Goodwill and Other Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Intangible assets, net	$ 209,710,910	$ 219,360,910	[1]
Gentex Patents
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	40,639,478	40,653,851
Finite-lived intangible assets, accumulated amortization	(28,251,342)	(27,820,383)
Finite-lived intangible assets, net	12,388,136	12,833,468
HomeLink® Technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	180,000,000	180,000,000
Finite-lived intangible assets, accumulated amortization	(146,250,000)	(138,750,000)
Finite-lived intangible assets, net	$ 33,750,000	$ 41,250,000
Finite-lived intangible asset, useful life	12 years	12 years
Existing Customer Platforms
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 43,000,000	$ 43,000,000
Finite-lived intangible assets, accumulated amortization	(41,925,000)	(39,775,000)
Finite-lived intangible assets, net	$ 1,075,000	$ 3,225,000
Finite-lived intangible asset, useful life	10 years	10 years
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, accumulated amortization	$ (188,175,000)	$ (178,525,000)
Intangible assets, gross	397,885,910	397,885,910
Intangible assets, net	209,710,910	219,360,910
Patents and Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Total Patents & Other Intangible Assets, Gross	438,525,388	438,539,761
Total Patents & Other Intangible Assets, Accumulated Amortization	(216,426,342)	(206,345,383)
Total Patents & Other Intangible Assets, Net	222,099,046	232,194,378
HomeLink® Trade Names and Trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	52,000,000	52,000,000
HomeLink® Trade Names and Trademarks | Guardian Optical Technologies
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1,300,000	1,300,000
Exclusive Licensing Agreement
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	96,000,000	96,000,000
In Process Research and Development | Vaporsens In-Process R&D
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	11,000,000	11,000,000
In Process Research and Development | Argil In-Process R&D
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	6,278,132	6,278,132
In Process Research and Development | Air-Craftglass In-Process R&D
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1,507,778	1,507,778
In Process Research and Development | Guardian Optical Technologies
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 6,800,000	$ 6,800,000

[1] The condensed consolidated balance sheet at December 31, 2022 has been derived from the audited consolidated financial statements at that date, but does not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.