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- Definition

Debt Instrument, Number of Loans

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of the required periodic payments applied to principal.

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

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Amount, after accumulated amortization, of debt discount.

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- Definition

Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date.

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Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Write-off of amounts previously capitalized as debt issuance cost in an extinguishment of debt.

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Debt (Additional Information) (Details)	1 Months Ended							3 Months Ended	12 Months Ended
Debt (Additional Information) (Details)	Feb. 21, 2020 USD ($)	Jan. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Apr. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 JPY (¥)	Oct. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jul. 31, 2019 USD ($) loan	May 30, 2017 USD ($)	Nov. 30, 2015 USD ($)	May 31, 2015 USD ($)
Debt Instrument [Line Items]
Total debt			$ 1,460,351,000						$ 1,460,351,000	$ 1,334,129,000
Loss on debt retirement									8,536,000	1,512,000	$ 4,835,000
Proceeds from issuance of long-term debt									975,575,000	596,226,000	$ 223,976,000
China \| Term loan, LIBOR plus 1.80% due December 2019
Debt Instrument [Line Items]
Amount of debt agreement							$ 50,000,000.0
Repayments of debt									48,000,000.0
Amount of principal payments							$ 500,000
China \| Term Loan, LIBOR plus 1.60% Due March 2022
Debt Instrument [Line Items]
Amount of debt agreement					$ 30,000,000.0
Proceeds from issuance of long-term debt					30,000,000.0
Amount of principal payments					$ 500,000
Senior notes \| 6.375% Senior notes, due October 2022
Debt Instrument [Line Items]
Total debt			0						0	$ 524,971,000
Interest rate (as a percent)				6.375%						6.375%
Redemption price (as a percent)				101.594%
Loss on debt retirement								$ 8,400,000
Amount of debt agreement				$ 525,000,000.0
Senior notes \| 6.625% Senior notes, due September 2027
Debt Instrument [Line Items]
Total debt			$ 525,000,000						$ 525,000,000	$ 0
Interest rate (as a percent)			6.625%		6.625%				6.625%			6.625%
Amount of debt agreement					$ 525,000,000.0
Debt discount, percentage of par					99.50%
Debt discount					$ 2,600,000
Debt issuance costs					$ 3,600,000
Subsidiary Term Loans \| Korea
Debt Instrument [Line Items]
Amount of debt agreement															$ 180,000,000.0
Number of loans \| loan															2
Subsidiary Term Loans \| Korea \| Term loan, fixed rate at 3.70%, due May 2020
Debt Instrument [Line Items]
Total debt			$ 0						$ 0	120,000,000
Interest rate (as a percent)			3.70%						3.70%			3.70%
Amount of debt agreement															$ 40,000,000.0	$ 120,000,000.0
Repayments of debt									$ 120,000,000.0
Subsidiary Term Loans \| Korea \| Term loan, fund floating rate plus 1.60%, due June 2020
Debt Instrument [Line Items]
Total debt			$ 24,000,000						24,000,000	125,000,000
Credit facility, borrowing capacity																		$ 150,000,000.0
Repayments of debt									101,000,000.0
Subsidiary Term Loans \| Korea \| Term loan, applicable bank rate plus 2.03%, due July 2022
Debt Instrument [Line Items]
Total debt			40,000,000						40,000,000	0
Interest rate (as a percent)															3.80%
Amount of debt agreement															$ 40,000,000.0
Subsidiary Term Loans \| Korea \| Term loan, applicable bank rate plus 2.03%, due September 2022
Debt Instrument [Line Items]
Total debt			60,000,000						60,000,000	0
Interest rate (as a percent)														3.59%
Amount of debt agreement														$ 60,000,000.0
Amount of unused borrowing capacity			80,000,000.0						80,000,000.0
Subsidiary Term Loans \| Korea \| Term loan, LIBOR plus 2.56%, due December 2023
Debt Instrument [Line Items]
Total debt			200,000,000						200,000,000	200,000,000
Subsidiary Term Loans \| Korea \| Term loan, applicable bank rate plus 1.98%, due December 2028
Debt Instrument [Line Items]
Total debt			66,000,000						66,000,000	$ 24,000,000
Interest rate (as a percent)										4.50%
Amount of debt agreement										$ 90,000,000.0
Amount of unused borrowing capacity			24,000,000.0						24,000,000.0
Proceeds from issuance of long-term debt									42,000,000.0
Subsidiary Term Loans \| Japan \| Short-term term loans, variable rates
Debt Instrument [Line Items]
Total debt			7,071,000						7,071,000	8,232,000
Amount of unused borrowing capacity			6,000,000.0						6,000,000.0
Subsidiary Term Loans \| Japan \| Term loan, fixed rate at 1.35%, due December 2024
Debt Instrument [Line Items]
Total debt			$ 262,407,000						$ 262,407,000	0
Interest rate (as a percent)			1.35%						1.35%			1.35%
Amount of debt agreement			$ 260,600,000						$ 260,600,000			¥ 28,500,000,000
Proceeds from issuance of long-term debt			260,600,000
Subsidiary Term Loans \| Japan \| Term loan, fixed rate at 1.30%, due July 2023
Debt Instrument [Line Items]
Total debt			$ 179,541,000						$ 179,541,000	225,180,000
Interest rate (as a percent)			1.30%						1.30%			1.30%
Payments of revolving credit facilities			$ 80,000,000.0
Subsidiary Term Loans \| China \| Term loan, LIBOR plus 1.80%, due December 2019
Debt Instrument [Line Items]
Total debt			0						$ 0	48,000,000
Subsidiary Term Loans \| China \| Term Loan, LIBOR plus 1.60% Due March 2022
Debt Instrument [Line Items]
Total debt			29,000,000						29,000,000	0
Subsidiary Term Loans \| China \| Term Loan, LIBOR plus 1.40% Due March 2022
Debt Instrument [Line Items]
Total debt			19,250,000						19,250,000	0
Amount of debt agreement				20,000,000.0
Proceeds from issuance of long-term debt				20,000,000.0
Amount of principal payments				$ 500,000
Revolving Credit Facility \| Line of Credit \| Amkor Technology Singapore Holding Pte, Ltd. Senior Secured Credit Facility
Debt Instrument [Line Items]
Write off of deferred debt issuance cost						$ 400,000
Revolving Credit Facility \| Line of Credit \| $250 million senior secured revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore)
Debt Instrument [Line Items]
Total debt			0						0	0
Credit facility, borrowing capacity			250,000,000						250,000,000
Remaining borrowing capacity			$ 250,000,000.0						$ 250,000,000.0
Revolving Credit Facility \| Line of Credit \| $250 million senior secured revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) \| Minimum
Debt Instrument [Line Items]
Interest rate (as a percent)			1.25%						1.25%			1.25%
Revolving Credit Facility \| Line of Credit \| $250 million senior secured revolving credit facility, LIBOR plus 1.25%-1.75%, due July 2023 (Singapore) \| Maximum
Debt Instrument [Line Items]
Interest rate (as a percent)			1.75%						1.75%			1.75%
Revolving Credit Facility \| Line of Credit \| Korea \| $30 million revolving credit facility, LIBOR plus the applicable bank rate, due October 2020
Debt Instrument [Line Items]
Total debt			$ 0						$ 0	0
Credit facility, borrowing capacity			30,000,000						30,000,000				$ 30,000,000.0
Remaining borrowing capacity			30,000,000.0						30,000,000.0
Revolving Credit Facility \| Line of Credit \| Taiwan \| Revolving credit facility, TAIFX plus a bank-determined spread, due November 2020
Debt Instrument [Line Items]
Total debt			0						0	20,000,000
Credit facility, borrowing capacity																	$ 39,000,000.0
Payments of revolving credit facilities			20,000,000.0
Revolving Credit Facility \| Line of Credit \| Taiwan \| Revolving credit facility, TAIFX plus the applicable bank rate, due December 2024
Debt Instrument [Line Items]
Total debt			20,000,000						20,000,000	$ 0
Credit facility, borrowing capacity			56,000,000.0						56,000,000.0
Remaining borrowing capacity			$ 36,000,000.0						$ 36,000,000.0
Subsequent Event \| Subsidiary Term Loans \| Korea \| Term loan, fund floating rate plus 1.60%, due June 2020
Debt Instrument [Line Items]
Repayments of debt	$ 24,000,000.0
Subsequent Event \| Subsidiary Term Loans \| Japan \| Term loan, LIBOR plus 2.56%, due December 2023
Debt Instrument [Line Items]
Repayments of debt		$ 120,000,000.0