Rackspace Hosting (RAX) 10-K 2 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 23, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	RACKSPACE HOSTING, INC.
Entity Central Index Key	1107694
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		141,489,172
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$2,614,923,113

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$213,505	$259,733
Accounts receivable, net of allowance for doubtful accounts and customer credits of $3,891 as of December 31, 2013 and $5,334 as of December 31, 2014	156,455	123,898
Deferred income taxes	9,260	12,637
Prepaid expenses	33,628	30,782
Other current assets	8,895	11,918
Total current assets	421,743	438,968
Property and equipment, net	1,057,684	890,776
Goodwill	81,084	81,084
Intangible assets, net	16,592	23,880
Other non-current assets	47,181	57,089
Total assets	1,624,284	1,491,797
Current liabilities:
Accounts payable and accrued expenses	137,295	122,047
Accrued compensation and benefits	66,696	62,459
Income and other taxes payable	11,783	11,388
Deferred revenue	20,851	22,868
Capital lease obligations	14,969	37,885
Debt	25,124	1,861
Total current liabilities	276,718	258,508
Non-current liabilities:
Deferred revenue	1,425	3,662
Capital lease obligations	8,946	25,048
Finance lease obligations for assets under construction	109,991	0
Debt	0	124
Deferred income taxes	71,228	69,729
Deferred rent	49,899	43,046
Other liabilities	32,283	36,268
Total liabilities	550,490	436,385
Commitments and Contingencies
Stockholders' equity:
Common stock, $0.001 par value per share: 300,000,000 shares authorized; 141,123,904 shares issued and outstanding as of December 31, 2013; 140,945,171 shares issued and outstanding as of December 31, 2014	141	141
Additional paid-in capital	696,029	636,660
Accumulated other comprehensive loss	-20,685	-4,536
Retained earnings	398,309	423,147
Total stockholders’ equity	1,073,794	1,055,412
Total liabilities and stockholders' equity	$1,624,284	$1,491,797

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parentheticals) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Current assets:
Allowance for doubtful accounts and customer credits	$5,334	$3,891
Stockholders' equity:
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	140,945,171	141,123,904
Common stock, shares outstanding	140,945,171	141,123,904

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net revenue	$1,794,357	$1,534,786	$1,309,239
Costs and expenses:
Cost of revenue	582,334	492,493	419,013
Research and development	117,006	90,213	56,736
Sales and marketing	237,548	208,417	166,172
General and administrative	322,056	297,520	244,732
Depreciation and amortization	371,884	313,007	249,845
Total costs and expenses	1,630,828	1,401,650	1,136,498
Income from operations	163,529	133,136	172,741
Other income (expense):
Interest expense	-1,913	-3,118	-4,749
Interest and other income (expense)	-2,012	741	15
Total other income (expense)	-3,925	-2,377	-4,734
Income before income taxes	159,604	130,759	168,007
Income taxes	49,051	44,022	62,589
Net income	110,553	86,737	105,418
Other comprehensive income, net of tax
Foreign currency translation adjustments	-16,149	3,553	6,643
Other comprehensive income (loss)	-16,149	3,553	6,643
Comprehensive income	$94,404	$90,290	$112,061
Net income per share
Basic	$0.78	$0.63	$0.78
Diluted	$0.77	$0.61	$0.75
Weighted average number of shares outstanding
Basic	141,971	138,577	135,279
Diluted	144,498	143,011	141,265

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows From Operating Activities
Net income	$110,553	$86,737	$105,418
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	371,884	313,007	249,845
Deferred income taxes	413	-2,102	-775
Share-based compensation expense	70,005	59,645	41,546
Excess tax benefits from share-based compensation arrangements	-34,473	-33,539	-46,046
Other operating activities	8,242	5,490	7,886
Changes in operating assets and liabilities:
Accounts receivable	-41,681	-34,473	-29,265
Prepaid expenses and other current assets	-1,116	-12,270	-4,903
Accounts payable, accrued expenses, and other current liabilities	55,424	35,303	66,268
Deferred revenue	-3,742	5,367	2,185
Deferred rent	7,417	11,564	9,259
Other non-current assets and liabilities	-416	9,331	-1,919
Net cash provided by operating activities	542,510	444,060	399,499
Cash Flows From Investing Activities
Purchases of property and equipment	-430,335	-452,596	-270,374
Acquisitions, net of cash acquired	0	-9,930	-5,945
All other investing activities	2,230	-1,698	98
Net cash used in investing activities	-428,105	-464,224	-276,221
Cash Flows From Financing Activities
Principal payments of capital leases	-39,635	-65,860	-75,928
Proceeds from debt	25,000	0	691
Repayments of debt	-1,901	-1,915	-1,962
Payments for deferred acquisition obligations	-223	-1,353	-6,176
Receipt of Texas Enterprise Fund grant	5,500	0	3,500
Repurchase of common stock	-200,000	0	0
Shares of common stock withheld for employee taxes	-13,620	0	0
Proceeds from employee stock plans	33,120	23,817	41,284
Excess tax benefits from share-based compensation arrangements	34,473	33,539	46,046
Net cash provided by (used in) financing activities	-157,286	-11,772	7,455
Effect of exchange rate changes on cash and cash equivalents	-3,347	-392	1,472
Increase (decrease) in cash and cash equivalents	-46,228	-32,328	132,205
Cash and cash equivalents, beginning of period	259,733	292,061	159,856
Cash and cash equivalents, end of period	213,505	259,733	292,061
Supplemental Cash Flow Information
Cash payments for interest, net of amount capitalized	1,765	3,234	4,900
Cash payments for income taxes, net of refunds	$13,518	$14,930	$11,906

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows, Non-cash Investing and Financing Activities (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Non-cash Purchases of Property and Equipment
Non-cash purchases of property and equipment	$4,804	$19,493	$67,308
Shares issued in business combinations	0	4,457	2,745
Additional finance lease obligations for assets under construction and other	117,644	0	0
Acquisition of property and equipment by capital leases
Non-cash Purchases of Property and Equipment
Non-cash purchases of property and equipment	929	7,190	59,833
Acquisition of property and equipment by notes payable
Non-cash Purchases of Property and Equipment
Non-cash purchases of property and equipment	0	0	3,950
Increase in property and equipment in accounts payable and accrued expenses
Non-cash Purchases of Property and Equipment
Non-cash purchases of property and equipment	$3,875	$12,303	$3,525

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Balance ($) at Dec. 31, 2011	$599,423,000	$132,000	$383,031,000	($14,732,000)	$230,992,000
Balance (shares) at Dec. 31, 2011		131,912,829
Issuance of common stock
Exercise of stock options and release of stock awards (including excess tax benefit), net of shares withheld for employee taxes ($)	82,314,000	6,000	82,308,000
Exercise of stock options and release of stock awards (including excess tax benefit), net of shares withheld for employee taxes (shares)		5,689,164
Stock-based activity and issuance of common stock to board of directors ($)	542,000	0	542,000
Stock-based activity and issuance of common stock to board of directors (shares)		12,862
Issuance of shares from Employee Stock Purchase Plans ($)	5,016,000	0	5,016,000
Issuance of shares from Employee Stock Purchase Plans (shares)		137,104
Issuance of shares in acquisitions ($)	2,745,000	0	2,745,000
Issuance of shares in acquisitions (shares)		45,896
Total issuance of common stock ($)	90,617,000	6,000	90,611,000
Total issuance of common stock (shares)		5,885,026
Share-based compensation expense	41,546,000		41,546,000
Net income	105,418,000				105,418,000
Foreign currency translation adjustments	6,643,000			6,643,000
Balance ($) at Dec. 31, 2012	843,647,000	138,000	515,188,000	-8,089,000	336,410,000
Balance (shares) at Dec. 31, 2012		137,797,855
Issuance of common stock
Exercise of stock options and release of stock awards (including excess tax benefit), net of shares withheld for employee taxes ($)	51,187,000	3,000	51,184,000
Exercise of stock options and release of stock awards (including excess tax benefit), net of shares withheld for employee taxes (shares)		3,027,169
Issuance of shares from Employee Stock Purchase Plans ($)	6,186,000	0	6,186,000
Issuance of shares from Employee Stock Purchase Plans (shares)		190,235
Issuance of shares in acquisitions ($)	4,457,000	0	4,457,000
Issuance of shares in acquisitions (shares)		108,645
Total issuance of common stock ($)	61,830,000	3,000	61,827,000
Total issuance of common stock (shares)		3,326,049
Share-based compensation expense	59,645,000		59,645,000
Net income	86,737,000				86,737,000
Foreign currency translation adjustments	3,553,000			3,553,000
Balance ($) at Dec. 31, 2013	1,055,412,000	141,000	636,660,000	-4,536,000	423,147,000
Balance (shares) at Dec. 31, 2013	141,123,904	141,123,904
Issuance of common stock
Exercise of stock options and release of stock awards (including excess tax benefit), net of shares withheld for employee taxes ($)	47,735,000	3,000	59,488,000		-11,756,000
Exercise of stock options and release of stock awards (including excess tax benefit), net of shares withheld for employee taxes (shares)		2,890,248
Issuance of shares from Employee Stock Purchase Plans ($)	6,238,000	0	6,238,000		0
Issuance of shares from Employee Stock Purchase Plans (shares)		217,404
Issuance of shares in acquisitions ($)	0
Total issuance of common stock ($)	53,973,000	3,000	65,726,000		-11,756,000
Total issuance of common stock (shares)		3,107,652
Repurchase of common stock ($)	-200,000,000	-3,000	-76,362,000		-123,635,000
Repurchase of common stock (shares)		-3,286,385
Share-based compensation expense	70,005,000		70,005,000
Net income	110,553,000				110,553,000
Foreign currency translation adjustments	-16,149,000			-16,149,000
Balance ($) at Dec. 31, 2014	$1,073,794,000	$141,000	$696,029,000	($20,685,000)	$398,309,000
Balance (shares) at Dec. 31, 2014	140,945,171	140,945,171

Consolidated_Statements_of_Sto1

Consolidated Statements of Stockholders' Equity (Parentheticals) (Additional Paid-In Capital, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Additional Paid-In Capital
Excess tax benefit included in exercise of stock options and release of stock awards	$34,473	$33,539	$46,046

Company_Overview_Basis_of_Pres

Company Overview, Basis of Presentation, and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Company Overview, Basis of Presentation, and Summary of Significant Accounting Policies	Company Overview, Basis of Presentation, and Summary of Significant Accounting Policies
	Nature of Operations
	As used in this report, the terms “Rackspace,” “Rackspace Hosting,” “we,” “our company,” “the company,” “us,” or “our” refer to Rackspace Hosting, Inc. and its subsidiaries. Rackspace Hosting, Inc., through its operating subsidiaries, is a provider of cloud computing services, managing web-based IT systems for small and medium-sized businesses as well as large enterprises. We focus on providing a service experience for our customers, which we call Fanatical Support.
	Our operations began in 1998 as a limited partnership, and Rackspace Hosting, Inc. was incorporated in Delaware in March 2000.
	Basis of Consolidation
	The accompanying consolidated financial statements include the accounts of Rackspace Hosting and our wholly-owned subsidiaries, which include, among others, Rackspace US, Inc., our domestic operating entity, and Rackspace Limited, our United Kingdom operating entity. Intercompany transactions and balances have been eliminated in consolidation.
	Use of Estimates
	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States ("GAAP") requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, we evaluate our estimates, including those related to accounts receivable and customer credits, property and equipment, fair values of intangible assets and goodwill, useful lives of intangible assets, fair value of share-based compensation, contingencies, and income taxes, among others. Whenever possible, we base our estimates and assumptions on historical experience. However, certain estimates require us to make assumptions about expected future cash flow, events and usage patterns that we cannot influence or control. Our judgments, assumptions and estimates are based upon facts and circumstances known to us when we prepare the consolidated financial statements and that we believe to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities or recording of revenue and expenses in our consolidated financial statements. Changes in facts and circumstances may cause us to change our assumptions and estimates in future periods, and it is possible that actual results could differ from our estimates. We engaged third-party consultants to assist management in the valuation of acquired assets, including other intangibles, as well as share-based compensation.
	Reclassifications
	Certain reclassifications have been made to the prior period consolidated financial statements to conform to the current period presentation.
	Cash and Cash Equivalents
	For the purposes of the consolidated financial statements, we consider all highly liquid investments with original maturities of three months or less when acquired to be cash equivalents. Our available cash and cash equivalents are held in bank deposits, overnight sweep accounts, and money market funds. Gains and losses are included in interest and other income in our accompanying consolidated statements of comprehensive income.
	We actively monitor the third-party depository institutions that hold our deposits. Our emphasis is primarily on safety of principal, secondly on the liquidity of our investments, and finally on maximizing yield on those funds. Our money market mutual funds comply with SEC Rule 2a-7 and invest exclusively in high-quality, short-term obligations that include securities issued or guaranteed by the U.S. government or by U.S. government agencies and floating rate and variable rate demand notes of U.S. and foreign corporations.
	Accounts Receivable, Net
	We classify as trade accounts receivable amounts due within twelve months, arising from the provision of services in the normal course of business. We generally do not request collateral from our customers, although in certain cases we may require the customer to prepay for services. We record an allowance for doubtful accounts for estimated losses resulting from the inability of our customers to make required payments. When evaluating the adequacy of the allowance, we analyze the overall quality of our accounts receivable portfolio, current economic conditions and trends, historical bad debt write-offs, customer creditworthiness, and specifically identified customer risks.
	In addition, our hosting arrangements contain service level commitments with our customers. To the extent that such service levels are not achieved or are otherwise disputed due to third-party power or service issues, unfavorable weather, or other service interruptions or conditions, we are required to issue service credits for a portion of the hosting service fees paid by our customers. At each reporting period, we estimate the amount of service level credits to be issued and record a reduction to revenue. To estimate service credits, we utilize historical data and specific knowledge of factors impacting the delivery of services to our customers.
	Prepaid Expenses and Other Assets
	Prepaid expenses and other assets consist primarily of prepaid software and equipment maintenance contracts and prepaid operating expenses. Software maintenance contracts are amortized over the agreement period, generally one to three years. Prepaid operating expenses are expensed in the period in which services are received.
	Property and Equipment, Net
	Property and equipment is stated at cost, net of accumulated depreciation. Property and equipment is depreciated on a straight-line basis over the estimated useful life of the asset. Replacements and major improvements are capitalized, while maintenance and repairs are charged to expense as incurred. Upon retirement or sale, the cost of assets disposed of and related accumulated depreciation are removed from the accounts, and any resulting gain or loss is credited or charged to operations.
	Internally Developed Software
	We capitalize certain costs of computer software developed or acquired for internal use. Capitalized computer software costs consist of purchased software licenses, implementation costs, and salaries and related compensation costs of employees and consultants for certain projects that qualify for capitalization. The capitalized software costs are amortized on a straight-line basis over the expected useful life of the software.
	Goodwill and Intangible Assets
	Goodwill consists of the excess of the purchase price over the fair value of identifiable net assets of businesses acquired. Goodwill is evaluated for impairment at a reporting unit level using a fair value approach on an annual basis at the beginning of the fourth quarter or whenever events or circumstances indicate that impairment may have occurred. Our assessment did not utilize the qualitative assessment as we went directly to Step 1 of the test. No goodwill impairment was recognized in any of the years presented.
	Intangible assets, including purchased technology, customer contracts and relationships, certain tradenames, license agreements, and non-compete agreements arising principally from acquisitions, are recorded at cost less accumulated amortization, and the definite-lived intangibles are amortized using a method that reflects the pattern in which the economic benefits of the related intangible asset are consumed or utilized.
	Impairment of Long-Lived Assets
	Long-lived assets, including property and equipment and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount should be evaluated. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset in conjunction with its asset group compared to the estimated undiscounted future cash flows expected to be generated by the asset group. If the carrying amount of the asset group exceeds its estimated future cash flows, an impairment charge is recognized in the amount by which the carrying amount of the asset group exceeds the fair value of the assets.
	Leases
	We lease certain property and equipment under capital lease agreements. The assets held under capital lease and related obligations are recorded at the lesser of the present value of aggregate future minimum lease payments, including estimated bargain purchase options, or the fair value of the assets held under capital lease. Such assets and the related leasehold improvements are amortized as depreciation expense over the shorter of the terms of the leases or the estimated useful lives of the assets, which typically range from two to five years for equipment and 30 years for property. For assets for which the lease agreement includes a bargain purchase option or transfer of ownership at the completion of the lease and the lease term is shorter than the estimated useful life of the asset, the asset is amortized over its estimated useful life.
	We also lease property and equipment under operating lease agreements. The lease terms typically range from two to five years for equipment and one to twenty years for property, including office space and data center facilities. Rent increases, rent holidays, leasehold incentives or any other unusual provisions or conditions are considered with total rent payments and are expensed on a straight-line basis over the lease period.
	Revenue and Deferred Revenue
	Revenue is reported net of customer credits and sales and use tax. We recognize revenue when persuasive evidence of an arrangement exists, service has been provided to the customer, the amount of fees to be paid by the customer is fixed or determinable, and collectibility is reasonably assured. We provide cloud computing services to our customers and do not sell hardware and software products. We recognize cloud computing revenue, including installation fees, beginning on the date the customer commences use of our services. Cloud computing revenue is recognized over the contractual term of the customer contract.
	Setup and other direct implementation activities performed by our personnel at the inception of a customer arrangement to enable us to perform under the terms of the arrangement are expensed as incurred.
	Customers using our dedicated cloud services typically pay us a monthly recurring charge based upon the capacity and complexity of the IT systems we manage, the type of technology used and the level of support we provide. Some customers also pay a non-refundable installation fee. Since our dedicated cloud customers usually continue to utilize our services beyond the initial contract term, these installation fees are recognized ratably over the estimated average life of a customer relationship.
	Our public cloud services offers pay-as-you-go cloud computing services that are billed according to customer usage. Revenue is recognized in the month in which the customer uses the services.
	Invoiced amounts and accrued unbilled usage is recorded in accounts receivable and either deferred revenue or revenue, depending on whether the revenue recognition criteria have been met. Therefore, deferred revenue primarily consists of amounts that have been prepaid or deferred installation fees. As of December 31, 2014, of the total $22.3 million in deferred revenue recorded on our balance sheet (the majority of which related to prepaid amounts), $20.9 million and $1.4 million will be amortized to revenue in 2015 and 2016, respectively.
	Cost of Revenue
	Cost of revenue consists primarily of expenses related to personnel, licenses, and our data center facilities. Personnel expenses include the salaries, non-equity incentive compensation, share-based compensation and related expenses of our support teams and data center employees, and data center facility costs include rental fees, power costs, maintenance fees, and bandwidth.
	Advertising Costs
	We charge advertising costs to expense in the period incurred. Advertising expenses for the years ended December 31, 2012, 2013 and 2014 were approximately $44.7 million, $58.9 million and $59.2 million, respectively.
	Share-Based Compensation
	The Black-Scholes valuation model that we use to determine the fair value of stock options requires us to make assumptions and judgments about variables related to our common stock and the related awards. These variables and assumptions include the fair value of our common stock, expected term, the expected volatility, the risk-free interest rate, expected dividends, and the estimated rate of forfeitures of unvested stock options.
	We used the following assumptions when determining the fair value of our stock options:
	•	Fair Value of our Common Stock—The end of day market price on the grant date is used to determine fair value.
	•	Expected Term—The expected term represents the period that our share-based awards are expected to be outstanding. In order to compute the expected term for the four-year period immediately following our IPO, we elected to use the simplified method due to insufficient historical exercise data available to provide a reasonable basis upon which to estimate the expected term. We have been a public company since August 2008, and our options generally vest over four years and expire seven to ten years from the grant date. Beginning in August 2012, management determined that sufficient historical data is available for a fair evaluation and therefore we began to use historical exercise data in our estimation of the expected term.
	•	Expected Volatility—Management estimates volatility for option grants by evaluating the weighted average of the implied volatility and the mean reversion volatility of the company’s stock.
	•	Risk-Free Interest Rate—The risk-free interest rate used in the Black-Scholes valuation model is based on the implied yield currently available on U.S. Treasury zero-coupon issues with an equivalent expected term.
	•	Expected Dividend—We have not issued dividends to date and do not anticipate issuing dividends.
	•	Estimated Rate of Forfeitures—We estimate expected forfeitures based on our historical experience. If actual forfeitures differ from our estimates, we will record the difference as an adjustment in the period we revise our estimates.
	In addition to stock options, our share-based compensation also comprises restricted stock. A portion of restricted stock grants have vesting conditions dependent upon the performance of the company’s total shareholder return ("TSR") on its common stock compared to certain market indices. Additionally, the company’s TSR must be positive for vesting to occur. We use a Monte Carlo simulation to estimate the fair value of these awards. For all other restricted stock granted that vests ratably over the requisite service period, we measure fair value based on the closing fair market value of the company’s common stock on the date of grant, and we recognize expense straight-line over the vesting period.
	We also grant restricted stock with vesting conditions dependent upon the financial performance of the company. The fair values of these performance-vesting awards is measured based on the closing fair market value of our common stock on the date of grant, and share-based compensation expense is recognized when the company determines the performance condition is likely to be met. The expense is recognized ratably over the company's best estimate of the period over which the performance condition will be met.
	Income Taxes
	Income taxes are accounted for using the asset and liability method. Deferred income taxes are provided for temporary differences in recognizing certain income, expense, and credit items for financial reporting purposes and tax reporting purposes. Such deferred income taxes primarily relate to the difference between the tax bases of assets and liabilities and their financial reporting amounts. Deferred tax assets and liabilities are measured by applying enacted statutory tax rates applicable to the future years in which deferred tax assets or liabilities are expected to be settled or realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversals of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. Based upon projections of future taxable income over the periods in which the deferred tax assets are deductible, management believes it is more likely than not that we will realize the benefits of these deductible differences.
	We are currently under income tax audits in the U.K. and California. Due to the complexity involved with certain tax matters, there is the possibility that the various taxing authorities may disagree with certain tax positions filed on our income tax returns. We have considered all relevant facts and circumstances and believe that we have made adequate provision for all income tax uncertainties. For a further discussion of the impact of uncertain tax positions, see Note 10, "Taxes."
	We do not provide for a U.S. income tax liability on undistributed earnings of our foreign subsidiaries. The earnings of non-U.S. subsidiaries, which reflect full provision for non-U.S. income taxes, are currently indefinitely reinvested in non-U.S. operations.
	Fair Value of Financial Instruments
	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:
	Level 1 – Observable inputs such as quoted prices in active markets for identical assets or liabilities;
	Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and
	Level 3 – Unobservable inputs that are supported by little or no market activity, which require management judgment or estimation.
	Money market funds, classified in cash and cash equivalents, were $102 million and $11 million as of December 31, 2013 and 2014, respectively, and are Level 1 financial instruments. The carrying value of our debt approximates the fair value as of December 31, 2013 and 2014.
	Foreign Currency
	We have assessed the functional currency of each of our international subsidiaries and have generally designated the local currency to be their respective functional currencies. The consolidated financial statements of these foreign subsidiaries are translated into the U.S. dollar. All assets and liabilities are translated to the U.S. dollar at the end-of-period exchange rates. Capital accounts are determined to be of a permanent nature and are therefore translated using historical exchange rates. Revenue and expenses are translated using average exchange rates.
	Foreign currency translation adjustments arising from differences in exchange rates from period to period are included in the foreign currency translation adjustment account in accumulated comprehensive income (loss). There was no income tax expense allocated in the years ended December 31, 2012, 2013 and 2014.
Transaction gains or losses in currencies other than the functional currency are included as a component of other income (expense) in the consolidated statements of comprehensive income.
Recent Accounting Pronouncements Not Yet Adopted
In May 2014, the Financial Accounting Standards Board ("FASB") issued guidance to clarify principles for recognizing revenue and to develop a common revenue standard for GAAP and International Financial Reporting Standards. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In addition, the standard requires capitalization of incremental costs to obtain a contract and significantly expanded quantitative and qualitative disclosures. The standard is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period, and is to be applied retrospectively using one of two methods. One method is to apply the guidance retrospectively to each prior period presented with practical expedients available. The second method is to apply the guidance retrospectively with the cumulative effect of initially applying the Update recognized at the date of initial application. Early application is not permitted. We are evaluating the impact on our consolidated financial statements of adopting this new accounting standard.
In April 2014, the FASB issued guidance to revise the definition of discontinued operations by limiting discontinued operations reporting to disposals of components of an entity that represent strategic shifts that have (or will have) a major effect on an entity's operations and financial results. This guidance also requires expanded disclosures for discontinued operations and adds new disclosures for individually significant dispositions that do not qualify as discontinued operations. This guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2014. The impact of the adoption of this guidance will be dependent on the nature of dispositions, if any, occurring after adoption.
In August 2014, the FASB issued guidance that will require management to evaluate, at each annual and interim reporting period, whether there are conditions or events that raise substantial doubt about the entity's ability to continue as a going concern and provide related footnote disclosures in certain circumstances. This guidance is effective for the annual period ending after December 15, 2016 and for annual and interim periods thereafter with early adoption permitted. We do not expect the adoption of this guidance to have an impact on our consolidated financial statements.

Net_Income_Per_Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income Per Share	Net Income Per Share
	The following table sets forth the computation of basic and diluted net income per share:
		Year Ended December 31,
	(In thousands except per share data)	2012		2013		2014
	Basic net income per share:
	Net income	$	105,418	$	86,737	$	110,553
	Weighted average shares outstanding:
	Common stock	135,279		138,577		141,971
	Number of shares used in per share computations	135,279		138,577		141,971
	Net income per share	$	0.78	$	0.63	$	0.78
	Diluted net income per share:
	Net income	$	105,418	$	86,737	$	110,553
	Weighted average shares outstanding:
	Common stock	135,279		138,577		141,971
	Stock options, awards and employee share purchase plans	5,986		4,434		2,527
	Number of shares used in per share computations	141,265		143,011		144,498
	Net income per share	$	0.75	$	0.61	$	0.77
	We excluded 1.1 million, 3.5 million and 5.0 million potential common shares from the computation of dilutive net income per share for the years ended December 31, 2012, 2013 and 2014, respectively, because the effect would have been anti-dilutive.

Property_and_Equipment_net

Property and Equipment, net	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment, net	roperty and Equipment, net
	Property and equipment consisted of:
	(Dollar amounts in thousands)	Estimated Useful Lives				December 31,			December 31,
						2013			2014
	Computers and equipment	3	-	5	years	$	1,242,690		$	1,495,206
	Computer software	1	-	5	years	245,416			318,888
	Furniture and fixtures	7	years			55,681			56,656
	Buildings and leasehold improvements	2	-	30	years	236,255			253,621
	Land					28,566			27,896
	Property and equipment, at cost					1,808,608			2,152,267
	Less accumulated depreciation and amortization					(983,618		)	(1,249,522		)
	Work in process					65,786			154,939
	Property and equipment, net					$	890,776		$	1,057,684
	Depreciation and amortization expense on property and equipment was $240.9 million, $303.2 million and $362.2 million for the years ended December 31, 2012, 2013 and 2014, respectively.
	At December 31, 2013, the work in process balance consisted of build outs of $32.6 million for office facilities, $2.4 million for data centers, and $30.7 million for capitalized software and other projects. At December 31, 2014, the work in process balance consisted of build outs of $51.3 million for office facilities, $80.5 million for data centers, and $23.1 million for capitalized software and other projects.
	For the year ended December 31, 2014, we capitalized non-cash interest of $2.1 million related to finance lease obligations for assets under construction. There was no interest capitalized during the years ended December 31, 2012 and 2013.
	The unamortized balance of computer software costs on our balance sheets was $88.7 million and $103.4 million as of December 31, 2013 and 2014, respectively. Amortization expense for capitalized computer software costs was $36.4 million, $50.6 million and $63.7 million for the years ended December 31, 2012, 2013 and 2014, respectively.

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets
	During the year ended December 31, 2014, we did not have any acquisitions. During the year ended December 31, 2013, we acquired three companies for total consideration of $16.2 million, including cash payments, deferred cash payments and equity consideration. Approximately $12.3 million was attributed to goodwill, $5.1 million to acquired intangible assets and $1.2 million to other net liabilities assumed. The goodwill balance of $81.1 million did not change from December 31, 2013 to December 31, 2014.
	The following tables provide information regarding our intangible assets, other than goodwill:
		December 31, 2013
	(In thousands)	Gross carrying amount		Accumulated amortization			Net carrying amount
	Intangible assets:
	Licenses	$	31,443	$	(21,216	)	$	10,227
	Purchased technologies	13,180		(7,428		)	5,752
	Non-compete agreements	2,165		(1,613		)	552
	Customer relationships	6,137		(5,442		)	695
	Other	11,562		(4,908		)	6,654
	Total	$	64,487	$	(40,607	)	$	23,880
		December 31, 2014
	(In thousands)	Gross carrying amount		Accumulated amortization			Net carrying amount
	Intangible assets:
	Licenses	$	32,466	$	(25,402	)	$	7,064
	Purchased technologies	13,180		(10,024		)	3,156
	Non-compete agreements	2,165		(1,952		)	213
	Customer relationships	6,137		(5,640		)	497
	Other	12,688		(7,026		)	5,662
	Total	$	66,636	$	(50,044	)	$	16,592
	Amortization expense on intangibles was $8.9 million, $9.8 million and $9.7 million in 2012, 2013 and 2014, respectively. Intangible assets are recorded at cost and are amortized on a straight-line basis over their estimated useful lives, which generally range from two to five years.
	As of December 31, 2014, amortization expense on intangible assets for the next five years was expected to be as follows:
	(In thousands)
	Year ending:	Amount
	2015	$	9,657
	2016	5,780
	2017	621
	2018	223
	2019	197
	Thereafter	114
	Total	$	16,592
	As of December 31, 2014, there were no indicators that our intangible assets were impaired.

Debt

Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt	Debt
	In 2011 we entered into a revolving credit facility with a syndicate of seven banks led by JPMorgan Chase. This facility, which matures in September 2016, has a total commitment of $200 million and is governed by financial and non-financial covenants, including a leverage ratio of not greater than 3.00 to 1.00, an interest coverage ratio of not less than 3.00 to 1.00, and a requirement to maintain a certain level of tangible assets in our U.S. entities. Our marginal borrowing costs on this facility are based on a floating base rate (LIBOR) plus a spread, which ranges from 1.25% to 2.00%, depending on our degree of financial leverage. We also pay a fee on the committed but unused amount of the facility, which ranges from 0.25% to 0.40%, also depending on our degree of financial leverage. The agreement further includes an accordion feature, which allows for an increase in the commitments to a total of $400 million under the same terms and conditions, subject to credit approval of the banking syndicate.
	As of December 31, 2014, we had outstanding borrowings of $25 million under this facility at an interest rate of 1.42%. Additionally there were insignificant letters of credit outstanding at the end of 2014. Therefore, as of December 31, 2014, we had $175 million available for future borrowings. As of the same date, we were in compliance with all of the covenants under our facility. The outstanding borrowings were fully repaid in January 2015.

Leases

Leases	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leases	Leases
	Capital Leases
	We have master lease agreements with our primary vendors that supply us with servers and computer equipment. Historically, we have financed most equipment purchases through their respective finance companies. The terms vary with each vendor but typically include a term of two to five years and interest rates ranging from 2% to 3%. A majority of these agreements allow us to purchase the equipment at the end of the lease for a nominal amount. The amount included in computers and equipment as of December 31, 2013 and December 31, 2014 is shown in the table below.
	Additionally, we have entered into multiple complex real estate development and lease arrangements with independent real estate developers to design, construct and lease certain real estate projects. While the independent developers legally own the real estate projects and must finance the overall construction, we agreed to fund certain structural improvements and/or retain obligations related to certain potential construction cost overruns which have triggered an accounting requirement to include construction costs in progress and a related long-term finance lease liability on our consolidated balance sheets as though we are the owner of the asset during the construction period. We do not depreciate the cost of the real estate projects or expect to fund this long-term finance lease liability during the construction period. The amount included in work in process as of December 31, 2013 and December 31, 2014 is shown in the table below.
	Upon completion of construction, we perform a sale-leaseback analysis pursuant to ASC 840, Leases, to determine if we can remove the asset and liability from our consolidated balance sheet. If the asset and corresponding liability can be derecognized, then the lease will be accounted for as an operating lease, and we will recognize rent expense over the lease term. However, certain factors are considered “continuing involvement” which precludes derecognizing the asset and liability when construction is complete. If the sale-leaseback criteria are not met, the asset would be considered to be owned for accounting purposes during the lease term. At this time, the amount recorded as a finance lease obligation for assets under construction would be transferred to a capital lease obligation. Accordingly, the asset would be depreciated and rental payments under the lease would be recorded as a reduction of the capital lease liability and interest expense.
	During 2014, construction of one of these real estate projects was completed, and we performed a sale-leaseback analysis. As a result of our continuing involvement in the project, we were precluded from derecognizing the asset and liability, and we will account for the lease as a capital lease obligation throughout the lease term. At the end of the lease term, we will derecognize the remaining lease obligation and residual asset balance. The amount included in buildings and leasehold improvements as of December 31, 2013 and December 31, 2014 is shown in the table below.
	Amounts in property and equipment under these capital leases and finance lease obligations for assets under construction consisted of:
	(In thousands)	December 31, 2013			December 31, 2014
	Computers and equipment	$	391,833		$	389,020
	Buildings and leasehold improvements	—			7,705
		391,833			396,725
	Less: accumulated depreciation and amortization	(335,599		)	(370,961		)
	Work in process	—			109,991
		$	56,234		$	135,755
	Future capital lease payments under non-cancelable leases as of December 31, 2014 were as follows:
	(In thousands)
	Year ending:	Amount
	2015	$	15,541
	2016	2,150
	2017	623
	2018	636
	2019	649
	Thereafter	2,795
	Total minimum capital lease payments	22,394
	Plus amount representing residual asset balance	5,394
	Less amount representing interest	(2,935		)
	Less amount representing executory costs	(938		)
	Present value of net minimum lease payments	23,915
	Less current portion of obligations under capital leases	(14,969		)
	Non-current obligations under capital leases	$	8,946
	Operating Leases
	We lease our data center facilities and certain office space under non-cancelable operating lease agreements. Facility leases generally include renewal options and may require us to pay a portion of the related operating expenses. Certain of these lease agreements have escalating rental payment provisions. We recognize rent expense for such arrangements on a straight-line basis.
	Future operating lease payments under non-cancelable leases with an initial term in excess of one year as of December 31, 2014 were as follows:
	(In thousands)
	Year ending:	Amount
	2015	$	71,130
	2016	65,948
	2017	65,195
	2018	59,464
	2019	57,885
	Thereafter	516,485
	Total minimum operating lease payments	$	836,107
	Rent expense for the years ended December 31, 2012, 2013 and 2014 was $46.1 million, $66.0 million and $74.0 million, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Purchase Commitments
	Non-cancelable purchase commitments primarily consist of commitments for certain software licenses, hardware purchases, and costs associated with our data centers, including bandwidth and electricity. The agreements can generally extend up to five years and provide for either penalties for early termination or may require minimum commitments for the remaining term. The minimum commitments for all of these agreements as of December 31, 2014 approximated $83.6 million, $18.4 million, $3.0 million, and $0.2 million for the years ended December 31, 2015, 2016, 2017 and 2018, respectively.
	We also have purchase orders and construction contracts primarily related to data center equipment and facility build-outs. We generally have the right to cancel these open purchase orders prior to delivery or terminate the contracts without cause.
	Legal Proceedings
	We are party to various legal and administrative proceedings, which we consider routine and incidental to our business. Although the outcome of these matters is currently not determinable, management expects that any losses that are incurred as a result of these matters, which are in excess of amounts already accrued in its consolidated balance sheet, would not be material to the consolidated financial statements as a whole.
	We are also a party to various claims that certain of our products, services, and technologies infringe the intellectual property rights of others. Adverse results in these lawsuits may include awards of substantial monetary damages, costly royalty or licensing agreements, or orders preventing us from offering certain features, products, or services, and may also cause us to change our business practices and require development of non-infringing products or technologies, which could result in a loss of revenue for us and otherwise harm our business. We have disputed the allegations of wrongdoing in these proceedings and intend to vigorously defend ourselves in all such matters.
	We cannot predict the impact, if any, that any of the matters described above may have on our business, results of operations, financial position, or cash flows. Because of the inherent uncertainties of such matters, including the early stage and lack of specific damage claims in many of them, we cannot estimate the range of possible losses from them.
	We record to cost of revenue state sales taxes related to software licenses acquired to provide hosting services to customers. We also remit state sales taxes collected from our customers for hosting services invoiced to our customers, with such services including the use of the aforementioned software licenses. During the year ended December 31, 2014, we recorded a $7 million benefit to cost of revenue for settlement of a dispute related to sales taxes paid on such software licenses for the period September 2007 through April 2014.
	Indemnifications
	As permitted under Delaware law, we have agreements whereby we indemnify our officers and directors for certain events or occurrences while the officer or director is, or was, serving at our request in such capacity. The term of the indemnification period is for the officer’s or director’s lifetime. The maximum potential amount of future payments we could be required to make under these indemnification agreements is unlimited; however, we have a director and officer insurance policy that limits our exposure and enables us to recover a portion of any future amounts paid. As a result of the insurance policy coverage, we believe the estimated fair value of these indemnification agreements is minimal. We had no significant liabilities recorded for these agreements as of December 31, 2013 or 2014.
	Additionally, in the normal course of business, we indemnify certain parties, including customers, vendors and lessors, with respect to certain matters. We have agreed to hold certain parties harmless against losses arising from a breach of representations or covenants or out of intellectual property infringement or other claims made against certain parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. We had no significant liabilities recorded for these agreements as of December 31, 2013 or 2014.
	Incentive Arrangements
	In August 2007, we entered into a lease for our corporate headquarters. In connection with this lease, we also entered into a Master Economic Incentives Agreement ("MEIA") with the Cities of Windcrest and San Antonio, Texas; Bexar County; and certain other parties, pursuant to which we agreed to locate existing and future employees at the new facility location. The agreement required that we meet certain employment levels each year in exchange for a 14-year exemption from most of the property taxes associated with the property. If we fail to meet these job creation requirements, we could lose a portion or all of the tax exemption provided during the 14-year period and would then be obligated to repay the exemption amount. We have met the requirements for the employment level for the year ended December 31, 2014, and we believe that it is probable that we will continue to meet the requirements throughout the exemption period. We elected to begin the exemption period in 2009.
	Further, we entered into an agreement with the State of Texas, under which we received $5.0 million in 2007, $3.5 million in 2012, and $5.5 million in 2014 and may receive up to an additional $8.0 million from the Texas Enterprise Fund in multiple installments, provided that we meet certain new employment levels in the State of Texas. We are responsible for maintaining the jobs until January 2022. If we eliminate jobs for which we have drawn funds, we are subject to a clawback on the amounts we have drawn plus 3.4% interest on such amounts per year. As of December 31, 2014, the $14.0 million received was deferred and recorded as other non-current liabilities. Amounts will be recognized into income upon the achievement of the performance criteria and the determination that the cash is no longer refundable to the State of Texas.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders' Equity
	Common Stock
	At December 31, 2013 and 2014, we had 141,123,904 and 140,945,171 shares of our common stock legally issued and outstanding, respectively.
	We have one class of authorized common stock. The rights and privileges provided to our common stockholders are as follows:
	•Dividend Rights—Subject to preferences that may apply to shares of preferred stock outstanding at the time, the holders of our common stock are entitled to receive dividends, at the discretion of our board of directors.
	•Voting Rights—All holders of common stock are entitled to one vote per share on all matters to be voted on by Rackspace Hosting's stockholders.
	•Right to Receive Liquidation Distributions—Upon liquidation, dissolution or winding-up, the holders of our common stock are entitled to share equally in all of our assets remaining after payment of all liabilities and the liquidation preferences of any outstanding preferred stock.
	Preferred Stock
	As of December 31, 2013 and 2014, there were 50 million authorized shares of preferred stock, of which none was issued or outstanding.
	Share Repurchase Program
	On November 6, 2014, our board of directors authorized a program to repurchase up to $500 million of our common stock over the next two years. Under this program, shares may be repurchased from time to time through both open market and privately negotiated transactions.
	On November 12, 2014, we entered into an accelerated share repurchase ("ASR") agreement with a financial institution to repurchase an aggregate $200 million of our common stock. Under the ASR agreement, we paid $200 million to the financial institution and received an initial delivery of 3.3 million shares of common stock which were subsequently retired. The final number of shares repurchased under the ASR agreement will be based generally upon the average daily volume weighted average price of our common stock during the repurchase period, less a discount and subject to adjustments pursuant to the terms and conditions of the ASR agreement. If the actual number of shares to be repurchased under the agreement exceeds the number of shares initially delivered, we will receive the excess shares at the end of the repurchase period. If the number of shares initially delivered exceeds the actual number of shares to be repurchased, we will either deliver shares of common stock or make a cash payment to the financial institution at our election. Final settlement is expected to occur within the first six months of 2015. The payment of $200 million was accounted for as a reduction to stockholders' equity in our Consolidated Balance Sheet.
	We reflected the ASR agreement as a repurchase of common stock for purposes of calculating earnings per share and as a forward contract indexed to our common stock. The forward contract met all the applicable criteria for equity classification, and therefore, was not accounted for as a derivative instrument.

ShareBased_Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation
	In December 2007, we adopted our 2007 Long-Term Incentive Plan (the "2007 Stock Plan"). Under the 2007 Stock Plan, incentive and non-qualified stock options or rights to purchase common stock may be granted to eligible participants. In addition to stock options, we may grant other equity awards such as stock appreciation rights, restricted stock awards, restricted stock units, performance awards, cash-based awards, and dividend equivalents. All awards, excluding incentive stock options, may be granted under the plan to employees, officers, directors, or any other non-employee service provider to the company. Incentive stock options may be granted only to employees of the company or a subsidiary. The exercise price of a stock option granted under the 2007 Stock Plan will be determined by the Compensation Committee at the time the option is granted and generally may not be less than 100% of the fair market value of a share of common stock as of the date of grant. The 2007 Stock Plan had an automatic share reserve increase effective the first day of each fiscal year, from 2009 through 2012. For fiscal year 2012, this resulted in an increase of approximately 5.9 million shares available under our Stock Plans.
	At our 2014 annual meeting of the stockholders, our stockholders approved certain amendments to the 2007 Stock Plan. The amendments included, among other things, adding 11.4 million shares available for future grants and requiring new grants of restricted stock, restricted stock units, performance units and performance shares to count against the numerical limits of the 2007 Stock Plan as 1.93 shares for every one share that is subject to such an award.
	The following have been granted under our 2007 Stock Plan: stock options, restricted stock units ("RSUs") and restricted stock awards ("RSAs"). Collectively, all such grants are referred to as "awards." All awards deduct one share from the 2007 Stock Plan shares available for issuance for each share granted, except as described above. To the extent awards granted under the 2007 Stock Plan terminate, expire or lapse, shares subject to such awards generally will again be available for future grant.
	In addition to the 2007 Stock Plan, we also maintain the 2005 Stock Plan and plans assumed through acquisitions, collectively referred to as the Stock Plans. Options are priced to be at least 100% of our common stock’s fair market value at the date of grant. Options have generally been granted for terms of either seven or ten years and generally vest ratably over a four-year period or cliff-vest at the third anniversary date of the grant.
	As of December 31, 2014, the total number of shares authorized, outstanding and available for future grants under the Stock Plans was as follows:
	Plan Name	Shares Authorized			Shares Outstanding			Shares
								Available for Future Grants
	Amended and Restated 2007 Long-Term Incentive Plan	40,189,197			10,269,849			13,290,221
	Other Stock Plans	11,740,760			789,247			—
	Total	51,929,957			11,059,096			13,290,221
	The composition of the equity awards outstanding as of December 31, 2013 and 2014 was as follows:
		December 31,		December 31,
		2013		2014
	Restricted stock	3,538,271		4,305,323
	Stock options	9,487,570		6,753,773
	Total outstanding awards	13,025,841		11,059,096
	Restricted Stock
	The following table summarizes our RSU and RSA activity for the year ended December 31, 2014:
		Number of Units or Shares		Weighted-Average Grant-Date Fair Value
	Outstanding at December 31, 2013	3,538,271		$	28.79
	Granted	3,236,458		$	34.87
	Released	-1,609,215		$	19.61
	Cancelled	-860,191		$	39.39
	Outstanding at December 31, 2014	4,305,323		$	34.49
	Expected to vest after December 31, 2014*	3,572,970		$	36.62
	*Includes reduction of shares outstanding due to estimated forfeitures
	The weighted-average grant-date fair value of RSUs and RSAs granted during 2012 and 2013 was $51.78 and $39.24, respectively. The total pre-tax intrinsic value of the RSUs and RSAs released during 2012, 2013 and 2014 was $75.5 million, $29.7 million and $52.7 million, respectively.
	In February 2009, our board approved grants of RSUs to our former chief executive officer and another member of the executive team. A total of 2,000,000 RSUs were granted. The vesting of these RSUs was dependent on the company’s total shareholder return ("TSR") on its common stock compared to other companies in the Russell 2000 Index. In addition, the company’s TSR had to be positive for vesting to occur. Of the total RSUs granted, 1,050,000 had a measurement period at the end of three years. The company's TSR was compared to the Russell 2000 Index in February 2012, and it was determined that the required market results were met. The remaining 950,000 RSUs had a measurement period at the end of five years. The company's TSR was compared to the Russell 2000 Index in February 2014, and it was determined that the required market results were met.
	During the period from 2010 through 2013, certain members of our executive team received RSUs and/or RSAs that contained vesting conditions dependent upon predetermined market results measured at the end of three years. The fair values of these market-vesting awards were measured using a Monte Carlo simulation based on the date of grant, and share-based compensation expense is recognized ratably over the three-year vesting period. During 2014, 38,502 of these awards reached their measurement date. The predetermined market results were not met and the awards were cancelled with no shares being issued. As of December 31, 2014, 291,689 of these awards remain outstanding with measurement dates occurring throughout 2016.
	In 2014, we granted 3,236,458 RSUs, of which 2,867,873 vest as the employee continues to be employed with us, in four equal installments, on each of the first, second, third and fourth anniversaries of the grant date. The fair value of these service-vesting awards is measured based on the closing fair market value of our common stock on the date of grant, and share-based compensation expense is recognized ratably over the four-year service period. The remaining 368,585 awards were granted to members of our executive team. The vesting of these awards is dependent upon the attainment of predetermined financial performance results over the next two to four years. The fair values of these performance-vesting awards is measured based on the closing fair market value of our common stock on the date of grant, and share-based compensation expense is recognized ratably over the company's best estimate of the period over which the performance condition will be met.
	Stock Options
	The following table summarizes the stock option activity for the year ended December 31, 2014:
		Number of Shares		Weighted-Average Exercise Price				Weighted-Average Remaining Contractual Life	Aggregate Intrinsic Value (in thousands)
	Outstanding at December 31, 2013	9,487,570		$	30.37			5.1	$	117,886
	Granted	339,807		$	37.8
	Exercised	-1,838,380		$	14.62
	Forfeited	-1,008,735		$	43.3
	Expired	-226,489		$	44.67
	Outstanding at December 31, 2014	6,753,773		$	32.62			4.21	$	104,330
	Vested and exercisable at December 31, 2014	3,962,344		$	24.16			3.53	$	93,847
	Vested and exercisable at December 31, 2014 and expected to vest thereafter*	6,367,890		$	31.9			4.14	$	102,959
	*Includes reduction of shares outstanding due to estimated forfeitures
	The stock options granted in 2012, 2013 and 2014 vest as the employee continues to be employed with us, in four equal installments, on each of the first, second, third and fourth anniversaries of the grant date and have a term of seven years. Included in the 339,807 stock options granted during 2014 are 106,200 stock options granted to certain members of our executive team that will become eligible to vest over four equal installments as the executive continues to be employed with us once predetermined market results are attained. The fair values of these market-vesting options were measured using a Monte Carlo simulation based on the date of grant, and share-based compensation expense is recognized ratably over the four-year vesting period.
	The total pre-tax intrinsic value of the stock options exercised during 2012, 2013 and 2014 was $193.1 million, $76.4 million and $44.1 million, respectively.
	The following table presents the assumptions used to estimate the fair values of the stock options granted in the periods presented:
		Years Ended December 31,
		2012		2013		2014
	Expected stock volatility	56% - 58%		46% - 47%		46% - 48%
	Expected dividend yield	—%		—%		—%
	Risk-free interest rate	0.50% - 0.77%		0.57% - 0.93%		1.08% - 1.27%
	Expected life	4.00 - 4.75 years		3.79 years		3.82 years
	Weighted-average grant-date fair value of options granted during the year	$24.38		$15.86		$15.34
	Employee Stock Purchase Plan
	An Employee Stock Purchase Plan (the "ESPP") for U.S. employees was approved by the company's board of directors in 2011 and adopted by the company on January 1, 2012. Under the ESPP, eligible employees may purchase a limited number of shares of the company's common stock at the lesser of 85% of the market value on the enrollment date or 85% of the market value on the purchase date. The ESPP is made up of a series of offering periods. Each offering period has a maximum term of 24 months and is divided into semi-annual purchase intervals. Eligible employees may enroll at the beginning of any semi-annual purchase interval. During 2014, we issued 203,469 shares through the ESPP.
	The fair value on each enrollment date was determined using the Black-Scholes option-pricing model. The following table presents the assumptions used to estimate the fair values of the shares granted through the ESPP in the periods presented:
		Years Ended December 31,
		2013		2014
	Expected stock volatility	32% - 62%		42% - 56%
	Expected dividend yield	—%		—%
	Risk-free interest rate	0.09% - 0.34%		0.06% - 0.47%
	Expected life	0.5 - 2.0 years		0.5 - 2.0 years
	Weighted-average grant-date fair value of shares granted during the year	$16.04		$12.83
	Share-Based Compensation Expense
Share-based compensation expense was recognized as follows:
	Year Ended December 31,
(in thousands)	2012				2013			2014
Cost of revenue	$	9,592			$	12,584		$	16,446
Research and development	4,856				8,168			12,581
Sales and marketing	6,379				7,317			9,573
General and administrative	20,719				31,576			31,405
Pre-tax share-based compensation	41,546				59,645			70,005
Less: Income tax benefit	(15,477		)		(20,080		)	(21,515		)
Total share-based compensation expense, net of tax	$	26,069			$	39,565		$	48,490
As of December 31, 2014, there was $175.4 million of total unrecognized compensation cost related to restricted stock, options and the ESPP, which will be amortized using the straight-line method over a weighted-average period of 2.6 years.

Taxes

Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Taxes	Taxes
	The provision for income taxes consisted of:
		Year Ended December 31,
	(In thousands)	2012				2013				2014
	Current:
	Federal	$	38,720			$	35,912			$	38,318
	Foreign	19,248				12,071				11,083
	State	4,296				4,121				5,337
	Total current	62,264				52,104				54,738
	Deferred:
	Federal	1,359				(3,886		)		(2,425		)
	Foreign	(910		)		(1,621		)		(2,878		)
	State	(124		)		(2,575		)		(384		)
	Total deferred	325				(8,082		)		(5,687		)
	Total provision for income taxes	$	62,589			$	44,022			$	49,051
	Income before income taxes included income from foreign operations of approximately $61.6 million, $39.7 million and $64.4 million for the years ended December 31, 2012, 2013 and 2014, respectively.
	A reconciliation of the statutory federal tax rate to the effective tax rate is as follows:
		Year Ended December 31,
		2012			2013			2014
	Statutory federal tax rate	35	%		35	%		35	%
	State taxes, net of federal benefit	1.5	%		0.7	%		1.7	%
	Tax rate differentials for international jurisdictions	-2	%		-3.8	%		-10.5	%
	Permanent differences	1.1	%		1.6	%		3.5	%
	Deferred impact of intercompany transfers	1.9	%		3.5	%		3.2	%
	Research and development credit (current year)	—	%		-3.1	%		-2.1	%
	Other, net	-0.2	%		-0.2	%		-0.1	%
	Effective tax rate	37.3	%		33.7	%		30.7	%
	The tax rate differential for international jurisdictions has increased from 2013 to 2014 as an increased portion of our profits were earned outside the U.S. Permanent differences increased from 2013 to 2014 due to an increase in nondeductible items in 2014.
	In December 2014, the U.S. Tax Increase Prevention Act of 2014 was signed into law which reinstated the Federal research credit, bonus depreciation and other expired subsidiaries. The extension of the Federal research credit resulted in a reduction of our effective tax rate in 2014. Unless the Federal research credit is extended in future periods, we expect an increase in our effective tax rate for years after 2014.
	Deferred Taxes
	Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes. Significant components of our deferred tax assets and liabilities are as follows:
	(In thousands)	December 31, 2013				December 31, 2014
	Deferred tax assets:
	Share-based compensation	$	23,487			$	27,158
	State income taxes	2,293				2,205
	Vacation accruals	5,235				3,502
	Deferred revenue	3,793				5,322
	Deferred rent	13,736				16,195
	Accruals not currently deductible	7,850				8,386
	Net operating loss carryforwards	3,534				4,832
	Foreign tax credit	1,723				1,723
	Research and development credits	13,871				13,341
	Other	3,703				4,318
	Total gross deferred tax assets	79,225				86,982
	Deferred tax liabilities:
	Depreciation	125,209				134,596
	Prepaids	2,981				4,002
	Other	107				60
	Total gross deferred tax liabilities	128,297				138,658
	Net deferred tax liabilities	$	(49,072	)		$	(51,676	)
	Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Valuation allowances were established in the year ended December 31, 2014 for an immaterial amount of foreign tax credits that are expected to expire before they are utilized. For the rest of the deferred tax assets, valuation allowances were not deemed necessary based upon the determination that future profits are anticipated to utilize deferred tax assets in the future.
	The company has not recognized a deferred tax liability for undistributed earnings of its foreign subsidiaries because such earnings are considered indefinitely invested in a foreign country. As of December 31, 2014, undistributed earnings of the company’s foreign subsidiaries considered indefinitely invested were $221.0 million. We intend to reinvest these earnings in active non-U.S. business operations and do not currently intend to repatriate these earnings to fund U.S. operations through either a dividend, liquidation or other means. In addition, estimates of future domestic cash generation will be sufficient to meet future domestic cash needs. Further, it is expected that the undistributed earnings of the company's foreign subsidiaries will be used to fund the additional investments made outside of the U.S. The determination of the amount of unrecognized deferred tax liability related to undistributed earnings is not practicable because of the complexities of the hypothetical calculation.
	We have $199.9 million of federal net operating loss carryforwards and $22.2 million of federal tax credit carryforwards expiring at various dates through 2034. Of the $199.9 million of federal net operating loss carryforwards, $196.6 million are due to gross excess tax benefits from stock option exercises that have not been recorded as of December 31, 2014. We have $3.9 million of foreign net operating loss carryforwards, which have an indefinite expiration date.
	Uncertain Tax Positions
	We file income tax returns in each jurisdiction in which we operate, both domestically and internationally. Due to the complexity involved with certain tax matters, we have considered all relevant facts and circumstances for the financial statement recognition, measurement, presentation and disclosure of uncertain tax positions taken or expected to be taken in income tax returns. We believe that there are no other jurisdictions in which the outcome of uncertain tax matters is likely to be material to our results of operations, financial position or cash flows. We further believe that we have made adequate provision for all income tax uncertainties.
	A reconciliation of our unrecognized tax benefits, excluding accrued interest, for 2013 and 2014 is as follows:
	(In thousands)	2013				2014
	Balance, beginning of year	$	18,664			$	23,246
	Additions based on tax positions related to the current year	3,919				2,523
	Additions for tax positions of prior years	663				3,633
	Reduction for statute expiration	—				(930		)
	Reductions for tax positions of prior years	—				(7,440		)
	Balance, end of year	$	23,246			$	21,032
	Unrecognized tax benefits of $23.2 million and $21.0 million for 2013 and 2014, respectively, are included in other non-current liabilities on the balance sheet. At December 31, 2013 and 2014, respectively, approximately $8.2 million and $13.1 million of these unrecognized tax benefits, if recognized, would favorably impact our effective tax rate in any future period. Also included in the balance of unrecognized tax benefits at December 31, 2014 are liabilities of $7.9 million that, if recognized, would be recorded as an adjustment to other current and non-current assets. We do not expect the amount of unrecognized tax benefits disclosed above to change significantly over the next 12 months.
We recognize interest expense and penalties related to income tax matters within income tax expense on our consolidated statements of comprehensive income. Accrued interest and penalties as of December 31, 2013 and 2014 were not material.
We are subject to U.S. federal income tax and various state, local, and international income taxes in numerous jurisdictions. Our domestic and international tax liabilities are subject to the allocation of revenue and expenses in different jurisdictions and the timing of recognizing revenue and expenses. As such, our effective tax rate is impacted by the geographical distribution of income and mix of profits in the various jurisdictions. Additionally, the amount of income taxes paid is subject to our interpretation of applicable tax laws in the jurisdictions in which we file.
We currently file income tax returns in the U.S. and all foreign jurisdictions in which we have entities, which are periodically under audit by federal, state, and international tax authorities. These audits can involve complex matters that may require an extended period of time for resolution. We remain subject to U.S. federal and state income tax examinations for the tax years 2009 through 2014 and in the international jurisdictions in which we operate for varying periods from 2007 through 2014. We currently have income tax examinations open in the State of California for 2010, 2011 and 2012, and the United Kingdom for 2012. Although the outcome of open tax audits is uncertain, in management’s opinion, adequate provisions for income taxes have been made. If actual outcomes differ materially from these estimates, they could have a material impact on our financial condition and results of operations. Differences between actual results and assumptions or changes in assumptions in future periods are recorded in the period they become known. To the extent additional information becomes available prior to resolution, such accruals are adjusted to reflect probable outcomes.
Other
During 2014 we did not receive any federal income tax refunds. We experienced taxable profits in the U.S. and U.K. in 2014 before consideration of excess tax benefits, and therefore we anticipate utilizing benefits of tax deductions related to stock compensation. As a result, we have recognized an excess tax benefit in the U.S. and U.K.
During 2011, 2012 and 2013, Rackspace US, Inc. sold certain intangible assets to a wholly-owned offshore subsidiary in taxable transactions. As a result of the transactions, there is an asset on the consolidated balance sheet as of December 31, 2014 of $27.4 million (of which $23.8 million was recorded in other non-current assets) that will be amortized through income tax expense over the lives of the applicable intangible assets. Although the transactions were taxable, the resulting gains were entirely offset against existing net operating losses, including excess stock compensation deductions. Thus, there was no cash tax impact from the sales of the intangible assets.

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	Segment Information
	We operate as one reportable segment based upon a number of factors including the basis for our budget and forecasts, the overall organization and management structure, and the consolidated financial information regularly used by our chief executive officer, who is the chief operating decision maker, to make key operating decisions and to assess performance. Since we operate in one reportable segment, all relevant financial information used to allocate resources and assess performance can be found in the consolidated financial statements.
	Total net revenue by our product categories was as follows:
		Year Ended December 31,
		2012		2013		2014
	Dedicated Cloud	$	1,005,165	$	1,119,636	$	1,254,666
	Public Cloud	304,074		415,150		539,691
	Total net revenue	$	1,309,239	$	1,534,786	$	1,794,357
	Prior to 2014, revenue was attributed to geographic location based on the Rackspace operating location that entered into the contractual relationship with the customer, either the U.S. or International, primarily the U.K. Total net revenue by geographic region in 2012 and 2013 was as follows:
		Year Ended December 31,
	(In thousands)	2012		2013
	United States	$	973,733	$	1,133,645
	International	335,506		401,141
	Total net revenue	$	1,309,239	$	1,534,786
	Beginning in 2014, we attribute revenue to geographic location based on the customer's billing address, either the U.S. or International, primarily the U.K. While the geographic information is not significantly different from the current method, we believe the customer billing address is the best indicator of customer location. Due to system limitations, we have determined that it is impracticable to restate the 2012 revenue information on this basis. Total net revenue by geographic region in 2013 and 2014 based upon the customer's billing address was as follows:
		Year Ended December 31,
	(In thousands)	2013		2014
	United States	$	1,076,248	$	1,232,136
	International	458,538		562,221
	Total net revenue	$	1,534,786	$	1,794,357
	Our long-lived assets are primarily located in the U.S. and the U.K., and to a lesser extent Hong Kong and Australia. Property and equipment, net by geographic region was as follows:
	(In thousands)	December 31,		December 31,
		2013		2014
	United States	$	654,507	$	718,305
	International	236,269		339,379
	Total property and equipment, net	$	890,776	$	1,057,684

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans
	We sponsor defined contribution plans whereby employees may elect to contribute a portion of their annual compensation to the plans, after complying with certain limitations. The plans also include a discretionary employer contribution. During 2012, 2013 and 2014, contribution expense recognized for these plans was $7.4 million, $10.3 million and $13.2 million, respectively.

Schedule_of_Valuation_and_Qual

Schedule of Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure
	(In thousands)	Beginning Balance		Additions (1)		Write-offs of Accounts Receivable and Credit Memos Paid			Ending Balance
	Allowance for doubtful accounts and customer credits for the years ending December 31:
	2012	$	3,420	$	18,863	$	(18,047	)	$	4,236
	2013	$	4,236	$	16,875	$	(17,220	)	$	3,891
	2014	$	3,891	$	16,562	$	(15,119	)	$	5,334
	-1	Additions to the allowance for doubtful accounts are charged to expense. Additions to the allowance for customer credits are charged to revenue.

Supplementary_Financial_Data_U

Supplementary Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplementary Financial Data (Unaudited)	SUPPLEMENTARY FINANCIAL DATA
	(UNAUDITED)
		Quarters Ended
	(In thousands, except per share amounts)	March 31,		June 30,		September 30,		December 31,
		2013		2013		2013		2013
	Net revenue	$	362,200	$	375,847	$	388,636	$	408,103
	Cost of revenue	$	113,610	$	117,658	$	127,404	$	133,821
	Net income	$	27,261	$	22,367	$	16,311	$	20,798
	Net income per share - basic	$	0.2	$	0.16	$	0.12	$	0.15
	Net income per share - diluted	$	0.19	$	0.16	$	0.11	$	0.14
		Quarters Ended
	(In thousands, except per share amounts)	March 31,		June 30,		September 30,		December 31,
		2014		2014		2014		2014
	Net revenue	$	421,047	$	441,112	$	459,776	$	472,422
	Cost of revenue	$	140,417	$	145,051	$	142,954	$	153,912
	Net income	$	25,446	$	22,451	$	25,740	$	36,916
	Net income per share - basic	$	0.18	$	0.16	$	0.18	$	0.26
	Net income per share - diluted	$	0.18	$	0.16	$	0.18	$	0.26

Summary_of_Significant_Account

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Consolidation	The accompanying consolidated financial statements include the accounts of Rackspace Hosting and our wholly-owned subsidiaries, which include, among others, Rackspace US, Inc., our domestic operating entity, and Rackspace Limited, our United Kingdom operating entity. Intercompany transactions and balances have been eliminated in consolidation.
Basis of Accounting	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States ("GAAP")
Use of Estimates	The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States ("GAAP") requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and reported amounts of revenue and expenses during the reporting period. On an ongoing basis, we evaluate our estimates, including those related to accounts receivable and customer credits, property and equipment, fair values of intangible assets and goodwill, useful lives of intangible assets, fair value of share-based compensation, contingencies, and income taxes, among others. Whenever possible, we base our estimates and assumptions on historical experience. However, certain estimates require us to make assumptions about expected future cash flow, events and usage patterns that we cannot influence or control. Our judgments, assumptions and estimates are based upon facts and circumstances known to us when we prepare the consolidated financial statements and that we believe to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities or recording of revenue and expenses in our consolidated financial statements. Changes in facts and circumstances may cause us to change our assumptions and estimates in future periods, and it is possible that actual results could differ from our estimates. We engaged third-party consultants to assist management in the valuation of acquired assets, including other intangibles, as well as share-based compensation.
Reclassifications	Certain reclassifications have been made to the prior period consolidated financial statements to conform to the current period presentation.
Cash and Cash Equivalents	For the purposes of the consolidated financial statements, we consider all highly liquid investments with original maturities of three months or less when acquired to be cash equivalents. Our available cash and cash equivalents are held in bank deposits, overnight sweep accounts, and money market funds. Gains and losses are included in interest and other income in our accompanying consolidated statements of comprehensive income.
	We actively monitor the third-party depository institutions that hold our deposits. Our emphasis is primarily on safety of principal, secondly on the liquidity of our investments, and finally on maximizing yield on those funds. Our money market mutual funds comply with SEC Rule 2a-7 and invest exclusively in high-quality, short-term obligations that include securities issued or guaranteed by the U.S. government or by U.S. government agencies and floating rate and variable rate demand notes of U.S. and foreign corporations.
Accounts Receivable, Net	We classify as trade accounts receivable amounts due within twelve months, arising from the provision of services in the normal course of business. We generally do not request collateral from our customers, although in certain cases we may require the customer to prepay for services. We record an allowance for doubtful accounts for estimated losses resulting from the inability of our customers to make required payments. When evaluating the adequacy of the allowance, we analyze the overall quality of our accounts receivable portfolio, current economic conditions and trends, historical bad debt write-offs, customer creditworthiness, and specifically identified customer risks.
	In addition, our hosting arrangements contain service level commitments with our customers. To the extent that such service levels are not achieved or are otherwise disputed due to third-party power or service issues, unfavorable weather, or other service interruptions or conditions, we are required to issue service credits for a portion of the hosting service fees paid by our customers. At each reporting period, we estimate the amount of service level credits to be issued and record a reduction to revenue. To estimate service credits, we utilize historical data and specific knowledge of factors impacting the delivery of services to our customers.
Prepaid Expense and Other Assets	Prepaid expenses and other assets consist primarily of prepaid software and equipment maintenance contracts and prepaid operating expenses. Software maintenance contracts are amortized over the agreement period, generally one to three years. Prepaid operating expenses are expensed in the period in which services are received.
Property and Equipment, Net	Property and equipment is stated at cost, net of accumulated depreciation. Property and equipment is depreciated on a straight-line basis over the estimated useful life of the asset. Replacements and major improvements are capitalized, while maintenance and repairs are charged to expense as incurred. Upon retirement or sale, the cost of assets disposed of and related accumulated depreciation are removed from the accounts, and any resulting gain or loss is credited or charged to operations.
Internally Developed Software	We capitalize certain costs of computer software developed or acquired for internal use. Capitalized computer software costs consist of purchased software licenses, implementation costs, and salaries and related compensation costs of employees and consultants for certain projects that qualify for capitalization. The capitalized software costs are amortized on a straight-line basis over the expected useful life of the software.
Goodwill and Intangible Assets	Goodwill consists of the excess of the purchase price over the fair value of identifiable net assets of businesses acquired. Goodwill is evaluated for impairment at a reporting unit level using a fair value approach on an annual basis at the beginning of the fourth quarter or whenever events or circumstances indicate that impairment may have occurred. Our assessment did not utilize the qualitative assessment as we went directly to Step 1 of the test. No goodwill impairment was recognized in any of the years presented.
	Intangible assets, including purchased technology, customer contracts and relationships, certain tradenames, license agreements, and non-compete agreements arising principally from acquisitions, are recorded at cost less accumulated amortization, and the definite-lived intangibles are amortized using a method that reflects the pattern in which the economic benefits of the related intangible asset are consumed or utilized.
Intangible Assets	Intangible assets are recorded at cost and are amortized on a straight-line basis over their estimated useful lives, which generally range from two to five years.
Impairment of Long-Lived Assets	Long-lived assets, including property and equipment and intangible assets, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount should be evaluated. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset in conjunction with its asset group compared to the estimated undiscounted future cash flows expected to be generated by the asset group. If the carrying amount of the asset group exceeds its estimated future cash flows, an impairment charge is recognized in the amount by which the carrying amount of the asset group exceeds the fair value of the assets.
Leases	We lease certain property and equipment under capital lease agreements. The assets held under capital lease and related obligations are recorded at the lesser of the present value of aggregate future minimum lease payments, including estimated bargain purchase options, or the fair value of the assets held under capital lease. Such assets and the related leasehold improvements are amortized as depreciation expense over the shorter of the terms of the leases or the estimated useful lives of the assets, which typically range from two to five years for equipment and 30 years for property. For assets for which the lease agreement includes a bargain purchase option or transfer of ownership at the completion of the lease and the lease term is shorter than the estimated useful life of the asset, the asset is amortized over its estimated useful life.
	We also lease property and equipment under operating lease agreements. The lease terms typically range from two to five years for equipment and one to twenty years for property, including office space and data center facilities. Rent increases, rent holidays, leasehold incentives or any other unusual provisions or conditions are considered with total rent payments and are expensed on a straight-line basis over the lease period.
Real Estate Development and Lease Arrangements	Additionally, we have entered into multiple complex real estate development and lease arrangements with independent real estate developers to design, construct and lease certain real estate projects. While the independent developers legally own the real estate projects and must finance the overall construction, we agreed to fund certain structural improvements and/or retain obligations related to certain potential construction cost overruns which have triggered an accounting requirement to include construction costs in progress and a related long-term finance lease liability on our consolidated balance sheets as though we are the owner of the asset during the construction period. We do not depreciate the cost of the real estate projects or expect to fund this long-term finance lease liability during the construction period. The amount included in work in process as of December 31, 2013 and December 31, 2014 is shown in the table below.
	Upon completion of construction, we perform a sale-leaseback analysis pursuant to ASC 840, Leases, to determine if we can remove the asset and liability from our consolidated balance sheet. If the asset and corresponding liability can be derecognized, then the lease will be accounted for as an operating lease, and we will recognize rent expense over the lease term. However, certain factors are considered “continuing involvement” which precludes derecognizing the asset and liability when construction is complete. If the sale-leaseback criteria are not met, the asset would be considered to be owned for accounting purposes during the lease term. At this time, the amount recorded as a finance lease obligation for assets under construction would be transferred to a capital lease obligation. Accordingly, the asset would be depreciated and rental payments under the lease would be recorded as a reduction of the capital lease liability and interest expense.
	During 2014, construction of one of these real estate projects was completed, and we performed a sale-leaseback analysis. As a result of our continuing involvement in the project, we were precluded from derecognizing the asset and liability, and we will account for the lease as a capital lease obligation throughout the lease term. At the end of the lease term, we will derecognize the remaining lease obligation and residual asset balance.
Revenue and Deferred Revenue	Revenue is reported net of customer credits and sales and use tax. We recognize revenue when persuasive evidence of an arrangement exists, service has been provided to the customer, the amount of fees to be paid by the customer is fixed or determinable, and collectibility is reasonably assured. We provide cloud computing services to our customers and do not sell hardware and software products. We recognize cloud computing revenue, including installation fees, beginning on the date the customer commences use of our services. Cloud computing revenue is recognized over the contractual term of the customer contract.
	Setup and other direct implementation activities performed by our personnel at the inception of a customer arrangement to enable us to perform under the terms of the arrangement are expensed as incurred.
	Customers using our dedicated cloud services typically pay us a monthly recurring charge based upon the capacity and complexity of the IT systems we manage, the type of technology used and the level of support we provide. Some customers also pay a non-refundable installation fee. Since our dedicated cloud customers usually continue to utilize our services beyond the initial contract term, these installation fees are recognized ratably over the estimated average life of a customer relationship.
	Our public cloud services offers pay-as-you-go cloud computing services that are billed according to customer usage. Revenue is recognized in the month in which the customer uses the services.
	Invoiced amounts and accrued unbilled usage is recorded in accounts receivable and either deferred revenue or revenue, depending on whether the revenue recognition criteria have been met. Therefore, deferred revenue primarily consists of amounts that have been prepaid or deferred installation fees.
Cost of Revenue	Cost of revenue consists primarily of expenses related to personnel, licenses, and our data center facilities. Personnel expenses include the salaries, non-equity incentive compensation, share-based compensation and related expenses of our support teams and data center employees, and data center facility costs include rental fees, power costs, maintenance fees, and bandwidth.
Advertising Costs	We charge advertising costs to expense in the period incurred.
Share-Based Compensation	The Black-Scholes valuation model that we use to determine the fair value of stock options requires us to make assumptions and judgments about variables related to our common stock and the related awards. These variables and assumptions include the fair value of our common stock, expected term, the expected volatility, the risk-free interest rate, expected dividends, and the estimated rate of forfeitures of unvested stock options.
	We used the following assumptions when determining the fair value of our stock options:
	•	Fair Value of our Common Stock—The end of day market price on the grant date is used to determine fair value.
	•	Expected Term—The expected term represents the period that our share-based awards are expected to be outstanding. In order to compute the expected term for the four-year period immediately following our IPO, we elected to use the simplified method due to insufficient historical exercise data available to provide a reasonable basis upon which to estimate the expected term. We have been a public company since August 2008, and our options generally vest over four years and expire seven to ten years from the grant date. Beginning in August 2012, management determined that sufficient historical data is available for a fair evaluation and therefore we began to use historical exercise data in our estimation of the expected term.
	•	Expected Volatility—Management estimates volatility for option grants by evaluating the weighted average of the implied volatility and the mean reversion volatility of the company’s stock.
	•	Risk-Free Interest Rate—The risk-free interest rate used in the Black-Scholes valuation model is based on the implied yield currently available on U.S. Treasury zero-coupon issues with an equivalent expected term.
	•	Expected Dividend—We have not issued dividends to date and do not anticipate issuing dividends.
	•	Estimated Rate of Forfeitures—We estimate expected forfeitures based on our historical experience. If actual forfeitures differ from our estimates, we will record the difference as an adjustment in the period we revise our estimates.
	In addition to stock options, our share-based compensation also comprises restricted stock. A portion of restricted stock grants have vesting conditions dependent upon the performance of the company’s total shareholder return ("TSR") on its common stock compared to certain market indices. Additionally, the company’s TSR must be positive for vesting to occur. We use a Monte Carlo simulation to estimate the fair value of these awards. For all other restricted stock granted that vests ratably over the requisite service period, we measure fair value based on the closing fair market value of the company’s common stock on the date of grant, and we recognize expense straight-line over the vesting period.
	We also grant restricted stock with vesting conditions dependent upon the financial performance of the company. The fair values of these performance-vesting awards is measured based on the closing fair market value of our common stock on the date of grant, and share-based compensation expense is recognized when the company determines the performance condition is likely to be met. The expense is recognized ratably over the company's best estimate of the period over which the performance condition will be met.
Income Taxes	Income taxes are accounted for using the asset and liability method. Deferred income taxes are provided for temporary differences in recognizing certain income, expense, and credit items for financial reporting purposes and tax reporting purposes. Such deferred income taxes primarily relate to the difference between the tax bases of assets and liabilities and their financial reporting amounts. Deferred tax assets and liabilities are measured by applying enacted statutory tax rates applicable to the future years in which deferred tax assets or liabilities are expected to be settled or realized. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversals of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. Based upon projections of future taxable income over the periods in which the deferred tax assets are deductible, management believes it is more likely than not that we will realize the benefits of these deductible differences.
	We are currently under income tax audits in the U.K. and California. Due to the complexity involved with certain tax matters, there is the possibility that the various taxing authorities may disagree with certain tax positions filed on our income tax returns. We have considered all relevant facts and circumstances and believe that we have made adequate provision for all income tax uncertainties. For a further discussion of the impact of uncertain tax positions, see Note 10, "Taxes."
	We do not provide for a U.S. income tax liability on undistributed earnings of our foreign subsidiaries. The earnings of non-U.S. subsidiaries, which reflect full provision for non-U.S. income taxes, are currently indefinitely reinvested in non-U.S. operations.
Undistributed Earnings of Foreign Subsidiaries	The company has not recognized a deferred tax liability for undistributed earnings of its foreign subsidiaries because such earnings are considered indefinitely invested in a foreign country. As of December 31, 2014, undistributed earnings of the company’s foreign subsidiaries considered indefinitely invested were $221.0 million. We intend to reinvest these earnings in active non-U.S. business operations and do not currently intend to repatriate these earnings to fund U.S. operations through either a dividend, liquidation or other means. In addition, estimates of future domestic cash generation will be sufficient to meet future domestic cash needs. Further, it is expected that the undistributed earnings of the company's foreign subsidiaries will be used to fund the additional investments made outside of the U.S. The determination of the amount of unrecognized deferred tax liability related to undistributed earnings is not practicable because of the complexities of the hypothetical calculation.
State Sales Taxes	We record to cost of revenue state sales taxes related to software licenses acquired to provide hosting services to customers. We also remit state sales taxes collected from our customers for hosting services invoiced to our customers, with such services including the use of the aforementioned software licenses.
Fair Value of Financial Instruments	Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. There is a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:
	Level 1 – Observable inputs such as quoted prices in active markets for identical assets or liabilities;
	Level 2 – Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities; and
	Level 3 – Unobservable inputs that are supported by little or no market activity, which require management judgment or estimation.
	Money market funds, classified in cash and cash equivalents, were $102 million and $11 million as of December 31, 2013 and 2014, respectively, and are Level 1 financial instruments. The carrying value of our debt approximates the fair value as of December 31, 2013 and 2014.
Foreign Currency	We have assessed the functional currency of each of our international subsidiaries and have generally designated the local currency to be their respective functional currencies. The consolidated financial statements of these foreign subsidiaries are translated into the U.S. dollar. All assets and liabilities are translated to the U.S. dollar at the end-of-period exchange rates. Capital accounts are determined to be of a permanent nature and are therefore translated using historical exchange rates. Revenue and expenses are translated using average exchange rates.
	Foreign currency translation adjustments arising from differences in exchange rates from period to period are included in the foreign currency translation adjustment account in accumulated comprehensive income (loss). There was no income tax expense allocated in the years ended December 31, 2012, 2013 and 2014.
	Transaction gains or losses in currencies other than the functional currency are included as a component of other income (expense) in the consolidated statements of comprehensive income.
Segment Reporting	We operate as one reportable segment based upon a number of factors including the basis for our budget and forecasts, the overall organization and management structure, and the consolidated financial information regularly used by our chief executive officer, who is the chief operating decision maker, to make key operating decisions and to assess performance.

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of Basic and Diluted Net Income Per Share	The following table sets forth the computation of basic and diluted net income per share:
		Year Ended December 31,
	(In thousands except per share data)	2012		2013		2014
	Basic net income per share:
	Net income	$	105,418	$	86,737	$	110,553
	Weighted average shares outstanding:
	Common stock	135,279		138,577		141,971
	Number of shares used in per share computations	135,279		138,577		141,971
	Net income per share	$	0.78	$	0.63	$	0.78
	Diluted net income per share:
	Net income	$	105,418	$	86,737	$	110,553
	Weighted average shares outstanding:
	Common stock	135,279		138,577		141,971
	Stock options, awards and employee share purchase plans	5,986		4,434		2,527
	Number of shares used in per share computations	141,265		143,011		144,498
	Net income per share	$	0.75	$	0.61	$	0.77

Property_and_Equipment_net_Tab

Property and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and equipment consisted of:
	(Dollar amounts in thousands)	Estimated Useful Lives				December 31,			December 31,
						2013			2014
	Computers and equipment	3	-	5	years	$	1,242,690		$	1,495,206
	Computer software	1	-	5	years	245,416			318,888
	Furniture and fixtures	7	years			55,681			56,656
	Buildings and leasehold improvements	2	-	30	years	236,255			253,621
	Land					28,566			27,896
	Property and equipment, at cost					1,808,608			2,152,267
	Less accumulated depreciation and amortization					(983,618		)	(1,249,522		)
	Work in process					65,786			154,939
	Property and equipment, net					$	890,776		$	1,057,684

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets, Other Than Goodwill	The following tables provide information regarding our intangible assets, other than goodwill:
		December 31, 2013
	(In thousands)	Gross carrying amount		Accumulated amortization			Net carrying amount
	Intangible assets:
	Licenses	$	31,443	$	(21,216	)	$	10,227
	Purchased technologies	13,180		(7,428		)	5,752
	Non-compete agreements	2,165		(1,613		)	552
	Customer relationships	6,137		(5,442		)	695
	Other	11,562		(4,908		)	6,654
	Total	$	64,487	$	(40,607	)	$	23,880
		December 31, 2014
	(In thousands)	Gross carrying amount		Accumulated amortization			Net carrying amount
	Intangible assets:
	Licenses	$	32,466	$	(25,402	)	$	7,064
	Purchased technologies	13,180		(10,024		)	3,156
	Non-compete agreements	2,165		(1,952		)	213
	Customer relationships	6,137		(5,640		)	497
	Other	12,688		(7,026		)	5,662
	Total	$	66,636	$	(50,044	)	$	16,592
Schedule of Future Amortization Expense on Intangible Assets	As of December 31, 2014, amortization expense on intangible assets for the next five years was expected to be as follows:
	(In thousands)
	Year ending:	Amount
	2015	$	9,657
	2016	5,780
	2017	621
	2018	223
	2019	197
	Thereafter	114
	Total	$	16,592

Leases_Tables

Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Amounts in property and equipment under capital leases and finance lease obligations for assets under construction	Amounts in property and equipment under these capital leases and finance lease obligations for assets under construction consisted of:
	(In thousands)	December 31, 2013			December 31, 2014
	Computers and equipment	$	391,833		$	389,020
	Buildings and leasehold improvements	—			7,705
		391,833			396,725
	Less: accumulated depreciation and amortization	(335,599		)	(370,961		)
	Work in process	—			109,991
		$	56,234		$	135,755
Future capital lease payments under non-cancelable leases	Future capital lease payments under non-cancelable leases as of December 31, 2014 were as follows:
	(In thousands)
	Year ending:	Amount
	2015	$	15,541
	2016	2,150
	2017	623
	2018	636
	2019	649
	Thereafter	2,795
	Total minimum capital lease payments	22,394
	Plus amount representing residual asset balance	5,394
	Less amount representing interest	(2,935		)
	Less amount representing executory costs	(938		)
	Present value of net minimum lease payments	23,915
	Less current portion of obligations under capital leases	(14,969		)
	Non-current obligations under capital leases	$	8,946
Future operating lease payments under non-cancelable leases	Future operating lease payments under non-cancelable leases with an initial term in excess of one year as of December 31, 2014 were as follows:
	(In thousands)
	Year ending:	Amount
	2015	$	71,130
	2016	65,948
	2017	65,195
	2018	59,464
	2019	57,885
	Thereafter	516,485
	Total minimum operating lease payments	$	836,107

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Total number of shares authorized, outstanding and available for future grants under the Stock Plans	As of December 31, 2014, the total number of shares authorized, outstanding and available for future grants under the Stock Plans was as follows:
	Plan Name	Shares Authorized			Shares Outstanding			Shares
								Available for Future Grants
	Amended and Restated 2007 Long-Term Incentive Plan	40,189,197			10,269,849			13,290,221
	Other Stock Plans	11,740,760			789,247			—
	Total	51,929,957			11,059,096			13,290,221
Composition of equity awards outstanding	The composition of the equity awards outstanding as of December 31, 2013 and 2014 was as follows:
		December 31,		December 31,
		2013		2014
	Restricted stock	3,538,271		4,305,323
	Stock options	9,487,570		6,753,773
	Total outstanding awards	13,025,841		11,059,096
Restricted Stock Unit (RSU) and Restricted Stock Award (RSA) activity	The following table summarizes our RSU and RSA activity for the year ended December 31, 2014:
		Number of Units or Shares		Weighted-Average Grant-Date Fair Value
	Outstanding at December 31, 2013	3,538,271		$	28.79
	Granted	3,236,458		$	34.87
	Released	-1,609,215		$	19.61
	Cancelled	-860,191		$	39.39
	Outstanding at December 31, 2014	4,305,323		$	34.49
	Expected to vest after December 31, 2014*	3,572,970		$	36.62
	*Includes reduction of shares outstanding due to estimated forfeitures
Stock option activity	The following table summarizes the stock option activity for the year ended December 31, 2014:
		Number of Shares		Weighted-Average Exercise Price				Weighted-Average Remaining Contractual Life	Aggregate Intrinsic Value (in thousands)
	Outstanding at December 31, 2013	9,487,570		$	30.37			5.1	$	117,886
	Granted	339,807		$	37.8
	Exercised	-1,838,380		$	14.62
	Forfeited	-1,008,735		$	43.3
	Expired	-226,489		$	44.67
	Outstanding at December 31, 2014	6,753,773		$	32.62			4.21	$	104,330
	Vested and exercisable at December 31, 2014	3,962,344		$	24.16			3.53	$	93,847
	Vested and exercisable at December 31, 2014 and expected to vest thereafter*	6,367,890		$	31.9			4.14	$	102,959
	*Includes reduction of shares outstanding due to estimated forfeitures
Assumptions used to estimate the fair values of the stock options granted	The following table presents the assumptions used to estimate the fair values of the stock options granted in the periods presented:
		Years Ended December 31,
		2012		2013		2014
	Expected stock volatility	56% - 58%		46% - 47%		46% - 48%
	Expected dividend yield	—%		—%		—%
	Risk-free interest rate	0.50% - 0.77%		0.57% - 0.93%		1.08% - 1.27%
	Expected life	4.00 - 4.75 years		3.79 years		3.82 years
	Weighted-average grant-date fair value of options granted during the year	$24.38		$15.86		$15.34
Assumptions used to estimate the fair values of the shares granted through the Employee Stock Purchase Program (ESPP)	The following table presents the assumptions used to estimate the fair values of the shares granted through the ESPP in the periods presented:
		Years Ended December 31,
		2013		2014
	Expected stock volatility	32% - 62%		42% - 56%
	Expected dividend yield	—%		—%
	Risk-free interest rate	0.09% - 0.34%		0.06% - 0.47%
	Expected life	0.5 - 2.0 years		0.5 - 2.0 years
	Weighted-average grant-date fair value of shares granted during the year	$16.04		$12.83
Allocation of share-based compensation expense to income statement line items	Share-based compensation expense was recognized as follows:
		Year Ended December 31,
	(in thousands)	2012				2013			2014
	Cost of revenue	$	9,592			$	12,584		$	16,446
	Research and development	4,856				8,168			12,581
	Sales and marketing	6,379				7,317			9,573
	General and administrative	20,719				31,576			31,405
	Pre-tax share-based compensation	41,546				59,645			70,005
	Less: Income tax benefit	(15,477		)		(20,080		)	(21,515		)
	Total share-based compensation expense, net of tax	$	26,069			$	39,565		$	48,490

Taxes_Tables

Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Provision for Income Taxes	The provision for income taxes consisted of:
		Year Ended December 31,
	(In thousands)	2012				2013				2014
	Current:
	Federal	$	38,720			$	35,912			$	38,318
	Foreign	19,248				12,071				11,083
	State	4,296				4,121				5,337
	Total current	62,264				52,104				54,738
	Deferred:
	Federal	1,359				(3,886		)		(2,425		)
	Foreign	(910		)		(1,621		)		(2,878		)
	State	(124		)		(2,575		)		(384		)
	Total deferred	325				(8,082		)		(5,687		)
	Total provision for income taxes	$	62,589			$	44,022			$	49,051
Reconciliation of Statutory Federal Tax Rate to Effective Tax Rate	A reconciliation of the statutory federal tax rate to the effective tax rate is as follows:
		Year Ended December 31,
		2012			2013			2014
	Statutory federal tax rate	35	%		35	%		35	%
	State taxes, net of federal benefit	1.5	%		0.7	%		1.7	%
	Tax rate differentials for international jurisdictions	-2	%		-3.8	%		-10.5	%
	Permanent differences	1.1	%		1.6	%		3.5	%
	Deferred impact of intercompany transfers	1.9	%		3.5	%		3.2	%
	Research and development credit (current year)	—	%		-3.1	%		-2.1	%
	Other, net	-0.2	%		-0.2	%		-0.1	%
	Effective tax rate	37.3	%		33.7	%		30.7	%
Significant Components of Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities are as follows:
	(In thousands)	December 31, 2013				December 31, 2014
	Deferred tax assets:
	Share-based compensation	$	23,487			$	27,158
	State income taxes	2,293				2,205
	Vacation accruals	5,235				3,502
	Deferred revenue	3,793				5,322
	Deferred rent	13,736				16,195
	Accruals not currently deductible	7,850				8,386
	Net operating loss carryforwards	3,534				4,832
	Foreign tax credit	1,723				1,723
	Research and development credits	13,871				13,341
	Other	3,703				4,318
	Total gross deferred tax assets	79,225				86,982
	Deferred tax liabilities:
	Depreciation	125,209				134,596
	Prepaids	2,981				4,002
	Other	107				60
	Total gross deferred tax liabilities	128,297				138,658
	Net deferred tax liabilities	$	(49,072	)		$	(51,676	)
Reconciliation of Unrecognized Tax Benefits, Excluding Accrued Interest	A reconciliation of our unrecognized tax benefits, excluding accrued interest, for 2013 and 2014 is as follows:
	(In thousands)	2013				2014
	Balance, beginning of year	$	18,664			$	23,246
	Additions based on tax positions related to the current year	3,919				2,523
	Additions for tax positions of prior years	663				3,633
	Reduction for statute expiration	—				(930		)
	Reductions for tax positions of prior years	—				(7,440		)
	Balance, end of year	$	23,246			$	21,032

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Total net revenue by product categories	Total net revenue by our product categories was as follows:
		Year Ended December 31,
		2012		2013		2014
	Dedicated Cloud	$	1,005,165	$	1,119,636	$	1,254,666
	Public Cloud	304,074		415,150		539,691
	Total net revenue	$	1,309,239	$	1,534,786	$	1,794,357
Total net revenue by geographic region, attributed based on operating location that enters into contractual relationship with customer	Total net revenue by geographic region in 2012 and 2013 was as follows:
		Year Ended December 31,
	(In thousands)	2012		2013
	United States	$	973,733	$	1,133,645
	International	335,506		401,141
	Total net revenue	$	1,309,239	$	1,534,786
Total net revenue by geographic region, attributed based on customer's billing address	Total net revenue by geographic region in 2013 and 2014 based upon the customer's billing address was as follows:
		Year Ended December 31,
	(In thousands)	2013		2014
	United States	$	1,076,248	$	1,232,136
	International	458,538		562,221
	Total net revenue	$	1,534,786	$	1,794,357
Property and equipment, net by geographic region	Property and equipment, net by geographic region was as follows:
	(In thousands)	December 31,		December 31,
		2013		2014
	United States	$	654,507	$	718,305
	International	236,269		339,379
	Total property and equipment, net	$	890,776	$	1,057,684

Supplementary_Financial_Data_U1

Supplementary Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Supplementary Financial Data
		Quarters Ended
	(In thousands, except per share amounts)	March 31,		June 30,		September 30,		December 31,
		2013		2013		2013		2013
	Net revenue	$	362,200	$	375,847	$	388,636	$	408,103
	Cost of revenue	$	113,610	$	117,658	$	127,404	$	133,821
	Net income	$	27,261	$	22,367	$	16,311	$	20,798
	Net income per share - basic	$	0.2	$	0.16	$	0.12	$	0.15
	Net income per share - diluted	$	0.19	$	0.16	$	0.11	$	0.14
		Quarters Ended
	(In thousands, except per share amounts)	March 31,		June 30,		September 30,		December 31,
		2014		2014		2014		2014
	Net revenue	$	421,047	$	441,112	$	459,776	$	472,422
	Cost of revenue	$	140,417	$	145,051	$	142,954	$	153,912
	Net income	$	25,446	$	22,451	$	25,740	$	36,916
	Net income per share - basic	$	0.18	$	0.16	$	0.18	$	0.26
	Net income per share - diluted	$	0.18	$	0.16	$	0.18	$	0.26

Company_Overview_Basis_of_Pres1

Company Overview, Basis of Presentation, and Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and Intangible Assets
Goodwill impairment recognized	$0	$0	$0
Revenue and Deferred Revenue
Deferred revenue, total	22,300,000
Deferred revenue, current portion	20,851,000	22,868,000
Deferred revenue, non-current portion	1,425,000	3,662,000
Advertising Costs
Advertising expenses	59,200,000	58,900,000	44,700,000
Foreign Currency
Income tax expense allocated to foreign currency translation adjustments	0	0	0
Minimum
Prepaid Expenses and Other Assets
Agreement period of software maintenance contracts	1 year
Maximum
Prepaid Expenses and Other Assets
Agreement period of software maintenance contracts	3 years
Level 1 financial instruments
Fair Value of Financial Instruments
Money market funds	11,000,000	102,000,000
Stock Options
Share-Based Compensation
Stock options vesting period	4 years
Stock options expiration period	7 years	7 years	7 years
Stock Options | Minimum
Share-Based Compensation
Stock options expiration period	7 years
Stock Options | Maximum
Share-Based Compensation
Stock options expiration period	10 years
Deferred revenue to be amortized to revenue in 2015
Revenue and Deferred Revenue
Deferred revenue, current portion	20,900,000
Deferred revenue to be amortized to revenue in 2016
Revenue and Deferred Revenue
Deferred revenue, non-current portion	$1,400,000
Equipment | Minimum
Leases
Operating lease terms	2 years
Equipment | Maximum
Leases
Operating lease terms	5 years
Equipment | Assets held under capital lease | Minimum
Leases
Period over which assets held under capital lease and related leasehold improvements are amortized as depreciation expense	2 years
Equipment | Assets held under capital lease | Maximum
Leases
Period over which assets held under capital lease and related leasehold improvements are amortized as depreciation expense	5 years
Property | Minimum
Leases
Operating lease terms	1 year
Property | Maximum
Leases
Operating lease terms	20 years
Property | Assets held under capital lease
Leases
Period over which assets held under capital lease and related leasehold improvements are amortized as depreciation expense	30 years

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basic net income per share:
Net income	$36,916	$25,740	$22,451	$25,446	$20,798	$16,311	$22,367	$27,261	$110,553	$86,737	$105,418
Weighted average shares outstanding:
Common stock									141,971,000	138,577,000	135,279,000
Number of shares used in per share computations									141,971,000	138,577,000	135,279,000
Net income per share - basic	$0.26	$0.18	$0.16	$0.18	$0.15	$0.12	$0.16	$0.20	$0.78	$0.63	$0.78
Diluted net income per share:
Net income	$36,916	$25,740	$22,451	$25,446	$20,798	$16,311	$22,367	$27,261	$110,553	$86,737	$105,418
Weighted average shares outstanding:
Common stock									141,971,000	138,577,000	135,279,000
Stock options, awards and employee share purchase plans									2,527,000	4,434,000	5,986,000
Number of shares used in per share computations									144,498,000	143,011,000	141,265,000
Net income per share - diluted	$0.26	$0.18	$0.16	$0.18	$0.14	$0.11	$0.16	$0.19	$0.77	$0.61	$0.75
Number of potential common shares excluded from the computation of dilutive net income per share because the effect would have been anti-dilutive									5,000,000	3,500,000	1,100,000

Property_and_Equipment_net_Det

Property and Equipment, net (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property and equipment
Property and equipment, at cost	$2,152,267,000	$1,808,608,000
Less accumulated depreciation and amortization	-1,249,522,000	-983,618,000
Work in process	154,939,000	65,786,000
Property and equipment, net	1,057,684,000	890,776,000
Depreciation and amortization expense	371,884,000	313,007,000	249,845,000
Interest capitalized	2,100,000	0	0
Computers and equipment
Property and equipment
Property and equipment, at cost	1,495,206,000	1,242,690,000
Computers and equipment | Minimum
Property and equipment
Estimated useful lives	3 years
Computers and equipment | Maximum
Property and equipment
Estimated useful lives	5 years
Computer software
Property and equipment
Property and equipment, at cost	318,888,000	245,416,000
Property and equipment, net	103,400,000	88,700,000
Depreciation and amortization expense	63,700,000	50,600,000	36,400,000
Computer software | Minimum
Property and equipment
Estimated useful lives	1 year
Computer software | Maximum
Property and equipment
Estimated useful lives	5 years
Furniture and fixtures
Property and equipment
Estimated useful lives	7 years
Property and equipment, at cost	56,656,000	55,681,000
Buildings and leasehold improvements
Property and equipment
Property and equipment, at cost	253,621,000	236,255,000
Buildings and leasehold improvements | Minimum
Property and equipment
Estimated useful lives	2 years
Buildings and leasehold improvements | Maximum
Property and equipment
Estimated useful lives	30 years
Land
Property and equipment
Property and equipment, at cost	27,896,000	28,566,000
Office facility build outs
Property and equipment
Work in process	51,300,000	32,600,000
Data center build outs
Property and equipment
Work in process	80,500,000	2,400,000
Capitalized software and other projects
Property and equipment
Work in process	23,100,000	30,700,000
Property and equipment
Property and equipment
Depreciation and amortization expense	$362,200,000	$303,200,000	$240,900,000

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets (Details 1) - Acquisitions & Goodwill (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	companies	companies
Acquisitions
Number of companies acquired	0	3
Total consideration transferred for businesses acquired		$16,200,000
Acquisitions, Allocation of Consideration Transfered
Amount of consideration attributed to goodwill		12,300,000
Amount of consideration attributed to acquired intangible assets		5,100,000
Amount of consideration attributed to other net liabilities assumed		1,200,000
Goodwill
Goodwill balance	$81,084,000	$81,084,000

Goodwill_and_Intangible_Assets3

Goodwill and Intangible Assets (Details 2) - Intangible Assets, Other Than Goodwill (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Intangible assets, other than goodwill
Gross carrying amount	$66,636,000	$64,487,000
Accumulated amortization	-50,044,000	-40,607,000
Net carrying amount	16,592,000	23,880,000
Amortization expense on intangibles	9,700,000	9,800,000	8,900,000
Minimum
Intangible assets, other than goodwill
Estimated useful lives of intangible assets	2 years
Maximum
Intangible assets, other than goodwill
Estimated useful lives of intangible assets	5 years
Licenses
Intangible assets, other than goodwill
Gross carrying amount	32,466,000	31,443,000
Accumulated amortization	-25,402,000	-21,216,000
Net carrying amount	7,064,000	10,227,000
Purchased technologies
Intangible assets, other than goodwill
Gross carrying amount	13,180,000	13,180,000
Accumulated amortization	-10,024,000	-7,428,000
Net carrying amount	3,156,000	5,752,000
Non-compete agreements
Intangible assets, other than goodwill
Gross carrying amount	2,165,000	2,165,000
Accumulated amortization	-1,952,000	-1,613,000
Net carrying amount	213,000	552,000
Customer relationships
Intangible assets, other than goodwill
Gross carrying amount	6,137,000	6,137,000
Accumulated amortization	-5,640,000	-5,442,000
Net carrying amount	497,000	695,000
Other
Intangible assets, other than goodwill
Gross carrying amount	12,688,000	11,562,000
Accumulated amortization	-7,026,000	-4,908,000
Net carrying amount	$5,662,000	$6,654,000

Goodwill_and_Intangible_Assets4

Goodwill and Intangible Assets (Details 3) - Future Amortization Expense on Intangible Assets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Amortization expense on intangible assets for the next five years
2015	$9,657
2016	5,780
2017	621
2018	223
2019	197
Thereafter	114
Net carrying amount	$16,592	$23,880

Debt_Details

Debt (Details) (Revolving Credit Facility, Bank Syndicate, led by JPMorgan Chase, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2011
Revolving Credit Facility
Maturity date		30-Sep-16
Total commitment		$200,000,000
Maximum leverage ratio		3
Minimum interest coverage ratio		3
Floating base rate used to calculate marginal borrowing costs		LIBOR
Total commitment allowed under accordion feature		400,000,000
Borrowings outstanding	25,000,000
Interest rate of credit facility at period end	1.42%
Available for future borrowings	$175,000,000
Status of compliance with covenants under facility	in compliance
Minimum
Revolving Credit Facility
Spread added to floating base rate		1.25%
Fee percentage on committed but unused amount of facility		0.25%
Maximum
Revolving Credit Facility
Spread added to floating base rate		2.00%
Fee percentage on committed but unused amount of facility		0.40%

Leases_Details_1_Capital_Lease

Leases (Details 1) - Capital Leases, Financing Terms (Capital Leases)	12 Months Ended
	Dec. 31, 2014
Minimum
Capital Leases
Typical term	2 years
Interest rates	2.00%
Maximum
Capital Leases
Typical term	5 years
Interest rates	3.00%

Leases_Details_2_Capital_Lease

Leases (Details 2) - Capital Leases, Leased Assets and Future Lease Payments (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Amounts in property and equipment under capital leases and finance lease obligations for assets under construction
Capital leased assets, gross	$396,725	$391,833
Less: accumulated depreciation and amortization	-370,961	-335,599
Work in process	109,991	0
Capital leased assets, net	135,755	56,234
Future capital lease payments under non-cancelable leases
2015	15,541
2016	2,150
2017	623
2018	636
2019	649
Thereafter	2,795
Total minimum capital lease payments	22,394
Plus amount representing residual asset balance	5,394
Less amount representing interest	-2,935
Less amount representing executory costs	-938
Present value of net minimum lease payments	23,915
Less current portion of obligations under capital leases	-14,969	-37,885
Non-current obligations under capital leases	8,946	25,048
Computers and equipment
Amounts in property and equipment under capital leases and finance lease obligations for assets under construction
Capital leased assets, gross	389,020	391,833
Buildings and leasehold improvements
Amounts in property and equipment under capital leases and finance lease obligations for assets under construction
Capital leased assets, gross	$7,705	$0

Leases_Details_3_Operating_Lea

Leases (Details 3) - Operating Leases (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Future operating lease payments under non-cancelable leases
2015	$71,130,000
2016	65,948,000
2017	65,195,000
2018	59,464,000
2019	57,885,000
Thereafter	516,485,000
Total minimum operating lease payments	836,107,000
Rent expense
Rent expense	$74,000,000	$66,000,000	$46,100,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details 1) - Purchase Commitments & Legal Proceedings (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Purchase Commitments
Maximum duration of non-cancelable purchase agreements	5 years
Minimum purchase commitments for the year ended December 31, 2015	$83.60
Minimum purchase commitments for the year ended December 31, 2016	18.4
Minimum purchase commitments for the year ended December 31, 2017	3
Minimum purchase commitments for the year ended December 31, 2018	0.2
Dispute related to sales taxes paid on certain software licenses | Cost of revenue
Loss Contingencies
Benefit recorded for resolution of loss contingency	$7

Commitments_and_Contingencies_1

Commitments and Contingencies (Details 2) - Incentive Arrangements (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2009	Dec. 31, 2007
Incentive Arrangements
Amounts received from the Texas Enterprise Fund	$5,500,000	$0	$3,500,000
Amount received that was deferred and recorded as other non-current liabilities	32,283,000	36,268,000
Master Economic Incentives Agreement | Certain Employment Levels
Incentive Arrangements
Duration of exemption from most of the property taxes associated with the corporate headquarters				14 years
Texas Enterprise Fund Grant
Incentive Arrangements
Amount received that was deferred and recorded as other non-current liabilities	14,000,000
Texas Enterprise Fund Grant | Certain Employment Levels
Incentive Arrangements
Amounts received from the Texas Enterprise Fund	5,500,000		3,500,000		5,000,000
Additional incentive that may be received for meeting certain new employment levels in the State of Texas	$8,000,000
Interest rate, per year, on amounts subject to a clawback if we eliminate jobs for which we have drawn funds	3.40%

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	12 Months Ended			3 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Nov. 06, 2014	Nov. 12, 2014
	votes
	classes
Common Stock
Shares of common stock legally issued	140,945,171	141,123,904		140,945,171
Shares of common stock outstanding	140,945,171	141,123,904		140,945,171
Number of classes of authorized common stock	1			1
Number of votes per share of common stock owned	1			1
Preferred Stock
Authorized shares of preferred stock	50,000,000	50,000,000		50,000,000
Shares of preferred stock issued	0	0		0
Shares of preferred stock outstanding	0	0		0
Accelerated Share Repurchase Agreement
Amount paid to financial institution under ASR agreement	$200,000,000	$0	$0
Reduction to stockholders' equity for payment under ASR agreement	200,000,000
ASR agreement entered into on November 12, 2014
Accelerated Share Repurchase Agreement
Amount paid to financial institution under ASR agreement				200,000,000
Reduction to stockholders' equity for payment under ASR agreement				200,000,000
Common Stock
Share Repurchase Program
Authorized value of stock that may be repurchased under the share repurchase program					500,000,000
Period over which stock may be repurchased under the share repurchase program					2 years
Common Stock | ASR agreement entered into on November 12, 2014
Accelerated Share Repurchase Agreement
Aggregate value of stock to be repurchased under ASR agreement						$200,000,000
Shares initially delivered under ASR agreement, which were subsequently retired				3,300,000

ShareBased_Compensation_Detail

Share-Based Compensation (Details 1) - General	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-Based Compensation
Shares authorized	51,929,957
Stock options outstanding	6,753,773	9,487,570
Shares outstanding	11,059,096	13,025,841
Shares available for future grants	13,290,221
Restricted Stock
Share-Based Compensation
Restricted stock outstanding	4,305,323	3,538,271
Stock Options
Share-Based Compensation
Terms of options granted	7 years	7 years	7 years
Stock options vesting period	4 years
Stock Options | Minimum
Share-Based Compensation
Terms of options granted	7 years
Stock Options | Vests ratably over service-period
Share-Based Compensation
Stock options vesting period	4 years
Stock Options | Cliff-vests at end of service period
Share-Based Compensation
Stock options vesting period	3 years
Stock Options, 7-year term
Share-Based Compensation
Terms of options granted	7 years
Stock Options, 10-year term
Share-Based Compensation
Terms of options granted	10 years
Amended and Restated 2007 Long-Term Incentive Plan
Share-Based Compensation
Increase in shares available under Stock Plans	11,400,000		5,900,000
Shares authorized	40,189,197
Shares outstanding	10,269,849
Shares available for future grants	13,290,221
Amended and Restated 2007 Long-Term Incentive Plan | Restricted stock, restricted stock units, performance units and performance shares | Granted after the 2014 annual meeting of the stockholders
Share-Based Compensation
Number of shares deducted from shares available for issuance under Stock Plans for each share granted	1.93
Amended and Restated 2007 Long-Term Incentive Plan | Other equity awards
Share-Based Compensation
Number of shares deducted from shares available for issuance under Stock Plans for each share granted	1
Amended and Restated 2007 Long-Term Incentive Plan | Stock Options | Minimum
Share-Based Compensation
Minimum exercise price of a stock option, as a percentage of the fair market value of a share of common stock at the date of grant	100.00%
Other Stock Plans
Share-Based Compensation
Shares authorized	11,740,760
Shares outstanding	789,247
Shares available for future grants	0
Other Stock Plans | Stock Options | Minimum
Share-Based Compensation
Minimum exercise price of a stock option, as a percentage of the fair market value of a share of common stock at the date of grant	100.00%

ShareBased_Compensation_Detail1

Share-Based Compensation (Details 2) - Restricted Stock (USD $)	12 Months Ended						1 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 28, 2009
RSUs and RSAs
Restricted Stock Roll Forward
Number of units or shares outstanding, beginning of year	3,538,271
Number of units or shares granted	3,236,458
Number of units or shares released	-1,609,215
Number of units or shares cancelled	-860,191
Number of units or shares outstanding, end of year	4,305,323		3,538,271
Restricted Stock, Weighted-Average Grant-Date Fair Value
Weighted-average grant-date fair value of units or shares outstanding, beginning of year	$28.79
Weighted-average grant-date fair value of units or shares granted	$34.87		$39.24	$51.78
Weighted-average grant-date fair value of units or shares released	$19.61
Weighted-average grant-date fair value of units or shares cancelled	$39.39
Weighted-average grant-date fair value of units or shares outstanding, end of year	$34.49		$28.79
Restricted Stock, Additional Disclosures
Number of units or shares expected to vest after December 31, 2014	3,572,970	[1]
Weighted-average grant-date fair value of units or shares expected to vest after December 31, 2014	$36.62	[1]
Pre-tax intrinsic value of the RSUs and RSAs released	$52.70		$29.70	$75.50
RSUs and RSAs | Certain members of our executive team | Market-vesting
Restricted Stock Roll Forward
Number of units or shares cancelled	-38,502
Number of units or shares outstanding, end of year	291,689
Restricted Stock, Additional Disclosures
Vesting period			3 years	3 years	3 years	3 years
RSUs
Restricted Stock Roll Forward
Number of units or shares granted	3,236,458
RSUs | Service-vesting, ratably over 4-yr service-period
Restricted Stock Roll Forward
Number of units or shares granted	2,867,873
Restricted Stock, Additional Disclosures
Vesting period	4 years
Number of equal installments in which awards vest	4
RSUs | Former chief executive officer and another member of the executive team | Performance-vesting, dependent on the company's TSR compared to other companies in the Russell 2000 Index
Restricted Stock Roll Forward
Number of units or shares granted							2,000,000
RSUs | Former chief executive officer and another member of the executive team | Performance-vesting, dependent on the company's TSR for a 3-yr performance period as compared to other companies in the Russell 2000 Index
Restricted Stock Roll Forward
Number of units or shares granted							1,050,000
Restricted Stock, Additional Disclosures
Vesting period							3 years
RSUs | Former chief executive officer and another member of the executive team | Performance-vesting, dependent on the company's TSR for a 5-yr performance period as compared to other companies in the Russell 2000 Index
Restricted Stock Roll Forward
Number of units or shares granted							950,000
Restricted Stock, Additional Disclosures
Vesting period							5 years
RSUs | Certain members of our executive team | Performance-vesting
Restricted Stock Roll Forward
Number of units or shares granted	368,585
RSUs | Certain members of our executive team | Performance-vesting | Minimum
Restricted Stock, Additional Disclosures
Vesting period	2 years
RSUs | Certain members of our executive team | Performance-vesting | Maximum
Restricted Stock, Additional Disclosures
Vesting period	4 years
[1]	Includes reduction of shares outstanding due to estimated forfeitures

ShareBased_Compensation_Detail2

Share-Based Compensation (Details 3) - Stock Options (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Stock Options Roll Forward
Number of shares outstanding, beginning of year	9,487,570
Number of shares granted	339,807
Number of shares exercised	-1,838,380
Number of shares forfeited	-1,008,735
Number of shares expired	-226,489
Number of shares outstanding, end of year	6,753,773		9,487,570
Stock Options, Weighted-Average Exercise Price
Weighted-average exercise price of shares outstanding, beginning of year	$30.37
Weighted-average exercise price of shares granted	$37.80
Weighted-average exercise price of shares exercised	$14.62
Weighted-average exercise price of shares forfeited	$43.30
Weighted-average exercise price of shares expired	$44.67
Weighted-average exercise price of shares outstanding, end of year	$32.62		$30.37
Stock Options, Additional Disclosures
Weighted-average remaining contractual life of shares outstanding	4 years 2 months 17 days		5 years 1 month 6 days
Aggregate intrinsic value of shares outstanding	$104,330,000		$117,886,000
Number of shares vested and exercisable at December 31, 2014	3,962,344
Weighted-average exercise price of shares vested and exercisable at December 31, 2014	$24.16
Weighted-average remaining contractual life of shares vested and exercisable at December 31, 2014	3 years 6 months 12 days
Aggregate intrinsic value of shares vested and exercisable at December 31, 2014	93,847,000
Total pre-tax intrinsic value of stock options exercised	44,100,000		76,400,000	193,100,000
Stock Options, Vested and Expected to Vest
Number of shares vested and exercisable at December 31, 2014 and expected to vest thereafter	6,367,890	[1]
Weighted-average exercise price of shares vested and exercisable at December 31, 2014 and expected to vest thereafter	$31.90	[1]
Weighted-average remaining contractual life of shares vested and exercisable at December 31, 2014 and expected to vest thereafter	4 years 1 month 21 days	[1]
Aggregate intrinsic value of shares vested and exercisable at December 31, 2014 and expected to vest thereafter	$102,959,000	[1]
Certain members of our executive team
Stock Options Roll Forward
Number of shares granted	106,200
Stock Options
Stock Options, Additional Disclosures
Number of equal installments in which awards granted during the year vest	4		4	4
Terms of options granted	7 years		7 years	7 years
Stock options vesting period	4 years
Stock Options, Fair Value Assumptions
Expected stock volatility (minimum)	46.00%		46.00%	56.00%
Expected stock volatility (maximum)	48.00%		47.00%	58.00%
Expected dividend yield	0.00%		0.00%	0.00%
Risk-free interest rate (minimum)	1.08%		0.57%	0.50%
Risk-free interest rate (maximum)	1.27%		0.93%	0.77%
Expected life	3 years 9 months 27 days		3 years 9 months 14 days
Weighted-average grant-date fair value of options granted during the year	$15.34		$15.86	$24.38
Stock Options | Minimum
Stock Options, Additional Disclosures
Terms of options granted	7 years
Stock Options, Fair Value Assumptions
Expected life				4 years
Stock Options | Maximum
Stock Options, Additional Disclosures
Terms of options granted	10 years
Stock Options, Fair Value Assumptions
Expected life				4 years 9 months
Stock Options | Certain members of our executive team
Stock Options, Additional Disclosures
Number of equal installments in which awards granted during the year vest	4
Stock options vesting period	4 years
[1]	Includes reduction of shares outstanding due to estimated forfeitures

ShareBased_Compensation_Detail3

Share-Based Compensation (Details 4) - Employee Stock Purchase Plan (Employee Stock Purchase Plan, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Employee Stock Purchase Plan
Number of shares issued	203,469
Employee Stock Purchase Plan, Fair Value Assumptions
Expected stock volatility (minimum)	42.00%	32.00%
Expected stock volatility (maximum)	56.00%	62.00%
Expected dividend yield	0.00%	0.00%
Risk-free interest rate (minimum)	0.06%	0.09%
Risk-free interest rate (maximum)	0.47%	0.34%
Weighted-average grant-date fair value of shares granted during the year	$12.83	$16.04
Minimum
Employee Stock Purchase Plan, Fair Value Assumptions
Expected life	6 months	6 months
Maximum
Employee Stock Purchase Plan, Fair Value Assumptions
Expected life	2 years	2 years
Enrollment Date | Maximum
Employee Stock Purchase Plan
Purchase price of common stock, as a percentage of market value	85.00%
Purchase Date | Maximum
Employee Stock Purchase Plan
Purchase price of common stock, as a percentage of market value	85.00%

ShareBased_Compensation_Detail4

Share-Based Compensation (Details 5) - Share-Based Compensation Expense (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allocation of share-based compensation expense to income statement line items
Pre-tax share-based compensation	$70,005,000	$59,645,000	$41,546,000
Less: Income tax benefit	-21,515,000	-20,080,000	-15,477,000
Total share-based compensation expense, net of tax	48,490,000	39,565,000	26,069,000
Share-Based Compensation, Aggregate Disclosures
Total unrecognized compensation cost related to restricted stock, options and the ESPP ($)	175,400,000
Remaining weighted-average period over which the unrecognized compensation cost related to restricted stock, options and the ESPP will be amortized on a straight line basis	2 years 7 months 9 days
Cost of revenue
Allocation of share-based compensation expense to income statement line items
Pre-tax share-based compensation	16,446,000	12,584,000	9,592,000
Research and development
Allocation of share-based compensation expense to income statement line items
Pre-tax share-based compensation	12,581,000	8,168,000	4,856,000
Sales and marketing
Allocation of share-based compensation expense to income statement line items
Pre-tax share-based compensation	9,573,000	7,317,000	6,379,000
General and administrative
Allocation of share-based compensation expense to income statement line items
Pre-tax share-based compensation	$31,405,000	$31,576,000	$20,719,000

Taxes_Details_1_Provision_for_

Taxes (Details 1) - Provision for Income Taxes and Tax Rate Reconciliation (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal	$38,318,000	$35,912,000	$38,720,000
Foreign	11,083,000	12,071,000	19,248,000
State	5,337,000	4,121,000	4,296,000
Total current	54,738,000	52,104,000	62,264,000
Deferred:
Federal	-2,425,000	-3,886,000	1,359,000
Foreign	-2,878,000	-1,621,000	-910,000
State	-384,000	-2,575,000	-124,000
Total deferred	-5,687,000	-8,082,000	325,000
Total provision for income taxes	49,051,000	44,022,000	62,589,000
Income Before Income Taxes
Income from foreign operations included in income before income taxes	$64,400,000	$39,700,000	$61,600,000
Reconciliation of Statutory Federal Tax Rate to Effective Tax Rate
Statutory federal tax rate	35.00%	35.00%	35.00%
State taxes, net of federal benefit	1.70%	0.70%	1.50%
Tax rate differentials for international jurisdictions	-10.50%	-3.80%	-2.00%
Permanent differences	3.50%	1.60%	1.10%
Deferred impact of intercompany transfers	3.20%	3.50%	1.90%
Research and development credit (current year)	-2.10%	-3.10%	0.00%
Other, net	-0.10%	-0.20%	-0.20%
Effective tax rate	30.70%	33.70%	37.30%

Taxes_Details_2_Deferred_Taxes

Taxes (Details 2) - Deferred Taxes (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Share-based compensation	$27,158,000	$23,487,000
State income taxes	2,205,000	2,293,000
Vacation accruals	3,502,000	5,235,000
Deferred revenue	5,322,000	3,793,000
Deferred rent	16,195,000	13,736,000
Accruals not currently deductible	8,386,000	7,850,000
Net operating loss carryforwards	4,832,000	3,534,000
Foreign tax credit	1,723,000	1,723,000
Research and development credits	13,341,000	13,871,000
Other	4,318,000	3,703,000
Total gross deferred tax assets	86,982,000	79,225,000
Deferred tax liabilities:
Depreciation	134,596,000	125,209,000
Prepaids	4,002,000	2,981,000
Other	60,000	107,000
Total gross deferred tax liabilities	138,658,000	128,297,000
Net deferred tax liabilities	-51,676,000	-49,072,000
Deferred Tax Liability Not Recognized, Undistributed Earnings of Foreign Subsidiaries
Deferred tax liability recognized for undistributed earnings of foreign subsidiaries	0	0
Undistributed earnings of the company's foreign subsidiaries considered indefinitely invested	221,000,000
Determination of unrecognized tax liability related to undistributed earnings	The determination of the amount of unrecognized deferred tax liability related to undistributed earnings is not practicable because of the complexities of the hypothetical calculation.
Federal
Operating Loss and Tax Credit Carryforwards
Net operating loss carryforwards	199,900,000
Tax credit carryforwards	22,200,000
Federal | Gross excess tax benefits from stock option exercises that have not been recorded
Operating Loss and Tax Credit Carryforwards
Net operating loss carryforwards	196,600,000
Foreign
Operating Loss and Tax Credit Carryforwards
Net operating loss carryforwards	$3,900,000

Taxes_Details_3_Uncertain_Tax_

Taxes (Details 3) - Uncertain Tax Positions (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Accrued Interest
Balance, beginning of year	$23,246,000	$18,664,000
Additions based on tax positions related to the current year	2,523,000	3,919,000
Additions for tax positions of prior years	3,633,000	663,000
Reduction for statute expiration	-930,000	0
Reductions for tax positions of prior years	-7,440,000	0
Balance, end of year	21,032,000	23,246,000
Uncertain Tax Positions, Additional Disclosures
Unrecognized tax benefits that, if recognized, would favorably impact effective tax rate	13,100,000	8,200,000
Unrecognized tax benefits that, if recognized, would be recorded as an adjustment to other current and non-current assets	$7,900,000
U.S. federal and state | Minimum
Uncertain Tax Positions, Additional Disclosures
Tax years for which we remain subject to income tax examinations	2009
U.S. federal and state | Maximum
Uncertain Tax Positions, Additional Disclosures
Tax years for which we remain subject to income tax examinations	2014
State of California | Tax Year 2010
Uncertain Tax Positions, Additional Disclosures
Tax years for which we currently have income tax examinations open	2010
State of California | Tax Year 2011
Uncertain Tax Positions, Additional Disclosures
Tax years for which we currently have income tax examinations open	2011
State of California | Tax Year 2012
Uncertain Tax Positions, Additional Disclosures
Tax years for which we currently have income tax examinations open	2012
International jurisdictions | Minimum
Uncertain Tax Positions, Additional Disclosures
Tax years for which we remain subject to income tax examinations	2007
International jurisdictions | Maximum
Uncertain Tax Positions, Additional Disclosures
Tax years for which we remain subject to income tax examinations	2014
United Kingdom | Tax Year 2012
Uncertain Tax Positions, Additional Disclosures
Tax years for which we currently have income tax examinations open	2012

Taxes_Details_4_Other

Taxes (Details 4) - Other (USD $)	36 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2014
Other Tax-Related Disclosures
Portion of asset on consolidated balance sheet as a result of taxable transactions recorded in other non-current assets	$57,089,000	$47,181,000
Sale of certain intangible assets to wholly-owned offshore subsidiary
Other Tax-Related Disclosures
Asset on consolidated balance sheet as a result of taxable transactions		27,400,000
Portion of asset on consolidated balance sheet as a result of taxable transactions recorded in other non-current assets		23,800,000
Cash tax impact	0
Federal
Other Tax-Related Disclosures
Income tax refunds received		$0

Segment_Information_Segment_In

Segment Information Segment Information (Details 1) - Reportable Segments	12 Months Ended
	Dec. 31, 2014
	segments
Segment Reporting [Abstract]
Number of reportable segments	1

Segment_Information_Details_2_

Segment Information (Details 2) - Revenue by Product Categories (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Total net revenue by product categories
Total net revenue	$472,422	$459,776	$441,112	$421,047	$408,103	$388,636	$375,847	$362,200	$1,794,357	$1,534,786	$1,309,239
Dedicated Cloud
Total net revenue by product categories
Total net revenue									1,254,666	1,119,636	1,005,165
Public Cloud
Total net revenue by product categories
Total net revenue									$539,691	$415,150	$304,074

Segment_Information_Details_3_

Segment Information (Details 3) - Geographic Areas (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue and Long-Lived Assets by Geography
Total net revenue	$472,422	$459,776	$441,112	$421,047	$408,103	$388,636	$375,847	$362,200	$1,794,357	$1,534,786	$1,309,239
Total property and equipment, net	1,057,684				890,776				1,057,684	890,776
United States
Revenue and Long-Lived Assets by Geography
Total property and equipment, net	718,305				654,507				718,305	654,507
International
Revenue and Long-Lived Assets by Geography
Total property and equipment, net	339,379				236,269				339,379	236,269
Operating location that enters into contractual relationship with customer | United States
Revenue and Long-Lived Assets by Geography
Total net revenue										1,133,645	973,733
Operating location that enters into contractual relationship with customer | International
Revenue and Long-Lived Assets by Geography
Total net revenue										401,141	335,506
Customer's billing address | United States
Revenue and Long-Lived Assets by Geography
Total net revenue									1,232,136	1,076,248
Customer's billing address | International
Revenue and Long-Lived Assets by Geography
Total net revenue									$562,221	$458,538

Employee_Benefit_Plans_Details

Employee Benefit Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Contribution expense recognized for defined contribution plans	$13.20	$10.30	$7.40

Schedule_of_Valuation_and_Qual1

Schedule of Valuation and Qualifying Accounts (Details) (Allowance for Doubtful Accounts and Customer Credits, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Allowance for Doubtful Accounts and Customer Credits
Allowance for doubtful accounts and customer credits
Beginning Balance	$3,891		$4,236		$3,420
Additions	16,562	[1]	16,875	[1]	18,863	[1]
Write-offs of Accounts Receivable and Credit Memos Paid	-15,119		-17,220		-18,047
Ending Balance	$5,334		$3,891		$4,236
[1]	Additions to the allowance for doubtful accounts are charged to expense. Additions to the allowance for customer credits are charged to revenue.

Supplementary_Financial_Data_U2

Supplementary Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplementary Financial Data (Unaudited)
Net revenue	$472,422	$459,776	$441,112	$421,047	$408,103	$388,636	$375,847	$362,200	$1,794,357	$1,534,786	$1,309,239
Cost of revenue	153,912	142,954	145,051	140,417	133,821	127,404	117,658	113,610	582,334	492,493	419,013
Net income	$36,916	$25,740	$22,451	$25,446	$20,798	$16,311	$22,367	$27,261	$110,553	$86,737	$105,418
Net income per share - basic	$0.26	$0.18	$0.16	$0.18	$0.15	$0.12	$0.16	$0.20	$0.78	$0.63	$0.78
Net income per share - diluted	$0.26	$0.18	$0.16	$0.18	$0.14	$0.11	$0.16	$0.19	$0.77	$0.61	$0.75