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Goodwill and Other Intangible Assets (Details) - USD ($) | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014 | Dec. 31, 2014 | Sep. 27, 2013
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |
Goodwill | $ 307,365,845 |  | $ 307,365,845 |  | $ 307,365,845 | [1] |
Amortization expense, 2015 | 22,000,000 |  | 22,000,000 |  |  |  |
HomeLink® |  |  |  |  |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |
Goodwill |  |  |  |  |  |  | $ 307,400,000
Accumulated amortization | 33,775,000 |  | 33,775,000 |  | 24,125,000 |  |
Amortization expense, 2016 | 22,000,000 |  | 22,000,000 |  |  |  |
Amortization expense, 2017 | 22,000,000 |  | 22,000,000 |  |  |  |
Amortization expense, 2018 | 22,000,000 |  | 22,000,000 |  |  |  |
Amortization expense, 2019 | 22,000,000 |  | 22,000,000 |  |  |  |
Gentex Patents |  |  |  |  |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |
Accumulated amortization | 12,396,365 |  | 12,396,365 |  | $ 11,065,153 |  |
Gentex Patents | HomeLink® |  |  |  |  |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |
Amortization expense | $ 5,500,000 | $ 5,500,000 | $ 11,000,000 | $ 11,000,000 |  |  |
Intangible Assets [Member] | HomeLink® |  |  |  |  |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |  |  |  |  |
Amortization expense |  |  |  | $ 5,500,000 |  |  |
[1] | Note: The condensed consolidated balance sheet at December 31, 2014 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.

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275 + Details
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