Inventories - Additional Information (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Capitalized direct labor expense included in work in process	$ 1.3	$ 1.2

Capitalized direct labor expense included in work in process.

No definition available.

Name:	altg_CapitalizedDirectLaborExpenseIncludedInWorkInProcess
Namespace Prefix:	altg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant