Reportable Segments - Product Sales Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information
Sales to external customers	$ 289.3	$ 244.1
Natural gas processing (including petrochemical) applications
Segment Reporting Information
Sales to external customers	70.3	58.7
Liquefied natural gas (LNG) applications
Segment Reporting Information
Sales to external customers	48.8	42.2
Industrial gas applications
Segment Reporting Information
Sales to external customers	7.1	3.4
HVAC, power and refining applications
Segment Reporting Information
Sales to external customers	13.6	18.8
Bulk industrial gas applications
Segment Reporting Information
Sales to external customers	77.7	53.0
Packaged gas industrial applications
Segment Reporting Information
Sales to external customers	51.5	48.9
Cryobiological storage
Segment Reporting Information
Sales to external customers	20.3	19.1
Operating Segments | Energy & Chemicals
Segment Reporting Information
Sales to external customers	105.6	89.9
Operating Segments | Energy & Chemicals | Natural gas processing (including petrochemical) applications
Segment Reporting Information
Sales to external customers	70.3	58.7
Operating Segments | Energy & Chemicals | Liquefied natural gas (LNG) applications
Segment Reporting Information
Sales to external customers	14.6	9.0
Operating Segments | Energy & Chemicals | Industrial gas applications
Segment Reporting Information
Sales to external customers	7.1	3.4
Operating Segments | Energy & Chemicals | HVAC, power and refining applications
Segment Reporting Information
Sales to external customers	13.6	18.8
Operating Segments | Energy & Chemicals | Bulk industrial gas applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | Energy & Chemicals | Packaged gas industrial applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | Energy & Chemicals | Cryobiological storage
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S West
Segment Reporting Information
Sales to external customers	118.0	100.6
Operating Segments | D&S West | Natural gas processing (including petrochemical) applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S West | Liquefied natural gas (LNG) applications
Segment Reporting Information
Sales to external customers	22.1	13.0
Operating Segments | D&S West | Industrial gas applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S West | HVAC, power and refining applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S West | Bulk industrial gas applications
Segment Reporting Information
Sales to external customers	37.8	28.6
Operating Segments | D&S West | Packaged gas industrial applications
Segment Reporting Information
Sales to external customers	36.1	39.9
Operating Segments | D&S West | Cryobiological storage
Segment Reporting Information
Sales to external customers	22.0	19.1
Operating Segments | D&S East
Segment Reporting Information
Sales to external customers	68.7	55.1
Operating Segments | D&S East | Natural gas processing (including petrochemical) applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S East | Liquefied natural gas (LNG) applications
Segment Reporting Information
Sales to external customers	12.1	20.4
Operating Segments | D&S East | Industrial gas applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S East | HVAC, power and refining applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Operating Segments | D&S East | Bulk industrial gas applications
Segment Reporting Information
Sales to external customers	40.2	24.8
Operating Segments | D&S East | Packaged gas industrial applications
Segment Reporting Information
Sales to external customers	16.4	9.9
Operating Segments | D&S East | Cryobiological storage
Segment Reporting Information
Sales to external customers	0.0	0.0
Intersegment Eliminations
Segment Reporting Information
Sales to external customers	(3.0)	(1.5)
Intersegment Eliminations | Natural gas processing (including petrochemical) applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Intersegment Eliminations | Liquefied natural gas (LNG) applications
Segment Reporting Information
Sales to external customers	0.0	(0.2)
Intersegment Eliminations | Industrial gas applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Intersegment Eliminations | HVAC, power and refining applications
Segment Reporting Information
Sales to external customers	0.0	0.0
Intersegment Eliminations | Bulk industrial gas applications
Segment Reporting Information
Sales to external customers	(0.3)	(0.4)
Intersegment Eliminations | Packaged gas industrial applications
Segment Reporting Information
Sales to external customers	(1.0)	(0.9)
Intersegment Eliminations | Cryobiological storage
Segment Reporting Information
Sales to external customers	$ (1.7)	$ 0.0