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v3.21.2

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) | 3 Months Ended | 4 Months Ended
--- | --- | ---
Mar. 31, 2021 | Dec. 31, 2020
Accounting Policies [Abstract] |  |
Warrants to purchase | 13,000,000 | 13,000,000
FDIC insured amount | $ 250,000 | $ 250,000

X
- Definition The number of warrants to purchase. + References No definition available. + Details
Name: | hlly_WarrantsToPurchase
Namespace Prefix: | hlly_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AccountingPoliciesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of cash deposited in financial institutions as of the balance sheet date that is insured by the Federal Deposit Insurance Corporation. + References No definition available. + Details
Name: | us-gaap_CashFDICInsuredAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant