Segment Information - Information Related to Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015	May 31, 2016
Segment Reporting Information
Revenue	$ 1,296,923	$ 1,219,080	$ 2,591,053	$ 2,417,970
Income (loss) before income taxes	189,622	184,289	382,476	353,503
Total assets	4,214,579	4,444,610	4,214,579	4,444,610	$ 4,098,815
Operating Segments | Uniform Rental and Facility Services
Segment Reporting Information
Revenue	1,005,565	937,704	2,005,161	1,876,112
Income (loss) before income taxes	177,361	169,295	362,606	334,676
Total assets	3,266,422	2,990,828	3,266,422	2,990,828
Operating Segments | First Aid and Safety Services
Segment Reporting Information
Revenue	124,797	120,438	249,636	219,926
Income (loss) before income taxes	14,779	14,847	26,290	23,439
Total assets	443,151	426,089	443,151	426,089
Operating Segments | All Other
Segment Reporting Information
Revenue	166,561	160,938	336,256	321,932
Income (loss) before income taxes	10,718	16,207	20,923	27,741
Total assets	361,433	355,082	361,433	355,082
Corporate
Segment Reporting Information
Revenue	0	0	0	0
Income (loss) before income taxes	(13,236)	(16,060)	(27,343)	(32,353)
Total assets	$ 143,573	$ 672,611	$ 143,573	$ 672,611