Restructuring - Restructuring Charges By Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 49.4	$ 59.4	$ 21.2
Severance | Services Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	32.5	23.5	6.2
Severance | Software Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	2.4	7.1	0.7
Severance | Systems Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	8.7	17.6	7.2
Severance | Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 5.8	$ 11.2	$ 7.1