Business Segment Information - Schedule of Net Sales, Operating Income, and Total Assets for Each of the Company's Business Segment (Details) - USD ($) $ in Millions		3 Months Ended
	Apr. 06, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Business segment
Net Sales		$ 284.8	$ 227.0
Operating income (loss)		12.2	13.6
Acquisition related costs, including due diligence and transaction costs		5.3	12.0
Reduction of restructuring charges		(0.6)
COVID-19 costs		0.6	0.5
Other restructuring and non-routine costs			0.0
Assets		1,105.8		$ 1,081.7
Merger Agreement
Business segment
Acquisition related costs, including due diligence and transaction costs		4.9
Itasa
Business segment
Acquisition related costs, including due diligence and transaction costs	$ 12.8		12.0
Acquisition related costs, integration related costs		0.4
Unallocated Corporate
Business segment
Operating income (loss)		(11.8)	(18.3)
COVID-19 costs		0.5	0.1
Other restructuring and non-routine costs			(0.2)
Assets		56.0		52.6
Unallocated Corporate | Itasa
Business segment
Acquisition related costs, integration related costs		0.2
Technical Products | Itasa
Business segment
Acquisition related costs, integration related costs		0.2
Technical Products | Operating segments
Business segment
Net Sales		185.6	145.2
Operating income (loss)		12.1	19.2
COVID-19 costs			0.1
Other restructuring and non-routine costs			0.2
Assets		802.9		800.7
Fine Paper and Packaging
Business segment
COVID-19 costs		0.1
Fine Paper and Packaging | Operating segments
Business segment
Net Sales		99.2	81.8
Operating income (loss)		11.9	12.7
COVID-19 costs			$ 0.3
Assets		$ 246.9		$ 228.4