Segment Information - Information Related to Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Feb. 28, 2018	Feb. 28, 2017	Feb. 28, 2018	Feb. 28, 2017	May 31, 2017
Segment Reporting Information
Revenue	$ 1,589,138	$ 1,255,367	$ 4,807,082	$ 3,793,094
Income (loss) before income taxes	174,507	178,306	599,959	555,356
Total assets	6,928,593	4,271,164	6,928,593	4,271,164	$ 6,844,057
Operating Segments \| Uniform Rental and Facility Services
Segment Reporting Information
Revenue	1,284,516	988,178	3,904,338	2,982,475
Income (loss) before income taxes	173,287	171,933	596,011	533,668
Total assets	5,900,987	3,283,382	5,900,987	3,283,382
Operating Segments \| First Aid and Safety Services
Segment Reporting Information
Revenue	137,327	124,239	416,999	373,875
Income (loss) before income taxes	16,705	12,235	54,091	38,525
Total assets	472,982	452,397	472,982	452,397
Operating Segments \| All Other
Segment Reporting Information
Revenue	167,295	142,950	485,745	436,744
Income (loss) before income taxes	10,032	7,823	34,232	24,191
Total assets	368,368	348,703	368,368	348,703
Corporate
Segment Reporting Information
Revenue	0	0	0	0
Income (loss) before income taxes	(25,517)	(13,685)	(84,375)	(41,028)
Total assets	$ 186,256	$ 186,682	$ 186,256	$ 186,682

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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