Subsequent Event Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Jan. 27, 2016	Dec. 31, 2014
Subsequent Event [Line Items]
Common stock issued, par value (in dollars per share)	$ 0.01		$ 0.01
Distribution to Grace from GCP	$ 750.0
Amount of distribution from GCP dividend used to pay down Grace debt	500.0
Separation of GCP from Grace [Member]
Subsequent Event [Line Items]
Common stock issued, par value (in dollars per share)		$ 0.01
Term Loan B (USD) [Member]
Subsequent Event [Line Items]
Amount of distribution from GCP dividend used to pay down Grace debt	426.9
Term Loan B (EUR) [Member]
Subsequent Event [Line Items]
Amount of distribution from GCP dividend used to pay down Grace debt	$ 67.0