Document and Entity Information [Abstract] Document and entity information. Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Entity Common Stock, Shares Outstanding Consolidated Balance Sheets [Abstract] Assets Assets [Abstract] Cash and cash equivalents Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Restricted cash Restricted Cash and Cash Equivalents, Current Accounts receivable, net Accounts Receivable, Net, Current Prepaid expenses Prepaid Expense, Current Deferred tax assets, net Deferred Tax Assets, Net of Valuation Allowance, Current Advance income tax, net Advance Income Tax, Net Carrying amount as of the balance sheet date of payments made in advance for income and other taxes, which will be charged against earnings within one year or the normal operating cycle, if longer, net of carrying amount as of the balance sheet date of the unpaid sum of known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations. Other current assets Other Assets, Current Total current assets Assets, Current Total Fixed assets Fixed assets, net Fixed assets, net Property, Plant and Equipment, Net Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Deferred tax assets, net Deferred Tax Assets, Net of Valuation Allowance, Noncurrent Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Goodwill Beginning Balance Ending Balance Goodwill Other assets Other Assets, Noncurrent Total assets Assets Liabilities and Stockholders' Equity Liabilities and Equity [Abstract] Accounts payable Accounts Payable, Current Deferred revenue Deferred Revenue, Current Accrued employee cost Employee-related Liabilities, Current Accrued expenses and other current liabilities Accrued expenses and other current liabilities Accrued Liabilities, Current Current portion of capital lease obligations Less: current portion Capital Lease Obligations, Current Total current liabilities Liabilities, Current Capital lease obligations, less current portion Long term capital lease obligation Capital Lease Obligations, Noncurrent Total liabilities Liabilities Commitments and contingencies Commitments and contingencies Stockholders' equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock, $0.001 par value; 100,000,000 shares authorized, 32,540,082 shares issued and 32,203,820 shares outstanding as of December 31, 2012 and 31,496,461 shares issued and 31,173,064 shares outstanding as of December 31, 2011 Common Stock, Value, Issued Additional paid-in-capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Less: 336,262 shares as of December 31,2012 and 323,397 shares as of December 31, 2011, held in treasury, at cost Treasury Stock, Value ExlService Holdings, Inc. stockholders' equity Stockholders' Equity Attributable to Parent Non-controlling interest Stockholders' Equity Attributable to Noncontrolling Interest Total stockholders' equity Beginning balance Ending balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and stockholders' equity Liabilities and Equity 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 Beginning balance, Shares Ending balance, Shares Common Stock, Shares, Outstanding Treasury stock, shares Treasury Stock, Shares Consolidated Statements of Income [Abstract] Revenues Revenue, Net Cost of revenues (exclusive of depreciation and amortization) Cost of Revenue Gross profit Gross profit Gross Profit Operating expenses: Operating Expenses [Abstract] General and administrative expenses General and Administrative Expense Selling and marketing expenses Selling and Marketing Expense Depreciation and amortization Depreciation, Depletion and Amortization Operating expenses Total operating expenses Operating Expenses Income from operations Operating Income (Loss) Other income/(expense): Nonoperating Income (Expense) [Abstract] Foreign exchange (loss)/gain Foreign Currency Transaction Gain (Loss), before Tax Interest and other income, net Other Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax provision Income tax provision Income Tax Expense (Benefit) Net income Net income Net Income (Loss) Attributable to Parent Earnings per share: Earnings Per Share [Abstract] Basic Earnings Per Share, Basic Diluted Earnings Per Share, Diluted Weighted-average number of shares used in computing earnings per share: Denominators: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic weighted average common shares outstanding Basic Weighted Average Number of Shares Outstanding, Basic Diluted weighted average common shares outstanding Diluted Weighted Average Number of Shares Outstanding, Diluted Consolidated Statements of Comprehensive Income/(Loss) [Abstract] Other comprehensive income/(loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized gain/(loss) on effective cash flow hedges, net of taxes $192, ($5,509) and $1,524 Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Retirement benefits, net of taxes ($65), ($66) and ($30) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax Total comprehensive income/(loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Consolidated Statements of Cash Flow [Abstract] Cash flows from 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] Stock-based compensation expense Share-based Compensation Unrealized foreign exchange (gain)/loss Foreign Currency Transaction Gain (Loss), Unrealized Deferred income taxes Total Deferred Income Tax Expense (Benefit) Change in operating assets and liabilities (net of effect of acquisitions): Increase (Decrease) in Operating Capital [Abstract] Restricted cash Increase (Decrease) in Restricted Cash Accounts receivable Increase (Decrease) in Accounts Receivable Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable Increase (Decrease) in Accounts Payable Deferred revenue Increase (Decrease) in Deferred Revenue Accrued expenses and other liabilities Increase (Decrease) in Other Operating Liabilities Advance income tax, net Increase (Decrease) in Income Taxes Payable Other assets Increase (Decrease) in Other Operating Assets Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchase of fixed assets Payments to Acquire Property, Plant, and Equipment Purchase of short-term investments Payments to Acquire Short-term Investments Proceeds from redemption of short-term investments Proceeds from Sale of Short-term Investments Net cash used for investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Principal payments on capital lease obligations Repayments of Long-term Capital Lease Obligations Acquisition of treasury stock Payments for Repurchase of Common Stock Proceeds from exercise of stock options Proceeds from Stock Options Exercised Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net increase/(decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Organization and Basis of Presentation [Abstract] Organization and Basis of Presentation Organization and Basis of Presentation [Text Block] Summary of Significant Accounting Policies [Abstract] Segment Information [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Business Combinations, Goodwill and Intangible Assets [Abstract] Business Combinations, Goodwill and Intangible Assets Business Combination Disclosure [Text Block] Fair Value Measurements [Abstract] Derivatives and Hedge Accounting Derivative Instruments and Hedging Activities Disclosure [Text Block] Fixed Assets [Abstract] Fixed Assets Property, Plant and Equipment Disclosure [Text Block] Capital Structure [Abstract] Capital Structure Capital Structure [Text Block] The changes in capital structure of the company. Employee Benefit Plans [Abstract] Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Leases [Abstract] Leases Leases of Lessee Disclosure [Text Block] Income Taxes [Abstract] Income Taxes Income Tax Disclosure [Text Block] Stock-Based Compensation [Abstract] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Geographical Information [Abstract] Geographical Information Geographical Information [Text Block] This element may be used to disclose in the entity's country of domicile and its entirety the names of foreign countries from which revenue is material and the amount of revenue from external customers attributed to those countries. An entity may also provide subtotals of geographic information about groups of countries. This element also include amount of long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets, located in the entity's country of domicile and in foreign countries in total in which the entity holds assets. Commitments and Contingencies [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Total other comprehensive income/(loss) Other comprehensive income/(loss) Other Comprehensive Income (Loss), Net of Tax Use of Estimates Use of Estimates, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Derivative instruments Derivative Instruments and Hedges, Liabilities Other current liabilities Other Liabilities, Current Derivative instruments Derivative Instruments and Hedges, Liabilities, Noncurrent Deferred rent Deferred Rent Credit, Noncurrent Other non-current liabilities Other Liabilities, Noncurrent Numerators: Net Income (Loss) Attributable to Parent [Abstract] Summary of accrued expenses and other current liabilities Accounts Payable and Accrued Liabilities, Current [Abstract] Summary of non-current liabilities Liabilities, Noncurrent [Abstract] Schedule Of Entity Wide Information Revenue From External Customers By Products And Services [Table] Outsourcing Services [Member] Outsourcing Services [Member] Outsourcing services. Transformation Services [Member] Transformation Services [Member] Transformation services. Revenues and cost of revenues for Company's outsourcing services and transformation services segments Table for Revenues and Cost of Revenues for Company's Outsourcing Services and Transformation Services Segments [Abstract] Table for revenues and cost of revenues for company's outsourcing services and transformation services segments. Other income/(expense) Other Operating Income (Expense), Net Products and Services [Axis] Products and Services [Domain] Revenue from External Customer [Line Items] Summary of Company's goodwill Schedule of Goodwill [Table Text Block] Currency translation adjustments Goodwill, Translation Adjustments Goodwill arising from OPI/ Landacorp acquisition Goodwill, Acquired During Period Trade names and trademarks [Member] Trade names [Member] Trade Names and Trademarks [Member] Trade names and trademarks. Non-compete agreements [Member] Noncompete Agreements [Member] Developed technology [Member] Developed Technology Rights [Member] Customer relationships [Member] Customer Relationships [Member] Estimated amortization of intangible assets Schedule of Expected Amortization Expense [Table Text Block] Estimated amortization of intangible assets Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2013 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2014 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2015 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2017 Finite-Lived Intangible Assets, Amortization Expense, Year Five Amortization expense Amortization of intangibles Amortization of Intangible Assets Indefinite lived trade names and trademarks Indefinite Life Trade Names and Trademarks Indefinite life trade names and trademarks. Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Acquired Finite-Lived Intangible Assets [Line Items] Assets and Liabilities Measured at Fair Value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Total Liabilities, Fair Value Disclosure Summary of fair value of the foreign currency exchange contracts Schedule of Foreign Exchange Contracts, Statement of Financial Position [Table Text Block] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Accrued expenses and other current liabilities [Member] Accrued Expenses and Other Current Liabilities [Member] Accrued expenses and other current liabilities. Other current assets [Member] Other Current Assets [Member] Other assets [Member] Other Assets [Member] Foreign currency exchange contracts, Asset Derivative Asset, Fair Value, Gross Asset Foreign Currency Exchange Contract [Member] Foreign Exchange Contract [Member] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] Hedging Designation [Axis] Hedging Designation [Domain] Derivatives designated as hedging instruments [Member] Designated as Hedging Instrument [Member] Derivatives not designated as hedging instruments [Member] Not Designated as Hedging Instrument [Member] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Derivatives, Fair Value [Line Items]