XML 25 R45.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Stock-Based Compensation Plans (Narrative) (Details) | 11 Months Ended | 12 Months Ended | 60 Months Ended | 72 Months Ended | 84 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Dec. 31, 2019 USD ($) plan shares | Dec. 31, 2019 USD ($) plan shares | Dec. 31, 2018 USD ($) shares | Dec. 31, 2017 USD ($) shares | Dec. 31, 2019 USD ($) plan shares | Dec. 31, 2019 USD ($) plan shares | Dec. 31, 2019 USD ($) plan shares | Dec. 31, 2013 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Shares, granted (in shares) |  | 1,049,000 | 1,613,000 | 1,295,000 |  |  |  |
Stock Compensation Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Number of plans | plan | 2 | 2 |  |  | 2 | 2 | 2 |
Performance Shares |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Unrecognized compensation cost | $ | $ 2,224,328 | $ 2,224,328 |  |  | $ 2,224,328 | $ 2,224,328 | $ 2,224,328 |
Amortization expense | $ |  | $ 897,136 | $ 0 | $ 0 |  |  |  |
Omnibus Incentive Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Shares approved (in shares) | 45,000,000 | 45,000,000 |  |  | 45,000,000 | 45,000,000 | 45,000,000 |
Shares issued under plan (in shares) | 4,919,256 | 4,919,256 |  |  | 4,919,256 | 4,919,256 | 4,919,256 |
Options granted net of shares from canceled/expired options (in shares) | 796,635 |  |  |  |  |  |  |
Restricted period, maximum, in years |  | 10 years |  |  |  |  |  |
Shares granted with restriction period (in shares) |  | 3,315,482 |  |  |  |  |  |
Shares, granted (in shares) | 854,633 |  |  |  |  |  |  |
Omnibus Incentive Plan | Minimum |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Option vesting period |  | 1 year |  |  |  |  |  |
Award expiration period |  | 5 years |  |  |  |  |  |
Omnibus Incentive Plan | Maximum |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Option vesting period |  | 5 years |  |  |  |  |  |
Award expiration period |  | 10 years |  |  |  |  |  |
Restricted Stock Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Shares approved (in shares) | 9,000,000 | 9,000,000 |  |  | 9,000,000 | 9,000,000 | 9,000,000 |
Shares granted with restriction period (in shares) |  | 3,315,482 |  |  |  |  |  |
Shares, granted (in shares) |  |  |  |  | 5,762,672 |  |  |
Unearned stock-based compensation | $ | $ 47,139,370 | $ 47,139,370 |  |  | $ 47,139,370 | $ 47,139,370 | $ 47,139,370 |
Amortization expense | $ |  | $ 13,770,917 | $ 8,841,985 | $ 5,353,339 |  |  |  |
Employee Stock Option Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Shares approved (in shares) | 24,000,000 | 24,000,000 |  |  | 24,000,000 | 24,000,000 | 24,000,000 |
Options granted net of shares from canceled/expired options (in shares) |  |  |  |  |  | 12,903,592 |  |
Unrecognized compensation cost | $ | $ 6,316,567 | $ 6,316,567 |  |  | $ 6,316,567 | $ 6,316,567 | $ 6,316,567 |
Weighted-average period for unrecognized compensation cost expected to be recognized |  | 1 year 10 months 24 days |  |  |  |  |  |
Employee Stock Purchase Plan |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |
Shares approved (in shares) |  |  |  |  |  |  |  | 2,000,000
Shares, granted (in shares) |  | 173,013 | 177,846 | 175,479 |  |  | 1,145,856 |
ESPP discount rate |  | 85.00% |  |  |  |  |  |
Discount recognized as compensation expense |  | 15.00% |  |  |  |  |  |

X
- Definition Share-based compensation arrangement by share-based payment award discount recognized as compensation expense. + References No definition available. + Details
Name: | gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountRecognizedAsCompensationExpense
Namespace Prefix: | gntx_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award options grants. + References No definition available. + Details
Name: | gntx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrants
Namespace Prefix: | gntx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share-based compensation, restricted period. + References No definition available. + Details
Name: | gntx_ShareBasedCompensationRestrictedPeriod
Namespace Prefix: | gntx_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Number of Plans + References No definition available. + Details
Name: | gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofPlans
Namespace Prefix: | gntx_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Issued, Net Of Shares Canceled Or Expired + References No definition available. + Details
Name: | gntx_SharebasedCompensationArrangementbySharebasedPaymentAwardNumberofSharesIssuedNetOfSharesCanceledOrExpired
Namespace Prefix: | gntx_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Value of stock issued under share-based plans to employees or officers which is the unearned portion, accounted for under the fair value method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 35 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116855982&loc=d3e4534-113899 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.30) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DeferredCompensationEquity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of cost not yet recognized for nonvested award under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 + Details
Name: | us-gaap_RestrictedStockExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discount rate from fair value on purchase date that participants pay for shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares authorized for issuance under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_StockCompensationPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=gntx_OmnibusIncentivePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=gntx_RestrictedStockPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=gntx_EmployeeStockOptionPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EmployeeStockOwnershipPlanESOPDisclosuresByPlanAxis=gntx_EmployeeStockPurchasePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |