Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Mar. 23, 2020	Jun. 28, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	ALTA EQUIPMENT GROUP INC.
Entity Central Index Key	0001759824
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019
Entity File Number	001-38864
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Public Float			$ 140,200,000
Entity Common Stock, Shares Outstanding		29,511,359
Entity Incorporation State Country Code	DE