Segment Information - Information Related to Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended
Aug. 31, 2017	Aug. 31, 2016	May 31, 2017
Segment Reporting Information
Revenue	$ 1,611,503	$ 1,266,650
Income (loss) before income taxes	219,079	189,830
Total assets	6,851,606	4,167,145	$ 6,844,057
Operating Segments \| Uniform Rental and Facility Services
Segment Reporting Information
Revenue	1,311,784	994,282
Income (loss) before income taxes	218,910	184,788
Total assets	5,844,718	3,191,835
Operating Segments \| First Aid and Safety Services
Segment Reporting Information
Revenue	140,582	124,839
Income (loss) before income taxes	19,411	11,511
Total assets	456,391	436,920
Operating Segments \| All Other
Segment Reporting Information
Revenue	159,137	147,529
Income (loss) before income taxes	10,778	7,638
Total assets	337,457	328,687
Corporate
Segment Reporting Information
Revenue	0	0
Income (loss) before income taxes	(30,020)	(14,107)
Total assets	$ 213,040	$ 209,703

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h)(1)(i))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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