Adoption of New Accounting Standards (Policies)	3 Months Ended
Mar. 31, 2026
Accounting Policies [Abstract]
Basis of Presentation	Basis of PresentationThe accompanying Unaudited Condensed Consolidated Financial Statements of Gentex Corporation and Subsidiaries ("Gentex" or the "Company") included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission as defined in the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 270 for interim financial information, and in accordance with financial standards generally accepted in the United States of America ("GAAP"). Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations, although the Company believes that the disclosures are adequate to make the information presented not misleading. It is suggested that these Unaudited Condensed Consolidated Financial Statements be read in conjunction with the financial statements and notes thereto included in the Company's 2025 annual report on Form 10-K. In the opinion of management, the accompanying Unaudited Condensed Consolidated Financial Statements contain all adjustments considered necessary for a fair presentation of the financial position of the Company as of March 31, 2026, and the results of operations and cash flows for the interim periods presented.
Adoption of New Accounting Standards	Adoption of New Accounting Standards In March 2024, the Securities and Exchange Commission ("SEC") issued Final Rule No. 33-11275, "The Enhancement and Standardization of Climate-Related Disclosures for Investors." If such rule becomes effective, the rule will require disclosure of climate-related information outside of the audited financial statements and disclosure in the footnotes to such financial statements addressing specified financial statement effects of severe weather events and other natural conditions above certain financial thresholds, certain carbon offsets and renewable energy credits or certificates, if material. Such disclosure requirements were scheduled to begin phasing in for fiscal years beginning on or after January 1, 2025. On April 4, 2024, the SEC exercised its discretion to voluntarily stay the effective date of the final rules pending completion of certain judicial review. In 2025, the SEC withdrew its defense of the climate disclosure rules and litigation has been held in abeyance. The SEC has launched a formal review, inviting public comment, with an eye toward facilitating disclosure of consistent, comparable, and reliable information on climate change. Though compliance with such rules is not currently required, and it is unclear when or if compliance will be required, the Company continues to evaluate the potential impact of compliance, as well as compliance with similar rules of other jurisdictions. In November 2024, the FASB issued ASU No. 2024-03, "Disaggregation of Income Statement Expenses (Subtopic 220-40)." The ASU requires public business entities to disaggregate, in a tabular presentation, certain income statement expenses into different categories, such as purchases of inventory, employee compensation, depreciation, and intangible asset amortization. The guidance is effective for fiscal years beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Companies have the option to apply the guidance either on a retrospective or prospective basis, and early adoption is permitted. In January 2025, the FASB issued ASU No. 2025-01, "Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date." This ASU amends the effective date of ASU 2024-03 to clarify that all public business entities are required to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. The Company is currently evaluating the impact of adopting these ASU's on the Consolidated Financial Statements and related disclosures. In May 2025, the FASB issued ASU 2025-03, Business Combinations (Topic 805) and Consolidation (Topic 810): Determining the Accounting Acquirer in the Acquisition of a Variable Interest Entity ("VIE"), which provides clarifying guidance on determining the accounting acquirer in certain transactions involving VIE's. The update aims to improve consistency and comparability in financial reporting. The guidance will be effective for annual periods beginning after December 15, 2026, including interim periods within those annual periods. Early adoption is permitted. Upon adoption, the guidance will be applied prospectively. The Company is currently evaluating the provisions of the guidance and the impact on its future Consolidated Financial Statements. In July 2025, the FASB issued ASU 2025-05, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, which introduces a practical expedient for the application of the current expected credit loss model to current accounts receivable and contract assets in which all entities can assume that current conditions as of the balance sheet date do not change for the remaining life of the assets. This ASU was effective for the Company in the first quarter of 2026 and did not have a material impact the Company's Consolidated Financial Statements and disclosures. In September 2025, the FASB issued ASU 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. This ASU updates the cost capitalization threshold for internal-use software development costs by removing all references to software project development stages and providing new guidance on how to evaluate whether the probable-to-complete recognition threshold has been met. ASU 2025-06, which can be applied prospectively, retrospectively, or with a modified transition approach, is effective for annual periods beginning after December 15, 2027, and interim periods within those annual reporting periods. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its Consolidated Financial Statements and disclosures. In November 2025, the FASB issued ASU 2025-09, Derivatives and Hedging - Hedge Accounting Improvements (Topic 815), which amends certain aspects of the hedge accounting guidance to better align financial reporting with the economics of an entity's risk management activities. ASU 2025-09 is effective for annual and interim periods beginning after December 15, 2026. Early adoption is permitted and is effective on a prospective basis. The Company is currently evaluating the impact that the adoption of this standard will have on its Consolidated Financial Statements and disclosures. In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements ("ASU 2025-11"). This ASU enhances consistency in interim reporting for all entities by clarifying interim disclosure requirements and the form and content of interim financial statements in accordance with GAAP. ASU 2025-11, which can be applied prospectively or retrospectively to any and all prior periods presented in the financial statements, is effective for the interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its Consolidated Financial Statements and related disclosures.

In March 2024, the Securities and Exchange Commission ("SEC") issued Final Rule No. 33-11275, "The Enhancement and Standardization of Climate-Related Disclosures for Investors." If such rule becomes effective, the rule will require disclosure of climate-related information outside of the audited financial statements and disclosure in the footnotes to such financial statements addressing specified financial statement effects of severe weather events and other natural conditions above certain financial thresholds, certain carbon offsets and renewable energy credits or certificates, if material. Such disclosure requirements were scheduled to begin phasing in for fiscal years beginning on or after January 1, 2025. On April 4, 2024, the SEC exercised its discretion to voluntarily stay the effective date of the final rules pending completion of certain judicial review. In 2025, the SEC withdrew its defense of the climate disclosure rules and litigation has been held in abeyance. The SEC has launched a formal review, inviting public comment, with an eye toward facilitating disclosure of consistent, comparable, and reliable information on climate change. Though compliance with such rules is not currently required, and it is unclear when or if compliance will be required, the Company continues to evaluate the potential impact of compliance, as well as compliance with similar rules of other jurisdictions.

In November 2024, the FASB issued ASU No. 2024-03, "Disaggregation of Income Statement Expenses (Subtopic 220-40)." The ASU requires public business entities to disaggregate, in a tabular presentation, certain income statement expenses into different categories, such as purchases of inventory, employee compensation, depreciation, and intangible asset amortization. The guidance is effective for fiscal years beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Companies have the option to apply the guidance either on a retrospective or prospective basis, and early adoption is permitted. In January 2025, the FASB issued ASU No. 2025-01, "Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date." This ASU amends the effective date of ASU 2024-03 to clarify that all public business entities are required to adopt the guidance in annual reporting periods beginning after December 15, 2026, and interim periods within annual reporting periods beginning after December 15, 2027. The Company is currently evaluating the impact of adopting these ASU's on the Consolidated Financial Statements and related disclosures.

In May 2025, the FASB issued ASU 2025-03, Business Combinations (Topic 805) and Consolidation (Topic 810): Determining the Accounting Acquirer in the Acquisition of a Variable Interest Entity ("VIE"), which provides clarifying guidance on determining the accounting acquirer in certain transactions involving VIE's. The update aims to improve consistency and comparability in financial reporting. The guidance will be effective for annual periods beginning after December 15, 2026, including interim periods within those annual periods. Early adoption is permitted. Upon adoption, the guidance will be applied prospectively. The Company is currently evaluating the provisions of the guidance and the impact on its future Consolidated Financial Statements.

In July 2025, the FASB issued ASU 2025-05, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, which introduces a practical expedient for the application of the current expected credit loss model to current accounts receivable and contract assets in which all entities can assume that current conditions as of the balance sheet date do not change for the remaining life of the assets. This ASU was effective for the Company in the first quarter of 2026 and did not have a material impact the Company's Consolidated Financial Statements and disclosures.

In September 2025, the FASB issued ASU 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. This ASU updates the cost capitalization threshold for internal-use software development costs by removing all references to software project development stages and providing new guidance on how to evaluate whether the probable-to-complete recognition threshold has

been met. ASU 2025-06, which can be applied prospectively, retrospectively, or with a modified transition approach, is effective for annual periods beginning after December 15, 2027, and interim periods within those annual reporting periods. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its Consolidated Financial Statements and disclosures.

In November 2025, the FASB issued ASU 2025-09, Derivatives and Hedging - Hedge Accounting Improvements (Topic 815), which amends certain aspects of the hedge accounting guidance to better align financial reporting with the economics of an entity's risk management activities. ASU 2025-09 is effective for annual and interim periods beginning after December 15, 2026. Early adoption is permitted and is effective on a prospective basis. The Company is currently evaluating the impact that the adoption of this standard will have on its Consolidated Financial Statements and disclosures.

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements ("ASU 2025-11"). This ASU enhances consistency in interim reporting for all entities by clarifying interim disclosure requirements and the form and content of interim financial statements in accordance with GAAP. ASU 2025-11, which can be applied prospectively or retrospectively to any and all prior periods presented in the financial statements, is effective for the interim reporting periods within annual reporting periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its Consolidated Financial Statements and related disclosures.