Factoring of Accounts Receivable [Abstract]
Factoring of Accounts Receivable [Abstract]
Factoring of Accounts Receivable
Factoring of Accounts Receivable [Table Text Block]
[Table Text Block] for Factoring of Accounts Receivable [Table]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation
Basis of Accounting, Policy [Policy Text Block]
Use of Estimates
Use of Estimates, Policy [Policy Text Block]
Goodwill
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]
Income Taxes
Income Tax, Policy [Policy Text Block]
Commitments and Contingencies
Commitments and Contingencies, Policy [Policy Text Block]
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation expense
Allocated Share-based Compensation Expense
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Geographical [Axis]
Geographical [Axis]
Geographical [Domain]
Geographical [Domain]
Korea
KOREA, REPUBLIC OF
Japan
JAPAN
Taiwan
TAIWAN, PROVINCE OF CHINA
China
CHINA
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]
6.625% Senior notes, due June 2021
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]
$100 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due June 2017
Revolving credit facility due June 2017 [Member]
Revolving credit facility due June 2017 [Member]
Term loan, LIBOR plus 2.60%, due May 2018
Term Loan Due May 2018 [Member]
Term Loan Due May 2018 [Member]
Term loan, LIBOR plus 2.70%, due December 2019
Term Loan Due December 2019 [Member]
Term Loan Due December 2019 [Member]
Term loan, foreign currency funding-linked base rate plus 1.32%, due May 2020
Term Loan Due May 2020 $150M [Member]
Term Loan Due May 2020 $150M [Member]
Term loan, foreign currency funding-linked base rate plus 1.33%, due May 2020
Term Loan Due May 2020 $80M [Member]
Term Loan Due May 2020 1.55% $80M [Member]
Term loan, fund floating rate plus 1.60%, due June 2020
Term Loan Due June 2020 [Member]
Term Loan Due June 2020[Member]
Short-term term loans, variable rate
Short term term loan, variable rate [Member]
Short term term loan, variable rate [Member]
Term loans, fixed rate at 0.53%, due April 2018
Term Loans Due April 2018 [Member]
Term Loans Due April 2018 [Member]
Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (Taiwan)
Revolving credit facility due November 2020 [Member]
Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (Taiwan) [Member]
Term Loan, LIBOR plus 1.80%, due December 2019 (China)
Term Loan, LIBOR plus 1.80% due December 2019 [Member]
Term Loan, LIBOR plus 1.80% due December 2019 [Member]
Credit Facility [Axis]
Credit Facility [Axis]
Credit Facility [Domain]
Credit Facility [Domain]
Revolving Credit Facility
Revolving Credit Facility [Member]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Line of Credit
Line of Credit [Member]
Senior Notes
Senior Notes [Member]
Subsidiary Term Loans
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.
Less: Unamortized premium and deferred debt costs, net
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net
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.
Fair Value Disclosures [Abstract]
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 Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]
Property, Plant and Equipment [Abstract]
Property, Plant And Equipment
Property, Plant and Equipment Disclosure [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]
Recurring Fair Value Measurements
Fair Value, Measurements, Recurring [Member]
Fair Value, Hierarchy [Axis]
Fair Value, Hierarchy [Axis]
Fair Value, Measurements, Fair Value Hierarchy [Domain]
Fair Value Hierarchy [Domain]
Level 1
Fair Value, Inputs, Level 1 [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
Inventory Disclosure [Abstract]
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
Compensation and Retirement Disclosure [Abstract]
Components of net periodic pension cost
Schedule of Net Benefit Costs [Table Text Block]
Defined contribution plan disclosures
Defined Contribution Plan Disclosures [Table Text Block]
Statement of Financial Position [Abstract]
ASSETS
Assets [Abstract]
Current assets:
Assets, Current [Abstract]
Cash and cash equivalents
Cash and Cash Equivalents, at Carrying Value
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
Property, Plant and Equipment, Net
Goodwill
Goodwill
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
Accrued Liabilities, Current
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
Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Noncurrent
Other non-current liabilities
Other Liabilities, Noncurrent
Total liabilities
Liabilities
Commitments and contingencies (Note 16)
Commitments and Contingencies
Stockholders’ equity:
Stockholders' Equity Attributable to Parent [Abstract]
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; 284,552 and 284,479 shares issued; and 238,717 and 238,665 shares outstanding, in 2017 and 2016, respectively
Common Stock, Value, Issued
Additional paid-in capital
Additional Paid in Capital
Accumulated deficit
Retained Earnings (Accumulated Deficit)
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax
Treasury stock, at cost, 45,835 and 45,814 shares, in 2017 and 2016, respectively
Treasury Stock, Value
Total Amkor stockholders’ equity
Stockholders' Equity Attributable to Parent
Non-controlling interests in subsidiaries
Stockholders' Equity Attributable to Noncontrolling Interest
Total equity
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
Total liabilities and equity
Liabilities and Equity
Equity [Abstract]
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
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Foreign Currency Translation
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
Total
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance
Other comprehensive income (loss) before reclassifications
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax
Amounts reclassified from accumulated other comprehensive income (loss)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax
Total other comprehensive income (loss)
Other Comprehensive Income (Loss), Net of Tax
Ending balance
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Standards
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]
Number of Shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares outstanding beginning balance
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number
Number of shares granted
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross
Number of shares exercised
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period
Number of shares forfeited or expired
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period
Number of shares outstanding ending balance
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
Number of shares exercisable
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number
Weighted-Average Exercise Price Per Share
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price per share outstanding beginning balance (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Weighted average exercise price per share granted (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price
Weighted average exercise price per share exercised (in dollars per share)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price
Weighted average exercise price per share forfeited or expired (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price
Weighted average exercise price per share outstanding ending balance (in dollars per share)
Weighted average exercise price per share fully vested and expected to vest (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price
Weighted average exercise price per share exercisable (in dollars per share)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price
Aggregate Intrinsic Value
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term outstanding
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term
Weighted average remaining contractual term fully vested and expected to vest
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term
Weighted average remaining contractual term exercisable
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, 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
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
Aggregate intrinsic value exercisable (in dollars)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value
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]
Fair Value
Estimate of Fair Value Measurement [Member]
Carrying Value
Reported Value Measurement [Member]
Senior notes (Level 1)
Revolving credit facilities and term loans (Level 2)
Subsidiary Term Loans and Revolving Credit Facilities [Member]
Subsidiary Term Loans and Revolving Credit Facilities [Member]
Level 2
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 disclosure for debt
Debt Instrument, Fair Value Disclosure
Other Income and Expenses [Abstract]
Interest income
Interest Income, Deposits with Financial Institutions
Foreign currency (gain) loss, net
Foreign Currency Transaction Gain (Loss), before Tax
Other
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)
Summary of Property, plant and equipment
Property, Plant and Equipment [Table Text Block]
Defined contribution expense
Defined Contribution Plan, Cost Recognized
Payables and Accruals [Abstract]
Payroll and benefits
Employee-related Liabilities, Current
Deferred revenue and customer advances
Deferred Revenue and Credits, Current
Accrued settlement costs
Accrued settlement costs, current
Accrued settlement costs, current
Accrued interest
Interest Payable, Current
Income taxes payable
Accrued Income Taxes, Current
Accrued severance plan obligations
Supplemental Unemployment Benefits, Severance Benefits
Other accrued expenses
Other Accrued Liabilities, Current
Total accrued expenses
Earnings Per Share [Abstract]
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]
Net income (loss) available to Amkor common stockholders
Net Income (Loss) Available to Common Stockholders, Basic
Weighted-average number of common shares outstanding — basic
Weighted Average Number of Shares Outstanding, Basic
Weighted-average number of common shares outstanding — diluted
Weighted Average Number of Shares Outstanding, Diluted
Net income (loss) attributable to Amkor per common share:
Earnings Per Share, Basic and Diluted [Abstract]
Basic (in dollars per share)
Earnings Per Share, Basic
Diluted (in dollars per share)
Earnings Per Share, Diluted
Accrued Expenses
Accounts Payable and Accrued Liabilities Disclosure [Text Block]
Pension Plans
Pension and Other Postretirement Benefits Disclosure [Text Block]
Statement of Cash Flows [Abstract]
Cash flows from operating activities:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Net income (loss)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
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
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]
Payments under revolving credit facilities
Repayments of Lines of Credit
Borrowings under short-term debt
Proceeds from Short-term Debt
Payments of short-term debt
Repayments of Short-term Debt
Proceeds from issuance of long-term debt
Proceeds from Issuance of Long-term Debt
Payments of long-term debt
Repayments of Long-term Debt
Payments for debt issuance costs
Payments of Debt Issuance Costs
Payment of deferred consideration for purchase of facility
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.
Payments for capital lease obligations
Repayments of Long-term Capital Lease Obligations
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
Payments of subsidiary dividends to non-controlling interests
Payments of Ordinary Dividends, Noncontrolling Interest
Net cash provided by (used in) financing activities
Net Cash Provided by (Used in) Financing Activities
Effect of exchange rate fluctuations on cash, cash equivalents and restricted cash
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Net increase (decrease) 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, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect
Cash, cash equivalents and restricted cash, beginning of period
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash, cash equivalents and restricted cash, 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
Equity and Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity Note Disclosure [Text Block]
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
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
Income Tax Disclosure [Abstract]
Income tax expense
Income Tax Expense (Benefit)
Gross unrecognized tax benefits
Unrecognized Tax Benefits
Schedule of Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
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
Land [Member]
Land use rights
Use Rights [Member]
Buildings and improvements
Building and Building Improvements [Member]
Machinery and equipment
Machinery and Equipment [Member]
Software and computer equipment
Software and Computer Equipment [Member]
Software and Computer Equipment [Member]
Furniture, fixtures and other equipment
Furniture and Fixtures [Member]
Construction in progress
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment
Property, Plant and Equipment, Gross
Accumulated depreciation and amortization
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Total property, plant and equipment, net
Share-Based Compensation Plans
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]
Schedule of Stockholders Equity [Table]
Schedule of Stockholders Equity [Table]
Schedule of Stockholders Equity [Table]
Amkor
Parent [Member]
Noncontrolling Interest
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]
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
Share-based compensation
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition
Subsidiary dividends paid to non-controlling interests
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Business Acquisition [Axis]
Business Acquisition [Axis]
Business Acquisition, Acquiree [Domain]
Business Acquisition, Acquiree [Domain]
Nanium S.A.
Nanium S.A. [Member]
Nanium S.A. [Member]
Business Acquisition [Line Items]
Business Acquisition [Line Items]
Ownership interest acquired (as a percent)
Business Acquisition, Percentage of Voting Interests Acquired
Fair Value Measurements
Fair Value Disclosures [Text Block]
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
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]
Commitments and Contingencies
Commitments and Contingencies Disclosure [Text Block]
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
Statement of Comprehensive Income [Abstract]
Net income (loss)
Other comprehensive income (loss), net of tax:
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Adjustments to unrealized components of defined benefit pension plans
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax
Foreign currency translation
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Comprehensive income
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Comprehensive income attributable to non-controlling interests
Net Income (Loss) Attributable to Noncontrolling Interest
Comprehensive income attributable to Amkor
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]
Award Type [Axis]
Award Type [Axis]
Award Type [Domain]
Equity Award [Domain]
Restricted shares
Restricted Stock [Member]
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
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of shares nonvested beginning balance
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number
Number of shares awards granted
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period
Number of shares awards vested
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period
Number of shares awards forfeited
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period
Number of shares nonvested ending balance
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 [Abstract]
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
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
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
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
Weighted average grant-date fair value nonvested ending balance (in dollars per share)
Summary of Short term Borrowings And Long term Debt
Schedule of Debt [Table Text Block]
Earnings Per Share
Earnings Per Share [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]
Factoring of Accounts Receivable [Line Items]
Factoring of Accounts Receivable [Line Items]
[Line Items] for Factoring of Accounts Receivable [Table]
Accounts receivable sold without recourse
Accounts Receivable Sold without Recourse
Accounts Receivable Sold without Recourse
Subsequent Event Type [Axis]
Subsequent Event Type [Axis]
Subsequent Event Type [Domain]
Subsequent Event Type [Domain]
Subsequent Event
Subsequent Event [Member]
Variable Rate [Axis]
Variable Rate [Axis]
Variable Rate [Domain]
Variable Rate [Domain]
TIBOR
Tokyo Interbank Offered Rate (TIBOR) [Member]
Tokyo Interbank Offered Rate (TIBOR) [Member]
LIBOR
London Interbank Offered Rate (LIBOR) [Member]
Range [Axis]
Range [Axis]
Range [Domain]
Range [Domain]
Minimum
Minimum [Member]
Maximum
Maximum [Member]
Weighted Average
Weighted Average [Member]
Letter of Credit
Letter of Credit [Member]
Credit facility, borrowing capacity
Line of Credit Facility, Maximum Borrowing Capacity
Basis spread on variable rate (as a percent)
Debt Instrument, Basis Spread on Variable Rate
Stated interest rate (as a percent)
Debt Instrument, Interest Rate, Stated Percentage
Current borrowing capacity
Line of Credit Facility, Current Borrowing Capacity
Standby letters of credit outstanding
Letters of Credit Outstanding, Amount
Remaining borrowing capacity
Line of Credit Facility, Remaining Borrowing Capacity
Proceeds from lines of credit
Proceeds from Lines of Credit
Repayments of debt
Repayments of Debt
Interest rate at period end (as a percent)
Line of Credit Facility, Interest Rate at Period End
Amount of debt agreement
Debt Instrument, Face Amount
Periodic principal payment
Debt Instrument, Periodic Payment, Principal
Stock options
Employee Stock Option [Member]
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
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition
Other Income and Expense
Other Income and Other Expense Disclosure [Text Block]
Document and Entity Information [Abstract]
Document And Entity Information.
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
Debt
Debt Disclosure [Text Block]
Income Taxes
Income Tax Disclosure [Text Block]
Summarized Accrued expenses
Schedule of Accrued Liabilities [Table Text Block]
Property, Plant and Equipment [Table]
Name of Property [Axis]
Name of Property [Axis]
Name of Property [Domain]
Name of Property [Domain]
K5 Facility
K5 Facility [Member]
K5 Facility [Member]
Depreciation
Depreciation
Property, plant and equipment, gross
Percentage of proceeds received
Percentage of Proceeds Received
The percentage of proceeds received from sale of property, plant, and equipment
Pre-tax gain at close
Gain (Loss) on Disposition of Property Plant Equipment
Assets held-for-sale, current
Long-lived Assets Held-for-Sale, Current
Long-lived Assets Held-for-Sale, Current
Schedule of share-based compensation costs
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [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]
Inventories
Inventory Disclosure [Text Block]
Changes in equity attributable to both Company and noncontrolling interests
Schedule of Stockholders Equity [Table Text Block]
Changes in accumulated other comprehensive income (loss)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
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 (loss) before taxes
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest
Income tax expense
Net income (loss)
Net income attributable to non-controlling interests
Net income (loss) attributable to Amkor
Net Income (Loss) Attributable to Parent
Net income (loss) attributable to Amkor per common share:
Shares used in computing per common share amounts:
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic (in shares)
Diluted (in shares)
Inventories
Schedule of Inventory, Current [Table Text Block]
Schedule of Other Nonoperating Income (Expense)
Schedule of Other Nonoperating Income (Expense) [Table Text Block]
Expected life
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
Acquisition
Business Combination Disclosure [Text Block]
Loss Contingencies [Table]
Loss Contingencies [Table]
Loss Contingencies [Line Items]
Loss Contingencies [Line Items]
Interim Financial Statements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]