Restructuring Activities - Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Reserve
Beginning balance, restructuring accrual	$ 1.9	$ 1.3	$ 0.9	$ 0.9
Restructuring costs	1.9	1.5	12.7	13.3
Property, plant and equipment impairment				(5.6)
Cash payments and other	(2.2)	(1.8)	(12.0)	(7.6)
Ending balance, restructuring accrual	1.6	1.0	1.6	1.0
Operating Segments | D&S East
Restructuring Reserve
Beginning balance, restructuring accrual	0.7	0.7	0.4	0.8
Restructuring costs	0.1	0.3	2.0	8.1
Property, plant and equipment impairment				(4.0)
Cash payments and other	(0.1)	(0.4)	(1.7)	(4.3)
Ending balance, restructuring accrual	0.7	0.6	0.7	0.6
Operating Segments | D&S West
Restructuring Reserve
Beginning balance, restructuring accrual	0.7	0.0	0.1	0.0
Restructuring costs	0.2	0.4	1.2	0.8
Property, plant and equipment impairment				0.0
Cash payments and other	(0.5)	(0.3)	(0.9)	(0.7)
Ending balance, restructuring accrual	0.4	0.1	0.4	0.1
Operating Segments | E&C Cryogenics
Restructuring Reserve
Beginning balance, restructuring accrual	0.3	0.6	0.2	0.0
Restructuring costs	0.0	0.2	0.8	2.4
Property, plant and equipment impairment				(1.6)
Cash payments and other	(0.3)	(0.5)	(1.0)	(0.5)
Ending balance, restructuring accrual	0.0	0.3	0.0	0.3
Operating Segments | E&C FinFans
Restructuring Reserve
Beginning balance, restructuring accrual	0.0	0.0	0.0	0.0
Restructuring costs	1.1	0.6	6.0	1.8
Property, plant and equipment impairment				0.0
Cash payments and other	(0.9)	(0.6)	(5.8)	(1.8)
Ending balance, restructuring accrual	0.2	0.0	0.2	0.0
Corporate
Restructuring Reserve
Beginning balance, restructuring accrual	0.2	0.0	0.2	0.1
Restructuring costs	0.5	0.0	2.7	0.2
Property, plant and equipment impairment				0.0
Cash payments and other	(0.4)	0.0	(2.6)	(0.3)
Ending balance, restructuring accrual	$ 0.3	$ 0.0	$ 0.3	$ 0.0