XML 40 R30.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Goodwill and Other Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2017 | Dec. 31, 2016
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Intangible assets, net | $ 303,450,000 | $ 308,275,000 | [1]
Gentex Patents |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Finite-lived intangible assets, gross | 33,620,379 | 33,002,468 |
Finite-lived intangible assets, accumulated amortization | (17,147,912) | (16,481,728) |
Finite-lived intangible assets, net | 16,472,467 | 16,520,740 |
Patents and Other Intangible Assets |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Finite-lived intangible assets, accumulated amortization | (84,697,912) | (79,206,728) |
Intangible assets, gross | 404,620,379 | 404,002,468 |
Intangible assets, net | 319,922,467 | 324,795,740 |
HomeLink® |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Finite-lived intangible assets, accumulated amortization | (67,550,000) | (62,725,000) |
Intangible assets, gross | 371,000,000 | 371,000,000 |
Intangible assets, net | 303,450,000 | 308,275,000 |
HomeLink® | Homelink Technology |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Finite-lived intangible assets, gross | 180,000,000 | 180,000,000 |
Finite-lived intangible assets, accumulated amortization | (52,500,000) | (48,750,000) |
Finite-lived intangible assets, net | $ 127,500,000 | $ 131,250,000 |
HomeLink® | Homelink Technology | Minimum [Member] |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Finite-lived intangible asset, useful life | 12 years | 12 years |
HomeLink® | Existing Customer Platforms |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Finite-lived intangible assets, gross | $ 43,000,000 | $ 43,000,000 |
Finite-lived intangible assets, accumulated amortization | (15,050,000) | (13,975,000) |
Finite-lived intangible assets, net | $ 27,950,000 | $ 29,025,000 |
Finite-lived intangible asset, useful life | 10 years | 10 years |
HomeLink® | HomeLink Trade Names and Trademarks |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Indefinite-lived intangible assets | $ 52,000,000 | $ 52,000,000 |
HomeLink® | Exclusive Licensing Agreement |  |  |
Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Line Items] |  |  |
Indefinite-lived intangible assets | $ 96,000,000 | $ 96,000,000 |
[1] | Note: The condensed consolidated balance sheet at December 31, 2016 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.

X
- Definition [Line Items] for Schedule of Finite-Lived and Indefinite-Lived Intangible Assets [Table] + References No definition available. + Details
Name: | gntx_ScheduleofFiniteLivedandIndefiniteLivedIntangibleAssetsLineItems
Namespace Prefix: | gntx_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before accumulated amortization of intangible assets, excluding goodwill. + References No definition available. + Details
Name: | us-gaap_IntangibleAssetsGrossExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph ((a)(1),(b)) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_IntangibleAssetsNetExcludingGoodwill
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_PatentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=gntx_PatentsandOtherIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=gntx_HomeLinkMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_DevelopedTechnologyRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TrademarksAndTradeNamesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_LicensingAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |