XML 58 R37.htm IDEA: XBRL DOCUMENT
v3.21.2

Fair Value Measurements - Summary of the changes in the fair value of the FPA liability (Detail) - Fair Value, Recurring [Member] - Level 3 [Member] - USD ($) | 3 Months Ended
--- | ---
Mar. 31, 2021 | Dec. 31, 2020
Fair Value Liabilities Measured On Recurring Basis [Line Items] |  |  |
Beginning balance |  | $ 2,050,000 | $ 50,000
Recognized gain on change in fair value | [1] | (300,000) | (2,000,000)
Ending balance |  | $ 1,750,000 | $ 2,050,000
[1] | Represents the non-cash loss on change in valuation of the FPA liability and is included in Recognized loss on change in fair value of FPA liability on the statement of operations.

X
- Definition Fair Value Liabilities Measured On Recurring Basis [Line Items] + References No definition available. + Details
Name: | hlly_FairValueLiabilitiesMeasuredOnRecurringBasisLineItems
Namespace Prefix: | hlly_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition FPA liability fair value. + References No definition available. + Details
Name: | hlly_FpaLiabilityFairValue
Namespace Prefix: | hlly_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Recognized Gain on change in fair value. + References No definition available. + Details
Name: | hlly_RecognizedGainOnChangeInFairValue
Namespace Prefix: | hlly_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |