Sale of Product Line (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015
Discontinued Operations
Amount received from sale of assets	$ 3.0	$ 6.5
Temperature-controlled container product line | Disposed of by sale
Discontinued Operations
Sales price	5.0
Amount received from sale of assets	3.0
Non-contingent deferred consideration amount in the sales price	$ 2.0
Non-contingent deferred consideration due over the period	2 years
Gain on sale of assets	$ 2.6