Revenue - Schedule of Revenues Disaggregation by Contract Type (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Revenues	$ 384.2	$ 296.8	$ 763.8	$ 592.5
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	(6.5)	(5.4)	(13.5)	(11.5)
Transferred at Point in Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	42.0	37.7	77.6	77.8
Transferred at Point in Time [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0	0.0	0.0
Transferred over Time [Member]
Disaggregation Of Revenue [Line Items]
Revenues	342.2	259.1	686.2	514.7
Transferred over Time [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	0.0	0.0	0.0	0.0
Entertainment and Communications [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	250.5	173.9	500.8	348.1
Entertainment and Communications [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	5.2	4.7	11.2	9.9
Entertainment and Communications [Member] | Transferred at Point in Time [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	7.8	5.6	15.9	10.4
Entertainment and Communications [Member] | Transferred over Time [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	237.5	163.6	473.7	327.8
IT Services and Hardware [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	140.2	128.3	276.5	255.9
IT Services and Hardware [Member] | Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	1.3	0.7	2.3	1.6
IT Services and Hardware [Member] | Transferred at Point in Time [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	34.2	32.1	61.7	67.4
IT Services and Hardware [Member] | Transferred over Time [Member] | Operating Segments
Disaggregation Of Revenue [Line Items]
Revenues	$ 104.7	$ 95.5	$ 212.5	$ 186.9