Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Business segment
Net sales	$ 266.5	$ 242.1
Operating income (loss)	24.1	27.0
Unallocated corporate costs
Business segment
Operating income (loss)	(6.2)	(5.5)
Technical Products | Operating segments
Business segment
Net sales	149.0	121.9
Operating income (loss)	17.5	12.5
Fine Paper and Packaging | Operating segments
Business segment
Net sales	111.6	114.3
Operating income (loss)	12.8	20.3
Other | Operating segments
Business segment
Net sales	5.9	5.9
Operating income (loss)	$ 0.0	$ (0.3)