Line of credit facility interest only or deferred payment period.

No definition available.

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Namespace Prefix:	altg_
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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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-URI https://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section S99
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-Subparagraph (SX 210.5-02.22(a)(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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-Section S99
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-Subparagraph (210.5-03(11))
-URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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+ Details

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

- Definition

Amount of increase (decrease) of the credit facility.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-URI https://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
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- 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=altg_YaleIndustrialTrucksIncMember
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Balance Type:
Period Type:

- Details

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- Details

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- Details

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- Details

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Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=altg_OEMFloorPlanFacilitiesMember
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Period Type:

- Details

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- Details

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Floor Plans - Additional Information (Details) - USD ($)		3 Months Ended
	Jul. 06, 2022	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Jun. 30, 2022
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 257,800,000		$ 219,500,000
Recognized interest expense		12,000,000.0	$ 6,100,000
First Lien Lender \| Floor Plans and ABL Facility
Line Of Credit Facility [Line Items]
Floor plan financing facility		572,800,000		476,400,000
Maximum borrowing capacity		780,000,000.0
Debt issuance costs		2,000,000.0		2,100,000
First Lien Lender \| JP Morgan Chase Bank \| First Lien Floor Plan Facility
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 59,600,000		$ 58,600,000
Effective interest rate		7.50%		7.00%
First Lien Lender \| JP Morgan Chase Bank \| First Lien Floor Plan Facility \| Yale Industrial Trucks Inc. \| Minimum
Line Of Credit Facility [Line Items]
Maximum borrowing capacity	$ 50,000,000.0
Borrowing capacity increased	$ 10,000,000.0
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					$ 60,000,000.0
Original Equipment Manufacturer ("OEM") Captive Lenders and Suppliers \| JP Morgan Chase Bank \| Floor Plan Facilities \| Minimum
Line Of Credit Facility [Line Items]
Maximum borrowing capacity		$ 100,000
Original Equipment Manufacturer ("OEM") Captive Lenders and Suppliers \| JP Morgan Chase Bank \| Floor Plan Facilities \| Maximum
Line Of Credit Facility [Line Items]
Maximum borrowing capacity		135,000,000.0
Original Equipment Manufacturer ("OEM") Captive Lenders and Suppliers \| JP Morgan Chase Bank \| OEM Floor Plan Facilities
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 255,400,000		$ 198,300,000
Original Equipment Manufacturer ("OEM") Captive Lenders and Suppliers \| JP Morgan Chase Bank \| OEM Floor Plan Facilities \| Minimum
Line Of Credit Facility [Line Items]
Effective interest rate		7.60%
Original Equipment Manufacturer ("OEM") Captive Lenders and Suppliers \| JP Morgan Chase Bank \| OEM Floor Plan Facilities \| Maximum
Line Of Credit Facility [Line Items]
Effective interest rate		9.80%
Interest only or deferred payment period		12 months
Alta Enterprises, LLC, NITCO, LLC and Other Credit Parties [Member] \| JP Morgan Chase Bank \| Floor Plans
Line Of Credit Facility [Line Items]
Weighted average rate on Floor Plan Facilities		7.30%	6.70%
Alta Enterprises, LLC, NITCO, LLC and Other Credit Parties [Member] \| JP Morgan Chase Bank \| Floor Plan Facilities
Line Of Credit Facility [Line Items]
Floor plan financing facility		$ 315,000,000.0		$ 256,900,000
Maximum borrowing capacity		350,000,000.0
Recognized interest expense		$ 1,500,000	$ 300,000