Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Business segment
Net sales	$ 239.7	$ 266.5
Operating income (loss)	17.4	24.1
Total Assets	875.9	861.2	$ 861.2
Unallocated corporate costs
Business segment
Operating income (loss)	(5.8)	(6.2)
SERP Settlement loss		0.8
Total Assets	35.6	27.2
Technical Products | Operating segments
Business segment
Net sales	140.0	153.5
Operating income (loss)	11.3	17.5
Total Assets	604.8	599.3
Fine Paper and Packaging | Operating segments
Business segment
Net sales	99.7	111.6
Operating income (loss)	11.9	12.8
Total Assets	235.5	234.7
Other | Operating segments
Business segment
Net sales	0.0	1.4
Operating income (loss)	$ 0.0	0.0
Restatement Adjustment | Technical Products | Operating segments
Business segment
Net sales		4.5
Total Assets			12.9
Restatement Adjustment | Other | Operating segments
Business segment
Net sales		$ (4.5)
Total Assets			$ (12.9)