Other Noncurrent Assets (Details 2) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2011	May. 31, 2015	May. 31, 2014
Intangible assets
License fees		$ 12.2	$ 13.0
Exclusive distribution rights | Unison Industries
Intangible assets
Term of agreement	10 years
Amount agreed to be paid	$ 20.0
Amount paid	$ 7.0
Amount payable in each calendar year		1.3
Licensing Agreements [Member]
Intangible assets
Current portion of the deferred payments		1.3
Licensing Agreements [Member] | Unison Industries
Intangible assets
License fees		$ 10.4	$ 11.9
Amortization period		10 years
Long-term portion		$ 5.1