Related Parties (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
EMC Corporation [Member]
Related Party Transaction [Line Items]
Purchases from related parties	$ 0.6	$ 4.9	$ 6.9
Staples, Inc. [Member]
Related Party Transaction [Line Items]
Purchases from related parties	$ 2.9	$ 2.3	$ 1.7