Commitments and Contingencies	3 Months Ended
Mar. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We have a letter of credit sub-facility of $25.0 million under our $150.0 million senior secured revolving credit facility that matures in June 2017. As of March 31, 2013, we had $0.3 million of standby letters of credit outstanding and had an additional $24.7 million available for letters of credit. Such standby letters of credit are used in the ordinary course of our business and are collateralized by our cash balances. We generally warrant that our services will be performed in a professional and workmanlike manner and in compliance with our customers' specifications. We accrue costs for known warranty issues. Historically, our warranty costs have been immaterial. Legal Proceedings We are involved in claims and legal proceedings and may become involved in other legal matters arising in the ordinary course of our business. We evaluate these claims and legal matters on a case-by-case basis to make a determination as to the impact, if any, on our business, liquidity, results of operations, financial condition or cash flows. Except as indicated below, 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. When the reasonable estimate of the loss is within a range of amounts, and no amount in the range constitutes a better estimate than any other amount, we accrue for the amount at the low end of the range. 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 there is at least a reasonable possibility that a loss has been incurred. Attorney fees related to legal matters are expensed as incurred. Arbitration Proceedings with Tessera, Inc. On March 2, 2006, Tessera, Inc. (“Tessera”) filed a request for arbitration with the International Court of Arbitration of the International Chamber of Commerce (the “ICC”), captioned Tessera, Inc. v. Amkor Technology, Inc. (the "First Tessera Arbitration"). The subject matter of the arbitration was a license agreement (“License Agreement”) entered into between Tessera and our predecessor in 1996. In its rulings in 2008 and 2009, the arbitration panel in the First Tessera Arbitration found that most of the packages accused by Tessera were not subject to the patent royalty provisions of the License Agreement, awarded Tessera $60.6 million as damages for some infringing packages for the period March 2, 2002, through December 1, 2008, and denied Tessera's request to terminate the License Agreement. The final award, plus interest and the royalties through December 2008 amounting to $64.7 million, was expensed in 2008 and paid when due in February 2009. Following Tessera's favorable decision in the U.S International Trade Commission (the “ITC”) in May 2009 against some of our customers, Tessera began making repeated statements to customers and others claiming that we were in breach of the royalty provisions of the License Agreement. We informed Tessera that we believed we were in full compliance with the License Agreement and of our intent to continue making the royalty payments when due in accordance with the terms of the License Agreement. On August 7, 2009, we filed a request for arbitration in the ICC against Tessera, captioned Amkor Technology, Inc. v. Tessera, Inc. (the “Second Tessera Arbitration”). We instituted the action in order to obtain declaratory relief confirming that we were a licensee in good standing under our 1996 License Agreement with Tessera and that the License Agreement remained in effect. On November 2, 2009, Tessera filed an answer to our request for arbitration and counterclaims in the ICC. In the answer and counterclaims, Tessera denied Amkor's claims, alleged breach of contract, sought termination of the License Agreement and asserted that Amkor owed Tessera additional royalties under the License Agreement, including royalties for use of thirteen U.S. and six foreign patents that Tessera did not assert in the First Tessera Arbitration. Tessera later dropped its claims on five of those patents. On February 17, 2011, Tessera sent Amkor a notice of termination of the License Agreement. In May 2011, Tessera filed a new request for arbitration against Amkor with the ICC captioned Tessera, Inc. v. Amkor Technology, Inc. (the "Third Tessera Arbitration") seeking undisclosed damages and a declaration that the License Agreement had been terminated. In July 2011, the panel issued its decision in the first phase of the Second Tessera Arbitration. The panel found that we did not owe any of the approximately $18 million of additional royalties claimed by Tessera for packages assembled by us for customers who had been involved in proceedings with Tessera before the ITC. Our request for a declaration confirming that we were in compliance with the License Agreement and that our royalty calculations from the First Tessera Arbitration were correct was denied. The panel found that we had materially breached the License Agreement by not paying the full amount of royalties due and by failing to satisfy the audit provisions of the License Agreement. The final amount of royalties and interest owed relating to the first phase of the Second Tessera Arbitration was approximately $0.5 million, which has been fully paid. In July 2012, the panel issued an interim order in the second phase of the Second Tessera Arbitration finding that royalties are due to Tessera on three of the ten asserted U.S. patents remaining at issue but not on the other seven, royalties are due on four foreign patents related to U.S. patents that the panel found to be royalty bearing in the First Tessera Arbitration and that the License Agreement was terminated by Tessera as of February 17, 2011. We do not believe the termination of the License Agreement will interfere in any significant way with our ability to use our technology, conduct our business or service our customers. The panel also raised the question of whether Tessera intends to pursue its allegations regarding other patents which have not yet been addressed by the panel, and in July 2012, Tessera informed the panel that it intends to proceed on its claims related to three additional U.S. patents. In February 2013, the panel issued another interim order in the second phase of the Second Tessera Arbitration. In the latest ruling, the panel determined that flip chip only packages and pin grid array only packages are not royalty bearing but that certain other packages, principally certain wirebond and combination flip chip wirebond packages are royalty bearing. The panel reserved for later decision the issues of the amount of royalties and pre-judgment interest due, and the allocation of costs. In February 2013, Tessera publicly announced its intention to seek an amount in excess of $150 million in the arbitration. During 2012, we recorded a charge of $56.0 million based on our estimates of the damages and interest due to date in respect of the Second Tessera Arbitration. We believe that $56.0 million of damages and interest is a reasonable estimate of the low end of the possible range of loss up to the amount claimed by Tessera. Because we believe that no amount in the range constitutes a better estimate than any other amount, we recorded the $56.0 million estimate. Of the total charge, $50.0 million was recorded as cost of goods sold and $6.0 million was recorded as interest expense. The ultimate amount of damages and interest is subject to determination by the panel based on a number of complex factors, including the panel's determination of which package families the patents apply to, whether those packages meet criteria previously laid out by the panel, overlaps among the packages, the final date through which royalties are applicable and other factors. The final award could be more than the amount recognized, and we expect to record our estimate of interest accruing with the passage of time and may record additional charges as information develops or upon the issuance of the final award. In August 2012, we paid $19.9 million to Tessera representing the undisputed amount and related interest that we owe in connection with the Second Tessera Arbitration. In July 2012, Tessera filed a complaint in the U.S. District Court for the District of Delaware. The complaint seeks injunctive relief and damages with respect to Amkor's alleged infringement of one of the U.S. patents that the panel found to be royalty bearing in the Second Tessera Arbitration. We strongly dispute Tessera's claims and intend to vigorously defend against them. However, the outcome of this matter is uncertain, and an adverse decision could have a material adverse effect on our results of operations, financial condition and cash flows. Amkor Technology, Inc. v. Carsem (M) Sdn Bhd, Carsem Semiconductor Sdn Bhd, and Carsem Inc. On November 17, 2003, we filed a complaint against Carsem (M) Sdn Bhd, Carsem Semiconductor Sdn Bhd, and Carsem Inc. (collectively “Carsem”) with the ITC in Washington, D.C., alleging infringement of our United States Patent Nos. 6,433,277; 6,455,356 and 6,630,728 (collectively the “Amkor Patents”) and seeking, under Section 337 of the Tariff Act of 1930, an exclusion order barring the importation by Carsem of infringing products. We allege that by making, using, selling, offering for sale or importing into the U.S. the Carsem Dual and Quad Flat No-Lead Packages, Carsem has infringed on one or more of our MicroLeadFrame packaging technology claims in the Amkor Patents. On November 18, 2003, we also filed a complaint in the U.S. District Court for the Northern District of California, alleging infringement of the Amkor Patents and seeking an injunction enjoining Carsem from further infringing the Amkor Patents, compensatory damages and treble damages due to willful infringement plus interest, costs and attorney's fees. This District Court action has been stayed pending resolution of the ITC case. The ITC Administrative Law Judge (“ALJ”) conducted an evidentiary hearing during July and August of 2004 in Washington D.C. and, on November 18, 2004, issued an Initial Determination that Carsem infringed some of our patent claims relating to our MicroLeadFrame package technology, that some of our 21 asserted patent claims are valid, that we have a domestic industry in our patents and that all of our asserted patent claims are enforceable. However, the ALJ did not find a statutory violation of Section 337 of the Tariff Act. We filed a petition in November 2004 to have the ALJ's ruling reviewed by the full ITC. On March 31, 2005, the ITC ordered a new claims construction related to various disputed claim terms and remanded the case to the ALJ for further proceedings. On November 9, 2005, the ALJ issued an Initial Determination on remand finding that Carsem infringed some of our patent claims and that Carsem had violated Section 337 of the Tariff Act. On remand, the ITC had also authorized the ALJ to reopen the record on certain discovery issues related to a subpoena of documents from a third party. An order by the U.S. District Court for the District of Columbia enforcing the subpoena became final on January 9, 2009, and the third party produced documents pursuant to the subpoena. On July 1, 2009, the ITC remanded the investigation for a second time to the ALJ to reopen the record to admit into evidence documents and related discovery obtained from the enforcement of the above-referenced third-party subpoena. Following a two-day hearing, on October 30, 2009, the ALJ issued an Initial Determination reaffirming his prior ruling that the Carsem Dual and Quad Flat No-Lead Packages infringe some of Amkor's patent claims relating to MicroLeadFrame package technology, that all of Amkor's asserted patent claims are valid and that Carsem violated Section 337 of the Tariff Act. On December 16, 2009, the ITC ordered a review of the ALJ's Initial Determination. On February 18, 2010, the Commission reversed a finding by the ALJ on the issue of whether a certain invention constitutes prior art to Amkor's asserted patents. The ITC remanded the investigation to the ALJ to make further findings in light of the ITC's ruling. On March 22, 2010, the ALJ issued a Supplemental Initial Determination. Although the ALJ's ruling did not disturb the prior finding that certain Carsem Dual and Quad Flat No-Lead Packages infringe some patent claims of Amkor's U.S. Patent No. 6,433,277 (the "277 Patent"), the ALJ found that these infringed claims are invalid and, as a result, the ALJ did not find a statutory violation of the Tariff Act. On July 20, 2010, the ITC issued a Notice of Commission Final Determination, in which the ITC determined that there is no violation of Section 337 of the Tariff Act and terminated the investigation. We appealed the ITC's ruling of invalidity for the claims of the 277 Patent to the U.S. Court of Appeals for the Federal Circuit (the "Federal Circuit"), and oral arguments were heard in November 2011. On August 22, 2012, the Federal Circuit issued a favorable ruling in Amkor's appeal in its patent infringement case against Carsem before the ITC. In its ruling, the Federal Circuit reversed the ITC's determination of invalidity on the 277 Patent, and remanded the matter to the ITC for further proceedings consistent with its opinion. On October 5, 2012, Carsem filed a Petition for Rehearing requesting the Federal Circuit to vacate its decision and affirm the ITC's determination of no violation of Section 337 of the Tariff Act. The Federal Circuit denied Carsem's petition on December 7, 2012, and remanded the matter to the ITC for further action consistent with its August 22, 2012 ruling. In September 2012, Carsem, Inc. filed requests for Inter Partes Reexamination of the 277 Patent with the United States Patent and Trademark Office (“Patent Office”). In December 2012, the Patent Office granted the requests for Reexamination. On January 10, 2012, the Patent Office issued an Office Action rejecting all of the 277 Patent claims over certain prior art references. Amkor believes that all of the 277 Patent claims are valid and filed a response to the Office Action in March 2013.

Commitments and Contingencies

We have a letter of credit sub-facility of $25.0 million under our $150.0 million senior secured revolving credit facility that matures in June 2017. As of March 31, 2013, we had $0.3 million of standby letters of credit outstanding and had an additional $24.7 million available for letters of credit. Such standby letters of credit are used in the ordinary course of our business and are collateralized by our cash balances.

We generally warrant that our services will be performed in a professional and workmanlike manner and in compliance with our customers' specifications. We accrue costs for known warranty issues. Historically, our warranty costs have been immaterial.

Legal Proceedings

We are involved in claims and legal proceedings and may become involved in other legal matters arising in the ordinary course of our business. We evaluate these claims and legal matters on a case-by-case basis to make a determination as to the impact, if any, on our business, liquidity, results of operations, financial condition or cash flows. Except as indicated below, 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. When the reasonable estimate of the loss is within a range of amounts, and no amount in the range constitutes a better estimate than any other amount, we accrue for the amount at the low end of the range. 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 there is at least a reasonable possibility that a loss has been incurred. Attorney fees related to legal matters are expensed as incurred.

Arbitration Proceedings with Tessera, Inc.

On March 2, 2006, Tessera, Inc. (“Tessera”) filed a request for arbitration with the International Court of Arbitration of the International Chamber of Commerce (the “ICC”), captioned Tessera, Inc. v. Amkor Technology, Inc. (the "First Tessera Arbitration"). The subject matter of the arbitration was a license agreement (“License Agreement”) entered into between Tessera and our predecessor in 1996. In its rulings in 2008 and 2009, the arbitration panel in the First Tessera Arbitration found that most of the packages accused by Tessera were not subject to the patent royalty provisions of the License Agreement, awarded Tessera $60.6 million as damages for some infringing packages for the period March 2, 2002, through December 1, 2008, and denied Tessera's request to terminate the License Agreement. The final award, plus interest and the royalties through December 2008 amounting to $64.7 million, was expensed in 2008 and paid when due in February 2009.

Following Tessera's favorable decision in the U.S International Trade Commission (the “ITC”) in May 2009 against some of our customers, Tessera began making repeated statements to customers and others claiming that we were in breach of the royalty provisions of the License Agreement. We informed Tessera that we believed we were in full compliance with the License Agreement and of our intent to continue making the royalty payments when due in accordance with the terms of the License Agreement.

On August 7, 2009, we filed a request for arbitration in the ICC against Tessera, captioned Amkor Technology, Inc. v. Tessera, Inc. (the “Second Tessera Arbitration”). We instituted the action in order to obtain declaratory relief confirming that we were a licensee in good standing under our 1996 License Agreement with Tessera and that the License Agreement remained in effect.

On November 2, 2009, Tessera filed an answer to our request for arbitration and counterclaims in the ICC. In the answer and counterclaims, Tessera denied Amkor's claims, alleged breach of contract, sought termination of the License Agreement and asserted that Amkor owed Tessera additional royalties under the License Agreement, including royalties for use of thirteen U.S. and six foreign patents that Tessera did not assert in the First Tessera Arbitration. Tessera later dropped its claims on five of those patents. On February 17, 2011, Tessera sent Amkor a notice of termination of the License Agreement.

In May 2011, Tessera filed a new request for arbitration against Amkor with the ICC captioned Tessera, Inc. v. Amkor Technology, Inc. (the "Third Tessera Arbitration") seeking undisclosed damages and a declaration that the License Agreement had been terminated.

In July 2011, the panel issued its decision in the first phase of the Second Tessera Arbitration. The panel found that we did not owe any of the approximately $18 million of additional royalties claimed by Tessera for packages assembled by us for customers who had been involved in proceedings with Tessera before the ITC. Our request for a declaration confirming that we were in compliance with the License Agreement and that our royalty calculations from the First Tessera Arbitration were correct was denied. The panel found that we had materially breached the License Agreement by not paying the full amount of royalties due and by failing to satisfy the audit provisions of the License Agreement. The final amount of royalties and interest owed relating to the first phase of the Second Tessera Arbitration was approximately $0.5 million, which has been fully paid.

In July 2012, the panel issued an interim order in the second phase of the Second Tessera Arbitration finding that royalties are due to Tessera on three of the ten asserted U.S. patents remaining at issue but not on the other seven, royalties are due on four foreign patents related to U.S. patents that the panel found to be royalty bearing in the First Tessera Arbitration and that the License Agreement was terminated by Tessera as of February 17, 2011. We do not believe the termination of the License Agreement will interfere in any significant way with our ability to use our technology, conduct our business or service our customers. The panel also raised the question of whether Tessera intends to pursue its allegations regarding other patents which have not yet been addressed by the panel, and in July 2012, Tessera informed the panel that it intends to proceed on its claims related to three additional U.S. patents.

In February 2013, the panel issued another interim order in the second phase of the Second Tessera Arbitration. In the latest ruling, the panel determined that flip chip only packages and pin grid array only packages are not royalty bearing but that certain other packages, principally certain wirebond and combination flip chip wirebond packages are royalty bearing. The panel reserved for later decision the issues of the amount of royalties and pre-judgment interest due, and the allocation of costs. In February 2013, Tessera publicly announced its intention to seek an amount in excess of $150 million in the arbitration.

During 2012, we recorded a charge of $56.0 million based on our estimates of the damages and interest due to date in respect of the Second Tessera Arbitration. We believe that $56.0 million of damages and interest is a reasonable estimate of the low end of the possible range of loss up to the amount claimed by Tessera. Because we believe that no amount in the range constitutes a better estimate than any other amount, we recorded the $56.0 million estimate. Of the total charge, $50.0 million was recorded as cost of goods sold and $6.0 million was recorded as interest expense. The ultimate amount of damages and interest is subject to determination by the panel based on a number of complex factors, including the panel's determination of which package families the patents apply to, whether those packages meet criteria previously laid out by the panel, overlaps among the packages, the final date through which royalties are applicable and other factors. The final award could be more than the amount recognized, and we expect to record our estimate of interest accruing with the passage of time and may record additional charges as information develops or upon the issuance of the final award.

In August 2012, we paid $19.9 million to Tessera representing the undisputed amount and related interest that we owe in connection with the Second Tessera Arbitration.

In July 2012, Tessera filed a complaint in the U.S. District Court for the District of Delaware. The complaint seeks injunctive relief and damages with respect to Amkor's alleged infringement of one of the U.S. patents that the panel found to be royalty bearing in the Second Tessera Arbitration. We strongly dispute Tessera's claims and intend to vigorously defend against them. However, the outcome of this matter is uncertain, and an adverse decision could have a material adverse effect on our results of operations, financial condition and cash flows.

Amkor Technology, Inc. v. Carsem (M) Sdn Bhd, Carsem Semiconductor Sdn Bhd, and Carsem Inc.

On November 17, 2003, we filed a complaint against Carsem (M) Sdn Bhd, Carsem Semiconductor Sdn Bhd, and Carsem Inc. (collectively “Carsem”) with the ITC in Washington, D.C., alleging infringement of our United States Patent Nos. 6,433,277; 6,455,356 and 6,630,728 (collectively the “Amkor Patents”) and seeking, under Section 337 of the Tariff Act of 1930, an exclusion order barring the importation by Carsem of infringing products. We allege that by making, using, selling, offering for sale or importing into the U.S. the Carsem Dual and Quad Flat No-Lead Packages, Carsem has infringed on one or more of our MicroLeadFrame packaging technology claims in the Amkor Patents.

On November 18, 2003, we also filed a complaint in the U.S. District Court for the Northern District of California, alleging infringement of the Amkor Patents and seeking an injunction enjoining Carsem from further infringing the Amkor Patents, compensatory damages and treble damages due to willful infringement plus interest, costs and attorney's fees. This District Court action has been stayed pending resolution of the ITC case.

The ITC Administrative Law Judge (“ALJ”) conducted an evidentiary hearing during July and August of 2004 in Washington D.C. and, on November 18, 2004, issued an Initial Determination that Carsem infringed some of our patent claims relating to our MicroLeadFrame package technology, that some of our 21 asserted patent claims are valid, that we have a domestic industry in our patents and that all of our asserted patent claims are enforceable. However, the ALJ did not find a statutory violation of Section 337 of the Tariff Act.

We filed a petition in November 2004 to have the ALJ's ruling reviewed by the full ITC. On March 31, 2005, the ITC ordered a new claims construction related to various disputed claim terms and remanded the case to the ALJ for further proceedings. On November 9, 2005, the ALJ issued an Initial Determination on remand finding that Carsem infringed some of our patent claims and that Carsem had violated Section 337 of the Tariff Act.

On remand, the ITC had also authorized the ALJ to reopen the record on certain discovery issues related to a subpoena of documents from a third party. An order by the U.S. District Court for the District of Columbia enforcing the subpoena became final on January 9, 2009, and the third party produced documents pursuant to the subpoena.

On July 1, 2009, the ITC remanded the investigation for a second time to the ALJ to reopen the record to admit into evidence documents and related discovery obtained from the enforcement of the above-referenced third-party subpoena.

Following a two-day hearing, on October 30, 2009, the ALJ issued an Initial Determination reaffirming his prior ruling that the Carsem Dual and Quad Flat No-Lead Packages infringe some of Amkor's patent claims relating to MicroLeadFrame package technology, that all of Amkor's asserted patent claims are valid and that Carsem violated Section 337 of the Tariff Act.

On December 16, 2009, the ITC ordered a review of the ALJ's Initial Determination. On February 18, 2010, the Commission reversed a finding by the ALJ on the issue of whether a certain invention constitutes prior art to Amkor's asserted patents. The ITC remanded the investigation to the ALJ to make further findings in light of the ITC's ruling. On March 22, 2010, the ALJ issued a Supplemental Initial Determination. Although the ALJ's ruling did not disturb the prior finding that certain Carsem Dual and Quad Flat No-Lead Packages infringe some patent claims of Amkor's U.S. Patent No. 6,433,277 (the "277 Patent"), the ALJ found that these infringed claims are invalid and, as a result, the ALJ did not find a statutory violation of the Tariff Act. On July 20, 2010, the ITC issued a Notice of Commission Final Determination, in which the ITC determined that there is no violation of Section 337 of the Tariff Act and terminated the investigation. We appealed the ITC's ruling of invalidity for the claims of the 277 Patent to the U.S. Court of Appeals for the Federal Circuit (the "Federal Circuit"), and oral arguments were heard in November 2011.

On August 22, 2012, the Federal Circuit issued a favorable ruling in Amkor's appeal in its patent infringement case against Carsem before the ITC. In its ruling, the Federal Circuit reversed the ITC's determination of invalidity on the 277 Patent, and remanded the matter to the ITC for further proceedings consistent with its opinion. On October 5, 2012, Carsem filed a Petition for Rehearing requesting the Federal Circuit to vacate its decision and affirm the ITC's determination of no violation of Section 337 of the Tariff Act. The Federal Circuit denied Carsem's petition on December 7, 2012, and remanded the matter to the ITC for further action consistent with its August 22, 2012 ruling.

In September 2012, Carsem, Inc. filed requests for Inter Partes Reexamination of the 277 Patent with the United States Patent and Trademark Office (“Patent Office”). In December 2012, the Patent Office granted the requests for Reexamination. On January 10, 2012, the Patent Office issued an Office Action rejecting all of the 277 Patent claims over certain prior art references. Amkor believes that all of the 277 Patent claims are valid and filed a response to the Office Action in March 2013.