XML 37 R26.htm IDEA: XBRL DOCUMENT
v3.8.0.1

The Company and Subsequent Events - Additional Information (Detail) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Dec. 31, 2017
Company And Subsequent Events [Abstract] |  |
Statutory Federal income tax rate | 21.00% | 35.00%
Tax cuts and jobs act of 2017, incomplete accounting, provisional income tax expense | $ 0 | $ 20,153,000
Tax cuts and jobs act of 2017, incomplete accounting, change in tax rate, deferred tax balances, provisional income tax expense |  | 5,808,000
Tax cuts and jobs act of 2017, incomplete accounting, provisional income tax expense related to onetime transition tax liability of foreign subsidiaries |  | 23,923,000
Tax cuts and jobs act of 2017, incomplete accounting, benefit included in provision for income taxes to offset one-time transition tax related to previous deferred tax liability that existed for undistributed foreign earnings that were not permanently reinvested |  | $ 9,578,000

X
- Definition Company and subsequent events. + References No definition available. + Details
Name: | thrm_CompanyAndSubsequentEventsAbstract
Namespace Prefix: | thrm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tax cuts and jobs act of 2017, incomplete accounting, benefit included in provision for income taxes to offset transition tax related to previous deferred tax liability for undistributed foreign earnings not permanently reinvested. + References No definition available. + Details
Name: | thrm_TaxCutsAndJobsActOf2017IncompleteAccountingBenefitIncludedInProvisionForIncomeTaxesToOffsetTransitionTaxRelatedToPreviousDeferredTaxLiabilityForUndistributedForeignEarningsNotPermanentlyReinvested
Namespace Prefix: | thrm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Tax cuts and jobs act of 2017, incomplete accounting, change in tax rate, deferred tax balances, provisional income tax expense (benefit). + References No definition available. + Details
Name: | thrm_TaxCutsAndJobsActOf2017IncompleteAccountingChangeInTaxRateDeferredTaxBalancesProvisionalIncomeTaxExpenseBenefit
Namespace Prefix: | thrm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 Tax cuts and jobs act of 2017, incomplete accounting, provisional income tax expense (benefit) related to onetime transition tax liability of foreign subsidiaries. + References No definition available. + Details
Name: | thrm_TaxCutsAndJobsActOf2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefitRelatedToOnetimeTransitionTaxLiabilityOfForeignSubsidiaries
Namespace Prefix: | thrm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of domestic federal statutory tax rate applicable to pretax income (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 6.I) -URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319 + Details
Name: | us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration