Operations by Industry Segment and Geographic Area - Segment Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 1,097.2	$ 1,024.4	$ 1,169.6
Restructuring, impairment and other asset charges, net	2.5	8.1	3.2
Interest expense	1.1	0.7	1.4
Interest income	0.5	0.8	1.2
Depreciation and amortization	30.2	26.9	26.2
Income taxes	(1.4)	(1.2)	3.0
Profit (loss)	17.5	45.8	21.0
Assets	2,313.6	2,113.4	1,895.1
Capital expenditures	20.1	15.4	22.6
Infrastructure Solutions
Segment Reporting Information [Line Items]
Revenues	748.0	702.8	764.6
Materials Solutions
Segment Reporting Information [Line Items]
Revenues	349.2	321.6	405.0
Operating Segments | Infrastructure Solutions
Segment Reporting Information [Line Items]
Revenues	748.0	702.8	764.6
Restructuring, impairment and other asset charges, net	1.9	6.6	2.9
Interest expense	0.1	0.0	0.0
Interest income	0.0	0.1	0.0
Depreciation and amortization	20.8	17.8	16.9
Income taxes	1.4	0.4	0.8
Profit (loss)	53.0	53.8	33.8
Assets	996.9	938.8	865.8
Capital expenditures	12.2	7.9	14.2
Operating Segments | Materials Solutions
Segment Reporting Information [Line Items]
Revenues	349.2	321.6	405.0
Restructuring, impairment and other asset charges, net	0.6	(1.3)	0.3
Interest expense	0.5	0.2	0.3
Interest income	0.2	0.3	0.6
Depreciation and amortization	8.0	7.9	8.2
Income taxes	(4.3)	1.2	0.6
Profit (loss)	29.3	32.1	22.8
Assets	667.8	639.3	608.4
Capital expenditures	5.6	4.8	7.4
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	105.5	74.2	51.4
Intersegment Eliminations | Infrastructure Solutions
Segment Reporting Information [Line Items]
Revenues	47.5	33.5	29.2
Intersegment Eliminations | Materials Solutions
Segment Reporting Information [Line Items]
Revenues	58.0	40.7	22.2
Corporate
Segment Reporting Information [Line Items]
Revenues	0.0	0.0	0.0
Restructuring, impairment and other asset charges, net	0.0	2.8	0.0
Interest expense	0.5	0.5	1.1
Interest income	0.3	0.4	0.6
Depreciation and amortization	1.4	1.2	1.1
Income taxes	1.5	(2.8)	1.6
Profit (loss)	(64.8)	(40.1)	(35.6)
Assets	648.9	535.3	420.9
Capital expenditures	$ 2.3	$ 2.7	$ 1.0