Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Condensed Consolidated Statements of Comprehensive Income
Net income	$ 12.1	$ 8.0	$ 21.6	$ 30.9
Other comprehensive income (loss), net of tax expense (benefit):
Currency translation adjustments	(1.1)	0.8	(2.6)	1.0
Pension and other post-retirement plans:
Amortization of actuarial loss and prior service cost included in net income, net of tax of $0 and $0.1 for the three months ended November 30, 2016 and 2015, respectively, and $0 and $0.2 for the six months ended November 30, 2016 and 2015, respectively	0.2	0.3	0.5	0.5
Other comprehensive income (loss), net of tax	(0.9)	1.1	(2.1)	1.5
Comprehensive income	$ 11.2	$ 9.1	$ 19.5	$ 32.4