Business Segment Information - Business Segment Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 1,818.5		$ 1,818.5		$ 1,858.8
Total long-lived assets, net	253.9		253.9		260.8
Total net sales to external customers	328.1	$ 309.2	638.5	$ 594.6
Total operating earnings	35.2	28.9	58.3	48.9
Total capital expenditures	8.6	12.3	15.9	25.0
Total depreciation and amortization	14.3	14.3	28.7	28.8
Corporate [Member]
Segment Reporting Information [Line Items]
Total assets	55.9		55.9		80.5
Total long-lived assets, net	6.8		6.8		6.2
Total operating earnings	(12.1)	(11.9)	(24.3)	(24.4)
Total capital expenditures	0.8	0.1	1.1	0.2
Total depreciation and amortization	0.3	0.2	0.6	0.5
Advanced Plastic Processing Technologies | Segments [Member]
Segment Reporting Information [Line Items]
Total assets	521.3		521.3		524.8
Total long-lived assets, net	119.7		119.7		123.5
Total net sales to external customers	170.4	166.3	332.3	322.9
Total operating earnings	10.6	5.2	13.2	7.6
Total capital expenditures	2.8	4.0	5.1	9.9
Total depreciation and amortization	4.5	4.9	9.0	9.7
Melt Delivery and Control Systems | Segments [Member]
Segment Reporting Information [Line Items]
Total assets	1,093.6		1,093.6		1,104.5
Total long-lived assets, net	110.4		110.4		113.3
Total net sales to external customers	124.1	112.4	240.6	212.2
Total operating earnings	30.3	30.1	57.0	55.6
Total capital expenditures	4.7	7.5	8.8	14.1
Total depreciation and amortization	8.4	8.0	16.9	16.2
Fluid Technologies | Segments [Member]
Segment Reporting Information [Line Items]
Total assets	147.7		147.7		149.0
Total long-lived assets, net	17.0		17.0		$ 17.8
Total net sales to external customers	33.6	30.5	65.6	59.5
Total operating earnings	6.4	5.5	12.4	10.1
Total capital expenditures	0.3	0.7	0.9	0.8
Total depreciation and amortization	$ 1.1	$ 1.2	$ 2.2	$ 2.4