57,911	96,440
Excess tax benefit on stock-based compensation	(1,320)	(74,442)	(21,667)
Other	(604)	582	104
Changes in operating assets and liabilities:
Accounts receivable	(1,923)	(3,504)	(10,966)
Inventory	(91)	262	(2,307)
Prepaid expenses and other current assets	(4,259)	(5,259)	(658)
Other assets	(4,855)	(5,619)	1,071
Accounts payable	(6,734)	19,525	2,168
Accrued liabilities	33,491	(7,440)	35,019
Income tax payable/receivable	54,340	32,756	8,831
Deferred rent	37,030	32,911	27,025
Other long-term liabilities	1,287	4,826	4,845
Net cash provided by operating activities	349,242	683,316	682,067
Investing activities
Purchases of leasehold improvements, property and equipment	(258,842)	(257,418)	(252,590)
Purchases of investments	0	(559,372)	(521,004)
Maturities of investments	45,000	352,650	254,750
Proceeds from sale of investments	540,648	0	0
Net cash provided by (used in) investing activities	326,806	(464,140)	(518,844)
Financing activities
Acquisition of treasury stock	(837,655)	(460,675)	(88,338)
Excess tax benefit on stock-based compensation	1,320	74,442	21,667
Stock plan transactions and other financing activities	52	(207)	(66)
Net cash used in financing activities	(836,283)	(386,440)	(66,737)
Effect of exchange rate changes on cash and cash equivalents	110	(4,196)	(224)
Net change in cash and cash equivalents	(160,125)	(171,460)	96,262
Cash and cash equivalents at beginning of period	248,005	419,465	323,203
Cash and cash equivalents at end of period	87,880	248,005	419,465
Supplemental disclosures of cash flow information
Income taxes paid	23,862	248,547	280,687
Increase (decrease) in purchases of leasehold improvements, property and equipment accrued in accounts payable and accrued liabilities	(1,781)	(2,870)	9,424
Increase (decrease) in acquistion of treasury stock accrued in accrued liabilities	$ (22,878)	$ 25,178	$ 0