Segmental Information - Financial Information by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Amortization	$ 2.5	$ 2.5	$ 4.9	$ 4.9
Restructuring charges	2.0	1.1	2.1	1.8
Total assets	399.2		399.2		$ 382.4
Capital expenditures	1.8	2.8	3.2	4.3
Discontinued operations
Segment Reporting Information [Line Items]
Total assets	7.0		7.0		7.7
Capital expenditures	0.2	0.0	0.2	0.0
Operating segments
Segment Reporting Information [Line Items]
Amortization	0.2	0.2	0.4	0.4
Restructuring charges	2.0	1.1	2.1	1.8
Total assets	320.8		320.8		310.4
Capital expenditures	1.6	2.8	3.0	4.3
Operating segments \| Gas Cylinders
Segment Reporting Information [Line Items]
Amortization	0.9	0.9	1.7	1.7
Restructuring charges	2.0	1.1	2.1	1.6
Total assets	130.1		130.1		122.5
Capital expenditures	0.5	1.3	0.8	2.1
Operating segments \| Elektron
Segment Reporting Information [Line Items]
Amortization	1.6	1.6	3.2	3.2
Restructuring charges	0.0	0.0	0.0	0.2
Total assets	175.1		175.1		173.1
Capital expenditures	1.1	1.4	2.1	2.1
Operating segments \| Graphic Arts
Segment Reporting Information [Line Items]
Amortization	0.0	0.0	0.0	0.0
Restructuring charges	0.0	0.0	0.0	0.0
Total assets	15.6		15.6		14.8
Capital expenditures	0.0	0.1	0.1	0.1
Other
Segment Reporting Information [Line Items]
Total assets	71.4		71.4		$ 64.3
Capital expenditures	$ 0.0	$ 0.0	$ 0.0	$ 0.0