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The amount of net gain (loss) recognized in net periodic benefit cost as a result of an event that significantly eliminates the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount of gain (loss) recognized in net periodic benefit (cost) credit from event reducing expected years of future service of present employees or eliminating accrual of defined benefits for some or all future services of present employees.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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The amount recovered from insurance. These recoveries reduce costs and losses that are reported as a separate line item under operating expenses.

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Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

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Business Segment and Geographic Information - Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business segment
Net sales									$ 938.5	$ 1,034.9	$ 979.9
Total Assets	$ 827.8				$ 861.2				827.8	861.2
Depreciation and amortization									38.9	36.1	33.3
Capital expenditures									21.4	38.1	42.7
Operating income (loss)	22.1	$ 19.0	$ 19.8	$ 17.4	17.8	$ 16.5	$ (4.3)	$ 24.1	78.3	54.1	104.3
Curtailment gain	1.6
Acquisition related adjustments					0.8	(3.1)			0.0	(3.9)	0.0
Insurance recoveries						0.4			0.0	0.4	3.2
Pension plan settlement charge		0.1					1.0				0.6
Long-Lived Assets	575.1				583.3				575.1	583.3
United States
Business segment
Long-Lived Assets	364.2				366.3				364.2	366.3
Germany
Business segment
Long-Lived Assets	153.3				157.9				153.3	157.9
Rest of Europe
Business segment
Long-Lived Assets	57.6				59.1				57.6	59.1
Pension Benefits
Business segment
Curtailment gain									1.6	0.0	0.0
Unallocated corporate costs
Business segment
Total Assets	36.3				27.2				36.3	27.2
Depreciation and amortization									1.6	1.6	1.7
Capital expenditures									0.6	1.4	0.5
Operating income (loss)									(19.5)	(19.8)	(20.1)
Pre-operating costs related to conversion of fine paper machine to filtration												$ 2.7
Unallocated corporate costs \| Supplemental Employee Retirement Plan
Business segment
Integration costs											1.3
Restructuring costs and pension settlement charges									0.3	1.9
Product
Business segment
Net sales	213.6	$ 231.8	$ 253.4	$ 239.7	240.9	$ 256.2	$ 271.3	$ 266.5	938.5	1,034.9	979.9
Product \| United States
Business segment
Net sales									673.0	744.4	748.9
Product \| Germany
Business segment
Net sales									196.3	216.5	210.3
Product \| Rest of Europe
Business segment
Net sales									69.2	74.0	20.7
Technical Products \| Operating Segments
Business segment
Total Assets	573.8				599.3				573.8	599.3
Depreciation and amortization									24.1	24.4	20.3
Capital expenditures									13.1	28.0	29.7
Operating income (loss)									44.6	50.9	55.3
Non-routine costs									0.3
Non-cash impairment loss, restructuring, integration and pension settlement charges									2.5
Acquisition related adjustments									3.9
Technical Products \| Product \| Operating Segments
Business segment
Net sales									$ 541.6	$ 583.2	$ 518.6
Technical Products \| Product Concentration Risk \| Sales
Business segment
Percentage of concentration risk									100.00%	100.00%	100.00%
Technical Products \| Product Concentration Risk \| Filtration \| Sales
Business segment
Percentage of concentration risk									42.00%	40.00%	42.00%
Technical Products \| Product Concentration Risk \| Backings \| Sales
Business segment
Percentage of concentration risk									24.00%	28.00%	31.00%
Technical Products \| Product Concentration Risk \| Specialty \| Sales
Business segment
Percentage of concentration risk									34.00%	32.00%	27.00%
Fine Paper and Packaging \| Operating Segments
Business segment
Total Assets	$ 217.7				234.7				$ 217.7	$ 234.7
Depreciation and amortization									13.2	9.9	$ 11.0
Capital expenditures									7.7	8.7	12.5
Operating income (loss)									53.2	29.4	69.5
Non-routine costs									5.7
Non-cash impairment loss, restructuring costs, and pension settlement charges										24.6
Insurance recoveries										0.3	2.9
Integration costs												1.8
Fine Paper and Packaging \| Product \| Operating Segments
Business segment
Net sales									$ 396.9	$ 445.8	$ 455.3
Fine Paper and Packaging \| Product Concentration Risk \| Sales
Business segment
Percentage of concentration risk									100.00%	100.00%	100.00%
Fine Paper and Packaging \| Product Concentration Risk \| Graphic Imaging \| Sales
Business segment
Percentage of concentration risk									79.00%	78.00%	80.00%
Fine Paper and Packaging \| Product Concentration Risk \| Packaging \| Sales
Business segment
Percentage of concentration risk									21.00%	18.00%	16.00%
Fine Paper and Packaging \| Product Concentration Risk \| Filing/Office \| Sales
Business segment
Percentage of concentration risk									0.00%	4.00%	4.00%
Other \| Operating Segments
Business segment
Depreciation and amortization									$ 0.0	$ 0.2	$ 0.3
Operating income (loss)									0.0	(6.4)	(0.4)
Insurance recoveries										0.1	0.3
Integration costs												1.1
Pension plan settlement charge										6.0		$ 0.8
Other \| Product \| Operating Segments
Business segment
Net sales									0.0	5.9	6.0
Restatement Adjustment \| Other \| Operating Segments
Business segment
Net sales										(15.6)	(16.5)
Total Assets					$ (12.9)					(12.9)
Depreciation and amortization										(0.7)	(0.9)
Capital expenditures										$ 0.0	$ (1.1)
Dutch Defined Benefit Plan \| Technical Products \| Pension Benefits
Business segment
Curtailment gain									$ 1.6