Document and Entity Information - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Mar. 20, 2020	Jun. 30, 2019
Document and Entity Information [Abstract]
Document Type	10-K
Entity Registrant Name	American Shared Hospital Services
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 12,757
Entity Common Stock, Shares Outstanding		5,817
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0000744825
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Trading Symbol	AMS
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	true