Goodwill, Service Contracts and Other Assets - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016
Goodwill [Roll Forward]
Balance at the beginning of the period	$ 1,276,076	$ 1,180,094
Goodwill acquired	1,507,554	97,097
Foreign currency translation	(1,295)	(1,115)
Balance at the end of the period	2,782,335	1,276,076
Operating Segments | Uniform Rental and Facility Services
Goodwill [Roll Forward]
Balance at the beginning of the period	949,730	940,423
Goodwill acquired	1,499,008	10,020
Foreign currency translation	(668)	(713)
Balance at the end of the period	2,448,070	949,730
Operating Segments | First Aid and Safety Services
Goodwill [Roll Forward]
Balance at the beginning of the period	241,448	154,954
Goodwill acquired	2,265	86,874
Foreign currency translation	(601)	(380)
Balance at the end of the period	243,112	241,448
Operating Segments | All Other
Goodwill [Roll Forward]
Balance at the beginning of the period	84,898	84,717
Goodwill acquired	6,281	203
Foreign currency translation	(26)	(22)
Balance at the end of the period	$ 91,153	$ 84,898