Segments Concerning the Operations Of Reportable Segments (Details) $ in Millions	3 Months Ended			6 Months Ended
	Jul. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2016 USD ($) segment	Jul. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment				4
Net revenue	$ 550.7		$ 609.5	$ 1,062.6	$ 1,256.0
Gross profit	465.6	$ 419.5	516.5	885.1	1,071.2
Segments
Segment Reporting Information [Line Items]
Net revenue	550.7		609.5	1,062.6	1,256.0
Unallocated
Segment Reporting Information [Line Items]
Gross profit	(14.1)		(14.4)	(28.4)	(30.8)	[1]
Architecture, Engineering and Construction | Segments
Segment Reporting Information [Line Items]
Net revenue	253.2		233.4	472.1	470.1
Gross profit	229.1		209.5	422.7	426.5
Manufacturing | Segments
Segment Reporting Information [Line Items]
Net revenue	176.9		171.2	334.9	355.8
Gross profit	156.4		151.2	292.5	309.3
Platform Solutions and Emerging Business | Segments
Segment Reporting Information [Line Items]
Net revenue	86.2		164.1	186.2	349.4
Gross profit	65.5		138.5	141.6	301.8
Media and Entertainment | Segments
Segment Reporting Information [Line Items]
Net revenue	34.4		40.8	69.4	80.7
Gross profit	$ 28.7		$ 31.7	$ 56.7	$ 64.4

[1] Unallocated amounts primarily relate to corporate expenses and other costs and expenses that are managed outside the reportable segments, including stock-based compensation expense.