Gentex (GNTX) 10-Q 1 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 18, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	0-10235
Entity Registrant Name	GENTEX CORPORATION
Entity Central Index Key	0000355811
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Incorporation, State or Country Code	MI
Entity Tax Identification Number	38-2030505
Entity Address, Address Line One	600 N. Centennial
Entity Address, City or Town	Zeeland
Entity Address, State or Province	MI
Entity Address, Postal Zip Code	49464
City Area Code	616
Local Phone Number	772-1800
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, par value $0.06 per share
Trading Symbol	GNTX
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		252,972,254

Unaudited Condensed Consolidate

Unaudited Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2019	Dec. 31, 2018	[1]
CURRENT ASSETS
Cash and cash equivalents	$ 260,151,083	$ 217,025,278
Short-term investments	207,156,287	169,412,999
Accounts receivable, net	253,108,715	213,537,799
Inventories	238,676,795	225,281,599
Prepaid expenses and other	28,402,524	25,672,579
Total current assets	987,495,404	850,930,254
PLANT AND EQUIPMENT—NET	491,968,638	498,473,766
OTHER ASSETS
Goodwill	307,365,845	307,365,845
Long-term investments	103,025,468	137,979,082
Intangible assets, net	255,200,000	269,675,000
Patents and other assets, net	22,241,049	21,010,121
Total other assets	687,832,362	736,030,048
Total assets	2,167,296,404	2,085,434,068
CURRENT LIABILITIES
Accounts payable	95,309,797	92,810,316
Accrued liabilities	86,994,334	76,350,603
Total current liabilities	182,304,131	169,160,919
OTHER NON-CURRENT LIABILITIES	6,952,703	0
DEFERRED INCOME TAXES	56,711,307	54,521,489
Total liabilities	245,968,141	223,682,408
SHAREHOLDERS’ INVESTMENT
Common stock	15,178,860	15,559,717
Additional paid-in capital	799,462,368	745,324,144
Retained earnings	1,107,449,540	1,102,468,137
Accumulated other comprehensive income (loss)	(762,505)	(1,600,338)
Total shareholders’ investment	1,921,328,263	1,861,751,660
Total liabilities and shareholders’ investment	$ 2,167,296,404	$ 2,085,434,068
[1]	The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited 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.

Unaudited Condensed Consolida_2

Unaudited Condensed Consolidated Statements of Income - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
NET SALES		$ 477,761,417	$ 460,253,433	$ 1,415,061,768	$ 1,380,654,978
COST OF GOODS SOLD		297,440,131	287,263,147	888,558,373	862,231,819
Gross profit		180,321,286	172,990,286	526,503,395	518,423,159
OPERATING EXPENSES:
Engineering, research and development		29,398,725	26,888,999	85,847,249	80,138,722
Selling, general & administrative		22,786,881	18,673,376	63,019,167	55,658,189
Total operating expenses		52,185,606	45,562,375	148,866,416	135,796,911
Income from operations		128,135,680	127,427,911	377,636,979	382,626,248
OTHER INCOME (LOSS)
Investment income		3,353,510	3,180,683	8,756,638	8,062,421
Other income (loss), net		90,323	(73,979)	376,983	578,655
Total other income		3,443,833	3,106,704	9,133,621	8,641,076
INCOME BEFORE PROVISION FOR INCOME TAXES		131,579,513	130,534,615	386,770,600	391,267,324
PROVISION FOR INCOME TAXES		19,681,661	19,198,798	61,633,712	59,658,782
NET INCOME		$ 111,897,852	$ 111,335,817	$ 325,136,888	$ 331,608,542
EARNINGS PER SHARE:
Basic (in dollars per share)	[1]	$ 0.44	$ 0.42	$ 1.27	$ 1.23
Diluted (in dollars per share)	[1]	0.44	0.42	1.26	1.22
Cash Dividends Declared per Share (in dollars per share)		$ 0.115	$ 0.110	$ 0.345	$ 0.330
[1]	(1) Earnings Per Share has been adjusted to exclude the portion of net income allocated to participating securities as a result of share-based payment awards.

Unaudited Condensed Consolida_3

Unaudited Condensed Consolidated Statements of Comprehensive Income - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 111,897,852	$ 111,335,817	$ 325,136,888	$ 331,608,542
Other comprehensive (loss) income before tax:
Foreign currency translation adjustments	(1,623,102)	(1,174,213)	(1,799,789)	(2,013,638)
Unrealized gains on derivatives	0	16,165	0	98,769
Unrealized gains (losses) on debt securities, net	457,438	(609,422)	3,338,762	(932,953)
Other comprehensive (loss) income, before tax	(1,165,664)	(1,767,470)	1,538,973	(2,847,822)
Income tax impact related to components of other comprehensive income	96,062	(124,584)	701,140	(175,177)
Other comprehensive (loss) income, net of tax	(1,261,726)	(1,642,886)	837,833	(2,672,645)
Comprehensive Income	$ 110,636,126	$ 109,692,931	$ 325,974,721	$ 328,935,897

Unaudited Condensed Consolida_4

Unaudited Condensed Consolidated Statements of Shareholders' Investment - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	$ 1,904,334,235	$ 1,921,499,312	$ 1,861,751,660	[1]	$ 2,049,518,261
Issuance of common stock and the tax benefit of stock plan transactions	26,287,061	8,383,073	$ 68,221,875		61,379,666
Repurchases of common stock (in shares)			(11,400,000)
Repurchases of common stock	(96,625,003)	(172,543,703)	$ (262,763,375)		(521,749,624)
Stock-based compensation expense related to stock options, employee stock purchases and restricted stock	5,788,286	4,905,626	15,927,434		13,558,565
Impact of ASU 2016-01 adoption					0
Dividends declared	(29,092,442)	(28,832,984)	(87,784,052)		(88,538,509)
Net income (loss)	111,897,852	111,335,817	325,136,888		331,608,542
Other comprehensive income (loss)	(1,261,726)	(1,642,886)	837,833		(2,672,647)
Balance at end of period	$ 1,921,328,263	$ 1,843,104,255	$ 1,921,328,263		$ 1,843,104,255
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	254,779,119	268,923,121	259,328,613		280,281,321
Balance at beginning of period	$ 15,286,747	$ 16,135,387	$ 15,559,717		$ 16,816,879
Issuance of common stock and the tax benefit of stock plan transactions (in shares)	1,771,463	702,296	5,021,616		4,960,412
Issuance of common stock and the tax benefit of stock plan transactions	$ 106,287	$ 42,138	$ 301,297		$ 297,625
Repurchases of common stock (in shares)	(3,569,577)	(7,508,249)	(11,369,224)		(23,124,565)
Repurchases of common stock	$ (214,174)	$ (450,495)	$ (682,154)		$ (1,387,474)
Ending balance (in shares)	252,981,005	262,117,168	252,981,005		262,117,168
Balance at end of period	$ 15,178,860	$ 15,727,030	$ 15,178,860		$ 15,727,030
Additional  Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	777,238,253	748,794,815	745,324,144		723,510,672
Issuance of common stock and the tax benefit of stock plan transactions	26,180,774	8,340,935	67,920,578		61,082,042
Repurchases of common stock	(9,744,945)	(18,545,378)	(29,709,788)		(54,655,280)
Stock-based compensation expense related to stock options, employee stock purchases and restricted stock	5,788,286	4,905,626	15,927,434		13,558,565
Balance at end of period	799,462,368	743,495,999	799,462,368		743,495,999
Retained  Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	1,111,310,014	1,157,048,214	1,102,468,137		1,301,997,327
Repurchases of common stock	(86,665,884)	(153,547,831)	(232,371,433)		(465,706,871)
Impact of ASU 2016-01 adoption					6,642,727
Dividends declared	(29,092,442)	(28,832,984)	(87,784,052)		(88,538,509)
Net income (loss)	111,897,852	111,335,817	325,136,888		331,608,542
Balance at end of period	1,107,449,540	1,086,003,216	1,107,449,540		1,086,003,216
Accumulated  Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	499,221	(479,104)	(1,600,338)		7,193,383
Impact of ASU 2016-01 adoption					(6,642,727)
Other comprehensive income (loss)	(1,261,726)	(1,642,886)	837,833		(2,672,645)
Balance at end of period	$ (762,505)	$ (2,121,990)	$ (762,505)		$ (2,121,990)
[1]	The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited 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.

Unaudited Condensed Consolida_5

Unaudited Condensed Consolidated Statements of Shareholders' Investment (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Stockholders' Equity [Abstract]
Dividends declared (in dollars per share)	$ 0.115	$ 0.110	$ 0.345	$ 0.330

Unaudited Condensed Consolida_6

Unaudited Condensed Consolidated Statements of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 325,136,888	$ 331,608,542
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	79,331,513	80,748,272
(Gain) on disposal of assets	(148,376)	(145,777)
Loss on disposal of assets	495,697	26,839
(Gain) on sale of investments	(593,351)	(1,508,411)
Loss on sale of investments	0	532,494
Change in deferred income taxes	2,189,818	(5,538,048)
Stock-based compensation expense related to employee stock options, employee stock purchases and restricted stock	15,927,434	13,558,557
Change in operating assets and liabilities:
Accounts receivable, net	(39,570,916)	(16,200,315)
Inventories	(13,395,196)	3,371,546
Prepaid expenses and other	(2,729,945)	(14,797,969)
Accounts payable	2,499,481	143,514
Accrued liabilities, excluding dividends declared and short-term debt	14,797,251	6,408,044
Net cash provided by operating activities	383,940,298	398,207,288
Activity in available-for-sale securities:
Sales proceeds	57,087,935	54,078,232
Maturities and calls	9,714,000	51,892,136
Purchases	(66,360,636)	(180,657,259)
Plant and equipment additions	(58,322,472)	(68,771,193)
Proceeds from sale of plant and equipment	1,937,207	194,200
Decrease in other assets	(3,111,644)	(4,557,125)
Net cash (used for) investing activities	(59,055,610)	(147,821,009)
CASH FLOWS (USED FOR) FINANCING ACTIVITIES:
Repayment of debt	0	(78,000,000)
Issuance of common stock from stock plan transactions	68,221,875	61,379,666
Cash dividends paid	(87,217,383)	(87,733,776)
Repurchases of common stock	(262,763,375)	(521,749,624)
Net cash (used for) financing activities	(281,758,883)	(626,103,734)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	43,125,805	(375,717,455)
CASH AND CASH EQUIVALENTS, beginning of period	217,025,278	569,734,496
CASH AND CASH EQUIVALENTS, end of period	$ 260,151,083	$ 194,017,041

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of PresentationThe unaudited condensed consolidated financial statements included herein have been prepared by the Company, pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States 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 2018 annual report on Form 10-K. In the opinion of management, the accompanying unaudited condensed consolidated financial statements contain all adjustments, consisting of only a normal and recurring nature, necessary to present fairly the financial position of the Company as of September 30, 2019, and the results of operations and cash flows for the interim periods presented.

Adoption of New Accounting Pron

Adoption of New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Adoption of New Accounting Pronouncements	Adoption of New Accounting Pronouncements New Accounting Pronouncements Adopted in Fiscal Year 2019 Effective January 1, 2019, the Company adopted Accounting Standards Update ("ASU") 2016-02, Leases , which provides guidance for lease accounting. The new guidance contained in the ASU stipulates that lessees will need to recognize a right-of-use ("ROU") asset and a lease liability for substantially all leases (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. Treatment in the consolidated statements of income will be similar to the historical treatment of operating and capital leases. The adoption of this standard did not have a material impact on the Company's consolidated balance sheet or consolidated income statement. Disclosures are now required to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instrument s. The standard requires a change in the measurement approach for credit losses on financial assets measured on an amortized cost basis from an incurred loss method to an expected loss method, thereby eliminating the requirement that a credit loss be considered probable to impact the valuation of a financial asset measured on an amortized cost basis. The standard requires the measurement of expected credit losses to be based on relevant information about past events, including historical experience, current conditions, and a reasonable and supportable forecast that affects the collectability of the related financial asset. The Company will be required to adopt ASU 2016-13 as of January 1, 2020. Early adoption is permitted. The Company does not anticipate a material impact on the Company’s consolidated financial statements.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill represents the cost of an acquisition in excess of the fair values assigned to identifiable net assets acquired. The Company recorded Goodwill of $307.4 million as part of the HomeLink ® acquisition. The carrying value of Goodwill as of both September 30, 2019 and December 31, 2018 was $307.4 million. In addition to annual impairment testing, which is performed as of the first day of the fourth quarter, the Company continuously monitors for events and circumstances that could negatively impact the key assumptions in determining fair value thus resulting in the need for interim impairment testing, including long-term revenue growth projections, profitability, discount rates, recent market valuations from transactions by comparable companies, volatility in the Company's market capitalization, and general industry, market and macroeconomic conditions. No such events or circumstances in the most recently completed quarter indicated the need for interim impairment testing. The patents and intangible assets and related change in carrying values are set forth in the tables below: As of September 30, 2019: Other Intangible Assets Gross Accumulated Amortization Net Assumed Useful Life Gentex Patents $ 37,160,431 $ (22,094,953) $ 15,065,478 Various Other Intangible Assets HomeLink ® Trade Names and Trademarks $ 52,000,000 $ — $ 52,000,000 Indefinite HomeLink ® Technology 180,000,000 (90,000,000) 90,000,000 12 years Existing Customer Platforms 43,000,000 (25,800,000) 17,200,000 10 years Exclusive Licensing Agreement 96,000,000 — 96,000,000 Indefinite Total Other Intangible Assets $ 371,000,000 $ (115,800,000) $ 255,200,000 Total Patents & Other Intangible Assets $ 408,160,431 $ (137,894,953) $ 270,265,478 As of December 31, 2018: Other Intangible Assets Gross Accumulated Amortization Net Assumed Useful Life Gentex Patents $ 36,737,434 $ (21,014,168) $ 15,723,266 Various Other Intangible Assets HomeLink ® Trade Names and Trademarks $ 52,000,000 $ — $ 52,000,000 Indefinite HomeLink ® Technology 180,000,000 (78,750,000) 101,250,000 12 years Existing Customer Platforms 43,000,000 (22,575,000) 20,425,000 10 years Exclusive Licensing Agreement 96,000,000 — 96,000,000 Indefinite Total Other Intangible Assets $ 371,000,000 $ (101,325,000) $ 269,675,000 Total Patents & Other Intangible Assets $ 407,737,434 $ (122,339,168) $ 285,398,266 Amortization expense on patents and intangible assets was approximately $5.6 million and $16.8 million during the three and nine months ended September 30, 2019, respectively, compared to approximately $5.6 million and $16.9 million for the same periods ended September 30, 2018, respectively. Excluding the impact of any future acquisitions, the Company continues to estimate amortization expense for each of the years ended December 31, 2019, 2020, and 2021 to be approximately $22 million annually, approximately $21 million for 2022, and approximately $19 million for the year ended December 31, 2023.

Investments

Investments	9 Months Ended
	Sep. 30, 2019
Investments [Abstract]
Investments	The Company follows the provisions of Accounting Standards Codification ("ASC") 820, Fair Value Measurements and Disclosures , for its financial assets and liabilities, and for its non-financial assets and liabilities subject to fair value measurements. ASC 820 provides a framework for measuring the fair value of assets and liabilities. This framework is intended to provide increased consistency in how fair value determinations are made under various existing accounting standards that permit, or in some cases, require estimates of fair-market value. This standard also expanded financial statement disclosure requirements about a company’s use of fair-value measurements, including the effect of such measurement on earnings. The cost of securities sold is based on the specific identification method. The Company determines the fair value of its government securities, municipal bonds, and corporate bonds by utilizing monthly valuation statements that are provided by its broker. The broker determines the investment valuation by utilizing the bid price in the market and also refers to third party sources to validate valuations, and as such are classified as Level 2 assets. The Company's certificates of deposit have remaining maturities of less than one year and are considered as Level 1 assets. These investments are carried at cost, which approximates fair value. The Company will also periodically make technology investments in certain non-consolidated third-parties. These equity investments are accounted for in accordance with ASC 321, Investments - Equity Securities . Equity investments that do not have readily determinable fair values, and where the Company has not identified any observable events that would cause adjustment of the valuation to date, such equity investments are held at cost. These technology investments totaled $8.6 million and $3.85 million as of September 30, 2019 and December 31, 2018, respectively. These investments are classified within Long-Term Investments in the consolidated balance sheet. Assets or liabilities that have recurring fair value measurements are shown below as of September 30, 2019 and December 31, 2018: As of September 30, 2019: Fair Value Measurements at Reporting Date Using Total as of Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description September 30, 2019 (Level 1) (Level 2) (Level 3) Cash & Cash Equivalents $ 260,151,083 $ 260,151,083 $ — $ — Short-Term Investments: Certificate of Deposit 150,299,384 150,299,384 — — Government Securities 38,163,353 — 38,163,353 — Corporate Bonds 16,050,560 — 16,050,560 — Municipal Bonds 1,671,264 — 1,671,264 — Other 971,726 971,726 — — Long-Term Investments: Corporate Bonds 42,320,659 — 42,320,659 — Municipal Bonds 40,467,299 — 40,467,299 — Government Securities 11,637,510 — 11,637,510 — Total $ 561,732,838 $ 411,422,193 $ 150,310,645 $ — As of December 31, 2018: Fair Value Measurements at Reporting Date Using Total as of Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description December 31, 2018 (Level 1) (Level 2) (Level 3) Cash & Cash Equivalents $ 217,025,278 $ 217,025,278 $ — $ — Short-Term Investments: Certificate of Deposit 150,299,384 150,299,384 — — Government Securities 9,176,227 — 9,176,227 — Corporate Bonds 6,967,700 — 6,967,700 — Other 2,219,688 2,219,688 — — Long-Term Investments: Corporate Bonds 60,369,930 — 60,369,930 — Municipal Bonds 18,025,432 — 18,025,432 — Government Securities 56,483,720 — 56,483,720 — Total $ 520,567,359 $ 369,544,350 $ 151,023,009 $ — The amortized cost, unrealized gains and losses, and market value of investment securities are shown as of September 30, 2019 and December 31, 2018: As of September 30, 2019: Unrealized Cost Gains Losses Market Value Short-Term Investments: Certificate of Deposit $ 150,299,384 $ — $ — $ 150,299,384 Government Securities 38,067,382 97,271 (1,300) 38,163,353 Municipal Bonds 1,673,133 13,163 (15,032) 1,671,264 Corporate Bonds 15,955,794 94,766 — 16,050,560 Other 971,726 — — 971,726 Long-Term Investments: Corporate Bonds 41,191,483 1,130,771 (1,595) 42,320,659 Municipal Bonds 39,170,735 1,296,564 — 40,467,299 Government Securities 11,539,947 97,563 — 11,637,510 Total $ 298,869,584 $ 2,730,098 $ (17,927) $ 301,581,755 As of December 31, 2018: Unrealized Cost Gains Losses Market Value Short-Term Investments: Certificate of Deposit $ 150,299,384 $ — $ — $ 150,299,384 Government Securities 9,186,586 — (10,359) 9,176,227 Corporate Bonds 6,981,305 — (13,605) 6,967,700 Other 2,219,688 — — 2,219,688 Long-Term Investments: Corporate Bonds 60,659,498 50,340 (339,908) 60,369,930 Municipal Bonds 17,840,518 184,914 — 18,025,432 Government Securities 56,280,552 205,553 (2,385) 56,483,720 Total $ 303,467,531 $ 440,807 $ (366,257) $ 303,542,081 Unrealized losses on investments as of September 30, 2019, are as follows: Aggregate Unrealized Losses Aggregate Fair Value Less than one year $ 17,927 $ 10,055,721 Greater than one year — — Total $ 17,927 $ 10,055,721 Unrealized losses on investments as of December 31, 2018, are as follows: Aggregate Unrealized Losses Aggregate Fair Value Less than one year $ 365,824 $ 68,722,980 Greater than one year 433 3,000,000 Total $ 366,257 $ 71,722,980 ASC 320, Accounting for Certain Investments in Debt and Equity Securities , as amended, provides guidance on determining when an investment is other than temporarily impaired. No investment losses were considered to be other than temporary during the periods presented. The Company has the intention and current ability to hold its debt investments until the amortized cost basis has been recovered. Fixed income securities as of September 30, 2019 have contractual maturities as follows: Due within one year $ 206,184,561 Due between one and five years 59,332,380 Due over five years 35,093,088 $ 300,610,029

Inventories

Inventories	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following at the respective balance sheet dates: September 30, 2019 December 31, 2018 Raw materials $ 158,436,983 $ 139,058,541 Work-in-process 32,096,512 35,386,615 Finished goods 48,143,300 50,836,443 Total Inventory $ 238,676,795 $ 225,281,599

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The Company has unvested share-based payment awards with a right to receive non-forfeitable dividends, which are considered participating securities under ASC 260, Earnings Per Share . The Company allocates earnings to participating securities and computes earnings per share using the two-class method. Under the two-class method, net income per share is computed by dividing net income allocated to common shareholders by the weighted average number of common shares outstanding for the period. In applying the two-class method, net income is allocated to both common shares and participating securities based on their respective weighted average shares outstanding for the period. The following table sets forth the computation of basic and diluted net income per common share under the two-class method for the three and nine months ended September 30, 2019: Three Months Ended September 30, Nine Months Ended September 30, 2019 2019 Basic Earnings Per Share Net Income $ 111,897,852 $ 325,136,888 Less: Allocated to participating securities 1,389,659 3,699,548 Net Income available to common shareholders $ 110,508,193 $ 321,437,340 Basic weighted average shares outstanding 251,075,859 252,811,950 Net Income per share - Basic $ 0.44 $ 1.27 Diluted Earnings Per Share Allocation of Net Income used in basic computation $ 110,508,193 $ 321,437,340 Reallocation of undistributed earnings 6,051 15,389 Net Income available to common shareholders - Diluted $ 110,514,244 $ 321,452,729 Number of shares used in basic computation 251,075,859 252,811,950 Additional weighted average dilutive common stock equivalents 1,503,123 1,455,901 Diluted weighted average shares outstanding 252,578,982 254,267,851 Net income per share - Diluted $ 0.44 $ 1.26 Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive 3,054 170,386

Stock-Based Compensation Plans

Stock-Based Compensation Plans	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation Plans	Stock-Based Compensation Plans As of September 30, 2019, the Company had two equity incentive plans, which include the Gentex Corporation 2019 Omnibus Incentive Plan ("2019 Omnibus Plan"), and an employee stock purchase plan. Those plans and any prior material amendments thereto have previously been approved by shareholders. In February 2019, the Company's Compensation Committee and Board of Directors approved the 2019 Omnibus Plan, which was then approved by shareholders in May 2019. The 2019 Omnibus Plan provides for the potential awards to: i) employees; and ii) non-employee directors of the Company or its subsidiaries, which potential awards may be stock options, both incentive stock options and non-qualified stock options, appreciation rights, restricted stock, restricted stock units, performance share awards and performance units, and other awards that are stock-based, cash-based or a combination of both. Upon shareholder approval, the 2019 Omnibus Plan replaced the Company's Employee Stock Option Plan, Second Restricted Stock Plan, and Amended and Restated Non-Employee Director Stock Option Plan (the "Prior Plans"), which were also approved by shareholders. Any existing awards previously granted under the Prior Plans, including those made to non-officers in the first quarter of 2019, remain outstanding in accordance with their terms and are governed by the Prior Plans as applicable. Readers should refer to Note 5 of the consolidated financial statements in the Company's Annual Report on Form 10-K for the calendar year ended December 31, 2018, for additional information related to the Prior Plans. The Company recognized compensation expense for share-based payments of $5,712,132 and $15,927,434 for the three and nine months ended September 30, 2019, respectively, and $4,829,463 and $13,196,413 for the three and nine months ended September 30, 2018, respectively. Compensation cost for share based payment awards capitalized as part of inventory as of September 30, 2019 and December 31, 2018 was $320,009 and $242,673, respectively. 2019 Omnibus Incentive Plan The Omnibus Incentive Plan was approved by shareholders during the second quarter of 2019 (thereby replacing the Prior Plans) and covers 45,000,000 shares of common stock. The purpose of the 2019 Omnibus Incentive Plan is to attract and retain employees, officers, and directors of the Company and its subsidiaries and to motivate and provide such persons incentives and rewards for performance. Employee Stock Options The 2019 Omnibus Plan replaced the Company's shareholder approved Employee Stock Option Plan. Under the 2019 Omnibus Plan and the Employee Stock Option Plan, the option exercise price equals the stock’s market price on the date of grant. The options vest after one to five years, and expire after five to ten years years. As of September 30, 2019, there was $7,235,605 of unearned compensation cost related to share-based payments, which is expected to be recognized over the remaining vesting periods. The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions for the indicated periods: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Dividend Yield (1) 1.99 % 1.99 % 2.02 % 2.09 % Expected volatility (2) 24.25 % 23.32 % 23.84 % 26.65 % Risk-free interest rate (3) 1.55 % 2.94 % 1.85 % 2.78 % Expected term of options (years) (4) 4.16 4.19 4.18 4.21 Weighted-avg. grant date fair value $4.76 $4.05 $4.23 $4.70 1. Represents the Company’s estimated cash dividend yield over the expected term of option grant. 2. Amount is determined based on analysis of historical price volatility of the Company’s common stock. The expected volatility is based on the daily percentage change in the price of the stock over a period equal to the expected term of the option grant. 3. Represents the U.S. Treasury yield over the expected term of the option grant. 4. Represents the period of time that options granted are expected to be outstanding. Based on analysis of historical option exercise activity, the Company has determined that all employee groups exhibit similar exercise and post-vesting termination behavior. Restricted Shares The 2019 Omnibus Plan replaced the Company's shareholder approved Second Restricted Stock Plan. Restricted shares awarded under the 2019 Omnibus Plan and the Second Restricted Stock Plan entitle the shareholder to all rights of common stock ownership except that the shares may not be sold, transferred, pledged, exchanged or otherwise disposed of during the restriction period. The restriction period is determined by the Compensation Committee, appointed by the Board of Directors, but may not exceed ten years under the terms of such plans. As of September 30, 2019, the Company had unearned stock-based compensation of $45,627,650 associated with the restricted stock grants issued under the 2019 Omnibus Plan and the prior plan. The unearned stock-based compensation related to these grants is being amortized to compensation expense over the applicable restriction periods. Amortization expense from restricted stock grants in the three and nine months ended September 30, 2019 was $3,843,962 and $9,890,137, respectively, and for the three and nine months ended September 30, 2018 was $2,480,911 and $6,314,544, respectively. Performance Shares Performance shares awarded under the 2019 Omnibus Plan are considered performance condition awards as attainment is based on the Company's performance relative to pre-established metrics. The fair value of such performance share awards was determined using the Company's closing stock price on the date of grant. The expected attainment of the metrics for these awards is then analyzed each reporting period, and the related expense is adjusted based on expected attainment, if the then expected attainment differs from previous expectations. The cumulative effect on current and prior periods of a change in expected attainment is recognized in the period of change. As of September 30, 2019, the Company had unearned stock-based compensation of $2,480,321 associated with these performance share grants. The unearned stock-based compensation related to these grants is being amortized to compensation expense over the applicable performance periods. Amortization expense from performance share grants in the three and nine months ended September 30, 2019 was $263,392 and $633,576, respectively. No amortization expense for performance share grants was incurred in 2018, as no such awards were issued and outstanding. Employee Stock Purchase Plan The Company has an employee stock purchase plan covering 2,000,000 shares of common stock. Under the plan, the Company sells shares at 85% of the stock’s market price at date of purchase. Under ASC 718, Compensation - Stock Compensation , the 15% discounted value is recognized as compensation expense. As of September 30, 2019, the Company has issued 1,105,438 shares under this plan.

Comprehensive Income

Comprehensive Income	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Comprehensive Income	Comprehensive Income Comprehensive income reflects the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. For the Company, comprehensive income represents net income adjusted for unrealized gains and losses on certain debt investments, foreign currency translation adjustments, and derivatives. The following table presents the net changes in the Company's accumulated other comprehensive income (loss) by component (all amounts shown are net of tax): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Foreign currency translation adjustments: Balance at beginning of period $ (1,851,574) $ (194,395) $ (1,674,887) $ 645,030 Other Comprehensive loss before reclassifications (1,623,102) (1,174,213) (1,799,789) (2,013,638) Net current-period change (1,623,102) (1,174,213) (1,799,789) (2,013,638) Balance at end of period (3,474,676) (1,368,608) (3,474,676) (1,368,608) Unrealized gains (losses) on available-for-sale debt securities: Balance at beginning of period 2,350,795 (271,939) 74,549 (16,349) Other Comprehensive income (loss) before reclassifications 657,128 (276,010) 3,106,369 33,941 Amounts reclassified from accumulated other comprehensive income (295,752) (205,433) (468,747) (770,974) Net current-period change 361,376 (481,443) 2,637,622 (737,033) Balance at end of period 2,712,171 (753,382) 2,712,171 (753,382) Unrealized gains on derivatives: Balance at beginning of period — (12,770) — (78,026) Other comprehensive income before reclassifications — 114,889 — 175,308 Amounts reclassified from accumulated other comprehensive income — (102,119) — (97,282) Net current-period change — 12,770 — 78,026 Balance at end of period — — — — Accumulated other comprehensive loss, end of period $ (762,505) $ (2,121,990) $ (762,505) $ (2,121,990) The following table presents details of reclassifications out of accumulated other comprehensive income for the three and nine months ended September 30, 2019 and 2018. Details about Accumulated Other Comprehensive Income Components Amounts Reclassified from Other Comprehensive Income Affected Line item in the Statement of Consolidated Income Three Months Ended September 30, Nine Months Ended September June 30, 2019 2018 2019 2018 Unrealized gains on available-for-sale debt securities Realized gain on sale $ 374,370 $ 260,042 $ 593,351 $ 975,917 Other income (loss), net Provision for income taxes (78,618) (54,609) (124,604) (204,943) Provision for income taxes $ 295,752 $ 205,433 $ 468,747 $ 770,974 Net of tax Unrealized gains on derivatives Realized gain on interest rate swap $ — $ 129,265 $ — $ 123,142 Other income (loss), net Provision for income taxes — (27,146) — (25,860) Provision for income taxes $ — $ 102,119 $ — $ 97,282 Net of tax Total net reclassifications for the period $ 295,752 $ 307,552 $ 468,747 $ 868,256 Net of tax

Debt and Financing Arrangements

Debt and Financing Arrangements	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Debt and Financing Arrangements	Debt and Financing Arrangements On October 15, 2018, the Company entered into a new Credit Agreement (“Credit Agreement”) with PNC as the administrative agent and sole lender. Pursuant to this new Credit Agreement, the Company has access to a $150 million senior revolving credit facility (“Revolver”). Under the terms of the Credit Agreement, the Company is entitled to further request an additional aggregate principal amount of up to $100 million, subject to the satisfaction of certain conditions. In addition, the Company is entitled to the benefit of swing loans from amounts otherwise available under the Revolver in the aggregate principal amount of up to $20 million and to request Letters of Credit from amounts otherwise available under the Revolver in the aggregate principle amount up to $20 million, both subject to certain conditions. The obligations of the Company under the Credit Agreement are not secured, but are subject to certain covenants. As of September 30, 2019, there was no outstanding balance on the Revolver. The Revolver expires on October 15, 2023. The Credit Agreement contains customary representations and warranties and certain covenants that place certain limitations on the Company. As of September 30, 2019, the Company was in compliance with its covenants under the Credit Agreement. During the three and nine months ended September 30, 2018, under a previous credit facility, interest expense was $0.1 million and $0.8 million, respectively, which was netted with the "Other income (loss), net" section of the Unaudited Consolidated Statements of Income .

Equity

Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Equity	Equity The decrease in common stock during the nine months ended September 30, 2019, was primarily due to the repurchases of 11.4 million shares, partially offset by the issuance of 5.1 million shares of the Company’s common stock under the Company’s stock-based compensation plans. The total net decrease was 6.3 million shares. The Company announced a $0.005 (1/2 cent) per share increase in its quarterly cash dividend rate during the first quarter of 2019. As such, the Company recorded a cash dividend of $0.115 during the third quarter of 2019 as compared to a cash dividend of $0.110 per share during the third quarter of 2018. The third quarter 2019 dividend of $29.1 million was declared on August 27, 2019, and was paid on October 23, 2019.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Contingencies	ContingenciesThe Company is periodically involved in legal proceedings, legal actions and claims arising in the normal course of business, including proceedings relating to product liability, intellectual property, safety and health, employment, regulatory, and other matters. Such matters are subject to many uncertainties and outcomes are not predictable. The Company does not believe, however, that at the current time any of these matters constitute material pending legal proceedings that will have a material adverse effect on the financial position or future results of operations or cash flows of the Company.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segment Reporting	Segment Reporting The Company's automotive segment develops and manufactures digital vision and connected car products and electronics, including: automatic-dimming rearview mirrors with and without electronic features; non-auto dimming rearview mirrors with and without electronic features; and other electronics. The Company also develops and manufactures variably dimming windows for the aerospace industry and fire protection products for the commercial construction industry, which are combined into the "Other" segment shown below. Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Revenue: Automotive Products $ 464,280,707 $ 449,184,447 $ 1,376,704,413 $ 1,348,395,245 Other 13,480,710 11,068,986 38,357,355 32,259,733 Total $ 477,761,417 $ 460,253,433 $ 1,415,061,768 $ 1,380,654,978 Income from operations: Automotive Products $ 123,342,538 $ 124,351,499 $ 364,590,462 $ 373,071,852 Other 4,793,142 3,076,412 13,046,517 9,554,396 Total $ 128,135,680 $ 127,427,911 $ 377,636,979 $ 382,626,248

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesThe effective tax rate was 15.9% in the nine months ended September 30, 2019 compared to 15.2% for the same period in 2018. Generally, effective tax rates for these periods differ from statutory federal income tax rates, due to provisions for state and local income taxes, permanent tax differences, and the foreign-derived intangible income tax deduction and research and development tax credits. The increase in the effective tax rate for the nine months ended September 30, 2019 compared to the same period of 2018 was primarily due to a decrease in discrete tax benefits related to stock-based compensation in the current year and other tax planning strategies.

Revenue

Revenue	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The following table shows the Company’s Automotive revenue and Other Products revenue disaggregated by geographical location for Automotive Products for the three and nine month periods ended September 30, 2019 and September 30, 2018: Revenue Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Automotive Products U.S. $ 145,798,028 $ 151,229,829 $ 431,729,037 $ 434,439,455 Germany 74,047,596 81,621,623 225,649,215 259,057,369 Japan 60,641,977 55,363,644 172,697,963 153,843,723 Mexico 43,884,609 28,410,998 130,473,702 73,868,425 Other 139,908,497 132,558,353 416,154,496 427,186,273 Total Automotive Products $ 464,280,707 $ 449,184,447 $ 1,376,704,413 $ 1,348,395,245 Other Products (U.S.) 13,480,710 11,068,986 38,357,355 32,259,733 Total Revenue $ 477,761,417 $ 460,253,433 $ 1,415,061,768 $ 1,380,654,978 Revenue by geographic area may fluctuate based on many factors, including: exposure to local economic, political and labor conditions; unexpected changes in laws, regulations, trade or monetary or fiscal policy, including interest rates, foreign currency exchange rates and changes in the rate of inflation in the U.S. and other foreign countries; and tariffs, quotas, customs and other import or export restrictions and other trade barriers. The following table disaggregates the Company’s Automotive revenue and Other revenue by major source for the three and nine month periods ended September 30, 2019 and September 30, 2018: Revenue Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Automotive Segment Automotive Mirrors & Electronics $ 418,746,334 $ 399,732,577 $ 1,241,147,268 $ 1,200,521,589 HomeLink Modules* 45,534,373 49,451,870 135,557,145 147,873,656 Total Automotive Products $ 464,280,707 $ 449,184,447 $ 1,376,704,413 $ 1,348,395,245 Other Segment Fire Protection Products 5,977,245 5,918,085 18,188,744 17,010,954 Windows Products 7,503,465 5,150,901 20,168,611 15,248,779 Total Other $ 13,480,710 $ 11,068,986 $ 38,357,355 $ 32,259,733 *Excludes HomeLink revenue where HomeLink electronics are integrated into interior auto-dimming mirrors.

Leases

Leases	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Leases	Leases The Company has operating leases for corporate offices, warehouses, vehicles, and other equipment, which are included within "Plant and Equipment - Net" section of the Condensed Consolidated Balance Sheets. The leases have remaining lease terms of 1 year to 5 years. The weighted average remaining lease term for operating leases as of September 30, 2019 was 2 years, with a weighted average discount rate of 2.9%. Future minimum lease payments for operating leases as of September 30, 2019 were as follows: Year ending December 31, 2019 (excluding the nine months ended September 30, 2019) $ 361,604 2020 575,861 2021 143,581 2022 57,143 2023 11,130 Thereafter 12,797 Total future minimum lease payments 1,162,116 Less imputed interest (20,423) Total $ 1,141,693 Reported as of September 30, 2019 Accrued Liabilities $ 870,930 Other Non-Current Liabilities 270,763 Total $ 1,141,693

Adoption of New Accounting Pr_2

Adoption of New Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Adoption of New Accounting Pronouncements	New Accounting Pronouncements Adopted in Fiscal Year 2019 Effective January 1, 2019, the Company adopted Accounting Standards Update ("ASU") 2016-02, Leases , which provides guidance for lease accounting. The new guidance contained in the ASU stipulates that lessees will need to recognize a right-of-use ("ROU") asset and a lease liability for substantially all leases (other than leases that meet the definition of a short-term lease). The liability will be equal to the present value of lease payments. Treatment in the consolidated statements of income will be similar to the historical treatment of operating and capital leases. The adoption of this standard did not have a material impact on the Company's consolidated balance sheet or consolidated income statement. Disclosures are now required to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instrument s. The standard requires a change in the measurement approach for credit losses on financial assets measured on an amortized cost basis from an incurred loss method to an expected loss method, thereby eliminating the requirement that a credit loss be considered probable to impact the valuation of a financial asset measured on an amortized cost basis. The standard requires the measurement of expected credit losses to be based on relevant information about past events, including historical experience, current conditions, and a reasonable and supportable forecast that affects the collectability of the related financial asset. The Company will be required to adopt ASU 2016-13 as of January 1, 2020. Early adoption is permitted. The Company does not anticipate a material impact on the Company’s consolidated financial statements.

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Intangible Assets	The patents and intangible assets and related change in carrying values are set forth in the tables below: As of September 30, 2019: Other Intangible Assets Gross Accumulated Amortization Net Assumed Useful Life Gentex Patents $ 37,160,431 $ (22,094,953) $ 15,065,478 Various Other Intangible Assets HomeLink ® Trade Names and Trademarks $ 52,000,000 $ — $ 52,000,000 Indefinite HomeLink ® Technology 180,000,000 (90,000,000) 90,000,000 12 years Existing Customer Platforms 43,000,000 (25,800,000) 17,200,000 10 years Exclusive Licensing Agreement 96,000,000 — 96,000,000 Indefinite Total Other Intangible Assets $ 371,000,000 $ (115,800,000) $ 255,200,000 Total Patents & Other Intangible Assets $ 408,160,431 $ (137,894,953) $ 270,265,478 As of December 31, 2018: Other Intangible Assets Gross Accumulated Amortization Net Assumed Useful Life Gentex Patents $ 36,737,434 $ (21,014,168) $ 15,723,266 Various Other Intangible Assets HomeLink ® Trade Names and Trademarks $ 52,000,000 $ — $ 52,000,000 Indefinite HomeLink ® Technology 180,000,000 (78,750,000) 101,250,000 12 years Existing Customer Platforms 43,000,000 (22,575,000) 20,425,000 10 years Exclusive Licensing Agreement 96,000,000 — 96,000,000 Indefinite Total Other Intangible Assets $ 371,000,000 $ (101,325,000) $ 269,675,000 Total Patents & Other Intangible Assets $ 407,737,434 $ (122,339,168) $ 285,398,266

Investments (Tables)

Investments (Tables)	9 Months Ended
	Sep. 30, 2019
Investments [Abstract]
Investment Securities Stated at Fair Value	Assets or liabilities that have recurring fair value measurements are shown below as of September 30, 2019 and December 31, 2018: As of September 30, 2019: Fair Value Measurements at Reporting Date Using Total as of Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description September 30, 2019 (Level 1) (Level 2) (Level 3) Cash & Cash Equivalents $ 260,151,083 $ 260,151,083 $ — $ — Short-Term Investments: Certificate of Deposit 150,299,384 150,299,384 — — Government Securities 38,163,353 — 38,163,353 — Corporate Bonds 16,050,560 — 16,050,560 — Municipal Bonds 1,671,264 — 1,671,264 — Other 971,726 971,726 — — Long-Term Investments: Corporate Bonds 42,320,659 — 42,320,659 — Municipal Bonds 40,467,299 — 40,467,299 — Government Securities 11,637,510 — 11,637,510 — Total $ 561,732,838 $ 411,422,193 $ 150,310,645 $ — As of December 31, 2018: Fair Value Measurements at Reporting Date Using Total as of Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description December 31, 2018 (Level 1) (Level 2) (Level 3) Cash & Cash Equivalents $ 217,025,278 $ 217,025,278 $ — $ — Short-Term Investments: Certificate of Deposit 150,299,384 150,299,384 — — Government Securities 9,176,227 — 9,176,227 — Corporate Bonds 6,967,700 — 6,967,700 — Other 2,219,688 2,219,688 — — Long-Term Investments: Corporate Bonds 60,369,930 — 60,369,930 — Municipal Bonds 18,025,432 — 18,025,432 — Government Securities 56,483,720 — 56,483,720 — Total $ 520,567,359 $ 369,544,350 $ 151,023,009 $ —
Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value of Investment Securities	The amortized cost, unrealized gains and losses, and market value of investment securities are shown as of September 30, 2019 and December 31, 2018: As of September 30, 2019: Unrealized Cost Gains Losses Market Value Short-Term Investments: Certificate of Deposit $ 150,299,384 $ — $ — $ 150,299,384 Government Securities 38,067,382 97,271 (1,300) 38,163,353 Municipal Bonds 1,673,133 13,163 (15,032) 1,671,264 Corporate Bonds 15,955,794 94,766 — 16,050,560 Other 971,726 — — 971,726 Long-Term Investments: Corporate Bonds 41,191,483 1,130,771 (1,595) 42,320,659 Municipal Bonds 39,170,735 1,296,564 — 40,467,299 Government Securities 11,539,947 97,563 — 11,637,510 Total $ 298,869,584 $ 2,730,098 $ (17,927) $ 301,581,755 As of December 31, 2018: Unrealized Cost Gains Losses Market Value Short-Term Investments: Certificate of Deposit $ 150,299,384 $ — $ — $ 150,299,384 Government Securities 9,186,586 — (10,359) 9,176,227 Corporate Bonds 6,981,305 — (13,605) 6,967,700 Other 2,219,688 — — 2,219,688 Long-Term Investments: Corporate Bonds 60,659,498 50,340 (339,908) 60,369,930 Municipal Bonds 17,840,518 184,914 — 18,025,432 Government Securities 56,280,552 205,553 (2,385) 56,483,720 Total $ 303,467,531 $ 440,807 $ (366,257) $ 303,542,081
Schedule of Unrealized Loss on Investments	Unrealized losses on investments as of September 30, 2019, are as follows: Aggregate Unrealized Losses Aggregate Fair Value Less than one year $ 17,927 $ 10,055,721 Greater than one year — — Total $ 17,927 $ 10,055,721 Unrealized losses on investments as of December 31, 2018, are as follows: Aggregate Unrealized Losses Aggregate Fair Value Less than one year $ 365,824 $ 68,722,980 Greater than one year 433 3,000,000 Total $ 366,257 $ 71,722,980
Investments Classified by Contractual Maturity Date	Fixed income securities as of September 30, 2019 have contractual maturities as follows: Due within one year $ 206,184,561 Due between one and five years 59,332,380 Due over five years 35,093,088 $ 300,610,029

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2019
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories consisted of the following at the respective balance sheet dates: September 30, 2019 December 31, 2018 Raw materials $ 158,436,983 $ 139,058,541 Work-in-process 32,096,512 35,386,615 Finished goods 48,143,300 50,836,443 Total Inventory $ 238,676,795 $ 225,281,599

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share Basic And Diluted	The following table sets forth the computation of basic and diluted net income per common share under the two-class method for the three and nine months ended September 30, 2019: Three Months Ended September 30, Nine Months Ended September 30, 2019 2019 Basic Earnings Per Share Net Income $ 111,897,852 $ 325,136,888 Less: Allocated to participating securities 1,389,659 3,699,548 Net Income available to common shareholders $ 110,508,193 $ 321,437,340 Basic weighted average shares outstanding 251,075,859 252,811,950 Net Income per share - Basic $ 0.44 $ 1.27 Diluted Earnings Per Share Allocation of Net Income used in basic computation $ 110,508,193 $ 321,437,340 Reallocation of undistributed earnings 6,051 15,389 Net Income available to common shareholders - Diluted $ 110,514,244 $ 321,452,729 Number of shares used in basic computation 251,075,859 252,811,950 Additional weighted average dilutive common stock equivalents 1,503,123 1,455,901 Diluted weighted average shares outstanding 252,578,982 254,267,851 Net income per share - Diluted $ 0.44 $ 1.26 Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive 3,054 170,386

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Weighted-Average Assumptions For The Employee Stock Option Plan	The fair value of each option grant was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions for the indicated periods: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Dividend Yield (1) 1.99 % 1.99 % 2.02 % 2.09 % Expected volatility (2) 24.25 % 23.32 % 23.84 % 26.65 % Risk-free interest rate (3) 1.55 % 2.94 % 1.85 % 2.78 % Expected term of options (years) (4) 4.16 4.19 4.18 4.21 Weighted-avg. grant date fair value $4.76 $4.05 $4.23 $4.70 1. Represents the Company’s estimated cash dividend yield over the expected term of option grant. 2. Amount is determined based on analysis of historical price volatility of the Company’s common stock. The expected volatility is based on the daily percentage change in the price of the stock over a period equal to the expected term of the option grant. 3. Represents the U.S. Treasury yield over the expected term of the option grant. 4. Represents the period of time that options granted are expected to be outstanding. Based on analysis of historical option exercise activity, the Company has determined that all employee groups exhibit similar exercise and post-vesting termination behavior.

Comprehensive Income (Tables)

Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Schedule of AOCI	The following table presents the net changes in the Company's accumulated other comprehensive income (loss) by component (all amounts shown are net of tax): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Foreign currency translation adjustments: Balance at beginning of period $ (1,851,574) $ (194,395) $ (1,674,887) $ 645,030 Other Comprehensive loss before reclassifications (1,623,102) (1,174,213) (1,799,789) (2,013,638) Net current-period change (1,623,102) (1,174,213) (1,799,789) (2,013,638) Balance at end of period (3,474,676) (1,368,608) (3,474,676) (1,368,608) Unrealized gains (losses) on available-for-sale debt securities: Balance at beginning of period 2,350,795 (271,939) 74,549 (16,349) Other Comprehensive income (loss) before reclassifications 657,128 (276,010) 3,106,369 33,941 Amounts reclassified from accumulated other comprehensive income (295,752) (205,433) (468,747) (770,974) Net current-period change 361,376 (481,443) 2,637,622 (737,033) Balance at end of period 2,712,171 (753,382) 2,712,171 (753,382) Unrealized gains on derivatives: Balance at beginning of period — (12,770) — (78,026) Other comprehensive income before reclassifications — 114,889 — 175,308 Amounts reclassified from accumulated other comprehensive income — (102,119) — (97,282) Net current-period change — 12,770 — 78,026 Balance at end of period — — — — Accumulated other comprehensive loss, end of period $ (762,505) $ (2,121,990) $ (762,505) $ (2,121,990)
Reclassifications out of other comprehensive income	The following table presents details of reclassifications out of accumulated other comprehensive income for the three and nine months ended September 30, 2019 and 2018. Details about Accumulated Other Comprehensive Income Components Amounts Reclassified from Other Comprehensive Income Affected Line item in the Statement of Consolidated Income Three Months Ended September 30, Nine Months Ended September June 30, 2019 2018 2019 2018 Unrealized gains on available-for-sale debt securities Realized gain on sale $ 374,370 $ 260,042 $ 593,351 $ 975,917 Other income (loss), net Provision for income taxes (78,618) (54,609) (124,604) (204,943) Provision for income taxes $ 295,752 $ 205,433 $ 468,747 $ 770,974 Net of tax Unrealized gains on derivatives Realized gain on interest rate swap $ — $ 129,265 $ — $ 123,142 Other income (loss), net Provision for income taxes — (27,146) — (25,860) Provision for income taxes $ — $ 102,119 $ — $ 97,282 Net of tax Total net reclassifications for the period $ 295,752 $ 307,552 $ 468,747 $ 868,256 Net of tax

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule of Automotive and Other Segment Reporting	The Company's automotive segment develops and manufactures digital vision and connected car products and electronics, including: automatic-dimming rearview mirrors with and without electronic features; non-auto dimming rearview mirrors with and without electronic features; and other electronics. The Company also develops and manufactures variably dimming windows for the aerospace industry and fire protection products for the commercial construction industry, which are combined into the "Other" segment shown below. Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Revenue: Automotive Products $ 464,280,707 $ 449,184,447 $ 1,376,704,413 $ 1,348,395,245 Other 13,480,710 11,068,986 38,357,355 32,259,733 Total $ 477,761,417 $ 460,253,433 $ 1,415,061,768 $ 1,380,654,978 Income from operations: Automotive Products $ 123,342,538 $ 124,351,499 $ 364,590,462 $ 373,071,852 Other 4,793,142 3,076,412 13,046,517 9,554,396 Total $ 128,135,680 $ 127,427,911 $ 377,636,979 $ 382,626,248

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table shows the Company’s Automotive revenue and Other Products revenue disaggregated by geographical location for Automotive Products for the three and nine month periods ended September 30, 2019 and September 30, 2018: Revenue Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Automotive Products U.S. $ 145,798,028 $ 151,229,829 $ 431,729,037 $ 434,439,455 Germany 74,047,596 81,621,623 225,649,215 259,057,369 Japan 60,641,977 55,363,644 172,697,963 153,843,723 Mexico 43,884,609 28,410,998 130,473,702 73,868,425 Other 139,908,497 132,558,353 416,154,496 427,186,273 Total Automotive Products $ 464,280,707 $ 449,184,447 $ 1,376,704,413 $ 1,348,395,245 Other Products (U.S.) 13,480,710 11,068,986 38,357,355 32,259,733 Total Revenue $ 477,761,417 $ 460,253,433 $ 1,415,061,768 $ 1,380,654,978 Revenue by geographic area may fluctuate based on many factors, including: exposure to local economic, political and labor conditions; unexpected changes in laws, regulations, trade or monetary or fiscal policy, including interest rates, foreign currency exchange rates and changes in the rate of inflation in the U.S. and other foreign countries; and tariffs, quotas, customs and other import or export restrictions and other trade barriers. The following table disaggregates the Company’s Automotive revenue and Other revenue by major source for the three and nine month periods ended September 30, 2019 and September 30, 2018: Revenue Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Automotive Segment Automotive Mirrors & Electronics $ 418,746,334 $ 399,732,577 $ 1,241,147,268 $ 1,200,521,589 HomeLink Modules* 45,534,373 49,451,870 135,557,145 147,873,656 Total Automotive Products $ 464,280,707 $ 449,184,447 $ 1,376,704,413 $ 1,348,395,245 Other Segment Fire Protection Products 5,977,245 5,918,085 18,188,744 17,010,954 Windows Products 7,503,465 5,150,901 20,168,611 15,248,779 Total Other $ 13,480,710 $ 11,068,986 $ 38,357,355 $ 32,259,733 *Excludes HomeLink revenue where HomeLink electronics are integrated into interior auto-dimming mirrors.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Future minimum lease payments	Future minimum lease payments for operating leases as of September 30, 2019 were as follows: Year ending December 31, 2019 (excluding the nine months ended September 30, 2019) $ 361,604 2020 575,861 2021 143,581 2022 57,143 2023 11,130 Thereafter 12,797 Total future minimum lease payments 1,162,116 Less imputed interest (20,423) Total $ 1,141,693
Lease liabilities	Reported as of September 30, 2019 Accrued Liabilities $ 870,930 Other Non-Current Liabilities 270,763 Total $ 1,141,693

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	[1]	Sep. 27, 2013
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 307,365,845		$ 307,365,845		$ 307,365,845
Amortization expense	5,600,000	$ 5,600,000	16,800,000	$ 16,900,000
Amortization expense, 2019	22,000,000		22,000,000
Amortization expense, 2020	22,000,000		22,000,000
Amortization expense, 2021	22,000,000		22,000,000
Amortization expense, 2022	21,000,000		21,000,000
Amortization expense, 2023	$ 19,000,000		$ 19,000,000
HomeLink®
Finite-Lived Intangible Assets [Line Items]
Goodwill							$ 307,400,000
[1]	The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited 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.

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($)	3 Months Ended	9 Months Ended
	Mar. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, accumulated amortization		$ (115,800,000)	$ (101,325,000)
Intangible assets, gross		371,000,000	371,000,000
Intangible assets, net		255,200,000	269,675,000	[1]
Gentex Patents
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		37,160,431	36,737,434
Finite-lived intangible assets, accumulated amortization		(22,094,953)	(21,014,168)
Finite-lived intangible assets, net		15,065,478	15,723,266
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		(90,000,000)	(78,750,000)
Finite-lived intangible assets, net		$ 90,000,000	101,250,000
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		(25,800,000)	(22,575,000)
Finite-lived intangible assets, net		$ 17,200,000	20,425,000
Finite-lived intangible asset, useful life	10 years	10 years
Patents and Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, accumulated amortization		$ (137,894,953)	(122,339,168)
Intangible assets, gross		408,160,431	407,737,434
Intangible assets, net		270,265,478	285,398,266
HomeLink Trade Names and Trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		52,000,000	52,000,000
Exclusive Licensing Agreement
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets		$ 96,000,000	$ 96,000,000
[1]	The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited 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.

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Technology investments	$ 8,600,000	$ 3,850,000
Equity investment losses were considered to be other than temporary	$ 0	$ 0

Investments (Schedule of Assets

Investments (Schedule of Assets or Liabilities, Recurring Fair Value Measurements) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash & Cash Equivalents	$ 260,151,083	$ 217,025,278
Market Value	301,581,755	303,542,081
Investments and Cash	561,732,838	520,567,359
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash & Cash Equivalents	260,151,083	217,025,278
Investments and Cash	411,422,193	369,544,350
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash & Cash Equivalents	0	0
Investments and Cash	150,310,645	151,023,009
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash & Cash Equivalents	0	0
Investments and Cash	0	0
Short-Term Investments | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	150,299,384	150,299,384
Short-Term Investments | Certificates of Deposit | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	150,299,384	150,299,384
Short-Term Investments | Certificates of Deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Certificates of Deposit | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	38,163,353	9,176,227
Short-Term Investments | Government Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Government Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	38,163,353	9,176,227
Short-Term Investments | Government Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	16,050,560	6,967,700
Short-Term Investments | Corporate Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Corporate Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	16,050,560	6,967,700
Short-Term Investments | Corporate Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	971,726	2,219,688
Short-Term Investments | Other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	971,726	2,219,688
Short-Term Investments | Other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Short-Term Investments | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	1,671,264
Short-Term Investments | Municipal Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0
Short-Term Investments | Municipal Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	1,671,264
Short-Term Investments | Municipal Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0
Long-Term Investments | Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	11,637,510	56,483,720
Long-Term Investments | Government Securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Long-Term Investments | Government Securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	11,637,510	56,483,720
Long-Term Investments | Government Securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Long-Term Investments | Corporate Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	42,320,659	60,369,930
Long-Term Investments | Corporate Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Long-Term Investments | Corporate Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	42,320,659	60,369,930
Long-Term Investments | Corporate Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Long-Term Investments | Municipal Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	40,467,299	18,025,432
Long-Term Investments | Municipal Bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	0	0
Long-Term Investments | Municipal Bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	40,467,299	18,025,432
Long-Term Investments | Municipal Bonds | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Market Value	$ 0	$ 0

Investments (Schedule of Amorti

Investments (Schedule of Amortized Cost, Unrealized Gains and Losses, and Market Value of Investment Securities) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Cost	$ 298,869,584	$ 303,467,531
Unrealized Gains	2,730,098	440,807
Unrealized Losses	(17,927)	(366,257)
Market Value	301,581,755	303,542,081
Short-Term Investments | Certificates of Deposit
Debt Securities, Available-for-sale [Line Items]
Cost	150,299,384	150,299,384
Unrealized Gains	0	0
Unrealized Losses	0	0
Market Value	150,299,384	150,299,384
Short-Term Investments | Government Securities
Debt Securities, Available-for-sale [Line Items]
Cost	38,067,382	9,186,586
Unrealized Gains	97,271	0
Unrealized Losses	(1,300)	(10,359)
Market Value	38,163,353	9,176,227
Short-Term Investments | Corporate Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	15,955,794	6,981,305
Unrealized Gains	94,766	0
Unrealized Losses	0	(13,605)
Market Value	16,050,560	6,967,700
Short-Term Investments | Other
Debt Securities, Available-for-sale [Line Items]
Cost	971,726	2,219,688
Unrealized Gains	0	0
Unrealized Losses	0	0
Market Value	971,726	2,219,688
Short-Term Investments | Municipal Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	1,673,133
Unrealized Gains	13,163
Unrealized Losses	(15,032)
Market Value	1,671,264
Long-Term Investments | Government Securities
Debt Securities, Available-for-sale [Line Items]
Cost	11,539,947	56,280,552
Unrealized Gains	97,563	205,553
Unrealized Losses	0	(2,385)
Market Value	11,637,510	56,483,720
Long-Term Investments | Corporate Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	41,191,483	60,659,498
Unrealized Gains	1,130,771	50,340
Unrealized Losses	(1,595)	(339,908)
Market Value	42,320,659	60,369,930
Long-Term Investments | Municipal Bonds
Debt Securities, Available-for-sale [Line Items]
Cost	39,170,735	17,840,518
Unrealized Gains	1,296,564	184,914
Unrealized Losses	0	0
Market Value	$ 40,467,299	$ 18,025,432

Investments (Schedule of Unreal

Investments (Schedule of Unrealized Loss on Investments) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Investments [Abstract]
Aggregate Unrealized Losses, Less than one year	$ 17,927	$ 365,824
Aggregate Fair Value, Less than one year	10,055,721	68,722,980
Aggregate Unrealized Losses, Greater than one year	0	433
Aggregate Fair Value, Greater than one year	0	3,000,000
Aggregate Unrealized Losses, Total	17,927	366,257
Aggregate Fair Value, Total	$ 10,055,721	$ 71,722,980

Investments (Investments Classi

Investments (Investments Classified by Contractual Maturity Date) (Details) - Fixed Income Securities	Sep. 30, 2019USD ($)
Debt Securities, Available-for-sale [Line Items]
Due within one year	$ 206,184,561
Due between one and five years	59,332,380
Due over five years	35,093,088
Total	$ 300,610,029

Inventories (Schedule of Invent

Inventories (Schedule of Inventories) (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 158,436,983	$ 139,058,541
Work-in-process	32,096,512	35,386,615
Finished goods	48,143,300	50,836,443
Total Inventory	$ 238,676,795	$ 225,281,599	[1]
[1]	The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited 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.

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Earnings Per Share, Basic and Diluted) (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income (loss)		$ 111,897,852	$ 111,335,817	$ 325,136,888	$ 331,608,542
Less: Allocated to participating securities		1,389,659		3,699,548
Net Income available to common shareholders		$ 110,508,193		$ 321,437,340
Basic weighted average shares outstanding (in shares)		251,075,859		252,811,950
Net Income per share - Basic (in dollars per share)	[1]	$ 0.44	$ 0.42	$ 1.27	$ 1.23
Reallocation of undistributed earnings		$ 6,051		$ 15,389
Net Income available to common shareholders - Diluted		$ 110,514,244		$ 321,452,729
Additional weighted average dilutive common stock equivalents (in shares)		1,503,123		1,455,901
Diluted weighted average shares outstanding (in shares)		252,578,982		254,267,851
Diluted (in dollars per share)	[1]	$ 0.44	$ 0.42	$ 1.26	$ 1.22
Shares related to stock plans not included in diluted average common shares outstanding because their effect would be anti-dilutive (in shares)		3,054		170,386
[1]	(1) Earnings Per Share has been adjusted to exclude the portion of net income allocated to participating securities as a result of share-based payment awards.

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans (Narrative) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019USD ($)planshares	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)planshares	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for share-based payments	$ 5,712,132	$ 4,829,463	$ 15,927,434	$ 13,196,413
Inventory
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense for share-based payments			320,009		$ 242,673
Employee Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 7,235,605		$ 7,235,605
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
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares approved (in shares) | shares	2,000,000		2,000,000
ESPP discount rate			85.00%
ESPP discount rate recognized as compensation expense			15.00%
Shares granted (in shares) | shares	1,105,438		1,105,438
Restricted Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 45,627,650		$ 45,627,650
Restricted period, maximum, in years			10 years
Amortization expense	$ 3,843,962	2,480,911	$ 9,890,137	6,314,544
Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares) | shares	45,000,000		45,000,000
Restricted period, maximum, in years			3 years
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]
Unrecognized compensation cost	$ 2,480,321		$ 2,480,321
Amortization expense	$ 263,392	$ 0	$ 633,576	$ 0

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans (Weighted-Average Assumptions for the ESOP) (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Payment Arrangement [Abstract]
Dividend yield	1.99%	1.99%	2.02%	2.09%
Expected volatility	24.25%	23.32%	23.84%	26.65%
Risk-free interest rate	1.55%	2.94%	1.85%	2.78%
Expected term of options	4 years 1 month 28 days	4 years 2 months 8 days	4 years 2 months 4 days	4 years 2 months 15 days
Weighted-avg. grant-date fair value (in dollars per share)	$ 4.76	$ 4.05	$ 4.23	$ 4.70

Comprehensive Income (AOCI Roll

Comprehensive Income (AOCI Rollforward) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018	Dec. 31, 2018	[1]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,904,334,235	$ 1,921,499,312	$ 1,861,751,660	[1]	$ 2,049,518,261
Comprehensive Income	110,636,126	109,692,931	325,974,721		328,935,897
Balance at end of period	1,921,328,263	1,843,104,255	1,921,328,263		1,843,104,255
Accumulated other comprehensive loss, end of period	(762,505)		(762,505)			$ (1,600,338)
Accumulated  Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	499,221	(479,104)	(1,600,338)		7,193,383
Balance at end of period	(762,505)	(2,121,990)	(762,505)		(2,121,990)
Accumulated other comprehensive loss, end of period	(762,505)	(2,121,990)	(762,505)		(2,121,990)
Foreign currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(1,851,574)	(194,395)	(1,674,887)		645,030
Other Comprehensive income (loss) before reclassifications	(1,623,102)	(1,174,213)	(1,799,789)		(2,013,638)
Comprehensive Income	(1,623,102)	(1,174,213)	(1,799,789)		(2,013,638)
Balance at end of period	(3,474,676)	(1,368,608)	(3,474,676)		(1,368,608)
Unrealized gains (losses) on available-for-sale debt securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	2,350,795	(271,939)	74,549		(16,349)
Other Comprehensive income (loss) before reclassifications	657,128	(276,010)	3,106,369		33,941
Amounts reclassified from accumulated other comprehensive income	(295,752)	(205,433)	(468,747)		(770,974)
Comprehensive Income	361,376	(481,443)	2,637,622		(737,033)
Balance at end of period	2,712,171	(753,382)	2,712,171		(753,382)
Unrealized gains (losses) on derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	0	(12,770)	0		(78,026)
Other Comprehensive income (loss) before reclassifications	0	114,889	0		175,308
Amounts reclassified from accumulated other comprehensive income	0	(102,119)	0		(97,282)
Comprehensive Income	0	12,770	0		78,026
Balance at end of period	$ 0	$ 0	$ 0		$ 0
[1]	The condensed consolidated balance sheet at December 31, 2018 has been derived from the audited 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.

Comprehensive Income (Reclassif

Comprehensive Income (Reclassification Out of Accumulated Other Comprehensive Income) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Provision for income taxes	$ (19,681,661)	$ (19,198,798)	$ (61,633,712)	$ (59,658,782)
Amounts Reclassified from Other Comprehensive Income
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Total net reclassifications for the period	295,752	307,552	468,747	868,256
Amounts Reclassified from Other Comprehensive Income | Unrealized gains (losses) on available-for-sale debt securities
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss) on sale of securities and interest rate swap	374,370	260,042	593,351	975,917
Provision for income taxes	(78,618)	(54,609)	(124,604)	(204,943)
Total net reclassifications for the period	295,752	205,433	468,747	770,974
Amounts Reclassified from Other Comprehensive Income | Unrealized gains (losses) on derivatives
Reclassification Out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss) on sale of securities and interest rate swap	0	129,265	0	123,142
Provision for income taxes	0	(27,146)	0	(25,860)
Total net reclassifications for the period	$ 0	$ 102,119	$ 0	$ 97,282

Debt and Financing Arrangemen_2

Debt and Financing Arrangements (Details) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2019	Oct. 15, 2018
Debt Instrument [Line Items]
Interest expense	$ 100,000	$ 800,000
Revolving Facility
Debt Instrument [Line Items]
Principal amount				$ 150,000,000
Long-term debt			$ 0
Credit Agreement
Debt Instrument [Line Items]
Additional borrowings available				100,000,000
Swing Loans
Debt Instrument [Line Items]
Additional borrowings available				20,000,000
Letter of Credit
Debt Instrument [Line Items]
Additional borrowings available				$ 20,000,000

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity [Abstract]
Stock repurchased (in shares)				11.4
Common stock issued under stock compensation plan (in shares)				5.1
Net decrease in period (in shares)				6.3
Increase in quarterly dividend rate (in dollars per share)		$ 0.005
Dividends declared (in dollars per share)	$ 0.115		$ 0.110	$ 0.345	$ 0.330
Dividends declared	$ 29.1

Segment Reporting (Schedule of

Segment Reporting (Schedule of Automotive and Other Segment Reporting) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Revenue	$ 477,761,417	$ 460,253,433	$ 1,415,061,768	$ 1,380,654,978
Income from operations	128,135,680	127,427,911	377,636,979	382,626,248
Automotive Products
Segment Reporting Information [Line Items]
Revenue	464,280,707	449,184,447	1,376,704,413	1,348,395,245
Income from operations	123,342,538	124,351,499	364,590,462	373,071,852
Other
Segment Reporting Information [Line Items]
Revenue	13,480,710	11,068,986	38,357,355	32,259,733
Income from operations	$ 4,793,142	$ 3,076,412	$ 13,046,517	$ 9,554,396

Income Taxes (Details)

Income Taxes (Details)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate	15.90%	15.20%

Revenue (Details)

Revenue (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 477,761,417	$ 460,253,433	$ 1,415,061,768	$ 1,380,654,978
Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue	464,280,707	449,184,447	1,376,704,413	1,348,395,245
Other Segment
Disaggregation of Revenue [Line Items]
Revenue	13,480,710	11,068,986	38,357,355	32,259,733
Automotive Products
Disaggregation of Revenue [Line Items]
Revenue	464,280,707	449,184,447	1,376,704,413	1,348,395,245
Automotive Mirrors & Electronics | Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue	418,746,334	399,732,577	1,241,147,268	1,200,521,589
HomeLink Modules | Automotive Segment
Disaggregation of Revenue [Line Items]
Revenue	45,534,373	49,451,870	135,557,145	147,873,656
Fire Protection Products | Other Segment
Disaggregation of Revenue [Line Items]
Revenue	5,977,245	5,918,085	18,188,744	17,010,954
Windows Products | Other Segment
Disaggregation of Revenue [Line Items]
Revenue	7,503,465	5,150,901	20,168,611	15,248,779
U.S. | Automotive Products
Disaggregation of Revenue [Line Items]
Revenue	145,798,028	151,229,829	431,729,037	434,439,455
U.S. | Other Products
Disaggregation of Revenue [Line Items]
Revenue	13,480,710	11,068,986	38,357,355	32,259,733
Germany | Automotive Products
Disaggregation of Revenue [Line Items]
Revenue	74,047,596	81,621,623	225,649,215	259,057,369
Japan | Automotive Products
Disaggregation of Revenue [Line Items]
Revenue	60,641,977	55,363,644	172,697,963	153,843,723
Mexico | Automotive Products
Disaggregation of Revenue [Line Items]
Revenue	43,884,609	28,410,998	130,473,702	73,868,425
Other | Automotive Products
Disaggregation of Revenue [Line Items]
Revenue	$ 139,908,497	$ 132,558,353	$ 416,154,496	$ 427,186,273

Leases (Details)

Leases (Details)	9 Months Ended
	Sep. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term	2 years
Weighted average discount rate	2.90%
2019 (excluding the nine months ended September 30, 2019)	$ 361,604
2020	575,861
2021	143,581
2022	57,143
2023	11,130
Thereafter	12,797
Total future minimum lease payments	1,162,116
Less imputed interest	(20,423)
Total	1,141,693
Accrued Liabilities	870,930
Other Non-Current Liabilities	$ 270,763
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms	5 years