Amkor Technology (AMKR) 10-Q 1 Aug 19 2019 Q2 Quarterly report Financial data

Cover

Cover - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Cover page.
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Common Stock, $0.001 par value
Entity Address, Address Line One	2045 East Innovation Circle
Entity File Number	000-29472
Document Quarterly Report	true
Document Transition Report	false
Entity Registrant Name	AMKOR TECHNOLOGY, INC.
Entity Central Index Key	0001047127
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		239,704,033
Entity Address, City or Town	Tempe
Entity Address, State or Province	AZ
Entity Address, Postal Zip Code	85284
City Area Code	480
Local Phone Number	821-5000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Trading Symbol	AMKR
Security Exchange Name	NASDAQ
Entity Shell Company	false
Entity Tax Identification Number	23-1722724

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement [Abstract]
Net sales	$ 895,305	$ 1,065,684	$ 1,790,269	$ 2,091,003
Cost of sales	771,851	895,967	1,546,054	1,763,515
Gross profit	123,454	169,717	244,215	327,488
Selling, general and administrative	64,758	74,700	136,345	155,423
Research and development	36,186	41,076	71,940	82,005
Total operating expenses	100,944	115,776	208,285	237,428
Operating income	22,510	53,941	35,930	90,060
Interest expense	18,653	21,127	37,926	41,138
Other (income) expense, net	6,966	(11,001)	2,401	(7,569)
Total other expense, net	25,619	10,126	40,327	33,569
Income (loss) before taxes	(3,109)	43,815	(4,397)	56,491
Income tax expense	5,897	10,631	27,277	13,112
Net income (loss)	(9,006)	33,184	(31,674)	43,379
Net income attributable to non-controlling interests	(444)	(593)	(655)	(1,244)
Net income (loss) attributable to Amkor	$ (9,450)	$ 32,591	$ (32,329)	$ 42,135
Net income (loss) attributable to Amkor per common share:
Basic (in dollars per share)	$ (0.04)	$ 0.14	$ (0.14)	$ 0.18
Diluted (in dollars per share)	$ (0.04)	$ 0.14	$ (0.14)	$ 0.18
Shares used in computing per common share amounts:
Basic (in shares)	239,508	239,351	239,461	239,283
Diluted (in shares)	239,508	239,804	239,461	239,805

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (9,006)	$ 33,184	$ (31,674)	$ 43,379
Other comprehensive income (loss), net of tax:
Adjustments to unrealized components of defined benefit pension plans	(57)	(42)	(189)	(81)
Foreign currency translation	5,918	(11,144)	3,694	3,947
Total other comprehensive income (loss)	5,861	(11,186)	3,505	3,866
Comprehensive income (loss)	(3,145)	21,998	(28,169)	47,245
Comprehensive income attributable to non-controlling interests	(444)	(593)	(655)	(1,244)
Comprehensive income (loss) attributable to Amkor	$ (3,589)	$ 21,405	$ (28,824)	$ 46,001

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 551,438	$ 681,569
Restricted cash	2,590	2,589
Accounts receivable, net of allowances	702,466	724,456
Inventories	217,638	230,589
Other current assets	38,988	32,005
Total current assets	1,513,120	1,671,208
Property, plant and equipment, net	2,515,533	2,650,448
Operating lease right of use asset	132,763	0
Goodwill	26,159	25,720
Restricted cash	2,878	3,893
Other assets	118,831	144,178
Total assets	4,309,284	4,495,447
Current liabilities:
Short-term borrowings and current portion of long-term debt	198,230	114,579
Trade accounts payable	459,548	530,398
Capital expenditures payable	134,500	255,237
Accrued expenses	246,615	258,209
Total current liabilities	1,038,893	1,158,423
Long-term debt	1,109,945	1,217,732
Pension and severance obligations	174,897	184,321
Long-term operating lease liability	80,049	0
Other non-current liabilities	74,324	79,071
Total liabilities	2,478,108	2,639,547
Commitments and contingencies (Note 15)
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; 285,510 and 285,352 shares issued; and 239,532 and 239,385 shares outstanding in 2019 and 2018, respectively	285	285
Additional paid-in capital	1,913,103	1,909,425
Retained earnings	80,860	113,189
Accumulated other comprehensive income (loss)	27,317	23,812
Treasury stock, at cost, 45,978 and 45,967 shares, in 2019 and 2018, respectively	(216,254)	(216,171)
Total Amkor stockholders’ equity	1,805,311	1,830,540
Non-controlling interests in subsidiaries	25,865	25,360
Total equity	1,831,176	1,855,900
Total liabilities and equity	$ 4,309,284	$ 4,495,447

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Stockholders’ equity:
Preferred stock designated Series A, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock designated Series A, shares authorized	10,000,000	10,000,000
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	500,000,000	500,000,000
Common stock, shares issued	285,510,000	285,352,000
Common stock, shares outstanding	239,532,000	239,385,000
Treasury stock, shares	45,978,000	45,967,000

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Total Amkor Stockholders' Equity	Common Stock	Additional Paid- In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Noncontrolling Interest in Subsidiaries
Balance at beginning of period, shares at Dec. 31, 2017			285,129
Balance at beginning of period, shares at Dec. 31, 2017							(45,945)
Balance at beginning of period at Dec. 31, 2017	$ 1,719,709	$ 1,696,276	$ 285	$ 1,903,357	$ (13,903)	$ 22,519	$ (215,982)	$ 23,433
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	43,379	42,135			42,135			1,244
Other comprehensive income (loss)	3,866	3,866				3,866
Treasury stock acquired through surrender of shares for tax withholding, shares							(11)
Treasury stock acquired through surrender of shares for tax withholding	(105)	(105)					$ (105)
Issuance of stock through share-based compensation plans, shares			193
Issuance of stock through share-based compensation plans	1,023	1,023		1,023
Share-based compensation	2,556	2,556		2,556
Subsidiary dividends to noncontrolling interests	(270)							(270)
Balance at end of period, shares at Jun. 30, 2018			285,322
Balance at end of period, shares at Jun. 30, 2018							(45,956)
Balance at end of period at Jun. 30, 2018	1,770,158	1,745,751	$ 285	1,906,936	28,232	26,385	$ (216,087)	24,407
Balance at beginning of period, shares at Mar. 31, 2018			285,284
Balance at beginning of period, shares at Mar. 31, 2018							(45,950)
Balance at beginning of period at Mar. 31, 2018	1,747,074	1,723,125	$ 285	1,905,666	(4,359)	37,571	$ (216,038)	23,949
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	33,184	32,591			32,591			593
Other comprehensive income (loss)	(11,186)	(11,186)				(11,186)
Treasury stock acquired through surrender of shares for tax withholding, shares							(6)
Treasury stock acquired through surrender of shares for tax withholding	(49)	(49)					$ (49)
Issuance of stock through share-based compensation plans, shares			38
Issuance of stock through share-based compensation plans	1	1		1
Share-based compensation	1,269	1,269		1,269
Subsidiary dividends to noncontrolling interests	(135)							(135)
Balance at end of period, shares at Jun. 30, 2018			285,322
Balance at end of period, shares at Jun. 30, 2018							(45,956)
Balance at end of period at Jun. 30, 2018	$ 1,770,158	1,745,751	$ 285	1,906,936	28,232	26,385	$ (216,087)	24,407
Balance at beginning of period, shares at Dec. 31, 2018	285,352		285,352
Balance at beginning of period, shares at Dec. 31, 2018	(45,967)						(45,967)
Balance at beginning of period at Dec. 31, 2018	$ 1,855,900	1,830,540	$ 285	1,909,425	113,189	23,812	$ (216,171)	25,360
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(31,674)	(32,329)			(32,329)			655
Other comprehensive income (loss)	3,505	3,505				3,505
Treasury stock acquired through surrender of shares for tax withholding, shares							(11)
Treasury stock acquired through surrender of shares for tax withholding	(83)	(83)					$ (83)
Issuance of stock through share-based compensation plans, shares			158
Issuance of stock through share-based compensation plans	436	436	$ 0	436
Share-based compensation	3,242	3,242		3,242
Subsidiary dividends to noncontrolling interests	$ (150)							(150)
Balance at end of period, shares at Jun. 30, 2019	285,510		285,510
Balance at end of period, shares at Jun. 30, 2019	(45,978)						(45,978)
Balance at end of period at Jun. 30, 2019	$ 1,831,176	1,805,311	$ 285	1,913,103	80,860	27,317	$ (216,254)	25,865
Balance at beginning of period, shares at Mar. 31, 2019			285,430
Balance at beginning of period, shares at Mar. 31, 2019							(45,972)
Balance at beginning of period at Mar. 31, 2019	1,832,582	1,807,011	$ 285	1,911,179	90,310	21,456	$ (216,219)	25,571
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(9,006)	(9,450)			(9,450)			444
Other comprehensive income (loss)	5,861	5,861				5,861
Treasury stock acquired through surrender of shares for tax withholding, shares							(6)
Treasury stock acquired through surrender of shares for tax withholding	(35)	(35)					$ (35)
Issuance of stock through share-based compensation plans, shares			80
Issuance of stock through share-based compensation plans	150	150		150
Share-based compensation	1,774	1,774		1,774
Subsidiary dividends to noncontrolling interests	$ (150)							(150)
Balance at end of period, shares at Jun. 30, 2019	285,510		285,510
Balance at end of period, shares at Jun. 30, 2019	(45,978)						(45,978)
Balance at end of period at Jun. 30, 2019	$ 1,831,176	$ 1,805,311	$ 285	$ 1,913,103	$ 80,860	$ 27,317	$ (216,254)	$ 25,865

Condensed Consolidated Statemen

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income (loss)	$ (31,674)	$ 43,379
Depreciation and amortization	268,819	285,515
Other operating activities and non-cash items	33,112	(3,239)
Changes in assets and liabilities	(101,329)	(119,276)
Net cash provided by operating activities	168,928	206,379
Cash flows from investing activities:
Payments for property, plant and equipment	(273,672)	(389,568)
Proceeds from sale of property, plant and equipment	8,247	603
Proceeds from insurance recovery for property, plant and equipment	1,538	0
Other investing activities	2,864	2,647
Net cash used in investing activities	(261,023)	(386,318)
Cash flows from financing activities:
Proceeds from revolving credit facilities	85,000	0
Payments of revolving credit facilities	(5,000)	0
Proceeds from short-term debt	29,781	7,264
Payments of short-term debt	(25,548)	(31,546)
Proceeds from issuance of long-term debt	614,375	64,000
Payments of long-term debt	(732,178)	(77,015)
Payments of finance lease obligations	(2,746)	(1,689)
Other financing activities	(3,865)	492
Net cash used in financing activities	(40,181)	(38,494)
Effect of exchange rate fluctuations on cash, cash equivalents and restricted cash	1,131	1,347
Net decrease in cash, cash equivalents and restricted cash	(131,145)	(217,086)
Cash, cash equivalents and restricted cash, beginning of period	688,051	602,851
Cash, cash equivalents and restricted cash, end of period	556,906	385,765
Non-cash investing and financing activities:
Property, plant and equipment included in capital expenditures payable	135,126	239,460
Right of use assets acquired through finance lease liabilities	2,304	6,477
Right of use assets acquired through operating lease liabilities	$ 21,238	$ 0

Interim Financial Statements

Interim Financial Statements	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interim Financial Statements	Interim Financial Statements Basis of Presentation. The Consolidated Financial Statements and related disclosures as of June 30, 2019 , and for the three and six months ended June 30, 2019 and 2018 , are unaudited, pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). The December 31, 2018 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, 2018 , filed on Form 10-K with the SEC on February 22, 2019. The results of operations for the three and six months ended June 30, 2019 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. 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. Unbilled Receivables . Total unbilled receivables as of June 30, 2019 and December 31, 2018 were $88.7 million and $89.3 million , respectively.

New Accounting Standards

New Accounting Standards	6 Months Ended
	Jun. 30, 2019
Accounting Changes and Error Corrections [Abstract]
New Accounting Standards	New Accounting Standards Recently Adopted Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , which was subsequently amended and clarified. Topic 842 requires a dual approach for lease accounting under which a lessee would account for leases as finance leases or operating leases. The standard also requires the lessee to recognize a right-of-use asset and a corresponding lease liability for both finance leases and operating leases. For finance leases, the lessee recognizes interest expense and amortization of the right-of-use asset, and for operating leases, the lessee recognizes a straight-line lease expense. The standard permits the use of two alternative transition approaches, either with application in all comparative periods presented, or with application beginning with the effective date without restating comparative period financial statements. Effective January 1, 2019, we adopted the requirements of Topic 842 using the modified transition approach without restating the comparative period financial statements. The new standard resulted in increases in our operating lease right of use asset, accrued expenses and long-term operating lease liability account balances to record our operating leases on our Consolidated Balance Sheet. The new standard also resulted in additional disclosures for our operating and finance leases ( Note 10 ). In accordance with Topic 842, we applied practical expedients permitted under the transition guidance, which allowed us to not: • Reassess whether any existing contracts are or contain a lease, • Reassess the lease classification for any existing contracts, • Reassess initial direct costs for any existing leases, and • Separate non-lease components from lease components and instead to account for them as a single lease component for all asset classes.

Net Sales by Product Group and

Net Sales by Product Group and End Market	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Net Sales by Product Group and End Market	Net Sales by Product Group and End Market Net sales by product group consist of the following: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) (In thousands) Advanced products (1) $ 432,639 $ 496,241 $ 855,084 $ 971,993 Mainstream products (2) 462,666 569,443 935,185 1,119,010 Total net sales $ 895,305 $ 1,065,684 $ 1,790,269 $ 2,091,003 (1) Advanced products include flip chip and wafer-level processing and related test services. (2) Mainstream products include wirebond packaging and related test services. Net sales by end market consist of the following : For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Communications (handheld devices, smartphones, tablets) 37 % 42 % 38 % 42 % Automotive, industrial and other (driver assist, infotainment, performance, safety) 29 % 26 % 29 % 26 % Computing (datacenter, infrastructure, PC/laptop, storage) 19 % 19 % 19 % 19 % Consumer (connected home, set-top boxes, televisions, visual imaging, wearables) 15 % 13 % 14 % 13 % Total net sales 100 % 100 % 100 % 100 %

Other Income and Expense

Other Income and Expense	6 Months Ended
	Jun. 30, 2019
Other Income and Expenses [Abstract]
Other Income and Expense	Other Income and Expense Other income and expense consists of the following: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Interest income $ (1,598 ) $ (955 ) $ (3,662 ) $ (1,943 ) Foreign currency (gain) loss, net 606 (7,110 ) (1,407 ) (2,397 ) Loss on debt retirement 8,356 18 8,356 18 Other (398 ) (2,954 ) (886 ) (3,247 ) Other (income) expense, net $ 6,966 $ (11,001 ) $ 2,401 $ (7,569 )

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income tax expense of $27.3 million for the six months ended June 30, 2019 reflects income taxes, foreign withholding taxes and minimum taxes. Income tax expense for the six months ended June 30, 2019 also includes a $14.9 million non-cash discrete tax expense primarily for the recognition of a valuation allowance for certain deferred tax assets. 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. Based on current projections of future taxable income in foreign jurisdictions, foreign deferred tax assets of $14.9 million are not expected to be realized, including certain tax credit carryforwards that are expected to expire unused. We maintain a valuation allowance on a portion of our U.S. net deferred tax assets for deferred interest expense carryforwards, net operating loss carryforwards and foreign tax credit carryforwards that are expected to expire unused. 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. Gross unrecognized tax benefits were $25.3 million at December 31, 2018 and $25.7 million as of June 30, 2019 . All 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 statutes of limitations and other factors.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	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 based on the weighted-average number of common shares outstanding 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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands, except per share data) Net income (loss) attributable to Amkor common stockholders $ (9,450 ) $ 32,591 $ (32,329 ) $ 42,135 Weighted-average number of common shares outstanding — basic 239,508 239,351 239,461 239,283 Effect of dilutive securities: Stock options and restricted share awards — 453 — 522 Weighted-average number of common shares outstanding — diluted 239,508 239,804 239,461 239,805 Net income (loss) attributable to Amkor per common share: Basic $ (0.04 ) $ 0.14 $ (0.14 ) $ 0.18 Diluted (0.04 ) 0.14 (0.14 ) 0.18 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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Stock options and restricted share awards 7,618 3,644 7,618 3,524

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Changes in accumulated other comprehensive income (loss), net of tax, consist of the following: Defined Benefit Pension Foreign Currency Translation Total (In thousands) Accumulated other comprehensive income (loss) at December 31, 2018 $ 2,659 $ 21,153 $ 23,812 Other comprehensive income (loss) before reclassifications — 3,694 3,694 Amounts reclassified from accumulated other comprehensive income (loss) (189 ) — (189 ) Other comprehensive income (loss) (189 ) 3,694 3,505 Accumulated other comprehensive income (loss) at June 30, 2019 $ 2,470 $ 24,847 $ 27,317 Defined Benefit Pension Foreign Currency Translation Total (In thousands) Accumulated other comprehensive income (loss) at December 31, 2017 $ 6,303 $ 16,216 $ 22,519 Other comprehensive income (loss) before reclassifications — 3,947 3,947 Amounts reclassified from accumulated other comprehensive income (loss) (81 ) — (81 ) Other comprehensive income (loss) (81 ) 3,947 3,866 Accumulated other comprehensive income (loss) at June 30, 2018 $ 6,222 $ 20,163 $ 26,385 Amounts reclassified out of accumulated other comprehensive income (loss) are included as a component of net periodic pension cost ( Note 13 ).

Factoring of Accounts Receivabl

Factoring of Accounts Receivable	6 Months Ended
	Jun. 30, 2019
Factoring of Accounts Receivable [Abstract]
Factoring of Accounts Receivable	Factoring of Accounts Receivable For certain accounts receivable, 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 six months ended June 30, 2019 , we sold receivables totaling $149.1 million and $304.8 million , net of discounts and fees of $1.1 million and $2.2 million , respectively. For the three and six months ended June 30, 2018 , we sold receivables totaling $203.1 million and $428.6 million , net of discounts and fees of $2.0 million and $3.8 million

Property, Plant and Equipment

Property, Plant and Equipment	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Property, Plant And Equipment	Property, Plant and Equipment Property, plant and equipment consist of the following: June 30, December 31, 2018 (In thousands) Land $ 219,991 $ 222,884 Land use rights (1) — 26,845 Buildings and improvements 1,569,785 1,523,065 Machinery and equipment 5,266,111 5,196,930 Finance lease assets 26,414 25,874 Software and computer equipment 218,268 213,440 Furniture, fixtures and other equipment 18,877 17,204 Construction in progress 16,753 44,381 Total property, plant and equipment 7,336,199 7,270,623 Accumulated depreciation and amortization (4,820,666 ) (4,620,175 ) Total property, plant and equipment, net $ 2,515,533 $ 2,650,448 (1) Effective January 1, 2019, and in connection with the adoption of Topic 842, land use rights were reclassified to operating lease right of use asset within our Consolidated Balance Sheet. The following table summarizes our depreciation expense: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Depreciation expense $ 132,642 $ 142,497 $ 268,139 $ 284,502

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	Leases We lease certain machinery and equipment, office space, and manufacturing facilities. Leases with an initial term of 12 months or less are not recorded on the balance sheet, and we recognize lease expense for these leases on a straight-line basis over the lease term. We account for lease components (e.g., fixed payments including rent, real estate taxes and insurance costs) combined with the non-lease components (e.g., common-area maintenance costs). We use our incremental borrowing rate based on the information available at the lease commencement date to determine the lease liability. Our leases have remaining lease terms ranging from less than one year to 86 years . For purposes of calculating our lease liabilities, our lease terms include options to extend or terminate the lease when it is reasonably certain that we will exercise those options. Certain leases also include options to purchase the leased property. The components of lease expense were as follows: For the Three Months Ended June 30, 2019 For the Six Months Ended June 30, 2019 (In thousands) Operating lease cost $ 9,679 $ 17,726 Finance lease cost Amortization of leased assets 1,145 2,210 Interest on lease liabilities 198 413 Total finance lease cost 1,343 2,623 Short-term lease cost 1,933 4,361 Variable lease cost 1,479 3,129 Net lease cost $ 14,434 $ 27,839 Rent expense was $11.2 million and $24.0 million for three and six months ended June 30, 2018 , respectively. Other information related to leases was as follows: For the Six Months Ended June 30, 2019 Supplemental Cash Flows Information (in thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 17,408 Operating cash flows for finance leases 419 Financing cash flows for finance leases 2,746 Weighted Average Remaining Lease Term (Years) Operating leases 4.8 Finance leases 4.3 Weighted Average Discount Rate Operating leases 4.3 % Finance leases 4.8 % Maturities of lease liabilities were as follows: June 30, 2019 December 31, 2018 Operating Leases Finance Leases Operating Leases Finance Leases (In thousands) 2019 - Remaining $ 19,752 $ 4,051 $ 32,461 $ 6,430 2020 34,340 5,557 24,630 4,555 2021 24,658 5,642 17,676 4,748 2022 13,349 1,410 10,942 936 2023 9,307 946 9,008 936 Thereafter 26,515 3,846 26,070 3,807 Total future minimum lease payments 127,921 21,452 $ 120,787 $ 21,412 Less: Imputed interest (13,952 ) (2,402 ) Total $ 113,969 $ 19,050 As of June 30, 2019 , we have entered into additional lease agreements that have not yet commenced of approximately $21.8 million
Leases	Leases We lease certain machinery and equipment, office space, and manufacturing facilities. Leases with an initial term of 12 months or less are not recorded on the balance sheet, and we recognize lease expense for these leases on a straight-line basis over the lease term. We account for lease components (e.g., fixed payments including rent, real estate taxes and insurance costs) combined with the non-lease components (e.g., common-area maintenance costs). We use our incremental borrowing rate based on the information available at the lease commencement date to determine the lease liability. Our leases have remaining lease terms ranging from less than one year to 86 years . For purposes of calculating our lease liabilities, our lease terms include options to extend or terminate the lease when it is reasonably certain that we will exercise those options. Certain leases also include options to purchase the leased property. The components of lease expense were as follows: For the Three Months Ended June 30, 2019 For the Six Months Ended June 30, 2019 (In thousands) Operating lease cost $ 9,679 $ 17,726 Finance lease cost Amortization of leased assets 1,145 2,210 Interest on lease liabilities 198 413 Total finance lease cost 1,343 2,623 Short-term lease cost 1,933 4,361 Variable lease cost 1,479 3,129 Net lease cost $ 14,434 $ 27,839 Rent expense was $11.2 million and $24.0 million for three and six months ended June 30, 2018 , respectively. Other information related to leases was as follows: For the Six Months Ended June 30, 2019 Supplemental Cash Flows Information (in thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 17,408 Operating cash flows for finance leases 419 Financing cash flows for finance leases 2,746 Weighted Average Remaining Lease Term (Years) Operating leases 4.8 Finance leases 4.3 Weighted Average Discount Rate Operating leases 4.3 % Finance leases 4.8 % Maturities of lease liabilities were as follows: June 30, 2019 December 31, 2018 Operating Leases Finance Leases Operating Leases Finance Leases (In thousands) 2019 - Remaining $ 19,752 $ 4,051 $ 32,461 $ 6,430 2020 34,340 5,557 24,630 4,555 2021 24,658 5,642 17,676 4,748 2022 13,349 1,410 10,942 936 2023 9,307 946 9,008 936 Thereafter 26,515 3,846 26,070 3,807 Total future minimum lease payments 127,921 21,452 $ 120,787 $ 21,412 Less: Imputed interest (13,952 ) (2,402 ) Total $ 113,969 $ 19,050 As of June 30, 2019 , we have entered into additional lease agreements that have not yet commenced of approximately $21.8 million

Accrued Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2019
Payables and Accruals [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consist of the following: June 30, December 31, (In thousands) Payroll and benefits $ 95,452 $ 124,943 Short-term operating lease liability 33,920 — Income taxes payable 19,748 38,567 Deferred revenue and customer advances 16,621 16,736 Accrued severance plan obligations 13,423 13,179 Accrued interest 11,652 10,302 Other accrued expenses 55,799 54,482 Total accrued expenses $ 246,615 $ 258,209

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt Following is a summary of short-term borrowings and long-term debt: June 30, December 31, (In thousands) Debt of Amkor Technology, Inc.: Senior notes: 6.375% Senior notes, due October 2022 (1) $ — $ 524,971 6.625% Senior notes, due September 2027 (1) 525,000 — Debt of subsidiaries: Amkor Technology Korea, Inc.: $30 million revolving credit facility, LIBOR plus the applicable bank rate, due October 2019 (2) — — Term loan, fixed rate at 3.70%, due May 2020 (3) 40,000 120,000 Term loan, fund floating rate plus 1.60%, due June 2020 (4) 84,000 125,000 Term loan, LIBOR plus 2.56%, due December 2023 200,000 200,000 Term loan, applicable bank rate plus 1.98%, due December 2028 (4) 66,000 24,000 J-Devices Corporation: Short-term term loans, variable rate (5) 12,888 8,232 Term loan, fixed rate at 0.86%, due June 2022 27,816 31,908 Term loan, fixed rate at 0.60%, due July 2022 6,027 6,838 Term loan, fixed rate at 1.30%, due July 2023 204,915 225,180 Amkor Assembly & Test (Shanghai) Co., Ltd.: Term loan, LIBOR plus 1.80%, due December 2019 (6) — 48,000 Term loan, LIBOR plus 1.60%, due March 2022 (6) 29,500 — Term loan, LIBOR Plus 1.40%, due March 2022 (6) 19,750 — Other: $250 million senior secured revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) (7) 80,000 — Revolving credit facility, TAIFX plus the applicable bank rate, due November 2020 (Taiwan) (8) 20,000 20,000 1,315,896 1,334,129 Less: Unamortized premium, discount and deferred debt costs, net (7,721 ) (1,818 ) Less: Short-term borrowings and current portion of long-term debt (198,230 ) (114,579 ) Long-term debt $ 1,109,945 $ 1,217,732 (1) In April 2019, we redeemed the outstanding $525 million aggregate principal amount of our 6.375% Senior Notes due 2022 (“2022 Notes”). In accordance with the terms of the indenture governing the 2022 Notes, the redemption price was 101.594% of the principal amount of the 2022 Notes plus accrued and unpaid interest. We recorded an $8.4 million loss on extinguishment related to the call premium paid and other debt related costs associated with the 2022 Notes. The redemption of the 2022 Notes was funded with net proceeds from our issuance of $525 million of 6.625% Senior Notes due September 2027 (“2027 Notes”) in March 2019, together with cash on hand. The 2027 Notes were issued at a discount of 99.5% or $2.6 million and are senior unsecured obligations. Interest is payable semiannually on March 15 and September 15 of each year, commencing September 15, 2019. We incurred $3.6 million of debt issuance costs associated with the 2027 Notes. (2) In October 2018, we entered into a revolving credit facility agreement with availability of $30.0 million . Principal will be payable at maturity in October 2019. Interest will be payable monthly in arrears, at LIBOR plus the applicable bank rate. As of June 30, 2019, $30.0 million was available to be drawn. (3) In May 2017, we entered into a $120.0 million term loan agreement due May 2020 with a fixed interest rate of 3.7% . During the six months ended June 30, 2019, we repaid $80 million . In July 2019, we entered into a term loan agreement pursuant to which we may borrow up to $180.0 million for purchases of materials. Principal is payable at maturity in July 2022. Interest will be payable quarterly in arrears, at the applicable bank rate plus 2.03% . We borrowed $40.0 million at 3.8% in July 2019 under this term loan to repay the remaining $40.0 million outstanding balance for the term loan due May 2020. (4) In May 2015, we entered into a term loan agreement pursuant to which we may borrow up to $150.0 million for capital expenditures. Principal is payable at maturity in June 2020. Interest is payable quarterly in arrears, at a fund floating rate plus 1.60% ( 4.54% as of June 30, 2019 ). During the six months ended June 30, 2019 , we repaid $41.0 million of the outstanding balance of this term loan using the proceeds from our term loan due December 2028. In December 2018, we entered into a term loan agreement pursuant to which we may borrow up to $90.0 million for capital expenditures. During the six months ended June 30, 2019 , we borrowed $42.0 million of this term loan and used the proceeds to repay part of the term loan due June 2020. Principal of this term loan is payable in semiannual installments beginning June 2022 and ending at maturity in December 2028. Interest is payable quarterly in arrears, at the applicable bank rate plus 1.98% ( 4.50% as of June 30, 2019 ). As of June 30, 2019 , $24.0 million was available to be drawn. (5) We entered into various short-term term loans which mature semiannually. Principal and interest are payable in monthly installments. Interest as of June 30, 2019 is at TIBOR plus 0.10% to 0.20% (weighted average of 0.20% as of June 30, 2019 ). As of June 30, 2019 , $4.0 million was available to be drawn. (6) In December 2016, we entered into a $50.0 million term loan agreement. Principal is payable in semiannual installments of $0.5 million , with the remaining balance due at maturity in December 2019. Interest is payable quarterly at a floating rate of LIBOR plus 1.80% . During the six months ended June 30, 2019 , we repaid the entire $48.0 million outstanding balance of this term loan using the proceeds from our term loans due March 2022. In March 2019, we entered into a $30.0 million term loan agreement due March 2022. We borrowed $30.0 million under this term loan and repaid part of the term loan due December 2019. Principal is payable in semiannual installments of $0.5 million , with the remaining balance due at maturity. Interest is payable quarterly at a floating rate of LIBOR plus 1.60% ( 4.06% as of June 30, 2019 ). In April 2019, we entered into a term loan agreement with availability of $20.0 million due March 2022. We borrowed $20.0 million under this term loan and repaid part of the term loan due December 2019. Principal is payable in semiannual installments of $0.5 million, with the remaining balance due at maturity. Interest is payable quarterly at a floating rate of LIBOR plus 1.40% ( 3.85% as of June 30, 2019 ). (7) In July 2018, our subsidiary, Amkor Technology Singapore Holding Pte, Ltd., entered into a $250.0 million senior secured revolving credit facility, which is guaranteed by Amkor Technology, Inc. The availability for our revolving credit facility is based on the amount of eligible accounts receivable. Principal is payable at maturity. Interest is payable monthly at LIBOR plus 1.25% to 1.75% ( 3.69% as of June 30, 2019 ). We borrowed $80 million in June 2019, which was repaid in July 2019. As of June 30, 2019 , $83.0 million was available to be drawn. (8) In November 2015, we entered into a $39.0 million revolving credit facility. Principal is payable at maturity. Interest is payable monthly at TAIFX plus the applicable bank rate ( 3.59% as of June 30, 2019 ). As of June 30, 2019 , $19.0 million was available to be drawn. Certain of our foreign debt is collateralized by the land, buildings, equipment and accounts receivable in the respective locations. 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. From time to time, Amkor Technology, Inc. also guarantees certain debt of our subsidiaries. The agreements governing our indebtedness contain 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 debt covenants at June 30, 2019 .

Pension Plans

Pension Plans	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Pension Plans	Pension 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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Service cost $ 7,789 $ 8,299 $ 15,766 $ 16,715 Interest cost 1,305 1,226 2,629 2,469 Expected return on plan assets (1,595 ) (1,417 ) (3,213 ) (2,859 ) Recognized actuarial gain (94 ) (42 ) (188 ) (77 ) Net periodic pension cost $ 7,405 $ 8,066 $ 14,994 $ 16,248 The components of net periodic pension cost other than the service cost component are included in other (income) expense, net in our Consolidated Statements of Income. 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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Defined contribution expense $ 3,352 $ 3,017 $ 7,756 $ 7,013

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	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 assets and 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. We also review goodwill for impairment annually during the fourth quarter of each year. 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. Recurring fair value measurements consist of the following: June 30, December 31, (In thousands) Cash equivalent money market funds (Level 1) $ 58,812 $ 74,407 Restricted cash money market funds (Level 1) 2,590 2,589 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: June 30, 2019 December 31, 2018 Fair Value Carrying Value Fair Value Carrying Value (In thousands) Senior notes (Level 1) $ 522,443 $ 518,930 $ 526,131 $ 524,978 Revolving credit facilities and term loans (Level 2) 795,096 789,245 803,867 807,333 Total debt $ 1,317,539 $ 1,308,175 $ 1,329,998 $ 1,332,311 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 is calculated using a discounted cash flow analysis, which utilizes market-based assumptions including forward interest rates adjusted for credit risk.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies 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.

Interim Financial Statements (P

Interim Financial Statements (Policies)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation. The Consolidated Financial Statements and related disclosures as of June 30, 2019 , and for the three and six months ended June 30, 2019 and 2018 , are unaudited, pursuant to the rules and regulations of the United States Securities and Exchange Commission (“SEC”). The December 31, 2018 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, 2018 , filed on Form 10-K with the SEC on February 22, 2019. The results of operations for the three and six months ended June 30, 2019 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.
Use of Estimates	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	Goodwill.
Unbilled Receivables	Unbilled Receivables . Total unbilled receivables as of June 30, 2019 and December 31, 2018 were $88.7 million and $89.3 million , respectively.
Recently Adopted Standards	Recently Adopted Standards In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) , which was subsequently amended and clarified. Topic 842 requires a dual approach for lease accounting under which a lessee would account for leases as finance leases or operating leases. The standard also requires the lessee to recognize a right-of-use asset and a corresponding lease liability for both finance leases and operating leases. For finance leases, the lessee recognizes interest expense and amortization of the right-of-use asset, and for operating leases, the lessee recognizes a straight-line lease expense. The standard permits the use of two alternative transition approaches, either with application in all comparative periods presented, or with application beginning with the effective date without restating comparative period financial statements. Effective January 1, 2019, we adopted the requirements of Topic 842 using the modified transition approach without restating the comparative period financial statements. The new standard resulted in increases in our operating lease right of use asset, accrued expenses and long-term operating lease liability account balances to record our operating leases on our Consolidated Balance Sheet. The new standard also resulted in additional disclosures for our operating and finance leases ( Note 10 ). In accordance with Topic 842, we applied practical expedients permitted under the transition guidance, which allowed us to not: • Reassess whether any existing contracts are or contain a lease, • Reassess the lease classification for any existing contracts, • Reassess initial direct costs for any existing leases, and • Separate non-lease components from lease components and instead to account for them as a single lease component for all asset classes.
Income Taxes	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. Based on current projections of future taxable income in foreign jurisdictions, foreign deferred tax assets of $14.9 million are not expected to be realized, including certain tax credit carryforwards that are expected to expire unused. We maintain a valuation allowance on a portion of our U.S. net deferred tax assets for deferred interest expense carryforwards, net operating loss carryforwards and foreign tax credit carryforwards that are expected to expire unused. 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.
Commitments and Contingencies	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.

Net Sales by Product Group an_2

Net Sales by Product Group and End Market (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Net sales by product group and end market	Net sales by product group consist of the following: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) (In thousands) Advanced products (1) $ 432,639 $ 496,241 $ 855,084 $ 971,993 Mainstream products (2) 462,666 569,443 935,185 1,119,010 Total net sales $ 895,305 $ 1,065,684 $ 1,790,269 $ 2,091,003 (1) Advanced products include flip chip and wafer-level processing and related test services. (2) Mainstream products include wirebond packaging and related test services. Net sales by end market consist of the following : For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 Communications (handheld devices, smartphones, tablets) 37 % 42 % 38 % 42 % Automotive, industrial and other (driver assist, infotainment, performance, safety) 29 % 26 % 29 % 26 % Computing (datacenter, infrastructure, PC/laptop, storage) 19 % 19 % 19 % 19 % Consumer (connected home, set-top boxes, televisions, visual imaging, wearables) 15 % 13 % 14 % 13 % Total net sales 100 % 100 % 100 % 100 %

Other Income and Expense (Table

Other Income and Expense (Tables)	6 Months Ended
	Jun. 30, 2019
Other Income and Expenses [Abstract]
Schedule of other income and expense	Other income and expense consists of the following: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Interest income $ (1,598 ) $ (955 ) $ (3,662 ) $ (1,943 ) Foreign currency (gain) loss, net 606 (7,110 ) (1,407 ) (2,397 ) Loss on debt retirement 8,356 18 8,356 18 Other (398 ) (2,954 ) (886 ) (3,247 ) Other (income) expense, net $ 6,966 $ (11,001 ) $ 2,401 $ (7,569 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands, except per share data) Net income (loss) attributable to Amkor common stockholders $ (9,450 ) $ 32,591 $ (32,329 ) $ 42,135 Weighted-average number of common shares outstanding — basic 239,508 239,351 239,461 239,283 Effect of dilutive securities: Stock options and restricted share awards — 453 — 522 Weighted-average number of common shares outstanding — diluted 239,508 239,804 239,461 239,805 Net income (loss) attributable to Amkor per common share: Basic $ (0.04 ) $ 0.14 $ (0.14 ) $ 0.18 Diluted (0.04 ) 0.14 (0.14 ) 0.18
Summary of potential shares of common stock 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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Stock options and restricted share awards 7,618 3,644 7,618 3,524

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Changes in accumulated other comprehensive income (loss), net of tax	Changes in accumulated other comprehensive income (loss), net of tax, consist of the following: Defined Benefit Pension Foreign Currency Translation Total (In thousands) Accumulated other comprehensive income (loss) at December 31, 2018 $ 2,659 $ 21,153 $ 23,812 Other comprehensive income (loss) before reclassifications — 3,694 3,694 Amounts reclassified from accumulated other comprehensive income (loss) (189 ) — (189 ) Other comprehensive income (loss) (189 ) 3,694 3,505 Accumulated other comprehensive income (loss) at June 30, 2019 $ 2,470 $ 24,847 $ 27,317 Defined Benefit Pension Foreign Currency Translation Total (In thousands) Accumulated other comprehensive income (loss) at December 31, 2017 $ 6,303 $ 16,216 $ 22,519 Other comprehensive income (loss) before reclassifications — 3,947 3,947 Amounts reclassified from accumulated other comprehensive income (loss) (81 ) — (81 ) Other comprehensive income (loss) (81 ) 3,947 3,866 Accumulated other comprehensive income (loss) at June 30, 2018 $ 6,222 $ 20,163 $ 26,385

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Summary of property, plant and equipment and depreciation expense	Property, plant and equipment consist of the following: June 30, December 31, 2018 (In thousands) Land $ 219,991 $ 222,884 Land use rights (1) — 26,845 Buildings and improvements 1,569,785 1,523,065 Machinery and equipment 5,266,111 5,196,930 Finance lease assets 26,414 25,874 Software and computer equipment 218,268 213,440 Furniture, fixtures and other equipment 18,877 17,204 Construction in progress 16,753 44,381 Total property, plant and equipment 7,336,199 7,270,623 Accumulated depreciation and amortization (4,820,666 ) (4,620,175 ) Total property, plant and equipment, net $ 2,515,533 $ 2,650,448 (1) Effective January 1, 2019, and in connection with the adoption of Topic 842, land use rights were reclassified to operating lease right of use asset within our Consolidated Balance Sheet. The following table summarizes our depreciation expense: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Depreciation expense $ 132,642 $ 142,497 $ 268,139 $ 284,502

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Components of Lease Expense	The components of lease expense were as follows: For the Three Months Ended June 30, 2019 For the Six Months Ended June 30, 2019 (In thousands) Operating lease cost $ 9,679 $ 17,726 Finance lease cost Amortization of leased assets 1,145 2,210 Interest on lease liabilities 198 413 Total finance lease cost 1,343 2,623 Short-term lease cost 1,933 4,361 Variable lease cost 1,479 3,129 Net lease cost $ 14,434 $ 27,839 Other information related to leases was as follows: For the Six Months Ended June 30, 2019 Supplemental Cash Flows Information (in thousands) Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 17,408 Operating cash flows for finance leases 419 Financing cash flows for finance leases 2,746 Weighted Average Remaining Lease Term (Years) Operating leases 4.8 Finance leases 4.3 Weighted Average Discount Rate Operating leases 4.3 % Finance leases 4.8 %
Maturity of Finance Lease Liabilities	were as follows: June 30, 2019 December 31, 2018 Operating Leases Finance Leases Operating Leases Finance Leases (In thousands) 2019 - Remaining $ 19,752 $ 4,051 $ 32,461 $ 6,430 2020 34,340 5,557 24,630 4,555 2021 24,658 5,642 17,676 4,748 2022 13,349 1,410 10,942 936 2023 9,307 946 9,008 936 Thereafter 26,515 3,846 26,070 3,807 Total future minimum lease payments 127,921 21,452 $ 120,787 $ 21,412 Less: Imputed interest (13,952 ) (2,402 ) Total $ 113,969 $ 19,050
Maturity of Operating Lease Liabilities	were as follows: June 30, 2019 December 31, 2018 Operating Leases Finance Leases Operating Leases Finance Leases (In thousands) 2019 - Remaining $ 19,752 $ 4,051 $ 32,461 $ 6,430 2020 34,340 5,557 24,630 4,555 2021 24,658 5,642 17,676 4,748 2022 13,349 1,410 10,942 936 2023 9,307 946 9,008 936 Thereafter 26,515 3,846 26,070 3,807 Total future minimum lease payments 127,921 21,452 $ 120,787 $ 21,412 Less: Imputed interest (13,952 ) (2,402 ) Total $ 113,969 $ 19,050
Future Minimum Lease Payments Under Non-cancellable Leases	were as follows: June 30, 2019 December 31, 2018 Operating Leases Finance Leases Operating Leases Finance Leases (In thousands) 2019 - Remaining $ 19,752 $ 4,051 $ 32,461 $ 6,430 2020 34,340 5,557 24,630 4,555 2021 24,658 5,642 17,676 4,748 2022 13,349 1,410 10,942 936 2023 9,307 946 9,008 936 Thereafter 26,515 3,846 26,070 3,807 Total future minimum lease payments 127,921 21,452 $ 120,787 $ 21,412 Less: Imputed interest (13,952 ) (2,402 ) Total $ 113,969 $ 19,050
Schedule of Capital Lease Obligations	were as follows: June 30, 2019 December 31, 2018 Operating Leases Finance Leases Operating Leases Finance Leases (In thousands) 2019 - Remaining $ 19,752 $ 4,051 $ 32,461 $ 6,430 2020 34,340 5,557 24,630 4,555 2021 24,658 5,642 17,676 4,748 2022 13,349 1,410 10,942 936 2023 9,307 946 9,008 936 Thereafter 26,515 3,846 26,070 3,807 Total future minimum lease payments 127,921 21,452 $ 120,787 $ 21,412 Less: Imputed interest (13,952 ) (2,402 ) Total $ 113,969 $ 19,050

Accrued Expenses (Tables)

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2019
Payables and Accruals [Abstract]
Summary of accrued expenses	Accrued expenses consist of the following: June 30, December 31, (In thousands) Payroll and benefits $ 95,452 $ 124,943 Short-term operating lease liability 33,920 — Income taxes payable 19,748 38,567 Deferred revenue and customer advances 16,621 16,736 Accrued severance plan obligations 13,423 13,179 Accrued interest 11,652 10,302 Other accrued expenses 55,799 54,482 Total accrued expenses $ 246,615 $ 258,209

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Summary of short-term borrowings and long-term debt	Following is a summary of short-term borrowings and long-term debt: June 30, December 31, (In thousands) Debt of Amkor Technology, Inc.: Senior notes: 6.375% Senior notes, due October 2022 (1) $ — $ 524,971 6.625% Senior notes, due September 2027 (1) 525,000 — Debt of subsidiaries: Amkor Technology Korea, Inc.: $30 million revolving credit facility, LIBOR plus the applicable bank rate, due October 2019 (2) — — Term loan, fixed rate at 3.70%, due May 2020 (3) 40,000 120,000 Term loan, fund floating rate plus 1.60%, due June 2020 (4) 84,000 125,000 Term loan, LIBOR plus 2.56%, due December 2023 200,000 200,000 Term loan, applicable bank rate plus 1.98%, due December 2028 (4) 66,000 24,000 J-Devices Corporation: Short-term term loans, variable rate (5) 12,888 8,232 Term loan, fixed rate at 0.86%, due June 2022 27,816 31,908 Term loan, fixed rate at 0.60%, due July 2022 6,027 6,838 Term loan, fixed rate at 1.30%, due July 2023 204,915 225,180 Amkor Assembly & Test (Shanghai) Co., Ltd.: Term loan, LIBOR plus 1.80%, due December 2019 (6) — 48,000 Term loan, LIBOR plus 1.60%, due March 2022 (6) 29,500 — Term loan, LIBOR Plus 1.40%, due March 2022 (6) 19,750 — Other: $250 million senior secured revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) (7) 80,000 — Revolving credit facility, TAIFX plus the applicable bank rate, due November 2020 (Taiwan) (8) 20,000 20,000 1,315,896 1,334,129 Less: Unamortized premium, discount and deferred debt costs, net (7,721 ) (1,818 ) Less: Short-term borrowings and current portion of long-term debt (198,230 ) (114,579 ) Long-term debt $ 1,109,945 $ 1,217,732 (1) In April 2019, we redeemed the outstanding $525 million aggregate principal amount of our 6.375% Senior Notes due 2022 (“2022 Notes”). In accordance with the terms of the indenture governing the 2022 Notes, the redemption price was 101.594% of the principal amount of the 2022 Notes plus accrued and unpaid interest. We recorded an $8.4 million loss on extinguishment related to the call premium paid and other debt related costs associated with the 2022 Notes. The redemption of the 2022 Notes was funded with net proceeds from our issuance of $525 million of 6.625% Senior Notes due September 2027 (“2027 Notes”) in March 2019, together with cash on hand. The 2027 Notes were issued at a discount of 99.5% or $2.6 million and are senior unsecured obligations. Interest is payable semiannually on March 15 and September 15 of each year, commencing September 15, 2019. We incurred $3.6 million of debt issuance costs associated with the 2027 Notes. (2) In October 2018, we entered into a revolving credit facility agreement with availability of $30.0 million . Principal will be payable at maturity in October 2019. Interest will be payable monthly in arrears, at LIBOR plus the applicable bank rate. As of June 30, 2019, $30.0 million was available to be drawn. (3) In May 2017, we entered into a $120.0 million term loan agreement due May 2020 with a fixed interest rate of 3.7% . During the six months ended June 30, 2019, we repaid $80 million . In July 2019, we entered into a term loan agreement pursuant to which we may borrow up to $180.0 million for purchases of materials. Principal is payable at maturity in July 2022. Interest will be payable quarterly in arrears, at the applicable bank rate plus 2.03% . We borrowed $40.0 million at 3.8% in July 2019 under this term loan to repay the remaining $40.0 million outstanding balance for the term loan due May 2020. (4) In May 2015, we entered into a term loan agreement pursuant to which we may borrow up to $150.0 million for capital expenditures. Principal is payable at maturity in June 2020. Interest is payable quarterly in arrears, at a fund floating rate plus 1.60% ( 4.54% as of June 30, 2019 ). During the six months ended June 30, 2019 , we repaid $41.0 million of the outstanding balance of this term loan using the proceeds from our term loan due December 2028. In December 2018, we entered into a term loan agreement pursuant to which we may borrow up to $90.0 million for capital expenditures. During the six months ended June 30, 2019 , we borrowed $42.0 million of this term loan and used the proceeds to repay part of the term loan due June 2020. Principal of this term loan is payable in semiannual installments beginning June 2022 and ending at maturity in December 2028. Interest is payable quarterly in arrears, at the applicable bank rate plus 1.98% ( 4.50% as of June 30, 2019 ). As of June 30, 2019 , $24.0 million was available to be drawn. (5) We entered into various short-term term loans which mature semiannually. Principal and interest are payable in monthly installments. Interest as of June 30, 2019 is at TIBOR plus 0.10% to 0.20% (weighted average of 0.20% as of June 30, 2019 ). As of June 30, 2019 , $4.0 million was available to be drawn. (6) In December 2016, we entered into a $50.0 million term loan agreement. Principal is payable in semiannual installments of $0.5 million , with the remaining balance due at maturity in December 2019. Interest is payable quarterly at a floating rate of LIBOR plus 1.80% . During the six months ended June 30, 2019 , we repaid the entire $48.0 million outstanding balance of this term loan using the proceeds from our term loans due March 2022. In March 2019, we entered into a $30.0 million term loan agreement due March 2022. We borrowed $30.0 million under this term loan and repaid part of the term loan due December 2019. Principal is payable in semiannual installments of $0.5 million , with the remaining balance due at maturity. Interest is payable quarterly at a floating rate of LIBOR plus 1.60% ( 4.06% as of June 30, 2019 ). In April 2019, we entered into a term loan agreement with availability of $20.0 million due March 2022. We borrowed $20.0 million under this term loan and repaid part of the term loan due December 2019. Principal is payable in semiannual installments of $0.5 million, with the remaining balance due at maturity. Interest is payable quarterly at a floating rate of LIBOR plus 1.40% ( 3.85% as of June 30, 2019 ). (7) In July 2018, our subsidiary, Amkor Technology Singapore Holding Pte, Ltd., entered into a $250.0 million senior secured revolving credit facility, which is guaranteed by Amkor Technology, Inc. The availability for our revolving credit facility is based on the amount of eligible accounts receivable. Principal is payable at maturity. Interest is payable monthly at LIBOR plus 1.25% to 1.75% ( 3.69% as of June 30, 2019 ). We borrowed $80 million in June 2019, which was repaid in July 2019. As of June 30, 2019 , $83.0 million was available to be drawn. (8) In November 2015, we entered into a $39.0 million revolving credit facility. Principal is payable at maturity. Interest is payable monthly at TAIFX plus the applicable bank rate ( 3.59% as of June 30, 2019 ). As of June 30, 2019 , $19.0 million was available to be drawn.

Pension Plans (Tables)

Pension Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [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 June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Service cost $ 7,789 $ 8,299 $ 15,766 $ 16,715 Interest cost 1,305 1,226 2,629 2,469 Expected return on plan assets (1,595 ) (1,417 ) (3,213 ) (2,859 ) Recognized actuarial gain (94 ) (42 ) (188 ) (77 ) Net periodic pension cost $ 7,405 $ 8,066 $ 14,994 $ 16,248
Summary of defined contribution expense	The following table summarizes our defined contribution expense: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (In thousands) Defined contribution expense $ 3,352 $ 3,017 $ 7,756 $ 7,013

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Recurring fair value measurements	Recurring fair value measurements consist of the following: June 30, December 31, (In thousands) Cash equivalent money market funds (Level 1) $ 58,812 $ 74,407 Restricted cash money market funds (Level 1) 2,590 2,589
Fair value of financial instruments that are not recorded at fair value on recurring basis	The following table presents the fair value of financial instruments that are not recorded at fair value on a recurring basis: June 30, 2019 December 31, 2018 Fair Value Carrying Value Fair Value Carrying Value (In thousands) Senior notes (Level 1) $ 522,443 $ 518,930 $ 526,131 $ 524,978 Revolving credit facilities and term loans (Level 2) 795,096 789,245 803,867 807,333 Total debt $ 1,317,539 $ 1,308,175 $ 1,329,998 $ 1,332,311

Interim Financial Statements (D

Interim Financial Statements (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unbilled receivables	$ 88.7	$ 89.3

Net Sales by Product Group an_3

Net Sales by Product Group and End Market - Product Group (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Net sales by product group	$ 895,305	$ 1,065,684	$ 1,790,269	$ 2,091,003
Advanced products
Disaggregation of Revenue [Line Items]
Net sales by product group	432,639	496,241	855,084	971,993
Mainstream products
Disaggregation of Revenue [Line Items]
Net sales by product group	$ 462,666	$ 569,443	$ 935,185	$ 1,119,010

Net Sales by Product Group an_4

Net Sales by Product Group and End Market - End Market (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total net sales	100.00%	100.00%	100.00%	100.00%
Revenue from Contract with Customer | End Market | Communications (handheld devices, smartphones, tablets)
Disaggregation of Revenue [Line Items]
Total net sales	37.00%	42.00%	38.00%	42.00%
Revenue from Contract with Customer | End Market | Automotive, industrial and other (driver assist, infotainment, performance, safety)
Disaggregation of Revenue [Line Items]
Total net sales	29.00%	26.00%	29.00%	26.00%
Revenue from Contract with Customer | End Market | Computing (datacenter, infrastructure, PC/laptop, storage)
Disaggregation of Revenue [Line Items]
Total net sales	19.00%	19.00%	19.00%	19.00%
Revenue from Contract with Customer | End Market | Consumer (connected home, set-top boxes, televisions, visual imaging, wearables)
Disaggregation of Revenue [Line Items]
Total net sales	15.00%	13.00%	14.00%	13.00%

Other Income and Expense (Detai

Other Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Other Income and Expenses [Abstract]
Interest income	$ (1,598)	$ (955)	$ (3,662)	$ (1,943)
Foreign currency (gain) loss, net	606	(7,110)	(1,407)	(2,397)
Loss on debt retirement	8,356	18	8,356	18
Other	(398)	(2,954)	(886)	(3,247)
Other (income) expense, net	$ 6,966	$ (11,001)	$ 2,401	$ (7,569)

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income tax expense	$ 5,897	$ 10,631	$ 27,277	$ 13,112
Amount of change in deferred tax assets valuation allowance			14,900
Gross unrecognized tax benefits	$ 25,700		$ 25,700		$ 25,300

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income (loss) attributable to Amkor common stockholders	$ (9,450)	$ 32,591	$ (32,329)	$ 42,135
Weighted-average number of common shares outstanding — basic	239,508	239,351	239,461	239,283
Effect of dilutive securities:
Stock options and restricted share awards (in shares)	0	453	0	522
Weighted-average number of common shares outstanding — diluted	239,508	239,804	239,461	239,805
Net income (loss) attributable to Amkor per common share:
Basic (in dollars per share)	$ (0.04)	$ 0.14	$ (0.14)	$ 0.18
Diluted (in dollars per share)	$ (0.04)	$ 0.14	$ (0.14)	$ 0.18

Earnings Per Share - Potential

Earnings Per Share - Potential Shares of Common Stock Excluded from Diluted EPS (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Stock options and restricted share awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options and restricted share awards	7,618	3,644	7,618	3,524

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,832,582	$ 1,747,074	$ 1,855,900	$ 1,719,709
Other comprehensive income (loss) before reclassifications			3,694	3,947
Amounts reclassified from accumulated other comprehensive income (loss)			(189)	(81)
Total other comprehensive income (loss)	5,861	(11,186)	3,505	3,866
Balance at end of period	1,831,176	1,770,158	1,831,176	1,770,158
Defined Benefit Pension
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			2,659	6,303
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive income (loss)			(189)	(81)
Total other comprehensive income (loss)			(189)	(81)
Balance at end of period	2,470	6,222	2,470	6,222
Foreign Currency Translation
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period			21,153	16,216
Other comprehensive income (loss) before reclassifications			3,694	3,947
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Total other comprehensive income (loss)			3,694	3,947
Balance at end of period	24,847	20,163	24,847	20,163
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	21,456	37,571	23,812	22,519
Total other comprehensive income (loss)	5,861	(11,186)	3,505	3,866
Balance at end of period	$ 27,317	$ 26,385	$ 27,317	$ 26,385

Factoring of Accounts Receiva_2

Factoring of Accounts Receivable (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Factored
Factoring of Accounts Receivable [Line Items]
Accounts receivable sold	$ 149.1	$ 203.1	$ 304.8	$ 428.6
Discounts and Fees
Factoring of Accounts Receivable [Line Items]
Accounts receivable sold	$ 1.1	$ 2	$ 2.2	$ 3.8

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 7,336,199	$ 7,270,623
Accumulated depreciation and amortization	(4,820,666)	(4,620,175)
Total property, plant and equipment, net	2,515,533	2,650,448
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	219,991	222,884
Land use rights
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	0	26,845
Buildings and improvements
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	1,569,785	1,523,065
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	5,266,111	5,196,930
Finance lease assets
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	26,414	25,874
Software and computer equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	218,268	213,440
Furniture, fixtures and other equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	18,877	17,204
Construction in progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 16,753	$ 44,381

Property, Plant and Equipment_2

Property, Plant and Equipment - Summary of Depreciation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 132,642	$ 142,497	$ 268,139	$ 284,502

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 9,679		$ 17,726
Finance lease cost
Amortization of leased assets	1,145		2,210
Interest on lease liabilities	198		413
Total finance lease cost	1,343		2,623
Short-term lease cost	1,933		4,361
Variable lease cost	1,479		3,129
Net lease cost	$ 14,434		27,839
Rent expense		$ 11,200		$ 24,000
Operating cash flows for operating leases			17,408
Operating cash flows for finance leases			419
Financing cash flows for finance leases			$ 2,746	$ 1,689
Operating leases, Weighted average remaining lease term	4 years 9 months 18 days		4 years 9 months 18 days
Finance leases, Weighted average remaining lease term	4 years 3 months 18 days		4 years 3 months 18 days
Operating leases, Weighted average discount rate	4.30%		4.30%
Finance leases, Weighted average discount rate	4.80%		4.80%
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term			1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term			86 years

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Operating Leases
2019 - Remaining	$ 19,752
2020	34,340
2021	24,658
2022	13,349
2023	9,307
Thereafter	26,515
Total future minimum lease payments	127,921
Less: Imputed interest	(13,952)
Total	113,969
2019		$ 32,461
2020		24,630
2021		17,676
2022		10,942
2023		9,008
Thereafter		26,070
Total future minimum lease payments		120,787
Finance Leases
2019 - Remaining	4,051
2020	5,557
2021	5,642
2022	1,410
2023	946
Thereafter	3,846
Total future minimum lease payments	21,452
Less: Imputed interest	(2,402)
Total	19,050
2019		6,430
2020		4,555
2021		4,748
2022		936
2023		936
Thereafter		3,807
Total future minimum lease payments		$ 21,412
Amount of leases not yet commenced	$ 21,800

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Payroll and benefits	$ 95,452	$ 124,943
Short-term operating lease liability	33,920	0
Income taxes payable	19,748	38,567
Deferred revenue and customer advances	16,621	16,736
Accrued severance plan obligations	13,423	13,179
Accrued interest	11,652	10,302
Other accrued expenses	55,799	54,482
Total accrued expenses	$ 246,615	$ 258,209

Debt (Details)

Debt (Details) - USD ($)	1 Months Ended								3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jun. 30, 2019	Apr. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2016	May 31, 2015	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Oct. 31, 2018	May 30, 2017	Nov. 30, 2015
Debt Instrument [Line Items]
Long-term Debt		$ 1,315,896,000			$ 1,334,129,000				$ 1,315,896,000		$ 1,315,896,000
Less: Unamortized premium, discount and deferred debt costs, net		(7,721,000)			(1,818,000)				(7,721,000)		(7,721,000)
Less: Short-term borrowings and current portion of long-term debt		(198,230,000)			(114,579,000)				(198,230,000)		(198,230,000)
Long-term debt		1,109,945,000			1,217,732,000				1,109,945,000		1,109,945,000
Early extinguishment of debt									8,356,000	$ 18,000	8,356,000	$ 18,000
Proceeds from issuance of long-term debt											614,375,000	64,000,000
Repayments of long-term debt											5,000,000	0
Payments of long-term debt											732,178,000	77,015,000
Proceeds from revolving credit facilities											85,000,000	$ 0
Term loan, LIBOR plus 1.80%, due December 2019 | China
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		0			48,000,000				0		0
Face amount of debt							$ 50,000,000
Payments of long-term debt											$ 48,000,000
Semiannual installment payments							$ 500,000
Term loan, LIBOR plus 1.80%, due December 2019 | China | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)							1.80%				1.80%
Term loan, LIBOR plus 1.60%, due March 2022 | China
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 29,500,000			0				$ 29,500,000		$ 29,500,000
Face amount of debt				$ 30,000,000
Proceeds from issuance of long-term debt				30,000,000
Interest rate at period end (as a percent)		4.06%							4.06%		4.06%
Semiannual installment payments				$ 500,000
Term loan, LIBOR plus 1.60%, due March 2022 | China | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)				1.60%							1.60%
Term Loan, LIBOR plus 1.40% due March 2022 | China
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 19,750,000			0				$ 19,750,000		$ 19,750,000
Term Loan, LIBOR plus 1.40% due March 2022 | China | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)											1.40%
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 80,000,000			0				$ 80,000,000		$ 80,000,000
Credit facility, borrowing capacity						$ 250,000,000
Interest rate at period end (as a percent)		3.69%							3.69%		3.69%
Remaining borrowing capacity		$ 83,000,000							$ 83,000,000		$ 83,000,000
Proceeds from revolving credit facilities		80,000,000
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Repayments of long-term debt	$ 80,000,000
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)						1.25%
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)						1.75%
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility | Singapore
Debt Instrument [Line Items]
Credit facility, borrowing capacity		250,000,000							250,000,000		$ 250,000,000
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility | Singapore | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)											1.25%
Line of Credit | $250 million revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) | Revolving Credit Facility | Singapore | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)											1.75%
Line of Credit | Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020 (Taiwan) | Revolving Credit Facility | Taiwan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 20,000,000			20,000,000				$ 20,000,000		$ 20,000,000
Credit facility, borrowing capacity															$ 39,000,000
Interest rate at period end (as a percent)		3.59%							3.59%		3.59%
Remaining borrowing capacity		$ 19,000,000							$ 19,000,000		$ 19,000,000
Senior Notes | 6.375% Senior notes, due October 2022
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 0			524,971,000				$ 0		$ 0
Stated interest rate (as a percent)		6.375%	6.375%						6.375%		6.375%
Face amount of debt			$ 525,000,000
Debt redemption price			101.594%
Early extinguishment of debt			$ 8,400,000
Senior Notes | 6.625% Senior notes, due September 2027
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 525,000,000			0				$ 525,000,000		$ 525,000,000
Stated interest rate (as a percent)		6.625%		6.625%					6.625%		6.625%
Face amount of debt				$ 525,000,000
Debt issuance costs				$ 3,600,000
Debt discount percentage of par				99.50%
Debt discount				$ 2,600,000
Subsidiary Term Loans | $30 million revolving credit facility, LIBOR plus the applicable bank rate, due October 2019 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 0			0				$ 0		$ 0
Credit facility, borrowing capacity		30,000,000							30,000,000		30,000,000		$ 30,000,000
Unused borrowing capacity		30,000,000							30,000,000		30,000,000
Subsidiary Term Loans | Term loan, fixed rate at 3.70%, due May 2020 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 40,000,000			120,000,000				$ 40,000,000		$ 40,000,000
Stated interest rate (as a percent)		3.70%							3.70%		3.70%			3.70%
Face amount of debt														$ 120,000,000
Payments of long-term debt											$ 80,000,000
Subsidiary Term Loans | Term loan, fixed rate at 3.70%, due May 2020 | Korea | Subsequent Event
Debt Instrument [Line Items]
Payments of long-term debt	40,000,000
Subsidiary Term Loans | Term loan, fund floating rate plus 1.60%, due June 2020 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 84,000,000			125,000,000				$ 84,000,000		84,000,000
Face amount of debt								$ 150,000,000
Payments of long-term debt											$ 41,000,000
Interest rate at period end (as a percent)		4.54%							4.54%		4.54%
Subsidiary Term Loans | Term loan, fund floating rate plus 1.60%, due June 2020 | Korea | Fund Floating Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)								1.60%			1.60%
Subsidiary Term Loans | Term loan, LIBOR plus 2.56%, due December 2023 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 200,000,000			200,000,000				$ 200,000,000		$ 200,000,000
Subsidiary Term Loans | Term loan, LIBOR plus 2.56%, due December 2023 | Korea | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)											2.56%
Subsidiary Term Loans | Term loan, applicable bank rate plus 1.98%, due December 2028 | Korea
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		66,000,000			24,000,000				66,000,000		$ 66,000,000
Face amount of debt					$ 90,000,000
Unused borrowing capacity		$ 24,000,000							$ 24,000,000		24,000,000
Proceeds from issuance of long-term debt											$ 42,000,000
Interest rate at period end (as a percent)		4.50%							4.50%		4.50%
Subsidiary Term Loans | Term loan, applicable bank rate plus 1.98%, due December 2028 | Korea | Applicable Bank Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)					1.98%						1.98%
Subsidiary Term Loans | Short-term term loans, variable rate | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 12,888,000			$ 8,232,000				$ 12,888,000		$ 12,888,000
Unused borrowing capacity		$ 4,000,000							$ 4,000,000		$ 4,000,000
Subsidiary Term Loans | Short-term term loans, variable rate | Japan | Weighted Average
Debt Instrument [Line Items]
Weighted average interest rate (as a percent)		0.20%							0.20%		0.20%
Subsidiary Term Loans | Short-term term loans, variable rate | Japan | TIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)											0.10%
Subsidiary Term Loans | Short-term term loans, variable rate | Japan | TIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)											0.20%
Subsidiary Term Loans | Term loan, fixed rate at 0.86%, due June 2022 | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 27,816,000			31,908,000				$ 27,816,000		$ 27,816,000
Stated interest rate (as a percent)		0.86%							0.86%		0.86%
Subsidiary Term Loans | Term loan, fixed rate at 0.60%, due July 2022 | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 6,027,000			6,838,000				$ 6,027,000		$ 6,027,000
Stated interest rate (as a percent)		0.60%							0.60%		0.60%
Subsidiary Term Loans | Term loan, fixed rate at 1.30% Due July 2023 | Japan
Debt Instrument [Line Items]
Short-term borrowings and long-term debt		$ 204,915,000			$ 225,180,000				$ 204,915,000		$ 204,915,000
Stated interest rate (as a percent)		1.30%							1.30%		1.30%
Subsidiary Term Loans | Amkor Assembly & Test (Shanghai) Co., Ltd. Term Loan | China
Debt Instrument [Line Items]
Face amount of debt			20,000,000
Proceeds from issuance of long-term debt			20,000,000
Interest rate at period end (as a percent)		3.85%							3.85%		3.85%
Semiannual installment payments			$ 500,000
Subsidiary Term Loans | Amkor Assembly & Test (Shanghai) Co., Ltd. Term Loan | China | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)			1.40%
Subsidiary Term Loans | Term loan, fixed rate due July 2022 | Korea | Subsequent Event
Debt Instrument [Line Items]
Face amount of debt	180,000,000
Proceeds from issuance of long-term debt	$ 40,000,000
Interest rate at period end (as a percent)	3.80%
Subsidiary Term Loans | Term loan, fixed rate due July 2022 | Korea | Applicable Bank Rate | Subsequent Event
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	2.03%

Pension Plans - Components of N

Pension Plans - Components of Net Periodic Pension Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Retirement Benefits [Abstract]
Service cost	$ 7,789	$ 8,299	$ 15,766	$ 16,715
Interest cost	1,305	1,226	2,629	2,469
Expected return on plan assets	(1,595)	(1,417)	(3,213)	(2,859)
Recognized actuarial gain	(94)	(42)	(188)	(77)
Net periodic pension cost	$ 7,405	$ 8,066	$ 14,994	$ 16,248

Pension Plans - Summary of Defi

Pension Plans - Summary of Defined Contribution Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Retirement Benefits [Abstract]
Defined contribution expense	$ 3,352	$ 3,017	$ 7,756	$ 7,013

Fair Value Measurements - Recur

Fair Value Measurements - Recurring Measurements (Details) - Recurring Fair Value Measurements - Level 1 - Money Market Funds - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalent money market funds	$ 58,812	$ 74,407
Restricted cash money market funds	$ 2,590	$ 2,589

Fair Value Measurements - Instr

Fair Value Measurements - Instruments Not Recorded on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 1,317,539	$ 1,329,998
Fair Value | Senior notes | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	522,443	526,131
Fair Value | Revolving credit facilities and term loans | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	795,096	803,867
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	1,308,175	1,332,311
Carrying Value | Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	518,930	524,978
Carrying Value | Revolving credit facilities and term loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 789,245	$ 807,333