Acquisitions and Discontinued Operations (Schedule of Business Details and Line Items Comprising Income From Discontinued Operations on Statements of Earnings and Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales		$ 446.1		$ 436.2		$ 681.6
Cost of goods sold		341.4		350.8		569.0
Gross profit		104.7		85.4		112.6
Selling, general and administrative expenses		85.8		78.3		120.2
Operating income (loss)		18.9		7.1		(7.6)
Interest expense		1.4		1.2		0.3
Other non-operating (income) expense, net		(0.3)		(1.9)		2.8
Earnings (loss) from discontinued operations before income tax		17.8		7.8		(10.7)
Income tax (benefit) expense		8.2		3.6		(0.8)
Gain (loss) from discontinued operations		9.6		4.2		(9.9)
Gain (Loss) on expected disposal of discontinued businesses before income tax		(19.3)	[1]	(74.1)	[1]	0.1
Income tax (benefit) expense		(6.0)		(4.1)		(15.2)
Net (loss) gain on disposal of discontinued businesses		(13.3)		(70.0)		15.3
Net (loss) gain from discontinued operations		(3.7)		(65.8)		5.4
EMEA and Pacific Rim Business [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales		446.1		436.2		397.2
Cost of goods sold		341.4		350.8		331.5
Gross profit		104.7		85.4		65.7
Selling, general and administrative expenses		85.8		78.3		69.7
Operating income (loss)		18.9		7.1		(4.0)
Interest expense		1.4		1.2		0.3
Other non-operating (income) expense, net		(0.3)		(1.9)		1.9
Earnings (loss) from discontinued operations before income tax		17.8		7.8		(6.2)
Income tax (benefit) expense		8.2		3.6		(0.9)
Gain (loss) from discontinued operations		9.6		4.2		(5.3)
Gain (Loss) on expected disposal of discontinued businesses before income tax	$ (74.0)	(19.3)	[1]	(74.0)	[1]
Net (loss) gain on disposal of discontinued businesses		(19.3)		(74.0)
Net (loss) gain from discontinued operations		(9.7)		(69.8)		(5.3)
Flooring Businesses [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales						284.4
Cost of goods sold						237.5
Gross profit						46.9
Selling, general and administrative expenses						50.5
Operating income (loss)						(3.6)
Other non-operating (income) expense, net						0.9
Earnings (loss) from discontinued operations before income tax						(4.5)
Income tax (benefit) expense						0.1
Gain (loss) from discontinued operations						(4.6)
Gain (Loss) on expected disposal of discontinued businesses before income tax				(0.1)	[1]	0.1
Income tax (benefit) expense		(6.0)		(4.1)		(15.2)
Net (loss) gain on disposal of discontinued businesses		6.0		4.0		15.3
Net (loss) gain from discontinued operations		$ 6.0		$ 4.0		$ 10.7

[1] Loss on disposal of EMEA and Pacific Rim businesses for the years ended December 31, 2018 and 2017 represents the estimated write-down of EMEA and Pacific Rim assets based on our expected sales proceeds to be received upon closure of the transaction.