XML 67 R53.htm IDEA: XBRL DOCUMENT
v3.22.4

Stock-Based Compensation Plans (Vested Restricted Stocks) (Details) - $ / shares | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 27 | $ 34 | $ 26
Restricted Stock |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Shares granted (in shares) | 949,089 | 1,098,611 | 832,948
Restricted Stock | Minimum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 23.84 | $ 32.98 | $ 20.68
Restricted Stock | Maximum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 30.85 | $ 35.67 | $ 31.08
Restricted Stock | 1 Year |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Shares granted (in shares) | 119,849 | 24,634 | 42,074
Restricted Stock | 1 Year | Minimum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 23.84 | $ 32.98 | $ 22.16
Restricted Stock | 1 Year | Maximum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 29.89 | $ 34.37 | $ 26.94
Restricted Stock | 2 Year |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Shares granted (in shares) | 82,538 | 0 | 21,669
Restricted Stock | 2 Year | Minimum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 23.84 |  | $ 23.88
Restricted Stock | 2 Year | Maximum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 29.17 |  | $ 26.94
Restricted Stock | 3 Years |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Shares granted (in shares) | 261,493 | 606,853 | 119,504
Restricted Stock | 3 Years | Minimum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 23.84 | $ 32.98 | $ 23.88
Restricted Stock | 3 Years | Maximum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 30.85 | $ 35.67 | $ 31.08
Restricted Stock | 4 Years |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Shares granted (in shares) | 260,149 | 309,955 | 479,346
Restricted Stock | 4 Years | Minimum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 23.84 | $ 32.98 | $ 20.68
Restricted Stock | 4 Years | Maximum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 29.17 | $ 35.67 | $ 28.98
Restricted Stock | 5 Years |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Shares granted (in shares) | 225,060 | 157,169 | 170,355
Restricted Stock | 5 Years | Minimum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 23.84 | $ 32.98 | $ 20.68
Restricted Stock | 5 Years | Maximum |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Market price at vesting date (in dollars per share) | $ 29.17 | $ 35.67 | $ 28.98

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 Net number of non-option equity instruments granted to participants. + 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)(1)(iv)(1) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(01) -URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
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_VestingAxis=gntx_A1YearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=gntx_TwoYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=gntx_ThreeYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=gntx_FourYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VestingAxis=gntx_FiveYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |