Amkor Technology (AMKR) 10-Q 4 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 28, 2016
Document Information [Line Items]
Entity Registrant Name	AMKOR TECHNOLOGY, INC.
Entity Central Index Key	1,047,127
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		237,694,980

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net sales	$ 1,086,014	$ 734,362	$ 2,872,022	$ 2,213,959
Cost of sales	872,214	607,762	2,403,732	1,837,314
Gross profit	213,800	126,600	468,290	376,645
Selling, general and administrative	72,363	54,232	216,894	173,609
Research and development	26,822	21,073	84,145	59,119
Total operating expenses	99,185	75,305	301,039	232,728
Operating income	114,615	51,295	167,251	143,917
Interest expense	21,488	17,695	58,496	64,317
Interest expense, related party	1,243	1,243	3,727	3,727
Other (income) expense, net	6,657	(11,576)	9,607	(4,784)
Total other expense, net	29,388	7,362	71,830	63,260
Income before taxes and equity in earnings of unconsolidated affiliate	85,227	43,933	95,421	80,657
Income tax expense	24,086	16,568	29,319	27,198
Income before equity in earnings of unconsolidated affiliate	61,141	27,365	66,102	53,459
Equity in earnings of J-Devices	0	1,217	0	10,587
Net income	61,141	28,582	66,102	64,046
Net income attributable to non-controlling interests	(1,052)	(847)	(2,175)	(2,386)
Net income attributable to Amkor	$ 60,089	$ 27,735	$ 63,927	$ 61,660
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.25	$ 0.12	$ 0.27	$ 0.26
Diluted (in dollars per share)	$ 0.25	$ 0.12	$ 0.27	$ 0.26
Shares used in computing per common share amounts:
Basic (in shares)	237,353	236,888	237,157	236,813
Diluted (in shares)	238,192	236,974	237,586	237,168

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income	$ 61,141	$ 28,582	$ 66,102	$ 64,046
Other comprehensive income (loss), net of tax:
Adjustments to unrealized components of defined benefit pension plans, net of tax	24	22	71	66
Foreign currency translation	5,883	10	52,161	(102)
Equity interest in J-Devices' other comprehensive income, net of tax	0	4,394	0	509
Total other comprehensive income (loss)	5,907	4,426	52,232	473
Comprehensive income	67,048	33,008	118,334	64,519
Comprehensive income attributable to non-controlling interests	(1,052)	(847)	(2,175)	(2,386)
Comprehensive income attributable to Amkor	$ 65,996	$ 32,161	$ 116,159	$ 62,133

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 549,836	$ 523,172
Restricted cash	2,000	2,000
Accounts receivable, net of allowances	630,984	526,143
Inventories	272,589	238,205
Other current assets	31,637	27,960
Total current assets	1,487,046	1,317,480
Property, plant and equipment, net	2,619,469	2,579,017
Goodwill	27,908	23,409
Restricted cash	4,209	2,176
Other assets	102,482	104,346
Total assets	4,241,114	4,026,428
Current liabilities:
Short-term borrowings and current portion of long-term debt	30,834	76,770
Trade accounts payable	517,745	434,222
Capital expenditures payable	179,768	242,980
Accrued expenses	346,613	264,212
Total current liabilities	1,074,960	1,018,184
Long-term debt	1,473,214	1,435,269
Long-term debt, related party	75,000	75,000
Pension and severance obligations	191,615	167,197
Other non-current liabilities	86,265	113,242
Total liabilities	2,901,054	2,808,892
Commitments and contingencies (Note 16)
Stockholders’ equity:
Preferred stock, $0.001 par value, 10,000 shares authorized, designated Series A, none issued	0	0
Common stock, $0.001 par value, 500,000 shares authorized, 283,483 and 282,724 shares issued, and 237,695 and 237,005 shares outstanding, in 2016 and 2015, respectively	283	283
Additional paid-in capital	1,888,641	1,883,592
Accumulated deficit	(403,820)	(467,747)
Accumulated other comprehensive income (loss)	50,148	(2,084)
Treasury stock, at cost, 45,788 and 45,719 shares in 2016 and 2015, respectively	(214,204)	(213,758)
Total Amkor stockholders’ equity	1,321,048	1,200,286
Non-controlling interests in subsidiaries	19,012	17,250
Total equity	1,340,060	1,217,536
Total liabilities and equity	$ 4,241,114	$ 4,026,428

Consolidated Balance Sheets (U5

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares shares in Thousands	Sep. 30, 2016	Dec. 31, 2015
Stockholders’ equity:
Preferred stock designated Series A, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock designated Series A, shares authorized	10,000	10,000
Preferred stock designated Series A, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	500,000	500,000
Common stock, shares issued	283,483	282,724
Common stock, shares outstanding	237,695	237,005
Treasury stock, shares	45,788	45,719

Condensed Consolidated Statemen

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 66,102	$ 64,046
Depreciation and amortization	416,517	371,968
Loss on debt retirement	0	(9,560)
Other operating activities and non-cash items	(4,382)	(9,879)
Changes in assets and liabilities	13,379	(5,299)
Net cash provided by operating activities	491,616	430,396
Cash flows from investing activities:
Payments for property, plant and equipment	(481,670)	(352,644)
Proceeds from sale of property, plant and equipment	13,687	5,212
Cash received on sale of subsidiary to J-Devices, net	0	8,355
Investment in J-Devices	0	(12,908)
Other investing activities	(2,176)	(869)
Net cash used in investing activities	(470,159)	(352,854)
Cash flows from financing activities:
Borrowings under revolving credit facilities	115,000	180,000
Payments under revolving credit facilities	(155,000)	(100,000)
Borrowings under short-term debt	27,594	0
Payments of short-term debt	(36,211)	0
Proceeds from issuance of long-term debt	45,000	360,000
Payments of long-term debt	(12,955)	(530,000)
Payments for debt issuance costs	(156)	0
Payments for the retirement of debt	0	(7,030)
Payments for capital lease obligations	(1,691)	0
Proceeds from the issuance of stock through share-based compensation plans	2,600	657
Payments of tax withholding for restricted shares	(446)	(548)
Payments of subsidiary dividends to non-controlling interests	(413)	(123)
Net cash used in financing activities	(16,678)	(97,044)
Effect of exchange rate fluctuations on cash and cash equivalents	21,885	0
Net increase (decrease) in cash and cash equivalents	26,664	(19,502)
Cash and cash equivalents, beginning of period	523,172	449,946
Cash and cash equivalents, end of period	549,836	430,444
Non cash investing and financing activities:
Property, plant and equipment included in capital expenditures payable	179,768	221,281
Capital Lease Obligations Incurred	$ 4,908	$ 0

Interim Financial Statements

Interim Financial Statements	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interim Financial Statements	1. Interim Financial Statements Basis of Presentation. The Consolidated Financial Statements and related disclosures as of September 30, 2016 , and for the three and nine months ended September 30, 2016 and 2015 , are unaudited, pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). The December 31, 2015 , Consolidated Balance Sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S.”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. In our opinion, these financial statements include all adjustments (consisting only of normal recurring adjustments) necessary for the fair statement of the results for the interim periods. These financial statements should be read in conjunction with the financial statements included in our Annual Report for the year ended December 31, 2015 , filed on Form 10-K with the SEC on February 22, 2016. The results of operations for the three and nine months ended September 30, 2016 , are not necessarily indicative of the results to be expected for the full year. Unless the context otherwise requires, all references to “Amkor,” “we,” “us,” “our” or the “company” are to Amkor Technology, Inc. and our subsidiaries. On December 30, 2015, we increased our ownership in J-Devices to 100% ( Note 3 ). As a result, our accounting for J-Devices changed from the equity method to the consolidation method effective December 30, 2015. The operating results of J-Devices were consolidated beginning in 2016. Revision to Previously Reported Financial Information. In the second quarter of 2016, we identified an error in the provision for income taxes in the financial statements for J-Devices for the periods beginning in 2012 through the fourth quarter of 2015. We believe that the error is not material to Amkor for the periods impacted and have elected to revise our previously issued consolidated financial statements. Periods presented herein are based on the revised financial results. See Note 17 for additional information. Use of Estimates. The Consolidated Financial Statements have been prepared in conformity with U.S. GAAP, using management’s best estimates and judgments where appropriate. These estimates and judgments affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. The estimates and judgments will also affect the reported amounts for certain revenues and expenses during the reporting period. Actual results could differ materially from these estimates and judgments. Goodwill. The balance of goodwill in our Consolidated Balance Sheets reflects adjustments for foreign currency translation.

New Accounting Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Standards	2. New Accounting Standards Recently Adopted Standards In April 2015, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2015-03, Interest-Imputation of Interest (Subtopic 835-30) - Simplifying the Presentation of Debt Issuance Costs . ASU 2015-03 requires debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. In August 2015, the FASB issued ASU 2015-15, Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements - Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting (SEC Update) , which clarifies that companies may continue to present unamortized debt issuance costs associated with line of credit arrangements as an asset. ASU 2015-03 and ASU 2015-15 are effective for interim and annual reporting periods beginning after December 15, 2015, and require retrospective application. We adopted ASU 2015-03 and ASU 2015-15 on January 1, 2016. The guidance was applied retrospectively and the consolidated balance sheet as of December 31, 2015 was adjusted to reclassify $8.8 million of debt issuance costs from other assets to a reduction in the carrying amount of the related debt liability. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation (Topic 718) - Improvements to Employee Share-Based Payment Accounting . ASU 2016-09 involves several aspects of the accounting for share-based transactions, including income tax consequences, classification of awards as either equity or liabilities, forfeitures and classification on the statement of cash flows. ASU 2016-09 is effective for reporting periods beginning after December 15, 2016 and early adoption is permitted. We adopted ASU 2016-09 on July 1, 2016. The adoption of ASU 2016-09 did not have a significant impact on our financial statements or disclosure. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230) - Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 provides guidance on eight specific cash flow issues with the objective of reducing diversity in practice in regard to how cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 is effective for reporting periods beginning after December 15, 2017 and is applied retrospectively. Early adoption is permitted. We adopted ASU 2016-15 at September 30, 2016. The guidance was applied retrospectively and the condensed consolidated statement of cash flows for the nine months ended September 30, 2015 was adjusted to reclassify $7.0 million of payments for debt retirement from operating activities to financing activities. Recently Issued Standards In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09 is based on the principle that revenue is recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers, including significant judgments and changes in judgments. ASU 2014-09 permits the use of either full retrospective or modified retrospective methods of adoption. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date , which defers the effective date by one year to December 15, 2017, for interim and annual reporting periods beginning after that date . In March, April and May 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net), ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, and ASU 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , respectively, which provide supplemental guidance and clarification to ASU 2014-09. Early adoption is permitted, but not before the original effective date of December 15, 2016. We are currently evaluating the method of adoption and the impact that this guidance will have on our financial statements and disclosure. In July 2015, the FASB issued ASU 2015-11, Inventory - Simplifying the Measurement of Inventory (Topic 330) . ASU 2015-11 requires inventory to be subsequently measured using the lower of cost and net realizable value, thereby eliminating the market value approach. Net realizable value is defined as the “estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation.” ASU 2015-11 is effective for reporting periods beginning after December 15, 2016 and is applied prospectively. Early adoption is permitted. ASU 2015-11 is not expected to have a significant impact on our financial statements or disclosure. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) . ASU 2016-02 requires a dual approach for lessee accounting under which a lessee would account for leases as finance leases or operating leases. Both finance leases and operating leases will result in the lessee recognizing a right-of-use asset and a corresponding lease liability. For finance leases the lessee would recognize interest expense and amortization of the right-of-use asset, and for operating leases the lessee would recognize a straight-line lease expense. ASU 2016-02 is effective for reporting periods beginning after December 15, 2018 using a modified retrospective approach. Early adoption is permitted. We are currently evaluating the impact that this guidance will have on our financial statements and disclosure. In October 2016, the FASB issued ASU 2016-16, Income Taxes (Topic 740) - Intra-Entity Transfers of Assets Other Than Inventory . ASU 2016-16 requires an entity to recognize income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. This removes the exception to postpone recognition until the asset has been sold to an outside party. ASU 2016-16 is effective for reporting periods beginning after December 15, 2017 using a modified retrospective approach. Early adoption is permitted. We are currently evaluating the impact that this guidance will have on our financial statements and disclosure.

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Business Combination Disclosure [Text Block]	3. Acquisition Acquisition of J-Devices Through the exercise of additional options, on December 30, 2015, we increased our ownership interest in J-Devices from 65.7% to 100% for a purchase price of $105.4 million . As a result, our accounting for J-Devices changed from the equity method to the consolidation method effective December 30, 2015. The operating results of J-Devices were consolidated beginning in 2016. During the three months ended June 30, 2016, we updated the purchase price allocation of J-Devices for a previously unrecognized tax provision liability at J-Devices of $11.6 million . See Note 1 and 17 for additional information. The following table presents the initial purchase price allocation and subsequent adjustments: Initial Allocation Adjustments Revised Allocation (In thousands) Fair value of consideration transferred: Cash $ 105,391 $ — $ 105,391 Fair value of our previously held equity interest in J-Devices 167,684 (7,597 ) 160,087 Total $ 273,075 $ (7,597 ) $ 265,478 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash $ 127,968 $ — $ 127,968 Accounts receivable 180,177 — 180,177 Inventory 42,502 — 42,502 Other current assets 2,363 — 2,363 Property, plant and equipment 230,319 — 230,319 Other assets 9,268 — 9,268 Short-term borrowings and current portion of long-term debt (36,770 ) — (36,770 ) Other current liabilities (251,405 ) — (251,405 ) Long-term debt (18,885 ) — (18,885 ) Pension obligations (22,250 ) — (22,250 ) Other non-current liabilities (9,655 ) (11,563 ) (21,218 ) Total identifiable net assets 253,632 (11,563 ) 242,069 Goodwill 19,443 3,966 23,409 Total $ 273,075 $ (7,597 ) $ 265,478

Share-Based Compensation Plans

Share-Based Compensation Plans	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation Plans	4. Share-Based Compensation Plans The following table summarizes our share-based compensation expense attributable to stock options and restricted shares: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Share-based compensation expense $ 824 $ 816 $ 2,449 $ 3,063 We recognized our share-based compensation costs primarily in selling, general and administrative expenses. There were no corresponding deferred income tax benefits for stock options or restricted shares. Stock Options The following table summarizes our stock option activity for the nine months ended September 30, 2016 : Number of Shares (In thousands) Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (In thousands) Outstanding at December 31, 2015 3,727 $ 6.49 Granted 415 5.73 Exercised (533 ) 4.88 Forfeited or expired (274 ) 6.63 Outstanding at September 30, 2016 3,335 $ 6.65 6.06 $ 11,051 Fully vested at September 30, 2016 and expected to vest thereafter 3,304 $ 6.65 6.03 $ 10,938 Exercisable at September 30, 2016 2,337 $ 7.05 5.06 $ 7,020 The following assumptions were used to calculate the weighted average fair values of the options granted: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 Expected life (in years) 5.9 6.0 6.5 5.8 Risk-free interest rate 1.4 % 1.8 % 1.5 % 1.8 % Volatility 43 % 44 % 48 % 45 % Dividend yield — — — — Weighted average grant date fair value per option granted $ 3.78 $ 2.33 $ 2.78 $ 3.20 Total unrecognized compensation expense from stock options was $2.4 million as of September 30, 2016 , which is expected to be recognized over a weighted-average period of approximately 2.0 years beginning October 1, 2016 . Restricted Shares The following table summarizes our restricted share activity for the nine months ended September 30, 2016 : Number of Shares (In thousands) Weighted Average Grant-Date Fair Value (Per share) Non-vested at December 31, 2015 385 $ 4.78 Awards granted 50 5.66 Awards vested (226 ) 4.91 Awards forfeited (5 ) 4.43 Non-vested at September 30, 2016 204 $ 4.86 Total unrecognized compensation cost from restricted shares was $0.7 million as of September 30, 2016 , which is expected to be recognized over a weighted average period of approximately 0.6 years beginning October 1, 2016 .

Other Income and Expense

Other Income and Expense	9 Months Ended
	Sep. 30, 2016
Other Income and Expenses [Abstract]
Other Income and Other Expense Disclosure [Text Block]	5. Other Income and Expense Other income and expense consists of the following: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Interest income $ (334 ) $ (523 ) $ (1,033 ) $ (2,196 ) Foreign currency (gain) loss, net 7,124 (8,499 ) 11,506 (9,751 ) Loss on debt retirement — — — 9,560 Other (income) expense, net (133 ) (2,554 ) (866 ) (2,397 ) Total other (income) expense, net $ 6,657 $ (11,576 ) $ 9,607 $ (4,784 )

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	6. Income Taxes Our income tax expense of $29.3 million for the nine months ended September 30, 2016 primarily reflects income taxes at certain of our foreign operations and foreign withholding taxes. Our income tax expense also reflects income taxed in foreign jurisdictions where we benefit from tax holidays. We monitor on an ongoing basis our ability to utilize our deferred tax assets and whether there is a need for a related valuation allowance. In evaluating our ability to recover our deferred tax assets in the jurisdictions from which they arise, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax-planning strategies and results of recent operations. For most of our foreign deferred tax assets, we consider it more likely than not that we will have sufficient taxable income to allow us to realize these deferred tax assets. A significant amount of our net deferred tax assets relate to our operations in Korea. At this time, we consider it more likely than not we will have sufficient taxable income in the future that will allow us to realize these deferred tax assets. However, it is possible that some or all of our Korean net operating loss carryforwards could ultimately expire unused, in the event future taxable income falls short of our current expectations. If our assessment of the recoverability of Korean deferred tax assets changes in the future, we may need to establish a valuation allowance against such deferred tax assets. We maintain a valuation allowance on all of our U.S. net deferred tax assets, including our net operating loss carryforwards. Such valuation allowances are released as the related tax benefits are realized or when sufficient evidence exists to conclude that it is more likely than not that the deferred tax assets will be realized. Unrecognized tax benefits represent reserves for potential tax deficiencies or reductions in tax benefits that could result from federal, state or foreign tax audits. Our gross unrecognized tax benefits increased from $23.3 million at December 31, 2015 , to $24.7 million as of September 30, 2016 . Most of our unrecognized tax benefits would reduce our effective tax rate, if recognized. Our unrecognized tax benefits are subject to change for effective settlement of examinations, changes in the recognition threshold of tax positions, the expiration of statues of limitations and other factors. Tax return examinations involve uncertainties, and there can be no assurance that the outcome of examinations will be favorable.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share	7. Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing net income attributable to Amkor common stockholders by the weighted average number of common shares outstanding during the period. The weighted average number of common shares outstanding is reduced for treasury stock. Diluted EPS is computed on the basis of the weighted average number of shares of common stock plus the effect of dilutive potential common shares outstanding during the period. Dilutive potential common shares include outstanding stock options and unvested restricted shares. The following table summarizes the computation of basic and diluted EPS: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands, except per share data) Net income attributable to Amkor $ 60,089 $ 27,735 $ 63,927 $ 61,660 Income allocated to participating securities — — — (94 ) Net income available to Amkor common stockholders $ 60,089 $ 27,735 $ 63,927 $ 61,566 Weighted average shares outstanding — basic 237,353 236,888 237,157 236,813 Effect of dilutive securities: Stock options and restricted share awards 839 86 429 355 Weighted average shares outstanding — diluted 238,192 236,974 237,586 237,168 Net income attributable to Amkor per common share: Basic $ 0.25 $ 0.12 $ 0.27 $ 0.26 Diluted 0.25 0.12 0.27 0.26 The following table summarizes the potential shares of common stock that were excluded from diluted EPS, because the effect of including these potential shares was anti-dilutive: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Stock options and restricted share awards 1,284 3,477 2,020 1,861

Equity and Accumulated Other Co

Equity and Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Equity and Accumulated Other Comprehensive Income	8. Equity and Accumulated Other Comprehensive Income (Loss) The following tables reflect the changes in equity attributable to both Amkor and the non-controlling interests: Attributable to Amkor Attributable to Non-controlling Interests Total (In thousands) Equity at December 31, 2015 $ 1,200,286 $ 17,250 $ 1,217,536 Net income 63,927 2,175 66,102 Other comprehensive income 52,232 — 52,232 Issuance of stock through employee share-based compensation plans 2,600 — 2,600 Treasury stock acquired through surrender of shares for tax withholding (446 ) — (446 ) Share-based compensation 2,449 — 2,449 Subsidiary dividends paid to non-controlling interests — (413 ) (413 ) Equity at September 30, 2016 $ 1,321,048 $ 19,012 $ 1,340,060 Attributable to Amkor Attributable to Non-controlling Interests Total (In thousands) Equity at December 31, 2014 $ 1,114,748 $ 14,701 $ 1,129,449 Net income 61,660 2,386 64,046 Other comprehensive income 473 — 473 Issuance of stock through employee share-based compensation plans 657 — 657 Treasury stock acquired through surrender of shares for tax withholding (548 ) — (548 ) Share-based compensation 3,063 — 3,063 Subsidiary dividends paid to non-controlling interest — (123 ) (123 ) Equity at September 30, 2015 $ 1,180,053 $ 16,964 $ 1,197,017 The following tables reflect the changes in accumulated other comprehensive income (loss), net of tax: Defined Benefit Pension Foreign Currency Translation Total (In thousands) Accumulated other comprehensive loss at $ (1,425 ) $ (659 ) $ (2,084 ) Other comprehensive income before reclassifications — 52,161 52,161 Amounts reclassified from accumulated other comprehensive loss 71 — 71 Other comprehensive income 71 52,161 52,232 Accumulated other comprehensive income (loss) at $ (1,354 ) $ 51,502 $ 50,148 Defined Benefit Pension Foreign Currency Translation Equity Interest in J-Devices' Other Comprehensive Income (Loss) Total (In thousands) Accumulated other comprehensive loss at $ (2,525 ) $ (513 ) $ (29,433 ) $ (32,471 ) Other comprehensive loss before reclassifications — (102 ) 509 407 Amounts reclassified from accumulated other comprehensive loss 66 — — 66 Other comprehensive income (loss) 66 (102 ) 509 473 Accumulated other comprehensive loss at $ (2,459 ) $ (615 ) $ (28,924 ) $ (31,998 ) Amounts reclassified out of accumulated other comprehensive income (loss) are included as a component of net periodic pension cost ( Note 14 ).

Factoring of Accounts Receivabl

Factoring of Accounts Receivable	9 Months Ended
	Sep. 30, 2016
Factoring of Accounts Receivable [Abstract]
Factoring of Accounts Receivable [Table Text Block]	9. Factoring of Accounts Receivable In certain foreign locations, we use non-recourse factoring arrangements with third party financial institutions to manage our working capital and cash flows. Under this program, we sell receivables to a financial institution for cash at a discount to the face amount. As part of the factoring arrangements, we perform certain collection and administrative functions for the receivables sold. For the three and nine months ended September 30, 2016 , we sold accounts receivable totaling $161.6 million and $431.8 million , respectively, for a discount, plus fees, of $0.8 million and $1.7 million , respectively. For the three and nine months ended September 30, 2015 , we sold accounts receivable totaling $82.4 million and $235.3 million , respectively, for a discount, plus fees, of $0.3 million and $1.1 million , respectively.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Inventories	10. Inventories Inventories consist of the following: September 30, December 31, 2015 (In thousands) Raw materials and purchased components $ 176,833 $ 163,024 Work-in-process 95,756 75,181 Total inventories $ 272,589 $ 238,205

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant And Equipment	11. Property, Plant and Equipment Property, plant and equipment consist of the following: September 30, December 31, 2015 (In thousands) Land $ 245,828 $ 237,815 Land use rights 26,845 26,845 Buildings and improvements 1,069,448 1,010,201 Machinery and equipment 4,428,531 4,226,401 Software and computer equipment 207,965 197,266 Furniture, fixtures and other equipment 21,875 21,259 Construction in progress 404,507 352,607 Total property, plant and equipment 6,404,999 6,072,394 Less accumulated depreciation and amortization (3,785,530 ) (3,493,377 ) Total property, plant and equipment, net $ 2,619,469 $ 2,579,017 The following table summarizes our depreciation expense: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Depreciation expense $ 140,728 $ 122,812 $ 414,687 $ 370,663 As of September 30, 2016 and December 31, 2015 , construction in progress reflects $365.8 million and $312.1 million , respectively, of costs for K5, including capitalized interest of $23.0 million and $18.7 million , respectively. As part of our plan to consolidate factory operations in Korea, we entered into an agreement in November 2016 to sell the land and buildings comprising our K1 factory for a purchase price of ₩162.1 billion (approximately $142 million ). We received 10% of the purchase price at signing and the balance is due at closing. The transaction is expected to close during the second quarter of 2017 at which time we expect to recognize a pre-tax gain of approximately $100 million .

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2016
Payables and Accruals [Abstract]
Accrued Expenses	12. Accrued Expenses Accrued expenses consist of the following: September 30, December 31, (In thousands) Payroll and benefits $ 131,523 $ 95,011 Deferred revenue and customer advances 61,727 49,243 Accrued settlement costs 34,725 32,987 Income taxes payable 31,315 21,448 Accrued interest 28,114 12,920 Accrued severance plan obligations 16,893 14,306 Other accrued expenses 42,316 38,297 Total accrued expenses $ 346,613 $ 264,212

Debt

Debt	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Debt	13. Debt Following is a summary of short-term borrowings and long-term debt: September 30, December 31, (In thousands) Debt of Amkor Technology, Inc.: Senior secured credit facilities: $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) $ 100,000 $ 100,000 Senior notes: 6.625% Senior notes, due June 2021, $75 million related party 400,000 400,000 6.375% Senior notes, due October 2022 524,971 525,000 Debt of subsidiaries: Amkor Technology Korea, Inc.: $100 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due June 2017 (2) — 40,000 Term loan, LIBOR plus 2.60%, due May 2018 120,000 120,000 Term loan, LIBOR plus 2.70%, due December 2019 70,000 70,000 Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020 150,000 150,000 Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020 80,000 80,000 Term loan, fund floating rate plus 1.60%, due June 2020 (3) 75,000 40,000 J-Devices Corporation: Short-term term loans, variable rate (4) 15,343 15,582 Short-term term loans, fixed rate at 0.50% — 5,808 Term loans, TIBOR plus 1.00%, due November 2016 494 2,800 Term loans, fixed rate at 0.53%, due April 2018 26,264 31,465 Amkor Technology Taiwan Ltd: Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (5) 20,000 10,000 1,582,072 1,590,655 Less: Unamortized premium and deferred debt costs, net (3,024 ) (3,616 ) Less: Short-term borrowings and current portion of long-term debt (30,834 ) (76,770 ) Long-term debt (including related party) $ 1,548,214 $ 1,510,269 (1) Our $200.0 million senior secured revolving credit facility has a letter of credit sub-limit of $25.0 million . Principal is payable at maturity. Interest is payable monthly in arrears, at LIBOR plus 1.25% to 1.75% ( 2.38% as of September 30, 2016 ). As of September 30, 2016 , the borrowing base of our revolving credit facility is $200.0 million , which is adjusted based on the amount of our eligible accounts receivable. Additionally, we had $ 0.5 million of standby letters of credit outstanding. As of September 30, 2016 , $99.5 million was available to be drawn. In October 2016, we repaid $40.0 million of the outstanding balance. (2) In June 2012, we entered into a $41.0 million revolving credit facility. In March 2016, we increased the facility to $100.0 million . In June 2016, we amended the maturity date to June 2017. Principal is payable at maturity. Interest is due monthly in arrears, at a foreign currency funding-linked base rate plus 1.60% ( 3.17% as of September 30, 2016 ). As of September 30, 2016 , $100.0 million was available to be drawn. (3) In May 2015, we entered into a term loan agreement pursuant to which we may borrow up to $150.0 million through November 2016 for capital expenditures. Principal is payable at maturity. Interest is payable quarterly in arrears, at a fund floating rate plus 1.60% ( 2.63% as of September 30, 2016 ). At September 30, 2016 , $75.0 million was available to be borrowed. (4) We entered into various short-term term loans which mature semi-annually. Interest is paid monthly, at TIBOR plus 0.30% to 0.38% (weighted average of 0.36% as of September 30, 2016 ). Principal is payable in monthly installments. As of September 30, 2016 , $2.5 million was available to be drawn. (5) In November 2015, we entered into a $39.0 million revolving credit facility. Principal is payable at maturity. Interest is due monthly, at TAIFX plus a bank determined spread ( 2.01% as of September 30, 2016 ). As of September 30, 2016 , $19.0 million was available to be drawn. Our foreign debt is collateralized by land, buildings and equipment in the respective location. The carrying value of the collateral exceeds the carrying amount of the debt. The debt of Amkor Technology, Inc. is structurally subordinated in right of payment to all existing and future debt and other liabilities of our subsidiaries. The agreements governing our indebtedness contain a number of affirmative and negative covenants which restrict our ability to pay dividends and could restrict our operations. We have never paid a dividend to our stockholders and we do not have any present plans for doing so. We were in compliance with all of our covenants at September 30, 2016 .

Pension and Severance Plans

Pension and Severance Plans	9 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Severance and Pension Plans	14. Pension and Severance Plans Foreign Defined Benefit Pension Plans Our subsidiaries in Japan, Korea, Malaysia, the Philippines and Taiwan sponsor defined benefit pension plans. Charges to expense are based upon actuarial analyses. The components of net periodic pension cost for these defined benefit pension plans are as follows: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Service cost $ 9,024 $ 4,177 $ 25,684 $ 6,605 Interest cost 925 725 2,753 2,251 Expected return on plan assets (961 ) (817 ) (2,864 ) (2,523 ) Amortization of prior service cost 9 8 26 25 Recognized actuarial loss 24 23 71 69 Net periodic pension cost $ 9,021 $ 4,116 $ 25,670 $ 6,427 As a result of the adoption of a defined benefit pension plan in Korea beginning on August 1, 2015, and the acquisition of J-Devices on December 30, 2015, our net periodic pension cost has increased from the prior period. Defined Contribution Pension Plans We sponsor defined contribution pension plans in Korea, Malaysia, Taiwan and the U.S. The following table summarizes our defined contribution expense: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Defined contribution expense $ 1,939 $ 1,810 $ 7,106 $ 6,934 Korean Severance Plan Our subsidiary in Korea maintains an unfunded severance plan that covers certain employees that were employed prior to August 1, 2015. To the extent eligible employees are terminated, our subsidiary in Korea would be required to make lump-sum severance payments on behalf of these eligible employees for service provided prior to August 1, 2015. Factors used to determine severance benefits include employees' length of service, seniority and rate of pay. The employees' length of service and seniority are fixed as of July 31, 2015. The employees' rate of pay is adjusted to the rate of pay at the time of termination. Accrued severance benefits are estimated assuming all eligible employees were to terminate their employment at the balance sheet date. Our contributions to the National Pension Plan of the Republic of Korea are deducted from accrued severance benefit liabilities. The provision recorded for severance benefits for the three and nine months ended September 30, 2016 was $6.1 million and $7.0 million , respectively. The provision recorded for severance benefits for the three and nine months ended September 30, 2015 was $5.9 million and $20.7 million , respectively. On August 1, 2015, our subsidiary in Korea began sponsoring a defined benefit pension plan and a defined contribution plan. Existing employees at that time were given the option of choosing either a defined benefit pension plan or a defined contribution plan for their future benefits and new employees since that date are enrolled in a defined contribution plan.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	15. Fair Value Measurements The accounting framework for determining fair value includes a hierarchy for ranking the quality and reliability of the information used to measure fair value, which enables the reader of the financial statements to assess the inputs used to develop those measurements. The fair value hierarchy consists of three tiers as follows: Level 1, defined as quoted market prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, model-based valuation techniques for which all significant assumptions are observable in the market or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities and Level 3, defined as unobservable inputs that are not corroborated by market data. The fair values of cash, accounts receivable, trade accounts payable, capital expenditures payable, and certain other current assets and accrued expenses approximate carrying values because of their short-term nature. The carrying value of certain other non-current liabilities approximates fair value. Our assets and liabilities recorded at fair value on a recurring basis include cash equivalent money market funds and restricted cash money market funds. Cash equivalent money market funds and restricted cash money market funds are invested in U.S. money market funds and various U.S. and foreign bank operating and time deposit accounts, which are due on demand or carry a maturity date of less than three months when purchased. No restrictions have been imposed on us regarding withdrawal of balances with respect to our cash equivalents as a result of liquidity or other credit market issues affecting the money market funds we invest in or the counterparty financial institutions holding our deposits. Money market funds are valued using quoted market prices in active markets for identical assets. Our recurring fair value measurements consist of the following: September 30, December 31, (In thousands) Cash equivalent money market funds (Level 1) $ 101,200 $ 81,473 Restricted cash money market funds (Level 1) 2,000 2,000 We also measure certain assets and liabilities, including property, plant and equipment and goodwill, at fair value on a nonrecurring basis. We measure the fair value of our debt for disclosure purposes. The following table presents the fair value of financial instruments that are not recorded at fair value on a recurring basis: September 30, 2016 December 31, 2015 Fair Value Carrying Value Fair Value Carrying Value (In thousands) Senior notes (Level 1) $ 952,707 $ 921,947 $ 902,563 $ 921,384 Revolving credit facilities and term loans (Level 2) 651,908 657,101 664,085 665,655 Total debt $ 1,604,615 $ 1,579,048 $ 1,566,648 $ 1,587,039 The estimated fair value of our senior notes is based primarily on quoted market prices reported on or near the respective balance sheet dates. The estimated fair value of our revolving credit facilities and term loans was calculated using a discounted cash flow analysis, which utilized market based assumptions including forward interest rates adjusted for credit risk.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	16. Commitments and Contingencies We have a letter of credit sub-facility of $25.0 million under our $ 200.0 million senior secured revolving credit facility that matures in December 2019. As of September 30, 2016 , we had $0.5 million of standby letters of credit outstanding. Such standby letters of credit are used in the ordinary course of our business and are collateralized by our cash balances. We generally warrant that our services will be performed in a professional and workmanlike manner and in compliance with our customers' specifications. We accrue costs for known warranty issues. Historically, our warranty costs have been immaterial. Legal Proceedings We are involved in claims and legal proceedings and may become involved in other legal matters arising in the ordinary course of our business. We evaluate these claims and legal matters on a case-by-case basis to make a determination as to the impact, if any, on our business, liquidity, results of operations, financial condition or cash flows. Although the outcome of these matters is uncertain, we believe that the ultimate outcome of these claims and proceedings, individually and in the aggregate, will not have a material adverse impact to us. Our evaluation of the potential impact of these claims and legal proceedings on our business, liquidity, results of operations, financial condition or cash flows could change in the future. In accordance with the accounting guidance for loss contingencies, including legal proceedings, lawsuits, pending claims and other legal matters, we accrue for a loss contingency when we conclude that the likelihood of a loss is probable and the amount of the loss can be reasonably estimated. We adjust our accruals from time to time as we receive additional information, but the loss we incur may be significantly greater than or less than the amount we have accrued. We disclose loss contingencies if we believe they are material and there is at least a reasonable possibility that a loss has been incurred. Attorney fees related to legal matters are expensed as incurred.

Revision of Previously Reported

Revision of Previously Reported Financial Information	9 Months Ended
	Sep. 30, 2016
Accounting Changes and Error Corrections [Abstract]
Accounting Changes and Error Corrections [Text Block]	In the second quarter of 2016, we identified an error in the provision for income taxes in the financial statements for J-Devices for the periods beginning in 2012 through the fourth quarter of 2015. We believe that the error is not material to Amkor for the periods impacted and have elected to revise our previously issued consolidated financial statements. Periods presented herein are based on the revised financial results. See Note 17 for additional information. 17. Revision of Previously Reported Financial Information In the second quarter of 2016, during our post-acquisition integration of J-Devices, we identified an error in the provision for income taxes in the financial statements for J-Devices for the periods beginning in 2012 through the fourth quarter of 2015. During those periods we did not control J-Devices and, accordingly, we accounted for our investment in J-Devices using the equity method. As a result of the J-Devices error, our equity in earnings of J-Devices was overstated by the cumulative amount of $ 8.0 million . We believe that the error is not material to Amkor for the periods impacted and have elected to revise our previously issued consolidated financial statements. We have also recorded the impact of the revision in our purchase accounting for the acquisition of J-Devices on December 30, 2015 ( Note 3 ). Periods presented herein are based on the revised financial results. The following table presents the effect of the aforementioned revisions on our Consolidated Balance Sheet as of December 31, 2015 : December 31, 2015 As Reported Adjustments As Revised (In thousands) Goodwill $ 19,443 $ 3,966 $ 23,409 Total assets 4,022,462 3,966 4,026,428 Other non-current liabilities 101,679 11,563 113,242 Total liabilities 2,797,329 11,563 2,808,892 Accumulated deficit (460,150 ) (7,597 ) (467,747 ) Total Amkor stockholders’ equity 1,207,883 (7,597 ) 1,200,286 Total equity 1,225,133 (7,597 ) 1,217,536 Total liabilities and equity 4,022,462 3,966 4,026,428 The following table presents the effect of the aforementioned revisions on our Consolidated Statements of Income for the three and nine months ended September 30, 2015 : For the Three Months Ended For the Nine Months Ended As Reported Adjustments As Revised As Reported Adjustments As Revised (In thousands, except per share data) Equity in earnings of J-Devices $ 1,656 $ (439 ) $ 1,217 $ 15,460 $ (4,873 ) $ 10,587 Net income 29,021 (439 ) 28,582 68,919 (4,873 ) 64,046 Net income attributable to Amkor 28,174 (439 ) 27,735 66,533 (4,873 ) 61,660 Net income attributable to Amkor per common share: Basic $ 0.12 $ — $ 0.12 $ 0.28 $ (0.02 ) $ 0.26 Diluted 0.12 — 0.12 0.28 (0.02 ) 0.26 The following tables present the effect of the aforementioned revisions on our Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2015 , and the three months ended March 31, 2016: For the Three Months Ended For the Nine Months Ended As Reported Adjustments As Revised As Reported Adjustments As Revised (In thousands) Net income $ 29,021 $ (439 ) $ 28,582 $ 68,919 $ (4,873 ) $ 64,046 Equity interest in J-Devices' other comprehensive loss, net of tax 4,587 (193 ) 4,394 537 (28 ) 509 Total other comprehensive loss 4,619 (193 ) 4,426 501 (28 ) 473 Comprehensive income 33,640 (632 ) 33,008 69,420 (4,901 ) 64,519 Comprehensive income attributable to Amkor 32,793 (632 ) 32,161 67,034 (4,901 ) 62,133 For the Three Months Ended March 31, 2016 As Reported Adjustments As Revised (In thousands) Foreign currency translation $ 19,864 $ (541 ) $ 19,323 Total other comprehensive income 19,888 (541 ) 19,347 Comprehensive income 19,483 (541 ) 18,942 Comprehensive income attributable to Amkor 19,013 (541 ) 18,472 The following table presents the effect of the aforementioned revisions on our Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2015 : For the Nine Months Ended September 30, 2015 As Reported Adjustments As Revised (In thousands) Net income $ 68,919 $ (4,873 ) $ 64,046 Other operating activities and non-cash items (14,752 ) 4,873 (9,879 )

Interim Financial Statements (P

Interim Financial Statements (Policies)	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The Consolidated Financial Statements and related disclosures as of September 30, 2016 , and for the three and nine months ended September 30, 2016 and 2015 , are unaudited, pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). The December 31, 2015 , Consolidated Balance Sheet data was derived from audited financial statements, but does not include all disclosures required by accounting principles generally accepted in the United States of America (“U.S.”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) have been condensed or omitted pursuant to such rules and regulations. In our opinion, these financial statements include all adjustments (consisting only of normal recurring adjustments) necessary for the fair statement of the results for the interim periods. These financial statements should be read in conjunction with the financial statements included in our Annual Report for the year ended December 31, 2015 , filed on Form 10-K with the SEC on February 22, 2016. The results of operations for the three and nine months ended September 30, 2016 , are not necessarily indicative of the results to be expected for the full year. Unless the context otherwise requires, all references to “Amkor,” “we,” “us,” “our” or the “company” are to Amkor Technology, Inc. and our subsidiaries. On December 30, 2015, we increased our ownership in J-Devices to 100% ( Note 3 ). As a result, our accounting for J-Devices changed from the equity method to the consolidation method effective December 30, 2015. The operating results of J-Devices were consolidated beginning in 2016.
Accounting Changes and Error Corrections [Text Block]	In the second quarter of 2016, we identified an error in the provision for income taxes in the financial statements for J-Devices for the periods beginning in 2012 through the fourth quarter of 2015. We believe that the error is not material to Amkor for the periods impacted and have elected to revise our previously issued consolidated financial statements. Periods presented herein are based on the revised financial results. See Note 17 for additional information. 17. Revision of Previously Reported Financial Information In the second quarter of 2016, during our post-acquisition integration of J-Devices, we identified an error in the provision for income taxes in the financial statements for J-Devices for the periods beginning in 2012 through the fourth quarter of 2015. During those periods we did not control J-Devices and, accordingly, we accounted for our investment in J-Devices using the equity method. As a result of the J-Devices error, our equity in earnings of J-Devices was overstated by the cumulative amount of $ 8.0 million . We believe that the error is not material to Amkor for the periods impacted and have elected to revise our previously issued consolidated financial statements. We have also recorded the impact of the revision in our purchase accounting for the acquisition of J-Devices on December 30, 2015 ( Note 3 ). Periods presented herein are based on the revised financial results. The following table presents the effect of the aforementioned revisions on our Consolidated Balance Sheet as of December 31, 2015 : December 31, 2015 As Reported Adjustments As Revised (In thousands) Goodwill $ 19,443 $ 3,966 $ 23,409 Total assets 4,022,462 3,966 4,026,428 Other non-current liabilities 101,679 11,563 113,242 Total liabilities 2,797,329 11,563 2,808,892 Accumulated deficit (460,150 ) (7,597 ) (467,747 ) Total Amkor stockholders’ equity 1,207,883 (7,597 ) 1,200,286 Total equity 1,225,133 (7,597 ) 1,217,536 Total liabilities and equity 4,022,462 3,966 4,026,428 The following table presents the effect of the aforementioned revisions on our Consolidated Statements of Income for the three and nine months ended September 30, 2015 : For the Three Months Ended For the Nine Months Ended As Reported Adjustments As Revised As Reported Adjustments As Revised (In thousands, except per share data) Equity in earnings of J-Devices $ 1,656 $ (439 ) $ 1,217 $ 15,460 $ (4,873 ) $ 10,587 Net income 29,021 (439 ) 28,582 68,919 (4,873 ) 64,046 Net income attributable to Amkor 28,174 (439 ) 27,735 66,533 (4,873 ) 61,660 Net income attributable to Amkor per common share: Basic $ 0.12 $ — $ 0.12 $ 0.28 $ (0.02 ) $ 0.26 Diluted 0.12 — 0.12 0.28 (0.02 ) 0.26 The following tables present the effect of the aforementioned revisions on our Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2015 , and the three months ended March 31, 2016: For the Three Months Ended For the Nine Months Ended As Reported Adjustments As Revised As Reported Adjustments As Revised (In thousands) Net income $ 29,021 $ (439 ) $ 28,582 $ 68,919 $ (4,873 ) $ 64,046 Equity interest in J-Devices' other comprehensive loss, net of tax 4,587 (193 ) 4,394 537 (28 ) 509 Total other comprehensive loss 4,619 (193 ) 4,426 501 (28 ) 473 Comprehensive income 33,640 (632 ) 33,008 69,420 (4,901 ) 64,519 Comprehensive income attributable to Amkor 32,793 (632 ) 32,161 67,034 (4,901 ) 62,133 For the Three Months Ended March 31, 2016 As Reported Adjustments As Revised (In thousands) Foreign currency translation $ 19,864 $ (541 ) $ 19,323 Total other comprehensive income 19,888 (541 ) 19,347 Comprehensive income 19,483 (541 ) 18,942 Comprehensive income attributable to Amkor 19,013 (541 ) 18,472 The following table presents the effect of the aforementioned revisions on our Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2015 : For the Nine Months Ended September 30, 2015 As Reported Adjustments As Revised (In thousands) Net income $ 68,919 $ (4,873 ) $ 64,046 Other operating activities and non-cash items (14,752 ) 4,873 (9,879 )
Use of Estimates	The Consolidated Financial Statements have been prepared in conformity with U.S. GAAP, using management’s best estimates and judgments where appropriate. These estimates and judgments affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. The estimates and judgments will also affect the reported amounts for certain revenues and expenses during the reporting period. Actual results could differ materially from these estimates and judgments.
Goodwill	The balance of goodwill in our Consolidated Balance Sheets reflects adjustments for foreign currency translation.

Income Taxes Income Taxes (Poli

Income Taxes Income Taxes (Policies)	9 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Tax, Policy [Policy Text Block]	we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax-planning strategies and results of recent operations.

Commitments and Contingencies C

Commitments and Contingencies Commitments and Contingencies (Policies)	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies, Policy [Policy Text Block]	In accordance with the accounting guidance for loss contingencies, including legal proceedings, lawsuits, pending claims and other legal matters, we accrue for a loss contingency when we conclude that the likelihood of a loss is probable and the amount of the loss can be reasonably estimated. We adjust our accruals from time to time as we receive additional information, but the loss we incur may be significantly greater than or less than the amount we have accrued. We disclose loss contingencies if we believe they are material and there is at least a reasonable possibility that a loss has been incurred. Attorney fees related to legal matters are expensed as incurred.

Acquisition Consideration trans

Acquisition Consideration transferred and assets obtained and liabilities assumed (Tables)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table presents the initial purchase price allocation and subsequent adjustments: Initial Allocation Adjustments Revised Allocation (In thousands) Fair value of consideration transferred: Cash $ 105,391 $ — $ 105,391 Fair value of our previously held equity interest in J-Devices 167,684 (7,597 ) 160,087 Total $ 273,075 $ (7,597 ) $ 265,478 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash $ 127,968 $ — $ 127,968 Accounts receivable 180,177 — 180,177 Inventory 42,502 — 42,502 Other current assets 2,363 — 2,363 Property, plant and equipment 230,319 — 230,319 Other assets 9,268 — 9,268 Short-term borrowings and current portion of long-term debt (36,770 ) — (36,770 ) Other current liabilities (251,405 ) — (251,405 ) Long-term debt (18,885 ) — (18,885 ) Pension obligations (22,250 ) — (22,250 ) Other non-current liabilities (9,655 ) (11,563 ) (21,218 ) Total identifiable net assets 253,632 (11,563 ) 242,069 Goodwill 19,443 3,966 23,409 Total $ 273,075 $ (7,597 ) $ 265,478

Share-Based Compensation Plans

Share-Based Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]	The following table summarizes our share-based compensation expense attributable to stock options and restricted shares: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Share-based compensation expense $ 824 $ 816 $ 2,449 $ 3,063
Summary of all common stock option activity	The following table summarizes our stock option activity for the nine months ended September 30, 2016 : Number of Shares (In thousands) Weighted Average Exercise Price Per Share Weighted Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (In thousands) Outstanding at December 31, 2015 3,727 $ 6.49 Granted 415 5.73 Exercised (533 ) 4.88 Forfeited or expired (274 ) 6.63 Outstanding at September 30, 2016 3,335 $ 6.65 6.06 $ 11,051 Fully vested at September 30, 2016 and expected to vest thereafter 3,304 $ 6.65 6.03 $ 10,938 Exercisable at September 30, 2016 2,337 $ 7.05 5.06 $ 7,020
Assumptions used in valuing the weighted average fair values of the options granted	The following assumptions were used to calculate the weighted average fair values of the options granted: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 Expected life (in years) 5.9 6.0 6.5 5.8 Risk-free interest rate 1.4 % 1.8 % 1.5 % 1.8 % Volatility 43 % 44 % 48 % 45 % Dividend yield — — — — Weighted average grant date fair value per option granted $ 3.78 $ 2.33 $ 2.78 $ 3.20
Restricted share activity	The following table summarizes our restricted share activity for the nine months ended September 30, 2016 : Number of Shares (In thousands) Weighted Average Grant-Date Fair Value (Per share) Non-vested at December 31, 2015 385 $ 4.78 Awards granted 50 5.66 Awards vested (226 ) 4.91 Awards forfeited (5 ) 4.43 Non-vested at September 30, 2016 204 $ 4.86

Other Income and Expense (Table

Other Income and Expense (Tables)	9 Months Ended
	Sep. 30, 2016
Other Income and Expenses [Abstract]
Schedule of Other Nonoperating Income (Expense) [Table Text Block]	Other income and expense consists of the following: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Interest income $ (334 ) $ (523 ) $ (1,033 ) $ (2,196 ) Foreign currency (gain) loss, net 7,124 (8,499 ) 11,506 (9,751 ) Loss on debt retirement — — — 9,560 Other (income) expense, net (133 ) (2,554 ) (866 ) (2,397 ) Total other (income) expense, net $ 6,657 $ (11,576 ) $ 9,607 $ (4,784 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	The following table summarizes the computation of basic and diluted EPS: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands, except per share data) Net income attributable to Amkor $ 60,089 $ 27,735 $ 63,927 $ 61,660 Income allocated to participating securities — — — (94 ) Net income available to Amkor common stockholders $ 60,089 $ 27,735 $ 63,927 $ 61,566 Weighted average shares outstanding — basic 237,353 236,888 237,157 236,813 Effect of dilutive securities: Stock options and restricted share awards 839 86 429 355 Weighted average shares outstanding — diluted 238,192 236,974 237,586 237,168 Net income attributable to Amkor per common share: Basic $ 0.25 $ 0.12 $ 0.27 $ 0.26 Diluted 0.25 0.12 0.27 0.26
Antidilutive effect of potential shares of common stock that were excluded from diluted earnings per share	The following table summarizes the potential shares of common stock that were excluded from diluted EPS, because the effect of including these potential shares was anti-dilutive: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Stock options and restricted share awards 1,284 3,477 2,020 1,861

Equity and Accumulated Other 31

Equity and Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Changes in equity attributable to both Company and noncontrolling interests	The following tables reflect the changes in equity attributable to both Amkor and the non-controlling interests: Attributable to Amkor Attributable to Non-controlling Interests Total (In thousands) Equity at December 31, 2015 $ 1,200,286 $ 17,250 $ 1,217,536 Net income 63,927 2,175 66,102 Other comprehensive income 52,232 — 52,232 Issuance of stock through employee share-based compensation plans 2,600 — 2,600 Treasury stock acquired through surrender of shares for tax withholding (446 ) — (446 ) Share-based compensation 2,449 — 2,449 Subsidiary dividends paid to non-controlling interests — (413 ) (413 ) Equity at September 30, 2016 $ 1,321,048 $ 19,012 $ 1,340,060 Attributable to Amkor Attributable to Non-controlling Interests Total (In thousands) Equity at December 31, 2014 $ 1,114,748 $ 14,701 $ 1,129,449 Net income 61,660 2,386 64,046 Other comprehensive income 473 — 473 Issuance of stock through employee share-based compensation plans 657 — 657 Treasury stock acquired through surrender of shares for tax withholding (548 ) — (548 ) Share-based compensation 3,063 — 3,063 Subsidiary dividends paid to non-controlling interest — (123 ) (123 ) Equity at September 30, 2015 $ 1,180,053 $ 16,964 $ 1,197,017
Schedule of Accumulated Other Comprehensive Income	The following tables reflect the changes in accumulated other comprehensive income (loss), net of tax: Defined Benefit Pension Foreign Currency Translation Total (In thousands) Accumulated other comprehensive loss at $ (1,425 ) $ (659 ) $ (2,084 ) Other comprehensive income before reclassifications — 52,161 52,161 Amounts reclassified from accumulated other comprehensive loss 71 — 71 Other comprehensive income 71 52,161 52,232 Accumulated other comprehensive income (loss) at $ (1,354 ) $ 51,502 $ 50,148 Defined Benefit Pension Foreign Currency Translation Equity Interest in J-Devices' Other Comprehensive Income (Loss) Total (In thousands) Accumulated other comprehensive loss at $ (2,525 ) $ (513 ) $ (29,433 ) $ (32,471 ) Other comprehensive loss before reclassifications — (102 ) 509 407 Amounts reclassified from accumulated other comprehensive loss 66 — — 66 Other comprehensive income (loss) 66 (102 ) 509 473 Accumulated other comprehensive loss at $ (2,459 ) $ (615 ) $ (28,924 ) $ (31,998 )

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories consist of the following: September 30, December 31, 2015 (In thousands) Raw materials and purchased components $ 176,833 $ 163,024 Work-in-process 95,756 75,181 Total inventories $ 272,589 $ 238,205

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Line Items]
Summary of Property, plant and equipment	Property, plant and equipment consist of the following: September 30, December 31, 2015 (In thousands) Land $ 245,828 $ 237,815 Land use rights 26,845 26,845 Buildings and improvements 1,069,448 1,010,201 Machinery and equipment 4,428,531 4,226,401 Software and computer equipment 207,965 197,266 Furniture, fixtures and other equipment 21,875 21,259 Construction in progress 404,507 352,607 Total property, plant and equipment 6,404,999 6,072,394 Less accumulated depreciation and amortization (3,785,530 ) (3,493,377 ) Total property, plant and equipment, net $ 2,619,469 $ 2,579,017 The following table summarizes our depreciation expense: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Depreciation expense $ 140,728 $ 122,812 $ 414,687 $ 370,663

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2016
Payables and Accruals [Abstract]
Summarized Accrued expenses	Accrued expenses consist of the following: September 30, December 31, (In thousands) Payroll and benefits $ 131,523 $ 95,011 Deferred revenue and customer advances 61,727 49,243 Accrued settlement costs 34,725 32,987 Income taxes payable 31,315 21,448 Accrued interest 28,114 12,920 Accrued severance plan obligations 16,893 14,306 Other accrued expenses 42,316 38,297 Total accrued expenses $ 346,613 $ 264,212

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Summary of Short term Borrowings And Long term Debt	Following is a summary of short-term borrowings and long-term debt: September 30, December 31, (In thousands) Debt of Amkor Technology, Inc.: Senior secured credit facilities: $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) $ 100,000 $ 100,000 Senior notes: 6.625% Senior notes, due June 2021, $75 million related party 400,000 400,000 6.375% Senior notes, due October 2022 524,971 525,000 Debt of subsidiaries: Amkor Technology Korea, Inc.: $100 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due June 2017 (2) — 40,000 Term loan, LIBOR plus 2.60%, due May 2018 120,000 120,000 Term loan, LIBOR plus 2.70%, due December 2019 70,000 70,000 Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020 150,000 150,000 Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020 80,000 80,000 Term loan, fund floating rate plus 1.60%, due June 2020 (3) 75,000 40,000 J-Devices Corporation: Short-term term loans, variable rate (4) 15,343 15,582 Short-term term loans, fixed rate at 0.50% — 5,808 Term loans, TIBOR plus 1.00%, due November 2016 494 2,800 Term loans, fixed rate at 0.53%, due April 2018 26,264 31,465 Amkor Technology Taiwan Ltd: Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (5) 20,000 10,000 1,582,072 1,590,655 Less: Unamortized premium and deferred debt costs, net (3,024 ) (3,616 ) Less: Short-term borrowings and current portion of long-term debt (30,834 ) (76,770 ) Long-term debt (including related party) $ 1,548,214 $ 1,510,269 (1) Our $200.0 million senior secured revolving credit facility has a letter of credit sub-limit of $25.0 million . Principal is payable at maturity. Interest is payable monthly in arrears, at LIBOR plus 1.25% to 1.75% ( 2.38% as of September 30, 2016 ). As of September 30, 2016 , the borrowing base of our revolving credit facility is $200.0 million , which is adjusted based on the amount of our eligible accounts receivable. Additionally, we had $ 0.5 million of standby letters of credit outstanding. As of September 30, 2016 , $99.5 million was available to be drawn. In October 2016, we repaid $40.0 million of the outstanding balance. (2) In June 2012, we entered into a $41.0 million revolving credit facility. In March 2016, we increased the facility to $100.0 million . In June 2016, we amended the maturity date to June 2017. Principal is payable at maturity. Interest is due monthly in arrears, at a foreign currency funding-linked base rate plus 1.60% ( 3.17% as of September 30, 2016 ). As of September 30, 2016 , $100.0 million was available to be drawn. (3) In May 2015, we entered into a term loan agreement pursuant to which we may borrow up to $150.0 million through November 2016 for capital expenditures. Principal is payable at maturity. Interest is payable quarterly in arrears, at a fund floating rate plus 1.60% ( 2.63% as of September 30, 2016 ). At September 30, 2016 , $75.0 million was available to be borrowed. (4) We entered into various short-term term loans which mature semi-annually. Interest is paid monthly, at TIBOR plus 0.30% to 0.38% (weighted average of 0.36% as of September 30, 2016 ). Principal is payable in monthly installments. As of September 30, 2016 , $2.5 million was available to be drawn. (5) In November 2015, we entered into a $39.0 million revolving credit facility. Principal is payable at maturity. Interest is due monthly, at TAIFX plus a bank determined spread ( 2.01% as of September 30, 2016 ). As of September 30, 2016 , $19.0 million was available to be drawn.

Pension and Severance Plans (Ta

Pension and Severance Plans (Tables)	9 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Components of net periodic pension cost	The components of net periodic pension cost for these defined benefit pension plans are as follows: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Service cost $ 9,024 $ 4,177 $ 25,684 $ 6,605 Interest cost 925 725 2,753 2,251 Expected return on plan assets (961 ) (817 ) (2,864 ) (2,523 ) Amortization of prior service cost 9 8 26 25 Recognized actuarial loss 24 23 71 69 Net periodic pension cost $ 9,021 $ 4,116 $ 25,670 $ 6,427
Defined Contribution Plan Disclosures [Table Text Block]	The following table summarizes our defined contribution expense: For the Three Months Ended For the Nine Months Ended 2016 2015 2016 2015 (In thousands) Defined contribution expense $ 1,939 $ 1,810 $ 7,106 $ 6,934

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Valuation of money market funds and restricted cash using quoted market prices in active markets for identical assets	Our recurring fair value measurements consist of the following: September 30, December 31, (In thousands) Cash equivalent money market funds (Level 1) $ 101,200 $ 81,473 Restricted cash money market funds (Level 1) 2,000 2,000
Financial instruments that are not recorded at fair value	The following table presents the fair value of financial instruments that are not recorded at fair value on a recurring basis: September 30, 2016 December 31, 2015 Fair Value Carrying Value Fair Value Carrying Value (In thousands) Senior notes (Level 1) $ 952,707 $ 921,947 $ 902,563 $ 921,384 Revolving credit facilities and term loans (Level 2) 651,908 657,101 664,085 665,655 Total debt $ 1,604,615 $ 1,579,048 $ 1,566,648 $ 1,587,039

Revision of Previously Report38

Revision of Previously Reported Financial Information (Tables)	9 Months Ended
	Sep. 30, 2016
Accounting Changes and Error Corrections [Abstract]
Schedule Prior Period Adjustments [Table Text Block]	The following table presents the effect of the aforementioned revisions on our Consolidated Balance Sheet as of December 31, 2015 : December 31, 2015 As Reported Adjustments As Revised (In thousands) Goodwill $ 19,443 $ 3,966 $ 23,409 Total assets 4,022,462 3,966 4,026,428 Other non-current liabilities 101,679 11,563 113,242 Total liabilities 2,797,329 11,563 2,808,892 Accumulated deficit (460,150 ) (7,597 ) (467,747 ) Total Amkor stockholders’ equity 1,207,883 (7,597 ) 1,200,286 Total equity 1,225,133 (7,597 ) 1,217,536 Total liabilities and equity 4,022,462 3,966 4,026,428 The following table presents the effect of the aforementioned revisions on our Consolidated Statements of Income for the three and nine months ended September 30, 2015 : For the Three Months Ended For the Nine Months Ended As Reported Adjustments As Revised As Reported Adjustments As Revised (In thousands, except per share data) Equity in earnings of J-Devices $ 1,656 $ (439 ) $ 1,217 $ 15,460 $ (4,873 ) $ 10,587 Net income 29,021 (439 ) 28,582 68,919 (4,873 ) 64,046 Net income attributable to Amkor 28,174 (439 ) 27,735 66,533 (4,873 ) 61,660 Net income attributable to Amkor per common share: Basic $ 0.12 $ — $ 0.12 $ 0.28 $ (0.02 ) $ 0.26 Diluted 0.12 — 0.12 0.28 (0.02 ) 0.26 The following tables present the effect of the aforementioned revisions on our Consolidated Statements of Comprehensive Income for the three and nine months ended September 30, 2015 , and the three months ended March 31, 2016: For the Three Months Ended For the Nine Months Ended As Reported Adjustments As Revised As Reported Adjustments As Revised (In thousands) Net income $ 29,021 $ (439 ) $ 28,582 $ 68,919 $ (4,873 ) $ 64,046 Equity interest in J-Devices' other comprehensive loss, net of tax 4,587 (193 ) 4,394 537 (28 ) 509 Total other comprehensive loss 4,619 (193 ) 4,426 501 (28 ) 473 Comprehensive income 33,640 (632 ) 33,008 69,420 (4,901 ) 64,519 Comprehensive income attributable to Amkor 32,793 (632 ) 32,161 67,034 (4,901 ) 62,133 For the Three Months Ended March 31, 2016 As Reported Adjustments As Revised (In thousands) Foreign currency translation $ 19,864 $ (541 ) $ 19,323 Total other comprehensive income 19,888 (541 ) 19,347 Comprehensive income 19,483 (541 ) 18,942 Comprehensive income attributable to Amkor 19,013 (541 ) 18,472 The following table presents the effect of the aforementioned revisions on our Condensed Consolidated Statement of Cash Flows for the nine months ended September 30, 2015 : For the Nine Months Ended September 30, 2015 As Reported Adjustments As Revised (In thousands) Net income $ 68,919 $ (4,873 ) $ 64,046 Other operating activities and non-cash items (14,752 ) 4,873 (9,879 )

New Accounting Standards New Ac

New Accounting Standards New Accounting Pronouncements or Change in Accounting Principle (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payments of Debt Extinguishment Costs	$ 0	$ 7,030
Adjustments for New Accounting Pronouncement [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred Finance Costs, Net			$ 8,800
Payments of Debt Extinguishment Costs		$ 7,000

Interim Financial Statements Re

Interim Financial Statements Revision of previously reported financial information (Details) $ in Millions	Dec. 31, 2015USD ($)
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cumulative Adjustment Equity in Earnings	$ 8

Interim Financial Statements Ac

Interim Financial Statements Acquisition of J-Devices (Details)	Dec. 30, 2015
J Devices [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage	100.00%

Acquisition of J-Devices Narrat

Acquisition of J-Devices Narrative (Details) - USD ($) $ in Thousands	Dec. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Jan. 30, 2015
Business Acquisition [Line Items]
Payments to acquire investment		$ 0	$ 12,908
Unrecognized Tax Benefits		$ 24,700		$ 23,300
J-Devices [Member]
Business Acquisition [Line Items]
Payments to acquire investment	$ 105,400
Ownership interest in acquiree (percent)	100.00%
J-Devices [Member]
Business Acquisition [Line Items]
Ownership Interest (percent)					65.70%
Adjustment [Member]
Business Acquisition [Line Items]
Unrecognized Tax Benefits	$ 11,600

Acquisition Consideration tra43

Acquisition Consideration transferred and assets obtained and liabilities assumed (Details) - USD ($) $ in Thousands	Dec. 30, 2015	Sep. 30, 2016	Dec. 31, 2015
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 27,908	$ 23,409
J Devices [Member]
Fair value of consideration transferred:
Cash	$ 105,391
Fair value of our previously held equity interest in J-Devices	160,087
Total	265,478
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	127,968
Accounts receivable	180,177
Inventory	42,502
Other current assets	2,363
Property, plant and equipment	230,319
Other assets	9,268
Short-term borrowings and current portion of long-term debt	(36,770)
Other current liabilities	(251,405)
Long-term debt	(18,885)
Pension obligations	(22,250)
Other non-current liabilities	(21,218)
Total identifiable net assets	242,069
Goodwill	23,409
Total	265,478
Previously Reported [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill			19,443
Previously Reported [Member] | J Devices [Member]
Fair value of consideration transferred:
Cash	105,391
Fair value of our previously held equity interest in J-Devices	167,684
Total	273,075
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	127,968
Accounts receivable	180,177
Inventory	42,502
Other current assets	2,363
Property, plant and equipment	230,319
Other assets	9,268
Short-term borrowings and current portion of long-term debt	(36,770)
Other current liabilities	(251,405)
Long-term debt	(18,885)
Pension obligations	(22,250)
Other non-current liabilities	(9,655)
Total identifiable net assets	253,632
Goodwill	19,443
Total	273,075
Adjustment [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill			$ 3,966
Adjustment [Member] | J Devices [Member]
Fair value of consideration transferred:
Cash	0
Fair value of our previously held equity interest in J-Devices	(7,597)
Total	(7,597)
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	0
Accounts receivable	0
Inventory	0
Other current assets	0
Property, plant and equipment	0
Other assets	0
Short-term borrowings and current portion of long-term debt	0
Other current liabilities	0
Long-term debt	0
Pension obligations	0
Other non-current liabilities	(11,563)
Total identifiable net assets	(11,563)
Goodwill	3,966
Total	$ (7,597)

Share-Based Compensation Plan44

Share-Based Compensation Plans Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated Share-based Compensation Expense	$ 824	$ 816	$ 2,449	$ 3,063

Share-Based Compensation Plan45

Share-Based Compensation Plans Stock Options (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares Outstanding beginning balance | shares	3,727
Number of shares granted | shares	415
Number of shares exercised | shares	(533)
Number of shares forfeited or expired | shares	(274)
Number of shares outstanding ending balance | shares	3,335
Number of shares fully vested and expected to vest | shares	3,304
Number of shares exercisable | shares	2,337
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 | $ / shares	$ 6.49
Weighted average exercise price per share granted | $ / shares	5.73
Weighted average exercise price per share exercised | $ / shares	4.88
Weighted average exercise price per share forfeited or expired | $ / shares	6.63
Weighted average exercise price per share outstanding ending balance | $ / shares	6.65
Weighted average exercise price per share fully vested and expected to vest | $ / shares	6.65
Weighted average exercise price per share exercisable | $ / shares	$ 7.05
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term outstanding (years)	6 years 22 days
Weighted average remaining contractual term fully vested and expected to vest (years)	6 years 11 days
Weighted average remaining contractual term exercisable (years)	5 years 22 days
Aggregate intrinsic value outstanding ending balance (in dollars) | $	$ 11,051
Aggregate intrinsic value fully vested and expected to vest (in dollars) | $	10,938
Aggregate intrinsic value exercisable (in dollars) | $	$ 7,020

Share-Based Compensation Plan46

Share-Based Compensation Plans Weighted Average Fair Value (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected life (in years)	5 years 10 months 24 days	6 years	6 years 6 months	5 years 9 months 18 days
Risk-free interest rate	1.40%	1.80%	1.50%	1.80%
Volatility	43.00%	44.00%	48.00%	45.00%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average grant date fair value per option granted	$ 3.78	$ 2.33	$ 2.78	$ 3.20

Share-Based Compensation Plan47

Share-Based Compensation Plans Restricted Shares (Details) - Restricted shares [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2016$ / sharesshares
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 | shares	385
Number of shares awards granted | shares	50
Number of shares awards vested | shares	(226)
Number of shares awards forfeited | shares	(5)
Number of shares nonvested ending balance | shares	204
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) | $ / shares	$ 4.78
Weighted average grant-date fair value awards granted (in dollars per share) | $ / shares	5.66
Weighted average grant-date fair value awards vested (in dollars per share) | $ / shares	4.91
Weighted average grant-date fair value awards forfeited (in dollars per share) | $ / shares	4.43
Weighted average grant-date fair value nonvested ending balance (in dollars per share) | $ / shares	$ 4.86

Share-Based Compensation Plan48

Share-Based Compensation Plans Textuals (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense from share-based compensation awards	$ 2.4
Weighted-average period of recognition of unrecognized compensation expense (in years)	2 years
Restricted shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense from share-based compensation awards	$ 0.7
Weighted-average period of recognition of unrecognized compensation expense (in years)	7 months 6 days

Other Income and Expense (Detai

Other Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other Income and Expenses [Abstract]
Interest income	$ (334)	$ (523)	$ (1,033)	$ (2,196)
Foreign currency (gain) loss, net	7,124	(8,499)	11,506	(9,751)
Loss on debt retirement	0	0	0	(9,560)
Other (income) expense, net	(133)	(2,554)	(866)	(2,397)
Total other (income) expense, net	$ 6,657	$ (11,576)	$ 9,607	$ (4,784)

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income tax expense	$ 24,086	$ 16,568	$ 29,319	$ 27,198

Income Taxes Unrecognized Tax B

Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits	$ 24.7	$ 23.3

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Dilutive Securities Adjustments [Line Items]
Net income attributable to Amkor	$ 60,089	$ 27,735	$ 63,927	$ 61,660
Income allocated to participating securities	0	0	0	(94)
Net income available to Amkor common stockholders	$ 60,089	$ 27,735	$ 63,927	$ 61,566
Adjustment for dilutive securities on net income:
Weighted average shares outstanding — basic	237,353	236,888	237,157	236,813
Effect of dilutive securities:
Stock options and restricted share awards	839	86	429	355
Weighted average shares outstanding — diluted	238,192	236,974	237,586	237,168
Net income attributable to Amkor per common share:
Basic (in dollars per share)	$ 0.25	$ 0.12	$ 0.27	$ 0.26
Diluted (in dollars per share)	$ 0.25	$ 0.12	$ 0.27	$ 0.26

Earnings Per Share Antidilutive

Earnings Per Share Antidilutive (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stock Options And Restricted Shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options and restricted share awards	1,284	3,477	2,020	1,861

Equity and Accumulated Other 54

Equity and Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, Beginning balance		$ 1,217,536		$ 1,217,536	$ 1,129,449
Net income	$ 61,141		$ 28,582	66,102	64,046
Other comprehensive income	5,907	19,347	4,426	52,232	473
Issuance of stock through employee share-based compensation plans				2,600	657
Treasury stock acquired through surrender of shares for tax withholding				(446)	(548)
Share-based compensation expense				2,449	3,063
Subsidiary dividends paid to non-controlling interests				(413)	(123)
Equity, Ending balance	1,340,060		1,197,017	1,340,060	1,197,017
Amkor [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, Beginning balance		1,200,286		1,200,286	1,114,748
Net income				63,927	61,660
Other comprehensive income				52,232	473
Issuance of stock through employee share-based compensation plans				2,600	657
Treasury stock acquired through surrender of shares for tax withholding				(446)	(548)
Share-based compensation expense				2,449	3,063
Subsidiary dividends paid to non-controlling interests				0	0
Equity, Ending balance	1,321,048		1,180,053	1,321,048	1,180,053
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Equity, Beginning balance		$ 17,250		17,250	14,701
Net income				2,175	2,386
Other comprehensive income				0	0
Issuance of stock through employee share-based compensation plans				0	0
Treasury stock acquired through surrender of shares for tax withholding				0	0
Share-based compensation expense				0	0
Subsidiary dividends paid to non-controlling interests				(413)	(123)
Equity, Ending balance	$ 19,012		$ 16,964	$ 19,012	$ 16,964

Equity and Accumulated Other 55

Equity and Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance		$ (2,084)		$ (2,084)	$ (32,471)
Other comprehensive income (loss) before reclassifications				52,161	407
Amounts reclassified from accumulated other comprehensive (loss) income				71	66
Total other comprehensive income (loss)	$ 5,907	19,347	$ 4,426	52,232	473
Accumulated other comprehensive (loss) income, ending balance	50,148		(31,998)	50,148	(31,998)
Defined Benefit Pension [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance		(1,425)		(1,425)	(2,525)
Other comprehensive income (loss) before reclassifications				0	0
Amounts reclassified from accumulated other comprehensive (loss) income				71	66
Total other comprehensive income (loss)				71	66
Accumulated other comprehensive (loss) income, ending balance	(1,354)		(2,459)	(1,354)	(2,459)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance		$ (659)		(659)	(513)
Other comprehensive income (loss) before reclassifications				52,161	(102)
Amounts reclassified from accumulated other comprehensive (loss) income				0	0
Total other comprehensive income (loss)				52,161	(102)
Accumulated other comprehensive (loss) income, ending balance	$ 51,502		(615)	$ 51,502	(615)
Equity Interest in J-Devices' Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive (loss) income, beginning balance					(29,433)
Other comprehensive income (loss) before reclassifications					509
Amounts reclassified from accumulated other comprehensive (loss) income					0
Total other comprehensive income (loss)					509
Accumulated other comprehensive (loss) income, ending balance			$ (28,924)		$ (28,924)

Factoring of Accounts Receiva56

Factoring of Accounts Receivable (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Total Factored [Member]
Factoring of Accounts Receivable [Line Items]
Accounts Receivable Sold without Recourse	$ 161.6	$ 82.4	$ 431.8	$ 235.3
Factoring Fees [Member]
Factoring of Accounts Receivable [Line Items]
Accounts Receivable Sold without Recourse	$ 0.8	$ 0.3	$ 1.7	$ 1.1

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Inventories
Raw materials and purchased components	$ 176,833	$ 163,024
Work-in-process	95,756	75,181
Total inventories	$ 272,589	$ 238,205

Property, Plant and Equipment58

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 6,404,999	$ 6,072,394
Less accumulated depreciation and amortization	(3,785,530)	(3,493,377)
Total property, plant and equipment, net	2,619,469	2,579,017
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	245,828	237,815
Land use rights
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	26,845	26,845
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,069,448	1,010,201
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	4,428,531	4,226,401
Software and computer equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	207,965	197,266
Furniture, fixtures and other equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	21,875	21,259
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 404,507	$ 352,607

Property, Plant and Equipment59

Property, Plant and Equipment (Narrative) (Details) $ in Thousands, ₩ in Billions	1 Months Ended			3 Months Ended			9 Months Ended
	Nov. 30, 2016	Oct. 31, 2016USD ($)	Oct. 31, 2016KRW (₩)	Jun. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Line Items]
Depreciation					$ 140,728	$ 122,812	$ 414,687	$ 370,663
Property, Plant and Equipment, Gross					6,404,999		6,404,999		$ 6,072,394
Proceeds from Sale of Property, Plant, and Equipment							13,687	$ 5,212
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross					404,507		404,507		352,607
Construction in Progress [Member] | K5 Facility [Member] | KOREA, REPUBLIC OF
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross					365,800		365,800		312,100
Accumulated Capitalized Interest Costs					$ 23,000		$ 23,000		$ 18,700
Subsequent Event [Member] | KOREA, REPUBLIC OF
Property, Plant and Equipment [Line Items]
Proceeds from Sale of Property, Plant, and Equipment		$ 142,000	₩ 162.1
Percentage of Proceeds Received	10.00%
Gain (Loss) on Disposition of Property Plant Equipment				$ 100,000

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Payroll and benefits	$ 131,523	$ 95,011
Deferred revenue and customer advances	61,727	49,243
Accrued settlement costs	34,725	32,987
Income taxes payable	31,315	21,448
Accrued interest	28,114	12,920
Accrued severance plan obligations	16,893	14,306
Other accrued expenses	42,316	38,297
Total accrued expenses	$ 346,613	$ 264,212

Debt Long Term Debt (Details)

Debt Long Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	$ 1,582,072	$ 1,590,655
Less: Unamortized premium and deferred debt costs, net	(3,024)	(3,616)
Less: Short-term borrowings and current portion of long-term debt	(30,834)	(76,770)
Long-term debt (including related party)	1,548,214	1,510,269
$200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	100,000	100,000
6.625% Senior notes, due June 2021, $75 million related party | Senior notes (Level 1)
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	400,000	400,000
6.375% Senior notes, due October 2022 | Senior notes (Level 1)
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	524,971	525,000
KOREA, REPUBLIC OF | $100 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due June 2017 (2) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	0	40,000
KOREA, REPUBLIC OF | Term loan, LIBOR plus 2.60%, due May 2018 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	120,000	120,000
KOREA, REPUBLIC OF | Term loan, LIBOR plus 2.70%, due December 2019 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	70,000	70,000
KOREA, REPUBLIC OF | Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	150,000	150,000
KOREA, REPUBLIC OF | Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	80,000	80,000
KOREA, REPUBLIC OF | Term loan, fund floating rate plus 1.60%, due June 2020 (3) | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	75,000	40,000
JAPAN | Short-term term loans, variable rate (4) | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	15,343	15,582
JAPAN | Short-term term loans, fixed rate at 0.50% | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	0	5,808
JAPAN | Term loans, TIBOR plus 1.00%, due November 2016 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	494	2,800
JAPAN | Term loans, fixed rate at 0.53%, due April 2018 | Subsidiary Term Loans [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	26,264	31,465
TAIWAN, PROVINCE OF CHINA | Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (5) | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Long-term Debt Including Related Party, Gross	$ 20,000	$ 10,000

Debt (Details)

Debt (Details) - USD ($)	1 Months Ended	9 Months Ended
	Oct. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Nov. 30, 2015	May 31, 2015	Jun. 30, 2012
Debt Instrument [Line Items]
Repayments of Lines of Credit		$ 155,000,000	$ 100,000,000
Long-term Debt Including Related Party, Gross		$ 1,582,072,000		$ 1,590,655,000
Subsidiary Term Loans [Member] | KOREA, REPUBLIC OF | Term loan, LIBOR plus 2.60%, due May 2018
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.60%
Debt, interest rate description		LIBOR plus 2.60%
Long-term Debt Including Related Party, Gross		$ 120,000,000		120,000,000
Subsidiary Term Loans [Member] | KOREA, REPUBLIC OF | Term loan, LIBOR plus 2.70%, due December 2019
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.70%
Debt, interest rate description		LIBOR plus 2.70%
Long-term Debt Including Related Party, Gross		$ 70,000,000		70,000,000
Subsidiary Term Loans [Member] | KOREA, REPUBLIC OF | Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.35%
Debt, interest rate description		foreign currency funding-linked base rate plus 1.35%
Long-term Debt Including Related Party, Gross		$ 150,000,000		150,000,000
Subsidiary Term Loans [Member] | KOREA, REPUBLIC OF | Term loan, foreign currency funding-linked base rate plus 1.35%, due May 2020
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.35%
Debt, interest rate description		foreign currency funding-linked base rate plus 1.35%
Long-term Debt Including Related Party, Gross		$ 80,000,000		80,000,000
Subsidiary Term Loans [Member] | KOREA, REPUBLIC OF | Term loan, fund floating rate plus 1.60%, due June 2020 (3)
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.60%
Debt, interest rate description		fund floating rate plus 1.60%
Total effective rate (percentage)		2.63%
Debt Instrument, Unused Borrowing Capacity, Amount		$ 75,000,000				$ 150,000,000
Long-term Debt Including Related Party, Gross		$ 75,000,000		40,000,000
Subsidiary Term Loans [Member] | JAPAN | Short-term term loans, variable rate (4)
Debt Instrument [Line Items]
Total effective rate (percentage)		0.36%
Debt Instrument, Unused Borrowing Capacity, Amount		$ 2,500,000
Long-term Debt Including Related Party, Gross		$ 15,343,000		15,582,000
Subsidiary Term Loans [Member] | JAPAN | Short-term term loans, fixed rate at 0.50%
Debt Instrument [Line Items]
Stated interest rate		0.50%
Long-term Debt Including Related Party, Gross		$ 0		5,808,000
Subsidiary Term Loans [Member] | JAPAN | Term loans, TIBOR plus 1.00%, due November 2016
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.00%
Debt, interest rate description		TIBOR plus 1.00%
Long-term Debt Including Related Party, Gross		$ 494,000		2,800,000
Subsidiary Term Loans [Member] | JAPAN | Term loans, fixed rate at 0.53%, due April 2018
Debt Instrument [Line Items]
Stated interest rate		0.53%
Long-term Debt Including Related Party, Gross		$ 26,264,000		31,465,000
Senior notes (Level 1) | 6.625% Senior notes, due June 2021, $75 million related party
Debt Instrument [Line Items]
Stated interest rate		6.625%
Debt Instrument Face Amount Related Party		$ 75,000,000
Long-term Debt Including Related Party, Gross		$ 400,000,000		400,000,000
Senior notes (Level 1) | 6.375% Senior notes, due October 2022
Debt Instrument [Line Items]
Stated interest rate		6.375%
Long-term Debt Including Related Party, Gross		$ 524,971,000		525,000,000
Revolving Credit Facility [Member] | Line of Credit [Member] | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1)
Debt Instrument [Line Items]
Credit facility, borrowing capacity		$ 200,000,000
Debt, interest rate description		LIBOR plus 1.25%-1.75%
Total effective rate (percentage)		2.375%
Line of Credit Facility, Remaining Borrowing Capacity		$ 99,500,000
Long-term Debt Including Related Party, Gross		100,000,000		100,000,000
Current borrowing capacity		200,000,000
Revolving Credit Facility [Member] | Line of Credit [Member] | KOREA, REPUBLIC OF | $100 million revolving credit facility, foreign currency funding-linked base rate plus 1.60%, due June 2017 (2)
Debt Instrument [Line Items]
Credit facility, borrowing capacity		$ 100,000,000					$ 41,000,000
Debt Instrument, Basis Spread on Variable Rate		1.60%
Debt, interest rate description		foreign currency funding-linked base rate plus 1.60%
Total effective rate (percentage)		3.17%
Line of Credit Facility, Remaining Borrowing Capacity		$ 100,000,000
Long-term Debt Including Related Party, Gross		$ 0		40,000,000
Revolving Credit Facility [Member] | Line of Credit [Member] | TAIWAN, PROVINCE OF CHINA | Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (5)
Debt Instrument [Line Items]
Credit facility, borrowing capacity					$ 39,000,000
Debt, interest rate description		TAIFX plus a bank-determined spread
Total effective rate (percentage)		2.01%
Line of Credit Facility, Remaining Borrowing Capacity		$ 19,000,000
Long-term Debt Including Related Party, Gross		20,000,000		$ 10,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount		500,000
Letter of Credit [Member] | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1)
Debt Instrument [Line Items]
Credit facility, borrowing capacity		$ 25,000,000
Maximum [Member] | Subsidiary Term Loans [Member] | JAPAN | Short-term term loans, variable rate (4)
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.38%
Maximum [Member] | Revolving Credit Facility [Member] | Line of Credit [Member] | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1)
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.75%
Minimum [Member] | Subsidiary Term Loans [Member] | JAPAN | Short-term term loans, variable rate (4)
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		0.30%
Minimum [Member] | Revolving Credit Facility [Member] | Line of Credit [Member] | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1)
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.25%
Subsequent Event [Member] | Revolving Credit Facility [Member] | Line of Credit [Member] | $200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1)
Debt Instrument [Line Items]
Repayments of Lines of Credit	$ 40,000,000

Pension and Severance Plans (De

Pension and Severance Plans (Details) - Foreign Pension Plans [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9,024	$ 4,177	$ 25,684	$ 6,605
Interest cost	925	725	2,753	2,251
Expected return on plan assets	(961)	(817)	(2,864)	(2,523)
Amortization of prior service cost	9	8	26	25
Recognized actuarial loss	24	23	71	69
Net periodic pension cost	$ 9,021	$ 4,116	$ 25,670	$ 6,427

Pension and Severance Plans Tex

Pension and Severance Plans Textuals (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 1,939	$ 1,810	$ 7,106	$ 6,934
Provision of Severance Benefits	$ 6,100	$ 5,900	$ 7,000	$ 20,700

Fair Value Measurements Fair Va

Fair Value Measurements Fair Value Measurements (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 1 [Member] - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalent money market funds (Level 1)	$ 101,200	$ 81,473
Restricted cash money market funds (Level 1)	$ 2,000	$ 2,000

Fair Value Measurements Fair 66

Fair Value Measurements Fair Value of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Debt	$ 1,604,615	$ 1,566,648
Senior notes (Level 1) | Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Debt	952,707	902,563
Revolving credit facilities and term loans (Level 2) | Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Debt	651,908	664,085
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Debt	1,579,048	1,587,039
Carrying Value [Member] | Senior notes (Level 1)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Debt	921,947	921,384
Carrying Value [Member] | Revolving credit facilities and term loans (Level 2)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Debt	$ 657,101	$ 665,655

Commitments and Contingencies (

Commitments and Contingencies (Details)	Sep. 30, 2016USD ($)
Letter of Credit [Member]
Loss Contingencies [Line Items]
Available letter of credit subfacility utilized	$ 500,000
$200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) | Letter of Credit [Member]
Loss Contingencies [Line Items]
Credit facility, borrowing capacity	25,000,000
$200 million revolving credit facility, LIBOR plus 1.25%-1.75%, due December 2019 (1) | Line of Credit [Member] | Revolving Credit Facility [Member]
Loss Contingencies [Line Items]
Credit facility, borrowing capacity	$ 200,000,000

Revision of Previously Report68

Revision of Previously Reported Financial Information Narrative (Details) $ in Millions	Dec. 31, 2015USD ($)
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cumulative Adjustment Equity in Earnings	$ 8

Revision of Previously Report69

Revision of Previously Reported Financial Information Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Goodwill	$ 27,908	$ 23,409
Total assets	4,241,114	4,026,428
Other non-current liabilities	86,265	113,242
Total liabilities	2,901,054	2,808,892
Accumulated deficit	(403,820)	(467,747)
Total Amkor stockholders’ equity	1,321,048	1,200,286
Total equity	1,340,060	1,217,536	$ 1,197,017	$ 1,129,449
Total liabilities and equity	$ 4,241,114	4,026,428
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Goodwill		19,443
Total assets		4,022,462
Other non-current liabilities		101,679
Total liabilities		2,797,329
Accumulated deficit		(460,150)
Total Amkor stockholders’ equity		1,207,883
Total equity		1,225,133
Total liabilities and equity		4,022,462
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Goodwill		3,966
Total assets		3,966
Other non-current liabilities		11,563
Total liabilities		11,563
Accumulated deficit		(7,597)
Total Amkor stockholders’ equity		(7,597)
Total equity		(7,597)
Total liabilities and equity		$ 3,966

Revision of Previously Report70

Revision of Previously Reported Financial Information Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Equity in earnings of J-Devices	$ 0	$ 1,217	$ 0	$ 10,587
Net income	61,141	28,582	66,102	64,046
Net income attributable to Amkor	$ 60,089	$ 27,735	$ 63,927	$ 61,660
Basic (in dollars per share)	$ 0.25	$ 0.12	$ 0.27	$ 0.26
Diluted (in dollars per share)	$ 0.25	$ 0.12	$ 0.27	$ 0.26
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Equity in earnings of J-Devices		$ 1,656		$ 15,460
Net income		29,021		68,919
Net income attributable to Amkor		$ 28,174		$ 66,533
Basic (in dollars per share)		$ 0.12		$ 0.28
Diluted (in dollars per share)		$ 0.12		$ 0.28
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Equity in earnings of J-Devices		$ (439)		$ (4,873)
Net income		(439)		(4,873)
Net income attributable to Amkor		$ (439)		$ (4,873)
Basic (in dollars per share)		$ 0		$ (0.02)
Diluted (in dollars per share)		$ 0		$ (0.02)

Revision of Previously Report71

Revision of Previously Reported Financial Information Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	$ 61,141		$ 28,582	$ 66,102	$ 64,046
Equity interest in J-Devices' other comprehensive income, net of tax	0		4,394	0	509
Foreign currency translation	5,883	$ 19,323	10	52,161	(102)
Total other comprehensive loss	5,907	19,347	4,426	52,232	473
Comprehensive income	67,048	18,942	33,008	118,334	64,519
Comprehensive income attributable to Amkor	$ 65,996	18,472	32,161	$ 116,159	62,133
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income			29,021		68,919
Equity interest in J-Devices' other comprehensive income, net of tax			4,587		537
Foreign currency translation		19,864
Total other comprehensive loss		19,888	4,619		501
Comprehensive income		19,483	33,640		69,420
Comprehensive income attributable to Amkor		19,013	32,793		67,034
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income			(439)		(4,873)
Equity interest in J-Devices' other comprehensive income, net of tax			(193)		(28)
Foreign currency translation		(541)
Total other comprehensive loss		(541)	(193)		(28)
Comprehensive income		(541)	(632)		(4,901)
Comprehensive income attributable to Amkor		$ (541)	$ (632)		$ (4,901)

Revision of Previously Report72

Revision of Previously Reported Financial Information Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income	$ 61,141	$ 28,582	$ 66,102	$ 64,046
Other operating activities and non-cash items			$ (4,382)	(9,879)
Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income		29,021		68,919
Other operating activities and non-cash items				(14,752)
Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net income		$ (439)		(4,873)
Other operating activities and non-cash items				$ 4,873