Line of credit facility percentage of annual increase.

No definition available.

Name:	altg_LineOfCreditFacilityPercentageOfAnnualIncrease
Namespace Prefix:	altg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in YYYY-MM-DD format.

+ References

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-Topic 210
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-02.19(b),22(b))
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+ Details

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Balance Type:	na
Period Type:	duration

- 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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=altg_FirstLienLenderMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=altg_JPMorganChaseBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=altg_FirstLienFloorPlanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=altg_YaleIndustrialTrucksIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=altg_OriginalEquipmentManufacturerCaptiveLendersAndSuppliersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=altg_FourthAmendedAndRestatedFirstLienCreditAgreementMember
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Floor Plans - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended
	Jun. 05, 2024	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 217,600,000		$ 217,600,000		$ 317,500,000
Recognized interest expense		19,200,000	$ 13,700,000	35,300,000	$ 25,700,000
First Lien Lender \| JP Morgan Chase Bank \| First Lien Floor Plan Facility
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 64,200,000		$ 64,200,000		$ 67,400,000
Effective interest rate		8.20%		8.20%		8.20%
First Lien Lender \| JP Morgan Chase Bank \| First Lien Floor Plan Facility \| Yale Industrial Trucks Inc.
Line Of Credit Facility [Line Items]
Maturity date	Jun. 01, 2029
First Lien Lender \| JP Morgan Chase Bank \| First Lien Floor Plan Facility \| Yale Industrial Trucks Inc. \| Maximum
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 90,000,000
OEM Captive Lenders and Suppliers \| JP Morgan Chase Bank \| Floor Plan Facilities \| Minimum
Line Of Credit Facility [Line Items]
Maximum borrowing capacity		$ 100,000		$ 100,000
OEM Captive Lenders and Suppliers \| JP Morgan Chase Bank \| Floor Plan Facilities \| Maximum
Line Of Credit Facility [Line Items]
Maximum borrowing capacity		160,000,000		160,000,000
OEM Captive Lenders and Suppliers \| JP Morgan Chase Bank \| OEM Floor Plan Facilities
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 334,600,000		$ 334,600,000		$ 330,100,000
OEM Captive Lenders and Suppliers \| JP Morgan Chase Bank \| OEM Floor Plan Facilities \| Minimum
Line Of Credit Facility [Line Items]
Effective interest rate		8.30%		8.30%		8.40%
OEM Captive Lenders and Suppliers \| JP Morgan Chase Bank \| OEM Floor Plan Facilities \| Maximum
Line Of Credit Facility [Line Items]
Effective interest rate		10.50%		10.50%		10.50%
Fourth Amended And Restated First Lien Credit Agreement \| JP Morgan Chase Bank \| Floor Plan Facilities
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 398,800,000		$ 398,800,000		$ 397,500,000
Maximum borrowing capacity		450,000,000		$ 450,000,000
Line of credit facility percentage of annual increase				10.00%
Recognized interest expense		$ 2,700,000	$ 1,900,000	$ 5,500,000	$ 3,400,000
Weighted average rate on Floor Plan Facilities		8.80%	7.70%	8.80%	7.70%