Income Taxes (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Mar. 31, 2016	Feb. 03, 2016	Jan. 01, 2016
Tax Credit Carryforward [Line Items]
Effective tax rate (percent)	37.90%	36.00%
Change in deferred tax assets valuation allowance	$ 12.8
Separation-related charges	8.8
Tax charges related to tax law change	4.0
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	4.7
Federal tax deductions relating to emergency bankruptcy	$ 1,800.0
Period allowed for carryforward of operation loss	20 years
Expected income tax deductions generated from deferred payment obligation	$ 30.0
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset (Net of Liabilities)	773.3
Valuation Allowance	(39.5)
Net Deferred Tax Asset	733.8
Taxable income required to realized DTA total amount	1,900.0
Taxable income required to realize DTA per year	100.0
Federal and state deferred tax assets utilized in separation	5.0
Foreign earnings repatriated		$ 173.1
Tax expense for repatriation attributable to current earnings	1.7	19.0
Deferred income taxes	736.4	714.3	$ 739.5
United States - Federal
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset (Net of Liabilities)	677.3
Valuation Allowance	(18.8)
Net Deferred Tax Asset	658.5
United States - States
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset (Net of Liabilities)	55.2
Valuation Allowance	(18.1)
Net Deferred Tax Asset	37.1
Germany
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset (Net of Liabilities)	31.2
Valuation Allowance	0.0
Net Deferred Tax Asset	31.2
Other foreign
Deferred Tax Assets, Net [Abstract]
Deferred Tax Asset (Net of Liabilities)	9.6
Valuation Allowance	(2.6)
Net Deferred Tax Asset	7.0
Grace Construction Products | Discontinued Operations, Disposed of by Sale
Deferred Tax Assets, Net [Abstract]
Deferred tax assets transferred		$ 32.0		$ 80.0
New Accounting Pronouncement, Early Adoption, Effect [Member]
Deferred Tax Assets, Net [Abstract]
Deferred income taxes	77.0		$ 75.5		$ 72.3
Deferred Tax Assets, Valuation Allowance, Noncurrent	$ 18.3				$ 18.3