Discontinued Operations (Summary of Total Gains and Losses, Capital Expenditures and Operating Lease) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net loss due to change in carrying value of discontinued operations net assets		$ (0.4)	$ (16.4)	$ (31.2)
EMEA and Pacific Rim Business [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net loss due to change in carrying value of discontinued operations net assets		(0.4)	(17.2)	(31.2)
European Resilient Flooring [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on dissolution of flooring entity	[1]		(0.8)
Knauf [Member] | EMEA and Pacific Rim Business [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Loss on sale to Knauf	[2]	$ 0.4	$ 17.2
Net loss due to change in carrying value of discontinued operations net assets	[3]			31.2
Purchases of property, plant and equipment				(3.0)
Operating lease cost	[4]			7.4
ROU assets obtained in exchange for lease obligations	[5]			$ 24.6

[1] Represents AOCI adjustments related to accumulated foreign currency translation amounts.

[2] Represents certain pension liabilities, working capital and other adjustments.

[3] Represents comparison of the EMEA and Pacific Rim net assets to the expected final sales proceeds.

[4] The amount of cash paid for amounts included in the measurement of lease liabilities was not materially different from the operating lease cost for the nine months ended September 30, 2019.

[5] Represents initial ROU assets recognized upon adoption on January 1, 2019. We did not obtain any new ROU assets in exchange for lease obligations during the nine months ended September 30, 2019.