Retirement Benefit Plans - Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning projected benefit obligation	$ 144.7	$ 62.2
Service cost	5.7	4.6	$ 5.4
Interest cost	3.3	3.9	1.1
Actuarial loss (gain)	6.3	18.8
Benefits paid	(6.5)	(7.5)
Foreign currency exchange rate changes	(10.1)	(1.2)
Curtailments and settlements	(2.2)	(2.9)
Contributions by plan participants	4.0	5.9
Business combinations	0.0	60.9
Ending projected benefit obligation	145.2	144.7	62.2
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning fair value of plan assets	104.2	40.7
Actual return on plan assets	1.3	4.1
Contributions paid by employer	4.5	4.9
Contributions paid by plan participants	4.0	5.9
Benefit payments	(6.5)	(7.5)
Curtailments and settlements	0.0	(2.9)
Foreign currency exchange rate changes	(6.1)	(1.2)
Business combinations	0.0	60.2
Ending fair value of plan assets	101.4	104.2	$ 40.7
Funded status	$ (43.8)	$ (40.5)