Revenue - Disaggregated Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue Reclassification Between Practices	$ 6.8
Revenues	379.6	$ 295.7
Entertainment and Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	250.3	174.2
IT Services and Hardware [Member]
Disaggregation of Revenue [Line Items]
Revenues	136.3	127.6
Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	(7.0)	(6.1)
Intersegment Eliminations [Member] | Entertainment and Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	6.0	5.2
Intersegment Eliminations [Member] | IT Services and Hardware [Member]
Disaggregation of Revenue [Line Items]
Revenues	1.0	0.9
Consolidation, Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	0.0	0.0
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	35.6	40.1
Transferred at Point in Time [Member] | Entertainment and Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	8.1	4.8
Transferred at Point in Time [Member] | IT Services and Hardware [Member]
Disaggregation of Revenue [Line Items]
Revenues	27.5	35.3
Transferred at Point in Time [Member] | Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	0.0	0.0
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenues	344.0	255.6
Transferred over Time [Member] | Entertainment and Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	236.2	164.2
Transferred over Time [Member] | IT Services and Hardware [Member]
Disaggregation of Revenue [Line Items]
Revenues	107.8	91.4
Transferred over Time [Member] | Intersegment Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenues	0.0	0.0
Data [Member]
Disaggregation of Revenue [Line Items]
Revenues	117.5	84.9
Video [Member]
Disaggregation of Revenue [Line Items]
Revenues	51.7	39.2
Voice [Member]
Disaggregation of Revenue [Line Items]
Revenues	73.4	47.0
Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	7.7	3.1
Consulting [Member]
Disaggregation of Revenue [Line Items]
Revenues	38.9	31.3
Cloud [Member]
Disaggregation of Revenue [Line Items]
Revenues	24.4	22.6
Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	47.4	40.6
Infrastructure Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 25.6	$ 33.1