Segment Information (as restated) - Schedule of Sales by Products and Services Offering (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue from External Customer [Line Items]
Net sales	$ 1,305.5	$ 1,162.0	$ 1,005.7	$ 897.3	$ 1,171.5	$ 1,070.7	$ 1,134.1	$ 1,054.8	$ 4,370.6	$ 4,431.2	$ 4,285.6
Critical infrastructure & solutions
Revenue from External Customer [Line Items]
Net sales									2,457.7	2,467.5	2,301.1
Critical infrastructure & solutions | Restatement Adjustment
Revenue from External Customer [Line Items]
Net sales										(165.1)	(150.7)
Services & spares
Revenue from External Customer [Line Items]
Net sales									1,324.8	1,338.1	1,305.3
Services & spares | Restatement Adjustment
Revenue from External Customer [Line Items]
Net sales										39.2	29.2
Integrated rack solutions
Revenue from External Customer [Line Items]
Net sales									$ 588.1	625.6	679.2
Integrated rack solutions | Restatement Adjustment
Revenue from External Customer [Line Items]
Net sales										$ 125.9	$ 121.5