Segment Information - Information Related to Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 29, 2016	Feb. 28, 2015	Feb. 29, 2016	Feb. 28, 2015	May. 31, 2015
Segment Reporting Information
Revenue	$ 1,216,083	$ 1,108,847	$ 3,634,053	$ 3,334,303
Income (loss) before income taxes	177,124	157,459	530,627	491,829
Total assets	4,231,210	4,266,346	4,231,210	4,266,346	$ 4,192,460
Operating Segments | Uniform Rental and Facility Services
Segment Reporting Information
Revenue	936,565	883,401	2,812,677	2,648,574
Income (loss) before income taxes	167,502	152,165	502,178	456,548
Total assets	3,050,138	2,908,813	3,050,138	2,908,813
Operating Segments | First Aid and Safety Services
Segment Reporting Information
Revenue	119,064	79,471	338,990	241,666
Income (loss) before income taxes	12,634	11,298	36,073	32,222
Total assets	436,390	264,357	436,390	264,357
Operating Segments | All Other
Segment Reporting Information
Revenue	160,454	145,975	482,386	444,063
Income (loss) before income taxes	12,816	10,154	40,557	29,918
Total assets	357,863	340,705	357,863	340,705
Corporate
Segment Reporting Information
Revenue	0	0	0	0
Income (loss) before income taxes	(15,828)	(16,158)	(48,181)	(26,859)
Total assets	$ 386,819	$ 752,471	$ 386,819	$ 752,471