New Accounting Pronouncements (Policies)	9 Months Ended
Sep. 30, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited consolidated condensed financial statements included herein have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to those rules and regulations. The information furnished in the consolidated condensed financial statements include all adjustments (consisting of only normal, recurring adjustments), considered necessary to present fairly the results of operations, financial position and cash flows of the Company. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. The operating results for interim periods are not necessarily indicative of results that may be expected for any other interim period or for the full year.
Impact of COVID-19	Impact of COVID-19 The COVID-19 pandemic began in China around December 2019. The impact of the outbreak quickly expanded beyond China and its surrounding region. The COVID-19 pandemic significantly disrupted and adversely impacted global economic activity and the global automotive markets in the first half of 2020, which had significant negative impacts on Gentherm’s financial performance in the first half of 2020. During the first quarter of 2020, customer plants in North America and Europe were closed beginning in the second half of March due to the pandemic. This resulted in temporary, partial closures of several of our manufacturing facilities in North America and Europe by the end of March 2020. Customer plants and our manufacturing facilities in Asia were closed for several weeks in February and operated at reduced volumes in March, resuming production to near full capacity by the end of the first quarter, which continued throughout the second quarter. Our manufacturing facilities in North America and Europe remained closed until the last week in May due to the pandemic, gradually resuming production to near full capacity in North America, and to about 70% capacity in Europe by the end of June. Other adverse impacts of the pandemic in the first nine months of the year included supply chain and production disruptions, workforce restrictions, travel restrictions and reduced consumer spending. The adverse impacts of the pandemic continued to a lesser extent in the third quarter of 2020. During the third quarter of 2020, our customers’ plants were open, and our production volumes were stronger than pre-COVID-19 levels at our manufacturing facilities. The consequences of the pandemic and adverse impact to the economy continue to evolve and the future adverse impact on our business and financial statements remains subject to significant uncertainty as of the date of this filing. In preparing these financial statements, management was required to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. These estimates and assumptions are based on our historical experience, the terms of existing contracts, our evaluation of trends in the industry, information provided by our customers and suppliers and information available from other outside sources, as appropriate. These estimates and assumptions are subject to an inherent degree of uncertainty. We are not presently aware of any events or circumstances that would require us to update such estimates and assumptions or revise the carrying value of our assets or liabilities. Our estimates may change, however, as new events occur and additional information is obtained. As a result, actual results may differ significantly from our estimates, and any such differences may be material to our financial statements.
Recently Adopted Accounting Pronouncements	Recently Adopted Accounting Pronouncements Expected Credit Losses In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets held. ASU 2016-13 is effective for annual and interim periods beginning after December 15, 2019. The Company adopted ASU 2016-13 as of January 1, 2020 and there was no significant impact on its consolidated condensed financial statements and related disclosures as a result. The Company considered, among other things, the current and expected future economic and market conditions related to the COVID-19 pandemic and determined that the estimate of credit losses was not significantly impacted. Cloud Computing Arrangements That Are Service Contracts In August 2018, the FASB issued ASU 2018-15, “Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract.” ASU 2018-15 requires implementation costs incurred by customers in cloud computing arrangements to be deferred and recognized over the term of the arrangement if those costs would be capitalized by the customer in a software licensing arrangement under the internal-use software guidance. ASU 2018-15 is effective for annual and interim periods beginning after December 15, 2019. The Company adopted ASU 2018-15 as of January 1, 2020 and there was no significant impact on its consolidated condensed financial statements and related disclosures as a result. Fair Value Measurement In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” ASU 2018-13 removes certain disclosure requirements, including (i) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, (ii) the policy for timing of transfer between levels, and (iii) the valuation processes for Level 3 fair value measurements. ASU 2018-13 also adds new disclosure requirements, including (i) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and (ii) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 is effective for annual and interim periods beginning after December 15, 2019. The Company adopted ASU 2018-13 as of January 1, 2020 and there was no significant impact on its consolidated condensed financial statements and related disclosures as a result.
Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Issued Accounting Pronouncements Not Yet Adopted Retirement Benefits In August 2018, the FASB issued ASU 2018-14, “Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework – Changes to the Disclosure Requirements for Defined Benefit Plans.” ASU 2018-14 removes certain disclosure requirements, including (i) the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next fiscal year, and (ii) the amount and timing of plan assets expected to be returned to the employer. ASU 2018-14 also adds new disclosure requirements, including (i) the weighted-average interest crediting rates for cash balance plans and other plans with promised interest crediting rates and (ii) an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. ASU 2018-14 is effective for annual periods ending after December 15, 2020. Early adoption of the amendments in this update is permitted. The Company is currently in the process of determining the impact the implementation of ASU 2018-14 will have on the Company’s financial statement note disclosures. Income Taxes In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes". This ASU simplifies the accounting for income taxes by removing certain exceptions previously included in the guidance. In addition, the ASU amends existing guidance to improve consistent application. ASU 2019-12 is effective for annual reporting periods beginning after December 15, 2020, and interim periods within those reporting periods. Early adoption of the amendments in this update is permitted. The adoption of this standard is not expected to have a significant impact on the Company’s financial statements or financial disclosures. Reference Rate Reform In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of Effects of Reference Rate Reform on Financial Reporting”. ASU 2020-04 provides practical expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The expedients and exceptions provided by the amendments in this update apply only to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued as a result of reference rate reform. These amendments are not applicable to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. ASU No. 2020-04 is effective as of March 12, 2020 through December 31, 2022 and may be applied to contract modifications and hedging relationships from the beginning of an interim period that includes or is subsequent to March 12, 2020. The Company will adopt this standard when LIBOR is discontinued and does not expect a material impact to its consolidated financial statements.

New Accounting Pronouncements (Policies)

9 Months Ended

Sep. 30, 2020

The unaudited consolidated condensed financial statements included herein have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and pursuant to the rules and regulations of the U.S. Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted pursuant to those rules and regulations. The information furnished in the consolidated condensed financial statements include all adjustments (consisting of only normal, recurring adjustments), considered necessary to present fairly the results of operations, financial position and cash flows of the Company. These financial statements should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2019. The operating results for interim periods are not necessarily indicative of results that may be expected for any other interim period or for the full year.

Impact of COVID-19

The COVID-19 pandemic began in China around December 2019. The impact of the outbreak quickly expanded beyond China and its surrounding region. The COVID-19 pandemic significantly disrupted and adversely impacted global economic activity and the global automotive markets in the first half of 2020, which had significant negative impacts on Gentherm’s financial performance in the first half of 2020. During the first quarter of 2020, customer plants in North America and Europe were closed beginning in the second half of March due to the pandemic. This resulted in temporary, partial closures of several of our manufacturing facilities in North America and Europe by the end of March 2020. Customer plants and our manufacturing facilities in Asia were closed for several weeks in February and operated at reduced volumes in March, resuming production to near full capacity by the end of the first quarter, which continued throughout the second quarter. Our manufacturing facilities in North America and Europe remained closed until the last week in May due to the pandemic, gradually resuming production to near full capacity in North America, and to about 70% capacity in Europe by the end of June. Other adverse impacts of the pandemic in the first nine months of the year included supply chain and production disruptions, workforce restrictions, travel restrictions and reduced consumer spending. The adverse impacts of the pandemic continued to a lesser extent in the third quarter of 2020. During the third quarter of 2020, our customers’ plants were open, and our production volumes were stronger than pre-COVID-19 levels at our manufacturing facilities. The consequences of the pandemic and adverse impact to the economy continue to evolve and the future adverse impact on our business and financial statements remains subject to significant uncertainty as of the date of this filing.

In preparing these financial statements, management was required to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses. These estimates and assumptions are based on our historical experience, the terms of existing contracts, our evaluation of trends in the industry, information provided by our customers and suppliers and information available from other outside sources, as appropriate. These estimates and assumptions are subject to an inherent degree of uncertainty. We are not presently aware of any events or circumstances that would require us to update such estimates and assumptions or revise the carrying value of our assets or liabilities. Our estimates may change, however, as new events occur and additional information is obtained. As a result, actual results may differ significantly from our estimates, and any such differences may be material to our financial statements.

Recently Adopted Accounting Pronouncements

Expected Credit Losses

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires measurement and recognition of expected credit losses for financial assets held. ASU 2016-13 is effective for annual and interim periods beginning after December 15, 2019. The Company adopted ASU 2016-13 as of January 1, 2020 and there was no significant impact on its consolidated condensed financial statements and related disclosures as a result. The Company considered, among other things, the current and expected future economic and market conditions related to the COVID-19 pandemic and determined that the estimate of credit losses was not significantly impacted.

Cloud Computing Arrangements That Are Service Contracts

In August 2018, the FASB issued ASU 2018-15, “Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract.” ASU 2018-15 requires implementation costs incurred by customers in cloud computing arrangements to be deferred and recognized over the term of the arrangement if those costs would be capitalized by the customer in a software licensing arrangement under the internal-use software guidance. ASU 2018-15 is effective for annual and interim periods beginning after December 15, 2019. The Company adopted ASU 2018-15 as of January 1, 2020 and there was no significant impact on its consolidated condensed financial statements and related disclosures as a result.

Fair Value Measurement

In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” ASU 2018-13 removes certain disclosure requirements, including (i) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, (ii) the policy for timing of transfer between levels, and (iii) the valuation processes for Level 3 fair value measurements. ASU 2018-13 also adds new disclosure requirements, including (i) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period and (ii) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 is effective for annual and interim periods beginning after December 15, 2019. The Company adopted ASU 2018-13 as of January 1, 2020 and there was no significant impact on its consolidated condensed financial statements and related disclosures as a result.

Recently Issued Accounting Pronouncements Not Yet Adopted

Retirement Benefits

In August 2018, the FASB issued ASU 2018-14, “Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework – Changes to the Disclosure Requirements for Defined Benefit Plans.” ASU 2018-14

removes certain disclosure requirements, including (i) the amounts in accumulated other comprehensive income expected to be recognized as components of net periodic benefit cost over the next fiscal year, and (ii) the amount and timing of plan assets expected to be returned to the employer. ASU 2018-14 also adds new disclosure requirements, including (i) the weighted-average interest crediting rates for cash balance plans and other plans with promised interest crediting rates and (ii) an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. ASU 2018-14 is effective for annual periods ending after December 15, 2020. Early adoption of the amendments in this update is permitted. The Company is currently in the process of determining the impact the implementation of ASU 2018-14 will have on the Company’s financial statement note disclosures.

Income Taxes

In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes". This ASU simplifies the accounting for income taxes by removing certain exceptions previously included in the guidance. In addition, the ASU amends existing guidance to improve consistent application. ASU 2019-12 is effective for annual reporting periods beginning after December 15, 2020, and interim periods within those reporting periods. Early adoption of the amendments in this update is permitted. The adoption of this standard is not expected to have a significant impact on the Company’s financial statements or financial disclosures.

Reference Rate Reform

In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of Effects of Reference Rate Reform on Financial Reporting”. ASU 2020-04 provides practical expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The expedients and exceptions provided by the amendments in this update apply only to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued as a result of reference rate reform. These amendments are not applicable to contract modifications made and hedging relationships entered into or evaluated after December 31, 2022. ASU No. 2020-04 is effective as of March 12, 2020 through December 31, 2022 and may be applied to contract modifications and hedging relationships from the beginning of an interim period that includes or is subsequent to March 12, 2020. The Company will adopt this standard when LIBOR is discontinued and does not expect a material impact to its consolidated financial statements.