Employee Benefit Plans (Details) - Schedule of change in benefit obligations - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Feb. 28, 2018	May 31, 2018	May 31, 2017	May 31, 2016
Change in benefit obligation:
Service cost			$ 0.1
Pension Plans [Member]
Change in benefit obligation:
Settlement		$ 0.0	0.0
Other Postretirement Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	$ 28.8	28.8	38.3
Service cost		0.0	0.0	$ 0.0
Interest cost		0.8	0.9	1.4
Plan participants’ contributions		0.4	0.2
Actuarial losses (gains)		(2.4)	(8.2)
Foreign currency translation		0.0	0.0
Settlement		0.0	0.0
Benefits paid, including expenses		(0.8)	(2.4)
Benefit obligation at end of year		26.8	28.8	38.3
U.S. [Member] | Pension Plans [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	127.8	127.8	125.0
Service cost		0.0	0.0	0.0
Interest cost		1.9	3.2	4.6
Plan participants’ contributions		0.0	0.0
Actuarial losses (gains)		1.7	9.2
Foreign currency translation		0.0	0.0
Settlement		(125.2)	0.0
Benefits paid, including expenses	(37.8)	(6.2)	(9.6)
Benefit obligation at end of year		0.0	127.8	125.0
U.K. [Member] | Pension Plans [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	$ 41.7	41.7	39.8
Service cost		0.0	0.0	0.0
Interest cost		1.1	1.2	1.5
Plan participants’ contributions		0.0	0.0
Actuarial losses (gains)		(2.0)	6.3
Foreign currency translation		1.3	(4.3)
Benefits paid, including expenses		(2.1)	(1.3)
Benefit obligation at end of year		$ 40.0	$ 41.7	$ 39.8