XML 70 R59.htm IDEA: XBRL DOCUMENT
v3.10.0.1

New Accounting Pronouncements - Additional Information (Details) - USD ($) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2018 | Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items] |  |
Income tax effects from Tax Act | $ 19,997,000 | $ 20,153,000
ASU 2018-02 |  |
New Accounting Pronouncements Or Change In Accounting Principle [Line Items] |  |
Adjustment against retained earnings for effect of change in federal corporate income tax rate | 40,000 |
Adjustments related to valuation allowance | 0 |
Income tax effects from Tax Act | $ 0 |
ASU 2016-02 |  |
New Accounting Pronouncements Or Change In Accounting Principle [Line Items] |  |
Maximum percentage of right-of-use assets and liabilities expected to be recognized upon adoption of ASU | 5.00% |
ASU 2016-16 |  |
New Accounting Pronouncements Or Change In Accounting Principle [Line Items] |  |
Favorable adjustment to retained earnings | $ 31,645,000 |

X
- Definition Maximum percentage right of use assets to be recognized upon adoption of ASU. + References No definition available. + Details
Name: | thrm_MaximumPercentageRightOfUseAssetsToBeRecognizedUponAdoptionOfASU
Namespace Prefix: | thrm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax cuts and jobs act of 2017, incomplete accounting, provisional income tax expense (benefit). + References No definition available. + Details
Name: | thrm_TaxCutsAndJobsActOf2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefit
Namespace Prefix: | thrm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act. + References No definition available. + Details
Name: | thrm_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect
Namespace Prefix: | thrm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cumulative effect of the change in accounting principle or new accounting pronouncement on retained earnings or other components of equity or net assets in the statement of financial position as of the beginning of the earliest period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22499-107794 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22583-107794 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109234566&loc=d3e22580-107794 + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleCumulativeEffectOfChangeOnEquityOrNetAssets1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) in valuation and qualifying accounts and reserves from adjustment. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
Name: | us-gaap_ValuationAllowancesAndReservesAdjustments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_NewAccountingPronouncementEarlyAdoptionAxis=thrm_AccountingStandardsUpdate201802Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_NewAccountingPronouncementEarlyAdoptionAxis=us-gaap_AccountingStandardsUpdate201602Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201616Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |