Retirement Benefit Plans - Funded Status (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2013
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning projected benefit obligation	$ 62.2	$ 61.5
Service cost	4.6	5.4	4.5
Interest cost	3.9	1.1	1.3
Actuarial loss (gain)	18.8	(3.2)
Benefits paid	(7.5)	(5.9)
Foreign currency exchange rate changes	(1.2)	0.8
Curtailments and settlements	(2.9)	0
Contributions by plan participants	5.9	2.5
Business combinations	60.9	0
Ending projected benefit obligation	144.7	62.2	61.5
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning fair value of plan assets	40.7	37.5
Actual return on plan assets	4.1	0.9
Contributions paid by employer	4.9	5.2
Contributions paid by plan participants	5.9	2.5
Benefit payments	(7.5)	(5.9)
Curtailments and settlements	(2.9)	0
Foreign currency exchange rate changes	(1.2)	0.5
Business combinations	60.2	0
Ending fair value of plan assets	104.2	40.7	37.5
Funded status	$ (40.5)	$ (21.5)