Segment Information - Information Related to Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016	May 31, 2016
Segment Reporting Information
Revenue	$ 1,281,135	$ 1,216,083	$ 3,872,188	$ 3,634,053
Income (loss) before income taxes	181,010	177,124	563,486	530,627
Total assets	4,271,164	4,231,210	4,271,164	4,231,210	$ 4,098,815
Operating Segments \| Uniform Rental and Facility Services
Segment Reporting Information
Revenue	993,398	936,565	2,998,559	2,812,677
Income (loss) before income taxes	172,543	167,502	535,149	502,178
Total assets	3,285,791	3,050,138	3,285,791	3,050,138
Operating Segments \| First Aid and Safety Services
Segment Reporting Information
Revenue	124,239	119,064	373,875	338,990
Income (loss) before income taxes	12,235	12,634	38,525	36,073
Total assets	452,397	436,390	452,397	436,390
Operating Segments \| All Other
Segment Reporting Information
Revenue	163,498	160,454	499,754	482,386
Income (loss) before income taxes	9,917	12,816	30,840	40,557
Total assets	385,732	357,863	385,732	357,863
Corporate
Segment Reporting Information
Revenue	0	0	0	0
Income (loss) before income taxes	(13,685)	(15,828)	(41,028)	(48,181)
Total assets	$ 147,244	$ 386,819	$ 147,244	$ 386,819

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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