Stock-Based Compensation Plans - Narrative (Details)		1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2022 shares	May 31, 2022 shares	Sep. 30, 2024 USD ($) plan shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) plan shares	Sep. 30, 2023 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for share-based payments | $			$ 9,590,588	$ 10,948,031	$ 31,042,268	$ 29,212,236
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued under the omnibus plan (in shares)					1,624,122
Number of shares authorized (in shares)	2,000,000
ESPP discount rate	85.00%
ESPP discount rate recognized as compensation expense	15.00%
Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grants in period (in shares)					11,109,647
Shares issued under the omnibus plan (in shares)					29,672,008
Number of shares authorized (in shares)			45,000,000		45,000,000
Employee Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $			$ 5,834,690		$ 5,834,690
Employee Stock Option Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period					1 year
Option expiration period					5 years
Employee Stock Option Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vesting period					5 years
Option expiration period					10 years
Restricted Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $			52,836,541		$ 52,836,541
Restricted period, maximum					10 years
Amortization expense | $			$ 5,915,930	6,369,348	$ 19,487,110	18,178,157
Gentex Corporation Employee Stock Purchase Plan | Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued under the omnibus plan (in shares)					442,718
Number of shares authorized (in shares)		2,000,000
ESPP discount rate		85.00%
ESPP discount rate recognized as compensation expense		15.00%
Equity Incentive Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of plans | plan			2		2
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for share-based payments | $			$ 1,573,201	2,463,158	$ 5,369,466	4,600,386
Unrecognized compensation cost | $			15,768,739		$ 15,768,739
Performance Shares | Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued under the omnibus plan (in shares)					4,127,603
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for share-based payments | $			$ 453,393	$ 441,115	$ 1,342,032	$ 1,082,333
Option vesting period					4 years