Entity Central Index Key Net income (loss) plus: (1) provision for income taxes; (2) other income (expense), net; (3) depreciation of property and equipment, including amortization of internal use software and website development; (4) amortization of intangible assets; (5) stock-based compensation and other stock-settled obligations; (6) goodwill, long-lived asset and intangible asset impairments; and (7) non-recurring expenses. Document and entity information. Document And Entity Information [Abstract] Document And Entity Information Document and entity information Document And Entity Information [Table] Document And Entity Information [Table] Class of Stock Statement Class Of Stock [Axis] Class of Stock Class Of Stock [Domain] Common stock, unclassified. Common Stock, Unclassified Common Stock Unclassified [Member] Class B Common Stock Common Class B [Member] Document And Entity Information [Line Items] Document And Entity Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Entity Registrant Name Entity Registrant Name Trading Symbol Trading Symbol Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock Shares Outstanding Income Statement [Abstract] Revenue (Note 3) Revenue From Contract With Customer Excluding Assessed Tax Costs and expenses: Costs And Expenses [Abstract] Cost of revenue Cost Of Services Excluding Depreciation Depletion And Amortization Selling and marketing Selling And Marketing Expense Technology and content Information Technology And Data Processing General and administrative General And Administrative Expense Depreciation Depreciation Amortization of intangible assets Amortization Of Intangible Assets Total costs and expenses: Costs And Expenses Operating income Operating Income Loss Other income (expense): Nonoperating Income Expense [Abstract] Interest expense Interest Expense Interest income and other, net Other Nonoperating Income Expense Total other income (expense), net Nonoperating Income Expense Income before income taxes Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Provision for income taxes Income Tax Expense Benefit Net income Net Income Loss Earnings per share attributable to common stockholders (Note 4): Earnings Per Share [Abstract] Basic Earnings Per Share Basic Diluted Earnings Per Share Diluted Weighted average common shares outstanding (Note 4): Weighted Average Number Of Shares Outstanding [Abstract] Basic Weighted Average Number Of Shares Outstanding Basic Diluted Weighted Average Number Of Diluted Shares Outstanding Statement [Table] Statement [Table] Property, Plant and Equipment, Type Property Plant And Equipment By Type [Axis] Property, Plant and Equipment, Type Property Plant And Equipment Type [Domain] Website Development Costs Software And Software Development Costs [Member] Finite-Lived Intangible Assets by Major Class Finite Lived Intangible Assets By Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name Finite Lived Intangible Assets Major Class Name [Domain] Acquired Technology Technology Based Intangible Assets [Member] Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Selling and Marketing Selling And Marketing Expense [Member] Technology and content. Technology and Content Technology And Content [Member] General and Administrative General And Administrative Expense [Member] Statement [Line Items] Statement [Line Items] Amortization adjustment Adjustment For Amortization Stock-based compensation: Share Based Compensation [Abstract] Stock-based compensation Allocated Share Based Compensation Expense Statement Of Income And Comprehensive Income [Abstract] Net income Other comprehensive income (loss): Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract] Foreign currency translation adjustments Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Before Tax Total other comprehensive income (loss) Other Comprehensive Income Loss Net Of Tax Comprehensive income Comprehensive Income Net Of Tax Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current. Statement Of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets Current [Abstract] Cash and cash equivalents (Note 6) Cash And Cash Equivalents At Carrying Value Short-term marketable securities (Note 6) Marketable Securities Current Accounts receivable and contract assets, net of allowance for doubtful accounts of $18 and $16, respectively Accounts Receivable And Contract Assets Net Current Prepaid expenses and other current assets Prepaid Expense And Other Assets Current Total current assets Assets Current Long-term marketable securities (Note 6) Marketable Securities Noncurrent Property and equipment, net of accumulated depreciation of $216 and $177, respectively Property Plant And Equipment Net Intangible assets, net of accumulated amortization of $124 and $112, respectively Intangible Assets Net Excluding Goodwill Goodwill Goodwill Deferred income taxes, net Deferred Income Tax Assets Net Other long-term assets Other Assets Noncurrent TOTAL ASSETS Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities And Stockholders Equity [Abstract] Current liabilities: Liabilities Current [Abstract] Accounts payable Accounts Payable Current Deferred merchant payables Customer Advances Current Deferred revenue Deferred Revenue Current Current portion of debt (Note 7) Short Term Borrowings Accrued expenses and other current liabilities Accrued Liabilities Current Total current liabilities Liabilities Current Long-term debt (Note 7) Long Term Debt Noncurrent Deferred income taxes, net Deferred Tax Liabilities Noncurrent Other long-term liabilities Other Liabilities Noncurrent Total Liabilities Liabilities Commitments and contingencies (Note 9) Commitments And Contingencies Stockholders’ equity: (Note 10) Stockholders Equity [Abstract] Preferred stock, $0.001 par value Authorized shares: 100,000,000 Shares issued and outstanding: 0 and 0 Preferred Stock Value Common stock Common Stock Value Additional paid-in capital Additional Paid In Capital Common Stock Retained earnings Retained Earnings Accumulated Deficit Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income Loss Net Of Tax Treasury stock-common stock, at cost, 12,056,688 and 9,474,490 shares, respectively Treasury Stock Value Total Stockholders’ Equity Stockholders Equity TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities And Stockholders Equity Allowance for doubtful accounts Allowance For Doubtful Accounts Receivable Current Property and equipment, accumulated depreciation Accumulated Depreciation Depletion And Amortization Property Plant And Equipment Intangible assets, accumulated amortization Finite Lived Intangible Assets Accumulated Amortization Preferred stock, par value Preferred Stock Par Or Stated Value Per Share Preferred stock, shares authorized Preferred Stock Shares Authorized Preferred stock, shares issued Preferred Stock Shares Issued Preferred stock, shares outstanding Preferred Stock Shares Outstanding Common stock, par value Common Stock Par Or Stated Value Per Share Common stock, shares authorized Common Stock Shares Authorized Common stock, shares issued Common Stock Shares Issued Common stock, shares outstanding Common Stock Shares Outstanding Treasury stock, shares Treasury Stock Shares Statement Of Stockholders Equity [Abstract] Equity Components Statement Equity Components [Axis] Equity Component Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-in Capital Additional Paid In Capital [Member] Retained Earnings Retained Earnings [Member] Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income [Member] Treasury Stock Treasury Stock [Member] Beginning balance Beginning balance, shares Net income Cumulative effect adjustment from adoption of new accounting guidance (Note 2) Cumulative Effect On Retained Earnings Net Of Tax1 Other comprehensive loss Issuance of common stock related to exercises of options and vesting of RSUs Stock Issued During Period Value Stock Options Exercised Issuance of common stock related to exercises of options and vesting of RSUs, shares Stock Issued During Period Shares Stock Options Exercised Repurchase of common stock Treasury Stock Value Acquired Cost Method Repurchase of common stock, shares Treasury Stock Shares Acquired Withholding taxes on net share settlements of equity awards Adjustments Related To Tax Withholding For Share Based Compensation Stock-based compensation Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value Ending balance Ending balance, shares Statement Of Cash Flows [Abstract] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Twenty fifteen credit facility. 2015 Credit Facility Twenty Fifteen Credit Facility [Member] 2016 Credit facility. 2016 Credit Facility Two Thousands And Sixteen Credit Facility [Member] Chinese credit facility. Chinese Credit Facilities Chinese Credit Facility [Member] Operating activities: Net Cash Provided By Used In Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments To Reconcile Net Income Loss To Cash Provided By Used In Operating Activities [Abstract] Depreciation of property and equipment, including amortization of internal-use software and website development Stock-based compensation expense Share Based Compensation Other, net Other Noncash Income Expense Changes in operating assets and liabilities, net of effects from acquisitions: Increase Decrease In Operating Capital [Abstract] Accounts receivable, prepaid expenses and other assets Increase Decrease In Prepaid Deferred Expense And Other Assets Accounts payable, accrued expenses and other liabilities Increase Decrease In Accrued Liabilities And Other Operating Liabilities Deferred merchant payables Increase Decrease In Customer Advances Income tax receivables/payables, net Increase Decrease In Income Taxes Payable Net Of Income Taxes Receivable Deferred revenue Increase Decrease In Deferred Revenue Net cash provided by operating activities Net Cash Provided By Used In Operating Activities Investing activities: Net Cash Provided By Used In Investing Activities [Abstract] Capital expenditures, including internal-use software and website development Payments To Acquire Property Plant And Equipment Purchases of marketable securities Payments To Acquire Marketable Securities Sales of marketable securities Proceeds From Sale Of Available For Sale Securities Maturities of marketable securities Proceeds From Maturities Prepayments And Calls Of Available For Sale Securities Acquisitions and other investments, net of cash acquired Payments To Acquire Businesses Net Of Cash Acquired Net cash (used in) provided by investing activities Net Cash Provided By Used In Investing Activities Financing activities: Net Cash Provided By Used In Financing Activities [Abstract] Repurchase of common stock Payments For Repurchase Of Common Stock Proceeds from credit facility, net of financing costs Proceeds From Debt Net Of Issuance Costs Payments to credit facility Repayments Of Lines Of Credit Proceeds from credit facility Proceeds From Lines Of Credit Proceeds from exercise of stock options Proceeds From Issuance Or Sale Of Equity Payment of withholding taxes on net share settlements of equity awards Payments Related To Tax Withholding For Share Based Compensation Net cash used in financing activities Net Cash Provided By Used In Financing Activities Effect of exchange rate changes on cash, cash equivalents and restricted cash Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Net (decrease) increase in cash, cash equivalents and restricted cash Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Supplemental disclosure of non-cash investing and financing activities: Cash Flow Noncash Investing And Financing Activities Disclosure [Abstract] Stock-based compensation capitalized with internal-use software and website development costs Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount Accounting Policies [Abstract] Business Description and Basis of Presentation Business Description And Basis Of Presentation [Text Block] Significant Accounting Policies Significant Accounting Policies [Text Block] Revenue From Contract With Customer [Abstract] Revenue Recognition Revenue From Contract With Customer [Text Block] Earnings Per Share Earnings Per Share [Text Block] Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] Stock Based Awards and Other Equity Instruments Disclosure Of Compensation Related Costs Share Based Payments [Text Block] Investments All Other Investments [Abstract] Financial Instruments Financial Instruments Disclosure [Text Block] Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Commitments And Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments And Contingencies Disclosure [Text Block] Equity [Abstract] Stockholders' Equity Stockholders Equity Note Disclosure [Text Block] Related Party Transactions [Abstract] Related Party Transactions Related Party Transactions Disclosure [Text Block] Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Basis of Presentation Basis Of Accounting Policy Policy [Text Block] Accounting Estimates Use Of Estimates Description of seasonality of business. Seasonality Seasonality Policy [Text Block] New Accounting Pronouncements Not Yet Adopted and Recently Adopted Accounting Pronouncements New Accounting Pronouncements Policy Policy [Text Block] Adjustments for New Accounting Pronouncements Adjustments For New Accounting Pronouncements [Axis] Type of Adoption Type Of Adoption [Member] ASC 606 Accounting Standards Update201409 [Member] Summary of Impact of New Revenue Recognition Guidance on Unaudited Condensed Consolidated Statement of Operations Schedule Of New Accounting Pronouncements And Changes In Accounting Principles [Text Block] Reconciliation of Disaggregated Revenue to Segment Revenue Disaggregation Of Revenue Table [Text Block] Summary of Balances of Accounts Receivables and Contract Assets from Contracts with Customers Contract With Customer Asset And Liability Table [Text Block] Reconciliation of Weighted Average Number of Shares of Common Stock Outstanding Schedule Of Earnings Per Share Basic And Diluted Table [Text Block] Award Type Award Type [Axis] Equity Award Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Market-based restricted stock units. MSUs Market Based Restricted Stock Units [Member] Amount of Stock-Based Compensation Expense Related to Stock-Based Awards, Primarily Stock Options and RSUs Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Text Block] Summary of Stock Option Activity Schedule Of Share Based Compensation Stock Options Activity Table [Text Block] Weighted-Average Assumptions of Estimated Fair Value of Stock Option Grants Schedule Of Share Based Payment Award Stock Options Valuation Assumptions Table [Text Block] Summary of RSU Activity, Including Service Based Awards and Performance-Based Awards Schedule Of Share Based Compensation Restricted Stock Units Award Activity Table [Text Block] Summary of Unrecognized Stock-Based Compensation Expense and Weighted Average Period Remaining Schedule Of Unrecognized Compensation Cost Nonvested Awards Table [Text Block] Tabular disclosure of available for sale securities including cash, cash equivalents and restricted cash. Schedule of Cash, Cash Equivalents, Restricted Cash and Marketable Securities Available For Sale Securities Including Cash Cash Equivalents And Restricted Cash Table [Text Block] Fair Value and Notional Principal Amounts of Outstanding or Unsettled Derivative Instruments Schedule Of Derivative Instruments In Statement Of Financial Position Fair Value [Text Block] Summary of Segment Information Schedule Of Segment Reporting Information By Segment [Text Block] Number of markets with localized websites. Number of languages worldwide. Number of other travel brands. Description of business and basis of presentation. Description of business and basis of presentation. Description Of Business And Basis Of Presentation [Table] Description Of Business And Basis Of Presentation [Table] Range Range [Axis] Range Range [Member] Minimum Minimum [Member] Maximum Maximum [Member] Description Of Business And Basis Of Presentation [Line Items] Description Of Business And Basis Of Presentation [Line Items] Number of markets with localized versions of website Number Of Markets With Localized Websites Number of languages worldwide Number Of Languages Worldwide Number of other media brands with websites Number Of Other Travel Brands Number of reportable segment Number Of Reportable Segments Schedule of accounting policies. Schedule of accounting policies. Schedule Of Accounting Policies [Table] Schedule Of Accounting Policies [Table] Schedule Of Accounting Policies [Line Items] Schedule Of Accounting Policies [Line Items] Recorded a net increase in opening retained earnings Customer invoices due period. Disaggregation Of Revenue [Table] Disaggregation Of Revenue [Table] Disaggregation Of Revenue [Line Items] Disaggregation Of Revenue [Line Items] Customer invoices due period Customer Invoices Due Period Capitalized costs to obtain a contract Capitalized Contract Cost Net Transaction price related to unsatisfied performance obligations expected period Revenue Remaining Performance Obligation Expected Timing Of Satisfaction Period1 New Accounting Pronouncements Or Change In Accounting Principle [Table] New Accounting Pronouncements Or Change In Accounting Principle [Table] Initial Application Period Cumulative Effect Transition Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition Initial Application Period Cumulative Effect Transition [Domain] Impact of Accounting ASC 606 Difference Between Revenue Guidance In Effect Before And After Topic606 [Member] Adjusted - ASC 605 Calculated Under Revenue Guidance In Effect Before Topic606 [Member] New Accounting Pronouncements Or Change In Accounting Principle [Line Items] New Accounting Pronouncements Or Change In Accounting Principle [Line Items] Operating income Income before income taxes Product and Service Product Or Service [Axis] Product and Service Products And Services [Domain] Click-based advertising and transaction revenue. Click-Based Advertising and Transaction Revenue Click Based Advertising And Transaction Revenue [Member] Display-based advertising and subscription revenue. Display-Based Advertising and Subscription Revenue Display Based Advertising And Subscription Revenue [Member] Other hotel revenue. Other Hotel Revenue Other Hotel Revenue [Member] Segments Statement Business Segments [Axis] Segments Segment [Domain] Hotel segment. Hotel Segment Hotel Segment [Member] Non-Hotel segment. Non-Hotel Segment Non Hotel Segment [Member] Total Revenue Accounts receivable Accounts Receivable Net Current Contract assets Contract With Customer Asset Net Current Total Deferred revenue Contract With Customer Liability Current Revenue recognized Contract With Customer Liability Revenue Recognized Numerator: Net Income Loss [Abstract] Denominator: Weighted Average Number Of Shares Outstanding Basic [Abstract] Weighted average shares used to compute Basic EPS Weighted average effect of dilutive securities: Weighted Average Number Diluted Shares Outstanding Adjustment [Abstract] Stock options Incremental Common Shares Attributable To Share Based Payment Arrangements RSUs/MSUs Incremental Common Shares Attributable To Contingently Issuable Shares Weighted average shares used to compute Diluted EPS Basic EPS Diluted EPS Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Antidilutive Securities Antidilutive Securities Excluded From Computation Of Earnings Per Share By Antidilutive Securities [Axis] Antidilutive Securities, Name Antidilutive Securities Name [Domain] Stock options, RSUs and MSUs. Stock Options, RSUs and MSUs Stock Options And Restricted Stock Units And Market Stock Units [Member] Performance shares and MSUs. Performance Shares Performance Shares And Market Stock Units [Member] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share, amount Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Two thousand eighteen stock and annual incentive plan. 2018 Plan Two Thousand Eighteen Stock And Annual Incentive Plan [Member] Two thousand eleven incentive plan. 2011 Plan Two Thousand Eleven Incentive Plan [Member] Stock Options Employee Stock Option [Member] RSU Restricted Stock Units R S U [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Shares reserved and available for issuance Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Schedule Of Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Table] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items] Total stock-based compensation Income tax benefit from stock-based compensation Employee Service Share Based Compensation Tax Benefit From Compensation Expense Total stock-based compensation, net of tax effect Allocated Share Based Compensation Expense Net Of Tax Capitalized stock based compensation as internal-use software and website development costs Number of stock options issued Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross Term of stock options, granted Sharebased Compensation Arrangement By Sharebased Payment Award Expiration Period Stock awards vest period Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Period1 Options Outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Roll Forward Options Outstanding, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number Options Outstanding, Granted Options Outstanding, Exercised Options Outstanding, Cancelled or expired Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Options Outstanding, Ending balance Options Outstanding, Exercisable Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number Options Outstanding, Vested and expected to vest Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Number Weighted Average Exercise Price per share Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Rollforward Options Outstanding, Weighted Average Exercise Price, Beginning Balance Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price Options Granted, Weighted Average Exercise Price Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price Options Exercised, Weighted Average Exercise Price Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price Options Cancelled or expired, Weighted Average Exercise Price Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures And Expirations In Period Weighted Average Exercise Price Options Outstanding, Weighted Average Exercise Price, Ending balance Options Exercisable, Weighted Average Exercise Price Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price Options Vested and expected to vest, Weighted Average Exercise Price Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Exercise Price Weighted Average Remaining Contractual Life and Aggregate Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Additional Disclosures [Abstract] Options Outstanding, Weighted Average Remaining Contractual Life Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 Options Exercisable, Weighted Average Remaining Contractual Life Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 Options Vested and expected to vest, Weighted Average Remaining Contractual Life Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested And Expected To Vest Outstanding Weighted Average Remaining Contractual Term1 Options Outstanding, Aggregate Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value Options Exercisable, Aggregate Intrinsic Value Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 Options Vested and expected to vest, Aggregate Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Outstanding Aggregate Intrinsic Value Options non converted into shares due to net share settlement Shares Paid For Tax Withholding For Share Based Compensation Closing stock price Share Price Total intrinsic value Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value Risk free interest rate Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate Expected term (in years) Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 Expected volatility Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate Expected dividend yield Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate Weighted-average grant date fair value of options granted Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value Total fair value of stock options vested Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 Cash received from stock option exercises RSU's issued under incentive plan Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period MSU awards transferred during the quarter to the MSU award activity roll forward table. As of the balance sheet date, the number of shares into which expected to vest RSU's outstanding can be converted under the equity plan. Restricted Stock Units RSUs outstanding Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Roll Forward Unvested outstanding, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Number Unvested RSUs, Transfer Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Transfer In Period Unvested RSUs, Granted Unvested RSUs, Vested and released Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Unvested RSUs, Cancelled Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeited In Period Unvested outstanding, Ending balance RSUs outstanding, Expected to vest Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Expected To Vest MSU awards transferred during the quarter to the MSU award activity roll forward table. As of the balance sheet date, the weighted-average grant-date fair value per share for expected to vest RSUs under the equity plan. Weighted Average Grant-Date Fair Value Per Share Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Roll Forward Unvested outstanding, Weighted Average Grant-Date Fair Value Per Share, Beginning balance Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Nonvested Weighted Average Grant Date Fair Value Weighted Average Grant-Date Fair Value Per Share, Transfer Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Transfer In Period Weighted Average Grant Date Fair Value Weighted Average Grant-Date Fair Value Per Share, Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period Weighted Average Grant Date Fair Value Weighted Average Grant-Date Fair Value Per Share, Vested and released Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Weighted Average Grant Date Fair Value Weighted Average Grant-Date Fair Value Per Share, Cancelled Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Forfeitures Weighted Average Grant Date Fair Value Unvested outstanding, Weighted Average Grant-Date Fair Value Per Share, Ending balance Weighted Average Grant-Date Fair Value Per Share, Expected to vest Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Expected To Vest Weighted Average Grant Date Fair Value Amount of the current fair value of the underlying stock multiplied by number of RSUs which are expected to vest under the equity plan. Aggregate Intrinsic Value Sharebased Compensation Arrangement By Sharebased Payment Award Equity Instruments Other Than Options Aggregate Intrinsic Value [Abstract] Unvested RSUs outstanding, Aggregate Intrinsic Value Sharebased Compensation Arrangement By Sharebased Payment Award Equity Instruments Other Than Options Aggregate Intrinsic Value Nonvested RSUs Vested and expected to vest, Aggregate Intrinsic Value Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Expected To Vest Aggregate Intrinsic Value Title of Individual Title Of Individual [Axis] Relationship to Entity Title Of Individual With Relationship To Entity [Domain] CEO Chief Executive Officer [Member] Share transfer award RSUs withheld to satisfy withholding tax requirements MSUs outstanding Unvested MSUs, Granted Unvested MSUs, Vested and released Unvested MSUs, Cancelled Unvested MSUs outstanding, Aggregate Intrinsic Value Sale of Stock Subsidiary Sale Of Stock [Axis] Sale of Stock Sale Of Stock Name Of Transaction [Domain] Employees Employee Stock [Member] Percentage of originally granted shares that may be earned upon performance achievement, maximum. Percentage of originally granted shares that may be earned upon performance achievement, minimum. Share based compensation arrangement by share based payment award award requisite service period date. Performance measurement period start date. Performance measurement period end date. Percentage of originally granted shares that may be earned upon performance achievement, maximum Percentage Of Originally Granted Shares That May Be Earned Upon Performance Achievement Maximum Percentage of originally granted shares that may be earned upon performance achievement, minimum Percentage Of Originally Granted Shares That May Be Earned Upon Performance Achievement Minimum Requisite service period for estimated grant-date fair value of stock awards Share Based Compensation Arrangement By Share Based Payment Award Award Requisite Service Period Date Stock awards vesting term Share Based Compensation Arrangement By Share Based Payment Award Award Vesting Rights Performance measurement period start date Performance Measurement Period Start Date Performance measurement period end date Performance Measurement Period End Date Income tax benefits associated with exercise settlement of stock based awards. Income tax benefits from exercise or settlement of stock-based awards Income Tax Benefits Associated With Exercise Settlement Of Stock Based Awards Unrecognized compensation expense Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Stock Options Weighted average period remaining (in years) Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 Unrecognized compensation expense Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Share Based Awards Other Than Options Fair Value Disclosures [Abstract] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value Hierarchy and NAV Fair Value By Fair Value Hierarchy Level [Axis] Fair Value Hierarchy and NAV Fair Value Measurements Fair Value Hierarchy [Domain] Level 2 Fair Value Inputs Level2 [Member] Asset Class Fair Value By Asset Class [Axis] Asset Class Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] U.S. Agency Securities U S Government Agencies Debt Securities [Member] US treasury securities U S Treasury Securities [Member] Certificates of Deposit Certificates Of Deposit [Member] Commercial Paper Commercial Paper [Member] Corporate Debt Securities Corporate Debt Securities [Member] Money Market Funds Money Market Funds [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Amortized Cost Available For Sale Securities Amortized Cost Unrealized Gains Available For Sale Securities Accumulated Gross Unrealized Gain Before Tax Unrealized Losses Available For Sale Securities Accumulated Gross Unrealized Loss Before Tax Fair Value Available For Sale Securities Cash and Cash Equivalents Cash And Cash Equivalents Fair Value Disclosure Short-Term Marketable Securities Long-Term Marketable Securities Cash Cash Cash equivalents Cash Equivalents At Carrying Value Cash, cash equivalents, restricted cash and marketable securities, amortized cost. Cash, cash equivalents, restricted cash and marketable securities, fair value. Cash, cash equivalents, restricted cash and marketable securities, amortized cost Cash Cash Equivalents Restricted Cash And Marketable Securities Amortized Cost Cash, cash equivalents, restricted cash and marketable securities, fair value Cash Cash Equivalents Restricted Cash And Marketable Securities Fair Value Cash and cash equivalents maximum maturity period. Long-term maturities have remaining terms of 1 to 3 years. Long-term maturities have remaining terms of 1 to 3 years. The maximum remaining maturity date that a marketable security can have left to still be classified as a Short Term Marketable security. The minimum original maturity period, on date of purchase, that a marketable security must be to be classified as a Short Term Marketable security. Investments Debt And Equity Securities [Abstract] Financial instruments including money market funds maturities period Cash And Cash Equivalents Maximum Maturity Period Maximum maturities period of long-term marketable securities Marketable Securities Long Term Maximum Maturity Period Minimum maturities period of long-term marketable securities Marketable Securities Long Term Minimum Maturity Period Maximum remaining maturity for short-term marketable securities Maximum Remaining Maturity Period For Short Term Securities Minimum maturities of short-term marketable securities Minimum Maturity Period For Short Term Securities Derivative instruments non designated as hedging instruments description Number of outstanding derivatives contracts. Net gain (loss) related to forward contracts Derivative Gain Loss On Derivative Net Derivative instruments not designated as hedging instruments, description of terms Derivative Instruments Non Designated As Hedging Instruments Description Number of outstanding derivatives contracts Number Of Outstanding Derivatives Contracts Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Fair Values Derivatives Balance Sheet Location By Derivative Contract Type By Hedging Designation [Table] Hedging Designation Hedging Designation [Axis] Hedging Designation Hedging Designation [Domain] Not Designated as Hedging Instrument Nondesignated [Member] Derivative Instrument Derivative Instrument Risk [Axis] Derivative Contract Derivative Contract Type [Domain] Foreign Exchange-forward Contracts Foreign Exchange Contract [Member] Financial Instrument Financial Instrument [Axis] Financial Instruments Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain] Accrued expenses and other liabilities. Accrued expenses and other current liabilities Accrued Expenses And Other Liabilities [Member] Derivatives Fair Value [Line Items] Derivatives Fair Value [Line Items] Fair Value of Derivative, Asset Derivative Asset Notional Amount Fair Value of Derivative, Liability Derivative Liability Notional Amount Fair Value of Derivative, National amount Derivative Notional Amount Cost method investments Cost Method Investments Debt Instrument [Table] Debt Instrument [Table] Long-term Debt, Type Longterm Debt Type [Axis] Long-term Debt, Type Longterm Debt Type [Domain] Revolving Credit Facility Revolving Credit Facility [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Eurocurrency Spread Eurodollar [Member] Adjusted London interbank offered rate. Adjusted London Interbank Offered Rate Adjusted London Interbank Offered Rate [Member] ABR Spread Base Rate [Member] New York Fed Bank Rate Federal Funds Effective Swap Rate [Member] Letter of Credit Letter Of Credit [Member] Borrowings on same-day notice. Borrowings On Same Day Notice Borrowings On Same Day Notice [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Borrowing capacity under Credit Facility Line Of Credit Facility Maximum Borrowing Capacity Interest rate description Line Of Credit Facility Interest Rate Description Credit facility, maturity date Line Of Credit Facility Expiration Date1 Credit facility, expiration period Line Of Credit Facility Expiration Period Basis spread on variable rate Debt Instrument Basis Spread On Variable Rate1 Borrowings, interest rate Debt Instrument Interest Rate Effective Percentage Line of credit facility additional borrowing. Cash repatriation of foreign earnings. Line of credit facility additional borrowing Line Of Credit Facility Additional Borrowing Repayments of debt Cash repatriation of foreign earnings Cash Repatriation Of Foreign Earnings Outstanding borrowings Line Of Credit Line Of Credit Facility Unused Capacity Commitment Fee Percentage Line Of Credit Facility Unused Capacity Commitment Fee Percentage Letters of credit outstanding amount Letters Of Credit Outstanding Amount Total interest expense and commitments fees Twenty sixteen credit facility. 2016 Credit Facility Twenty Sixteen Credit Facility [Member] Lender Name Line Of Credit Facility [Axis] Line of Credit Facility, Lender Line Of Credit Facility Lender [Domain] Bank of America Merrill Lynch International Limited. Lender Bank Of America Merrill Lynch International Limited [Member] Credit facility, termination date Number of credit facilities. Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument Name [Domain] Chinese credit facility boa. Chinese Credit Facility Boa Chinese Credit Facility Boa [Member] Chinese credit facility JPM. Chinese Credit Facility JPM Chinese Credit Facility J P M [Member] Number of credit facilities Number Of Credit Facilities Period of credit facility Line of credit, interest rate basis Debt Weighted Average Interest Rate Income taxes. Income taxes. Income Taxes [Table] Income Taxes [Table] Customer Major Customers [Axis] Customer Name Of Major Customer [Domain] Expedia. Expedia Expedia [Member] Income Tax Authority, Name Income Tax Authority Name [Axis] Income Tax Authority, Name Income Tax Authority Name [Domain] IRS Internal Revenue Service I R S [Member] Tax Period Tax Period [Axis] Tax Period Tax Period [Domain] Tax years 2009 and 2010. Tax Years 2009 and 2010 Tax Years2009 And2010 [Member] Income Taxes [Line Items] Income Taxes [Line Items] Effective tax rate Effective Income Tax Rate Continuing Operations Income tax expense at federal statutory rate Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate Income tax expense related to transition tax from 2017 Tax Act. Income tax expense benefit related to transition tax Income Tax Expense Benefit Related To Transition Tax Tax cuts and jobs act of 2017 change in tax rate income tax expense benefit. Tax cuts and jobs act, income tax benefit Tax Cuts And Jobs Act Of2017 Change In Tax Rate Income Tax Expense Benefit Accrued interest Unrecognized Tax Benefits Interest On Income Taxes Accrued Accrued penalties Unrecognized Tax Benefits Income Tax Penalties Accrued Estimated potential increase in income tax expense for tax years of 2009 and 2010 IRS audits based on received NOPA's from IRS. Increase in income tax expense due to proposed adjustments related to transfer pricing with foreign subsidiary, estimated Tax Adjustments Increase Decrease In Income Tax Expense Expected tax benefits related to change in cost-sharing treatment of stock based compensation. Tax benefit from subsidiary Income Tax Reconciliation Change In Cost Sharing Treatment Of Stock Based Compensation Schedule Of Capitalization Equity [Table] Schedule Of Capitalization Equity [Table] Schedule Of Capitalization Equity [Line Items] Schedule Of Capitalization Equity [Line Items] Repurchase of shares of common stock authorized Stock Repurchase Program Authorized Amount1 Repurchase of common stock, shares Aggregate cost of shares repurchased, common stock Average price of shares repurchased, common stock Treasury Stock Acquired Average Cost Per Share Remaining authorized share repurchased amount Stock Repurchase Program Remaining Authorized Repurchase Amount1 Common stock shares held by related party. The percentage of common stock owned by a related party. The percentage of common stock owned by a related party if Class B shares were converted to common shares. The voting rights percentage assuming the related party voted both common and class B stock. Compensation Related Costs [Abstract] Schedule Of Related Party Transactions By Related Party [Table] Schedule Of Related Party Transactions By Related Party [Table] Related Party Related Party Transactions By Related Party [Axis] Related Party Related Party [Domain] LTRIP. LTRIP L T R I P [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Beneficially ownership of shares of common stock Common Stock Shares Held By Related Party Percentage taken from outstanding shares of common stock Percent Of Common Stock Held By Related Party Current Percentage of beneficially ownership of shares of common stock class B Percent Of Common Stock Held By Related Party If Class B Converted Right to voting Common Stock Voting Rights Beneficially ownership of equity securities Related Party Voting Rights Percent Current Related party transactions Related Party Transaction Amounts Of Transaction Schedule Of Segment Reporting Information By Segment [Table] Schedule Of Segment Reporting Information By Segment [Table] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Number of operating segments Number Of Operating Segments Consolidation Items Consolidation Items [Axis] Consolidation Items Consolidation Items [Domain] Operating Segments Operating Segments [Member] Corporate and Unallocated Corporate Non Segment [Member] Hotel Segment Revenue Adjusted EBITDA Adjusted Earnings Before Interest Taxes Depreciation And Amortization Depreciation Amortization of intangible assets Stock-based compensation Other expense, net Non-Hotel Segment General and administrative