Consolidated Statements Of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning of year balance at Dec. 31, 2013	$ 673.2	$ 0.6	$ 1,098.4	$ 207.2	$ (261.4)	$ (371.6)
Beginning of year balance at Dec. 31, 2013		54,406,927
Beginning of year balance at Dec. 31, 2013					5,057,382
Stock issuance, net		719,226
Share-based employee compensation	36.0		36.0
Net earnings	63.8			63.8
Other comprehensive income (loss)	(123.9)					(123.9)
End of year balance at Dec. 31, 2014	649.1	$ 0.6	1,134.4	271.0	$ (261.4)	(495.5)
End of year balance at Dec. 31, 2014		55,126,153
End of year balance at Dec. 31, 2014					5,057,382
Stock issuance, net		232,911
Share-based employee compensation	17.4		17.4
Net earnings	94.2			94.2
Other comprehensive income (loss)	8.1					8.1
End of year balance at Dec. 31, 2015	$ 768.8	$ 0.6	1,151.8	365.2	$ (261.4)	(487.4)
End of year balance at Dec. 31, 2015	55,359,064	55,359,064
End of year balance at Dec. 31, 2015	5,057,382				5,057,382
Stock issuance, net		180,694
Share-based employee compensation	$ 9.2		9.2
Net earnings	104.7			104.7
Other comprehensive income (loss)	23.6					23.6
Separation of Armstrong Flooring, Inc.	(596.1)		(656.1)			60.0
Acquisition of treasury stock	(43.8)	$ (43.8)			$ (43.8)
Acquisition of treasury stock, shares		(1,111,525)			1,111,525
End of year balance at Dec. 31, 2016	$ 266.4	$ 0.6	$ 504.9	$ 469.9	$ (305.2)	$ (403.8)
End of year balance at Dec. 31, 2016	54,428,233	54,428,233
End of year balance at Dec. 31, 2016	6,168,907				6,168,907