Other Income (Expense), Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Income And Expenses [Abstract]
DeRidder mill incident	$ 2.5		$ (2.5)
Integration-related, facilities closure and other costs	(0.5)	$ (2.6)	(1.3)	$ (4.5)
Hexacomb working capital adjustment			2.3
Asset disposals and write-offs	(2.4)	(1.1)	(4.7)	(2.9)
Other	(0.2)	(1.4)	(1.4)	(1.6)
Total	$ (0.6)	$ (5.1)	$ (7.6)	$ (9.0)