Discontinued Operations (Schedule of Business Details and Line Items Comprising Discontinued Operations on Statements of Earnings and Comprehensive Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales	$ 106.7	$ 114.6	$ 203.6	$ 219.0
Cost of goods sold	83.2	87.3	158.9	165.1
Gross profit	23.5	27.3	44.7	53.9
Selling, general and administrative expenses	20.4	19.7	41.2	41.7
Operating income	3.1	7.6	3.5	12.2
Interest expense		0.5		0.9
Other non-operating expense, net	0.6	1.4	0.6	0.2
Earnings from discontinued operations before income tax	2.5	5.7	2.9	11.1
Income tax expense	4.8	0.2	4.7	1.7
Net earnings (loss) from discontinued operations, net of tax	(2.3)	5.5	(1.8)	9.4
(Loss) from disposal of discontinued businesses, before income tax	(6.8)	(5.7)	(4.6)	(23.4)
Income tax expense (benefit)	0.1	0.1	0.1	(0.3)
(Loss) gain from disposal of discontinued businesses, net of tax	(6.9)	(5.8)	(4.7)	(23.1)
Net (loss) from discontinued operations	(9.2)	(0.3)	(6.5)	(13.7)
EMEA and Pacific Rim Business [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales	106.7	114.6	203.6	219.0
Cost of goods sold	83.2	87.3	158.9	165.1
Gross profit	23.5	27.3	44.7	53.9
Selling, general and administrative expenses	20.4	19.7	41.2	41.7
Operating income	3.1	7.6	3.5	12.2
Interest expense		0.5		0.9
Other non-operating expense, net	0.6	1.4	0.6	0.2
Earnings from discontinued operations before income tax	2.5	5.7	2.9	11.1
Income tax expense	4.8	0.2	4.7	1.7
Net earnings (loss) from discontinued operations, net of tax	(2.3)	5.5	(1.8)	9.4
(Loss) from disposal of discontinued businesses, before income tax	(6.8)	(5.7)	(4.6)	(23.4)
(Loss) gain from disposal of discontinued businesses, net of tax	(6.8)	(5.7)	(4.6)	(23.4)	$ (19.3)	$ (74.0)
Net (loss) from discontinued operations	(9.1)	(0.2)	(6.4)	(14.0)
Flooring Businesses [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income tax expense (benefit)	0.1	0.1	0.1	(0.3)
(Loss) gain from disposal of discontinued businesses, net of tax	(0.1)	(0.1)	(0.1)	0.3
Net (loss) from discontinued operations	$ (0.1)	$ (0.1)	$ (0.1)	$ 0.3