Other Income and Expenses [Abstract] Interest income Interest Income, Deposits with Financial Institutions Foreign currency loss, net Foreign Currency Transaction Gain (Loss), before Tax Other expense, net Other Nonoperating Income (Expense), Net The net of miscellaneous income and expense items that are combined together as a component of Other Nonoperating Income (Expense). Total other (income) expense, net Other Nonoperating Income (Expense) Schedule of Other Nonoperating Income (Expense) [Table Text Block] Schedule of Other Nonoperating Income (Expense) [Table Text Block] Payables and Accruals [Abstract] Payroll and benefits Employee-related Liabilities, Current Deferred revenue and customer advances Deferred Revenue and Credits, Current Income taxes payable Accrued Income Taxes, Current Accrued interest Interest Payable, Current Accrued settlement costs (Note 17) Accrued settlement costs, current Accrued settlement costs, current Accrued severance plan obligations (Note 15) Supplemental Unemployment Benefits, Severance Benefits Other accrued expenses Other Accrued Liabilities, Current Total accrued expenses Accrued Liabilities, Current Factoring of Accounts Receivable [Abstract] Factoring of Accounts Receivable [Abstract] Factoring of Accounts Receivable [Table Text Block] Factoring of Accounts Receivable [Table Text Block] [Table Text Block] for Factoring of Accounts Receivable [Table] Equity Method Investments and Joint Ventures [Abstract] Investments Equity Method Investments and Joint Ventures Disclosure [Text Block] Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Income Tax Disclosure [Abstract] Gross unrecognized tax benefits Unrecognized Tax Benefits Equity [Abstract] Changes in equity attributable to both Company and noncontrolling interests Schedule of Stockholders Equity [Table Text Block] Schedule of Accumulated Other Comprehensive Income Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Summarized Accrued expenses Schedule of Accrued Liabilities [Table Text Block] Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Statement [Line Items] Statement [Line Items] Amkor stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock designated Series A, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock designated Series A, shares authorized Preferred Stock, Shares Authorized Preferred stock designated Series A, shares issued Preferred Stock, Shares Issued Common stock, par value (in dollars per share) 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 Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Disposal Group, Not Discontinued Operation, Disposal Disclosures [Abstract] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] Disposal Groups, Including Discontinued Operations, Name [Domain] Amkor Iwate Company Ltd [Member] Japanese Subsidiary [Member] Japanese Subsidiary Equity Method Investee, Name [Axis] Investment, Name [Axis] Equity Method Investee, Name [Domain] Investment, Name [Domain] J-Devices [Member] J Devices [Member] J Devices [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Sale of Stock, Percentage of Ownership before Transaction Sale of Stock, Percentage of Ownership before Transaction Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds Proceeds from Divestiture of Interest in Consolidated Subsidiaries Proceeds from Divestiture of Interest in Consolidated Subsidiaries Proceeds to Be Received from Divestiture of Interest in Consolidated Subsidiaries Proceeds to Be Received from Divestiture of Interest in Consolidated Subsidiaries Proceeds to Be Received from Divestiture of Interest in Consolidated Subsidiaries Gain (Loss) on Disposition of Business Gain (Loss) on Disposition of Business Disposal Group, Including Discontinued Operation, Foreign Currency Translation Gains (Losses) Disposal Group, Including Discontinued Operation, Foreign Currency Translation Gains (Losses) Business Combination, Bargain Purchase, Gain Recognized, Amount Business Combination, Bargain Purchase, Gain Recognized, Amount Proportionate Share Of Investee Bargain Purchase Gain Proportionate Share Of Investee Bargain Purchase Gain Of the bargain purchase gain realized by the equity method investee upon its purchase of a subsidiary from the entity, the portion of the gain that is attributable to and realized by the reporting entity. Combined Net Gain from Sale of Subsidiary Combined Net Gain from Sale of Subsidiary The combined net gain (loss) realized by the entity includes the gain on the sale of the subsidiary as well as the entity's share of the increase in equity that the equity method investee related party realized upon the purchase of the former subsidiary. Compensation and Retirement Disclosure [Abstract] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Foreign Pension Plans [Member] Foreign Postretirement Benefit Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Recognized actuarial loss Defined Benefit Plan, Actuarial Gain (Loss) Net periodic pension cost Defined Benefit Plan, Net Periodic Benefit Cost Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 Senior Secured Revolving Credit Facility due December 2019 [Member] Senior Secured Revolving Credit Facility due December 2019 [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Line of Credit [Member] Line of Credit [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Letter of Credit [Member] Letter of Credit [Member] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Cost of Sales [Member] Cost of Sales [Member] Interest Expense [Member] Interest Expense [Member] Litigation Case [Axis] Litigation Case [Axis] Litigation Case Type [Domain] Litigation Case [Domain] Tessera Inc Legal Proceedings [Member] Tessera Inc Legal Proceedings [Member] Tessera inc legal proceedings. Loss Contingencies [Line Items] Loss Contingencies [Line Items] Credit facility, borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Available letter of credit subfacility utilized Letters of Credit Outstanding, Amount Litigation Settlement, Amount Litigation Settlement, Amount Number of Quarterly Settlement Payments Number of Quarterly Settlement Payments Number of Quarterly Settlement Payments Litigation Settlement, Expense Litigation Settlement, Expense Estimated Litigation Liability, Current Estimated Litigation Liability, Noncurrent Accrued settlement costs, noncurrent Accrued settlement costs, noncurrent Accrued settlement cost, unamortized interest Accrued settlement cost, unamortized interest Disclosure of Compensation Related Costs, Share-based Payments [Abstract] 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] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Stock options [Member] Employee Stock Option [Member] Restricted shares [Member] Restricted Stock [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Share-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Korean Severance Plan [Member] Korean Severance Plan [Member] Severance plan in the form of a lump-sum payment upon termination of employment (employees and directors), based on length of service, seniority and average monthly wages at the time of termination, which is not related to restructurings, pension plans or other post retirement benefit plans. Provision of Severance Benefits Provision of Severance Benefits Provision related to lump-sum payment upon termination of employment (employees and directors), based on length of service, seniority and average monthly wages at the time of termination, which is not related to restructurings, pension plans or other post retirement benefit plans. Severance benefits are estimated assuming all eligible employees were to terminate their employment at the balance sheet date. Accrued severance plan, minimum service period Deferred Compensation Arrangement with Individual, Requisite Service Period Current (Accrued expenses) Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Current Non-current (Pension and severance obligations) Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Noncurrent Total Korean severance obligation Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Defined Benefit Pension [Member] Accumulated Defined Benefit Plans Adjustment [Member] Foreign Currency Translation [Member] Accumulated Translation Adjustment [Member] Equity Interest in J-Devices' Other Comprehensive Income (Loss) [Member] Equity Interest in Investee Other Comprehensive Income (Loss) [Member] Equity Interest in Investee Other Comprehensive Income (Loss) [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] Accumulated other comprehensive (loss) income, beginning balance Accumulated Other Comprehensive Income (Loss), Net of Tax Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from accumulated other comprehensive (loss) income Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Total other comprehensive income Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive (loss) income, ending balance Document and Entity Information [Abstract] Document And Entity Information. Document Information [Table] Document Information [Table] Document Information, Document [Axis] Document Information, Document [Axis] Document [Domain] Document [Domain] Document Information [Line Items] Document Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 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 Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Stock Options And Restricted Shares [Member] Stock Options And Restricted Shares [Member] Stock options and restricted shares. Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Stock options and restricted share awards Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Debt Disclosure [Abstract] Debt Debt Disclosure [Text Block] Schedule of Equity Method Investments [Table] Japanese Subsidiary [Member] Minority Shareholder in Equity Method Investment [Axis] Minority Shareholder in Equity Method Investment [Axis] Minority Shareholders in Equity Method Investment Minority Shareholder in Equity Method Investment [Domain] Minority Shareholder in Equity Method Investment [Domain] Minority Shareholder in Equity Method Investment Former NMD Shareholders [Member] Former NMD Shareholders [Member] Former NMD Shareholders [Member] Option Ownership Thresholds [Axis] Option Ownership Thresholds [Axis] Option Ownership Thresholds [Axis] Option Ownership Thresholds [Domain] [Domain] for Option Ownership Thresholds [Axis] Ownership Threshold 2015 [Member] Ownership Threshold 2015 [Member] Ownership Threshold 2015 [Member] Schedule of Equity Method Investments [Line Items] Ownership interest Equity Method Investment, Ownership Percentage Payments to Acquire Businesses and Interest in Affiliates Payments to Acquire Businesses and Interest in Affiliates Maximum ownership ratio of call options Maximum Ownership Ratio Of Call Options Maximum Ownership Ratio Of Call Options Minimum ownership threshold, put option Minimum ownership threshold, put option Minimum ownership threshold, put option Income Statement [Abstract] Net sales Revenue, Net Cost of sales Cost of Goods and Services Sold Gross profit Gross Profit Selling, general and administrative Selling, General and Administrative Expense Research and development Research and Development Expense Total operating expenses Operating Expenses Operating income Operating Income (Loss) Interest expense Interest Expense Interest expense, related party Interest Expense, Related Party Other (income) expense, net Total other expense, net Nonoperating Income (Expense) Income before taxes and equity in earnings of unconsolidated affiliate Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Income before equity in earnings of unconsolidated affiliate Income Before Equity In Earnings Of Unconsolidated Affiliate Net income before the entity's share of its equity method investee's earnings. Equity in earnings of J-Devices Income (Loss) from Equity Method Investments Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to Amkor Net Income (Loss) Attributable to Parent Net income attributable to Amkor per common share: Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Shares used in computing per common share amounts: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Computation of basic and diluted earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Antidilutive effect of potential shares of common stock that were excluded from diluted earnings per share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Summary of all common stock option activity Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Assumptions used in valuing the weighted average fair values of the options granted Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Restricted share activity Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Property, Plant and Equipment [Abstract] Schedule of property, plant and equipment additional [Table] Schedule of Property, Plant and Equipment Additional [Table] Schedule of property, plant and equipment additional [Table] Name of Property [Axis] Name of Property [Axis] Name of Property [Domain] Name of Property [Domain] K5 Factory [Member] K5 Facility [Member] K5 Facility [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Land [Member] Land [Member] Construction in Progress [Member] Construction in Progress [Member] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] KOREA, REPUBLIC OF KOREA, REPUBLIC OF Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Total depreciation expense Depreciation Property, Plant and Equipment, Gross Property, Plant and Equipment, Gross Accumulated Capitalized Interest Costs Accumulated Capitalized Interest Costs Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] TAIWAN, PROVINCE OF CHINA TAIWAN, PROVINCE OF CHINA 7.375% Senior notes, due May 2018 Senior Notes Due May 2018 [Member] Senior notes. 6.625% Senior notes, due June 2021, $75 million related party Senior Notes Due June 2021 [Member] Senior notes due 2021. 6.375% Senior notes, due October 2022 Senior Notes Due October 2022 [Member] Senior Notes Due October 2022 [Member] Revolving credit facility due June 2016 [Member] Revolving credit facility due June 2016 [Member] Revolving credit facility due June 2016 [Member] Term loan, LIBOR plus 3.70%, due June 2016 (2) Term Loan Due June 2016 [Member] Term Loan Due June 2016 [Member] Term loan, foreign currency funding-linked base rate plus 1.80%, due March 2017 (3) Term Loan Due March 2017 [Member] Term Loan Due March 2017 [Member] Term loan, LIBOR plus 3.70%, due July 2017 (1) Term Loan Due July 2017 [Member] Term Loan Due July 2017 [Member] Term loan, foreign currency funding-linked base rate plus 1.75%, due September 2017 (4) Term Loan Due September 2017 [Member] Term Loan Due September 2017 [Member] Term loan, LIBOR plus 3.70%, due December 2019 (5) Term Loan Due December 2019 [Member] Term Loan Due December 2019 [Member] Revolving credit facility, TAIFX plus a bank-determined spread, due April 2015 (Taiwan) (6) Revolving Credit Facility Due April 2015 [Member] Revolving Credit Facility Due April 2015 [Member] Senior notes (Level 1) Senior Notes [Member] Subsidiary Term Loans [Member] Subsidiary Term Loans [Member] Subsidiary Term Loans [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term Debt Including Related Party, Gross Long-term Debt Including Related Party, Gross Amount of long-term debt, including related party debt, before deduction of unamortized discount or premium. Add: Unamortized premium Debt Instrument, Unamortized Premium Less: Short-term borrowings and current portion of long-term debt Debt, Current Long-term debt (including related party) Non Current Long term Debt Including Related Party Non current long-term debt including related party. Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Depreciation and amortization Depreciation, Depletion and Amortization Other operating activities and non-cash items Other Noncash Income (Expense) Changes in assets and liabilities Increase (Decrease) in Operating Capital 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] Payments for property, plant and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sale of property, plant and equipment Proceeds from Sale of Property, Plant, and Equipment Investment in J-Devices Other investing activities Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Borrowings under revolving credit facilities Proceeds from Lines of Credit Proceeds from issuance of long-term debt Proceeds from Debt, Maturing in More than Three Months Payments of long-term debt Repayments of Long-term Debt Payment of deferred consideration for an acquisition Final Installment Payment for Previous Acquisition The cash outflow attributable to a prior period acquisition whereby a portion of the fixed consideration was deferred to the current period. Proceeds from the issuance of stock through share-based compensation plans Proceeds from Stock Options Exercised Payments of tax withholding for restricted shares 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 fluctuations on cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Net increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of period Non cash investing and financing activities: Noncash Investing and Financing Items [Abstract] Property, plant and equipment included in capital expenditures payable Capital Expenditures Incurred but Not yet Paid Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Land [Member] Land use rights [Member] Use Rights [Member] Buildings and improvements [Member] Building and Building Improvements [Member] Machinery and equipment [Member] Machinery and Equipment [Member] Software and computer equipment [Member] Software and Computer Equipment [Member] Software and Computer Equipment [Member] Furniture, fixtures and other equipment [Member] Furniture and Fixtures [Member] Construction in progress [Member] Property, plant and equipment, gross Less accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total property, plant and equipment, net Property, Plant and Equipment, Net Schedule of Stockholders Equity [Table] Schedule of Stockholders Equity [Table] Schedule of Stockholders Equity [Table] Amkor [Member] Parent [Member] Noncontrolling Interest [Member] Noncontrolling Interest [Member] Schedule of Stockholders Equity [Line Items] Schedule of Stockholders Equity [Line Items] Schedule of Stockholders Equity [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Equity, Beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Other comprehensive income (loss) Issuance of stock through employee share-based compensation plans Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Treasury stock acquired through surrender of shares for tax withholding Adjustments Related to Tax Withholding for Share-based Compensation Equity, Ending balance Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of shares nonvested beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Weighted average grant-date fair value nonvested beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Number of shares awards granted Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Weighted average grant-date fair value awards granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Number of shares awards vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Weighted average grant-date fair value awards vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Number of shares awards forfeited Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Weighted average grant-date fair value awards forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Number of shares nonvested ending balance Weighted average grant-date fair value nonvested ending balance (in dollars per share) Fair Value By Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value [Member] Reported Value Measurement [Member] Revolving credit facility and term loans (Level 2) Subsidiary Term Loans and Revolving Credit Facility [Member] Subsidiary Term Loans and Revolving Credit Facility [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value Debt Instrument, Fair Value Disclosure Sale of Subsidiary to J-Devices Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Factoring of Accounts Receivable [Table] Factoring of Accounts Receivable [Table] Factoring of Accounts Receivable [Table] Factoring of Accounts Receivable [Axis] Factoring of Accounts Receivable [Axis] Factoring of Accounts Receivable [Axis] Factoring of Accounts Receivable [Domain] Factoring of Accounts Receivable [Domain] [Domain] for Factoring of Accounts Receivable [Axis] Total Factored [Member] Total Factored [Member] Total Accounts Receivable Factored [Member] Factoring Fees [Member] Factoring Fees [Member] Factoring Fees [Member] Accounts Receivable Sold without Recourse [Line Items] Accounts Receivable Sold without Recourse [Line Items] Accounts Receivable Sold without Recourse [Line Items] Accounts Receivable Sold without Recourse Accounts Receivable Sold without Recourse Accounts Receivable Sold without Recourse Pension and Severance Plans Pension And Severance Plans [Text Block] The entire disclosure for pension and severance defined benefit plans. Property, Plant And Equipment Property, Plant and Equipment Disclosure [Text Block] Summary of Short term Borrowings And Long term Debt Schedule of Debt [Table Text Block] Share-Based Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Inventory Disclosure [Abstract] Inventories Schedule of Inventory, Current [Table Text Block] Inventories Inventory Disclosure [Text Block] Number of shares outstanding beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Weighted average exercise price per share outstanding beginning balance Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Number of shares granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Weighted average exercise price per share granted Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Number of shares exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Weighted average exercise price per share exercised Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Number of shares forfeited or expired Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Weighted average exercise price per share forfeited or expired Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Number of shares outstanding ending balance Weighted average exercise price per share outstanding ending balance Weighted average exercise price per share average contractual term (years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Aggregate intrinsic value outstanding ending balance (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Number of shares fully 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 fully vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted average remaining contractual term fully vested and expected to vest (years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Aggregate intrinsic value fully vested and expected to vest (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Number of shares exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted average exercise price per share exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Weighted average remaining contractual term exercisable (years) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Aggregate intrinsic value exercisable (in dollars) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Other Income and Other Expense Disclosure [Text Block] Other Income and Other Expense Disclosure [Text Block] Income tax expense Accrued Expenses Accounts Payable and Accrued Liabilities Disclosure [Text Block] Income Taxes Income Tax Disclosure [Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Standards New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Summary of Property, plant and equipment Property, Plant and Equipment [Table Text Block] Dilutive Securities Adjustments [Table] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Equity Award [Domain] Stock Options Dilutive Effect [Member] Stock Options Dilutive Effect [Member] Stock Options Dilutive Effect Convertible Senior Subordinated Notes Due April 2014 [Member] Convertible Senior Subordinated Notes Due April 2014 [Member] Convertible senior subordinated notes due April 2014. Dilutive Securities Adjustments [Line Items] Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Net income attributable to Amkor Income allocated to participating securities Undistributed Earnings (Loss) Allocated to Participating Securities, Basic Net income available to Amkor common stockholders — basic Net Income (Loss) Available to Common Stockholders, Basic Adjustment for dilutive securities on net income: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Net income reallocated to participating securities Reallocation of Net Income to Participating Securities Adjustment for dilutive securities on net income, net income reallocated to participating securities Interest on 6.0% convertible notes due 2014, net of tax Interest on Convertible Debt, Net of Tax Net income attributable to Amkor — diluted Net Income (Loss) Available to Common Stockholders, Diluted Weighted average shares outstanding — basic Effect of dilutive securities: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Stock options Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements 6.0% convertible notes due 2014 Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Weighted average shares outstanding — diluted Net income attributable to Amkor per common share: Earnings Per Share, Basic and Diluted [Abstract] Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Equity and Accumulated Other Comprehensive Income Stockholders' Equity Note Disclosure [Text Block] Unrecognized compensation expense from share-based compensation awards Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted-average period of recognition of unrecognized compensation expense (in years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Statement of Comprehensive Income [Abstract] Net income Other comprehensive income, net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Adjustments to unrealized components of defined benefit pension plans, net of tax Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Equity interest in J-Devices' other comprehensive income, net of tax Other Comprehensive Income (Loss), Portion Attributable to Equity Method Investment, Net of Tax Other Comprehensive Income (Loss), Portion Attributable to Equity Method Investment, Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income attributable to noncontrolling interests Comprehensive income attributable to Amkor Comprehensive Income (Loss), Net of Tax, Attributable to Parent Maximum [Member] Maximum [Member] Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Periodic Payment, Principal Debt Instrument, Periodic Payment, Principal Debt, interest rate description Debt Instrument, Description of Variable Rate Basis Face amount for related party Debt Instrument Face Amount Related Party Debt Instrument Face Amount Related Party Debt Instrument, Unused Borrowing Capacity, Amount Debt Instrument, Unused Borrowing Capacity, Amount Total effective rate (percentage) Debt Instrument, Interest Rate, Effective Percentage Current borrowing capacity Line of Credit Facility, Current Borrowing Capacity Line of Credit Facility, Step Down Provision Line of Credit Facility, Step Down Provision Line of Credit Facility, Step Down Provision Line of Credit Facility, Step Down Provision, Step Down Period Line of Credit Facility, Step Down Provision, Step Down Period Represents the time period between step downs under the step down provision for a line of credit. Inventories Inventory, Net, Combining Work in Process and Raw Materials Alternative [Abstract] Raw materials and purchased components Inventory, Raw Materials, Net of Reserves Work-in-process Inventory, Work in Process, Net of Reserves Total inventories Inventory, Net Valuation of money market funds and restricted cash using quoted market prices in active markets for identical assets Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block] Financial instruments that are not recorded at fair value Schedule of Fair Value, Debt [Table Text Block] Schedule of Fair Value, Debt [Table Text Block] Components of net periodic pension cost Schedule of Net Benefit Costs [Table Text Block] Schedule of Korean severance obligation Schedule Of Accrued Severance Obligation [Table Text Block] Schedule Of Accrued Severance Obligation [Table Text Block] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Restricted cash Restricted Cash and Cash Equivalents, Current Accounts receivable, net of allowances Accounts Receivable, Net, Current Inventories Other current assets Other Assets, Current Total current assets Assets, Current Property, plant and equipment, net Investments Equity Method Investments Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Other assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Short-term borrowings and current portion of long-term debt Trade accounts payable Accounts Payable, Current Capital expenditures payable Capital expenditures payable Amount owed for capital expenditures. Accrued expenses Total current liabilities Liabilities, Current Long-term debt Long-term Debt, Excluding Current Maturities Long-term debt, related party Due to Related Parties, Noncurrent Pension and severance obligations Other non-current liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 17) Commitments and Contingencies Preferred stock, $0.001 par value, 10,000 shares authorized, designated Series A, none issued Preferred Stock, Value, Issued Common stock, $0.001 par value, 500,000 shares authorized, 282,439 and 282,231 shares issued, and 236,804 and 236,627 shares outstanding, in 2015 and 2014, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Treasury stock, at cost, 45,635 and 45,604 shares in 2015 and 2014, respectively Treasury Stock, Value Total Amkor stockholders’ equity Stockholders' Equity Attributable to Parent Noncontrolling interests in subsidiaries Stockholders' Equity Attributable to Noncontrolling Interest Total equity Total liabilities and equity Liabilities and Equity Expected life (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Weighted average grant date fair value per option granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Interim Financial Statements Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Investments Equity Method Investments [Table Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value by Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [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] Cash equivalent money market funds (Level 1) Cash and Cash Equivalents, Fair Value Disclosure Restricted cash money market funds (Level 1) Restricted Cash Fair Value Disclosure Restricted Cash Fair Value Disclosure Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Line Items] Carrying value