Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Jul. 30, 2021	Jun. 30, 2020
Cover [Abstract]
Entity Registrant Name	GlassBridge Enterprises, Inc.
Entity Central Index Key	0001014111
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filer	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business flag	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 1,500
Entity Common Stock, Shares Outstanding		25,170
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020