Significant Accounting Policies - Impact of Adoption of ASU 2014-09 (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2019	May 31, 2018	May 31, 2017	Jun. 01, 2018	May 31, 2016
Assets
Accounts receivable, net	$ 910,120				$ 804,583				$ 910,120	$ 804,583		$ 818,009
Inventories, net	334,589				280,347				334,589	280,347		269,082
Income taxes, current	7,475				19,634				7,475	19,634
Prepaid expenses and other current assets	103,318				32,383				103,318	32,383		95,846
Total current assets	2,236,280				1,977,932				2,236,280	1,977,932		2,043,556
Other assets, net	240,315				29,315				240,315	29,315		216,818
Total assets	7,436,662				6,958,214				7,436,662	6,958,214	$ 6,844,057	7,211,341
Liabilities and Shareholders' Equity
Deferred income taxes	438,179				352,581				438,179	352,581		416,516
Total long-term liabilities	3,306,208				3,165,831				3,306,208	3,165,831		3,229,766
Retained earnings	6,691,236				5,837,827				6,691,236	5,837,827		6,027,019
Total shareholders' equity	3,002,721				3,016,526				3,002,721	3,016,526	2,302,793	3,205,718	$ 1,842,659
Total liabilities and shareholders' equity	7,436,662				6,958,214				7,436,662	6,958,214		7,211,341
Revenue:
Revenue									6,892,303	6,476,632	5,323,381
Costs and expenses:
Selling and administrative expenses									1,980,644	1,916,792	1,527,380
Operating income									1,133,534	949,834	773,691
Income before income taxes									1,102,399	841,001	687,404
Income taxes									219,764	57,069	230,118
Income from continuing operations	226,171	$ 200,923	$ 242,994	$ 212,547	$ 189,298	$ 295,789	$ 137,737	$ 161,108	882,635	783,932	457,286
Net income									$ 884,981	$ 842,586	$ 480,708
Diluted earnings per share (dollars per share)									$ 7.99	$ 7.56	$ 4.38
Calculated under Revenue Guidance in Effect before Topic 606
Assets
Accounts receivable, net	894,301								$ 894,301
Inventories, net	346,267								346,267
Income taxes, current	7,904								7,904
Prepaid expenses and other current assets	33,759								33,759
Total current assets	2,163,009								2,163,009
Other assets, net	38,518								38,518
Total assets	7,161,594								7,161,594
Liabilities and Shareholders' Equity
Deferred income taxes	369,215								369,215
Total long-term liabilities	3,237,244								3,237,244
Retained earnings	6,485,132								6,485,132
Total shareholders' equity	2,796,617								2,796,617
Total liabilities and shareholders' equity	7,161,594								7,161,594
Revenue:
Revenue									6,895,010
Costs and expenses:
Selling and administrative expenses									2,006,134
Operating income									1,111,164
Income before income taxes									1,080,029
Income taxes									214,306
Income from continuing operations									865,723
Net income									$ 868,069
Diluted earnings per share (dollars per share)									$ 7.84
Uniform rental and facility services
Revenue:
Revenue									$ 5,552,430	$ 5,247,124	$ 4,202,490
Costs and expenses:
Cost of revenue									3,027,599	2,886,959	2,307,774
Uniform rental and facility services | Calculated under Revenue Guidance in Effect before Topic 606
Revenue:
Revenue									5,557,056
Other
Revenue:
Revenue									1,339,873	1,229,508	1,120,891
Costs and expenses:
Cost of revenue									736,116	$ 681,150	$ 635,312
Other | Calculated under Revenue Guidance in Effect before Topic 606
Revenue:
Revenue									1,337,954
Costs and expenses:
Cost of revenue									735,703
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Assets
Accounts receivable, net	15,819								15,819
Inventories, net	(11,678)								(11,678)
Income taxes, current	(429)								(429)
Prepaid expenses and other current assets	69,559								69,559
Total current assets	73,271								73,271
Other assets, net	201,797								201,797
Total assets	275,068								275,068
Liabilities and Shareholders' Equity
Deferred income taxes	68,964								68,964
Total long-term liabilities	68,964								68,964
Retained earnings	206,104								206,104
Total shareholders' equity	206,104								206,104
Total liabilities and shareholders' equity	$ 275,068								275,068
Revenue:
Revenue									(2,707)
Costs and expenses:
Selling and administrative expenses									(25,490)
Operating income									22,370
Income before income taxes									22,370
Income taxes									5,458
Income from continuing operations									16,912
Net income									$ 16,912
Diluted earnings per share (dollars per share)									$ 0.15
Accounting Standards Update 2014-09 | Uniform rental and facility services | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue:
Revenue									$ (4,626)
Accounting Standards Update 2014-09 | Other | Difference between Revenue Guidance in Effect before and after Topic 606
Revenue:
Revenue									1,919
Costs and expenses:
Cost of revenue									$ 413
Accounting Standards Update 2014-09 | Capitalization of Contract Costs
Assets
Accounts receivable, net												0
Inventories, net												0
Prepaid expenses and other current assets												63,463
Total current assets												63,463
Other assets, net												187,503
Total assets												250,966
Liabilities and Shareholders' Equity
Deferred income taxes												63,389
Total long-term liabilities												63,389
Retained earnings												187,577
Total shareholders' equity												187,577
Total liabilities and shareholders' equity												250,966
Accounting Standards Update 2014-09 | Assets With No Alternative Use
Assets
Accounts receivable, net												13,426
Inventories, net												(11,265)
Prepaid expenses and other current assets												0
Total current assets												2,161
Other assets, net												0
Total assets												2,161
Liabilities and Shareholders' Equity
Deferred income taxes												546
Total long-term liabilities												546
Retained earnings												1,615
Total shareholders' equity												1,615
Total liabilities and shareholders' equity												$ 2,161