Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net income (loss)	$ (63,600)	$ 23,100
Net pension adjustments, net of tax:
Reclassification of adjustments for defined benefit plans recorded in net loss	20,600	100
Total net pension adjustments	20,600	100
Total other comprehensive income, net of tax	20,600	100
Comprehensive income (loss)	(43,000)	23,200
Less: Comprehensive income (loss) attributable to noncontrolling interest	(1,300)	2,900
Comprehensive income attributable to GlassBridge Enterprises, Inc.	$ (41,700)	$ 20,300