Restructuring Expenses and Repositioning Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 2.6	$ 14.0	$ 11.5
Accruals for severance and other costs	2.6	10.1	11.4
Grace Catalysts Technologies
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	1.6	13.7	3.7
Grace Materials Technologies
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	1.0	0.5	(0.1)
Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 0.0	$ (0.2)	$ 7.9