Segment Results (Schedule Of Segment Operating Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Segment operating income (loss)	$ 69.0	$ 93.6	$ 179.3	$ 208.2
Building Products [Member]
Segment Reporting Information [Line Items]
Segment operating income (loss)	86.6	86.7	209.3	210.7
Resilient Flooring [Member]
Segment Reporting Information [Line Items]
Segment operating income (loss)	(1.7)	22.5	22.8	46.6
Wood Flooring [Member]
Segment Reporting Information [Line Items]
Segment operating income (loss)	2.0	2.6	4.5	5.6
Unallocated Corporate Segment [Member]
Segment Reporting Information [Line Items]
Segment operating income (loss)	$ (17.9)	$ (18.2)	$ (57.3)	$ (54.7)