Revenue - Schedule of Revenues Disaggregation by Contract Type (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 07, 2021	Sep. 30, 2020	Sep. 07, 2021	Sep. 30, 2020
Disaggregation Of Revenue [Line Items]
Revenues	$ 111.4	$ 314.6	$ 389.5	$ 1,138.7	$ 1,149.5
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	(2.3)	(4.5)	(6.7)	(17.9)	(19.5)
Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	13.2	29.2	40.7	105.9	112.3
Transferred at Point in Time [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0	0.0	0.0	0.0
Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	98.2	285.4	348.8	1,032.8	1,037.2
Transferred over Time [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0	0.0	0.0	0.0
Entertainment and Communications [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues	61.7	180.4	241.0	664.2	724.5
Entertainment and Communications [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	1.6	3.4	4.9	13.1	14.8
Entertainment and Communications [Member] | Transferred at Point in Time [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues	2.1	4.1	6.6	15.8	19.1
Entertainment and Communications [Member] | Transferred over Time [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues	58.0	172.9	229.5	635.3	690.6
IT Services and Hardware [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues	52.0	138.7	155.2	492.4	444.5
IT Services and Hardware [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.7	1.1	1.8	4.8	4.7
IT Services and Hardware [Member] | Transferred at Point in Time [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues	11.1	25.1	34.1	90.1	93.2
IT Services and Hardware [Member] | Transferred over Time [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues	$ 40.2	$ 112.5	$ 119.3	$ 397.5	$ 346.6