Income (Loss) Per Common Share - Computation of Weighted Average Basic and Diluted Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Loss from operations	$ (2,300)	$ (13,200)
Less: loss attributable to noncontrolling interest	(100)	(400)
Net loss attributable to GlassBridge Enterprises, Inc.	$ (2,200)	$ (12,800)
Weighted average number of common shares outstanding during the period - basic and diluted (in thousands)	25,200	25,200
Net loss	$ (87.30)	$ (507.69)
Anti-dilutive shares excluded from calculation	0.0	0.0