Income (loss) Per Common Share - Computation of Weighted Average Basic and Diluted Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Numerator: Loss from continuing operations	$ (3,500)	$ (500)	$ (18,500)	$ (2,500)
Numerator: Less: loss attributable to noncontrolling interest	(200)		(900)
Numerator: Net loss from continuing operations attributable to GlassBridge Enterprises, Inc.	(3,300)	(500)	(17,600)	(2,500)
Numerator: Income (loss) from discontinued operations, net of income taxes		(200)		10,800
Net income (loss) attributable to GlassBridge Enterprises, Inc.	$ (3,300)	$ (700)	$ (17,600)	$ 8,300
Denominator: Weighted average number of common shares outstanding during the period - basic and diluted	25,200,000	25,100,000	25,200,000	25,600,000
Income (loss) per common share attributable to GlassBridge Enterprises, Inc. common stockholders - basic and diluted: Continuing operations	$ (131.13)	$ (19.86)	$ (698.19)	$ (99.44)
Income (loss) per common share attributable to GlassBridge Enterprises, Inc. common stockholders - basic and diluted: Discontinued operations		7.95		421.67
Net income (loss)	$ (131.13)	$ (27.81)		$ 322.23
Anti-dilutive shares excluded from calculation	0	0	0	0