Segment Information - Information Related to Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016	May 31, 2017
Segment Reporting Information
Revenue	$ 1,606,441	$ 1,271,077	$ 3,217,944	$ 2,537,727
Income (loss) before income taxes	206,373	187,220	425,452	377,050
Total assets	6,978,801	4,214,579	6,978,801	4,214,579	$ 6,844,057
Operating Segments | Uniform Rental and Facility Services
Segment Reporting Information
Revenue	1,308,038	1,000,015	2,619,822	1,994,297
Income (loss) before income taxes	203,814	176,947	422,724	361,735
Total assets	5,899,010	3,262,448	5,899,010	3,262,448
Operating Segments | First Aid and Safety Services
Segment Reporting Information
Revenue	139,090	124,797	279,672	249,636
Income (loss) before income taxes	17,975	14,779	37,386	26,290
Total assets	467,902	443,151	467,902	443,151
Operating Segments | All Other
Segment Reporting Information
Revenue	159,313	146,265	318,450	293,794
Income (loss) before income taxes	13,422	8,730	24,200	16,368
Total assets	353,155	326,039	353,155	326,039
Corporate
Segment Reporting Information
Revenue	0	0	0	0
Income (loss) before income taxes	(28,838)	(13,236)	(58,858)	(27,343)
Total assets	$ 258,734	$ 182,941	$ 258,734	$ 182,941