Gain (Loss) per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Loss from continuing operations	$ (1,700,000)	$ (7,300,000)	$ (14,900,000)	$ (28,200,000)
Less: loss attributable to noncontrolling interest	(2,000,000)	0	(5,500,000)	0
Net income (loss) from continuing operations attributable to GlassBridge Enterprises, Inc.	300,000	(7,300,000)	(9,400,000)	(28,200,000)
Income (loss) from discontinued operations, net of income taxes	7,700,000	200,000	4,500,000	(75,600,000)
Net income (loss) attributable to GlassBridge Enterprises, Inc.	$ 8,000,000	$ (7,100,000)	$ (4,900,000)	$ (103,800,000)
Denominator:
Weighted average number of common shares outstanding during the period - basic and diluted (in shares)	5.0	3.7	4.6	3.7
Income (loss) per common share attributable to GlassBridge common shareholders — basic and diluted:
Continuing operations (in dollars per share)	$ 0.06	$ (1.97)	$ (2.04)	$ (7.62)
Discontinued operations (in dollars per share)	1.54	0.05	0.98	(20.43)
Net income (loss) (in dollars per share)	$ 1.60	$ (1.92)	$ (1.06)	$ (28.05)
Anti-dilutive shares excluded from calculation (in shares)	0.3	0.4	0.3	0.4