Supplemental Guarantor Information - Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Feb. 29, 2020	Nov. 30, 2019	Aug. 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	Feb. 29, 2020	Feb. 28, 2019
Cash flows from operating activities:
Net income	$ 234,520	$ 246,120	$ 250,812	$ 203,334	$ 243,013	$ 212,515	$ 731,452	$ 658,862
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation							175,261	164,380
Amortization of intangible assets and capitalized contract costs							107,232	101,949
Stock-based compensation							96,428	105,553
Gain on sale of a cost method investment	0			0			0	(69,373)
Gain on sale of business							0	(2,419)
Deferred income taxes							5,013	25,079
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(31,135)	(61,102)
Inventories, net							(17,780)	(70,716)
Uniforms and other rental items in service							(33,732)	(72,336)
Prepaid expenses and other current assets and capitalized contract costs							(95,169)	(85,123)
Accounts payable							14,271	79
Accrued compensation and related liabilities							(4,792)	(3,866)
Accrued liabilities and other							3,426	3,614
Income taxes, current							(15,926)	(23,864)
Net cash provided by operating activities							934,549	670,717
Cash flows from investing activities:
Capital expenditures							(189,379)	(207,805)
Purchases of investments							(10,461)	(17,544)
Proceeds from sale of assets							13,300	0
Proceeds from sale of a cost method investment							0	73,342
Proceeds from sale of business							0	3,200
Acquisitions of businesses, net of cash acquired							(47,850)	(7,403)
Other, net							(2,090)	(6,804)
Net cash used in investing activities							(236,480)	(163,014)
Cash flows from financing activities:
(Payments) issuance of commercial paper, net							(112,500)	217,500
Proceeds from exercise of stock-based compensation awards							81,547	54,274
Dividends paid							(268,042)	(220,760)
Repurchase of common stock							(261,327)	(608,224)
Other, net							30	(8,088)
Net cash used in financing activities							(560,292)	(565,298)
Effect of exchange rate changes on cash and cash equivalents							19	(270)
Net increase (decrease) in cash and cash equivalents							137,796	(57,865)
Cash and cash equivalents at beginning of period			96,645			138,724	96,645	138,724
Cash and cash equivalents at end of period	234,441			80,859			234,441	80,859
Eliminations
Cash flows from operating activities:
Net income	(234,630)			(199,324)			(744,642)	(650,444)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation							0	0
Amortization of intangible assets and capitalized contract costs							0	0
Stock-based compensation							0	0
Gain on sale of a cost method investment								0
Gain on sale of business								0
Deferred income taxes							0	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							0	(4,280)
Inventories, net							0	(3,780)
Uniforms and other rental items in service							5,020	0
Prepaid expenses and other current assets and capitalized contract costs							0	0
Accounts payable							(365)	(361)
Accrued compensation and related liabilities							0	0
Accrued liabilities and other							0	0
Income taxes, current							0	0
Net cash provided by operating activities							(739,987)	(658,865)
Cash flows from investing activities:
Capital expenditures							0	0
Purchases of investments							0	750
Proceeds from sale of assets							0
Proceeds from sale of a cost method investment								0
Proceeds from sale of business								0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							739,987	658,115
Net cash used in investing activities							739,987	658,865
Cash flows from financing activities:
(Payments) issuance of commercial paper, net							0	0
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							0	0
Repurchase of common stock							0	0
Other, net							0	0
Net cash used in financing activities							0	0
Effect of exchange rate changes on cash and cash equivalents							0	0
Net increase (decrease) in cash and cash equivalents							0	0
Cash and cash equivalents at beginning of period			0			0	0	0
Cash and cash equivalents at end of period	0			0			0	0
Cintas Corporation | Reportable Legal Entities
Cash flows from operating activities:
Net income	234,520			203,334			731,452	658,862
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation							0	0
Amortization of intangible assets and capitalized contract costs							0	0
Stock-based compensation							96,428	105,553
Gain on sale of a cost method investment								0
Gain on sale of business								0
Deferred income taxes							0	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							0	0
Inventories, net							0	0
Uniforms and other rental items in service							0	0
Prepaid expenses and other current assets and capitalized contract costs							0	0
Accounts payable							0	0
Accrued compensation and related liabilities							0	0
Accrued liabilities and other							0	0
Income taxes, current							0	0
Net cash provided by operating activities							827,880	764,415
Cash flows from investing activities:
Capital expenditures							0	0
Purchases of investments							0	0
Proceeds from sale of assets							0
Proceeds from sale of a cost method investment								0
Proceeds from sale of business								0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							(380,159)	10,201
Net cash used in investing activities							(380,159)	10,201
Cash flows from financing activities:
(Payments) issuance of commercial paper, net							0	0
Proceeds from exercise of stock-based compensation awards							81,547	54,274
Dividends paid							(267,941)	(220,666)
Repurchase of common stock							(261,327)	(608,224)
Other, net							0	0
Net cash used in financing activities							(447,721)	(774,616)
Effect of exchange rate changes on cash and cash equivalents							0	0
Net increase (decrease) in cash and cash equivalents							0	0
Cash and cash equivalents at beginning of period			0			0	0	0
Cash and cash equivalents at end of period	0			0			0	0
Corp. 2 | Reportable Legal Entities
Cash flows from operating activities:
Net income	68,208			62,239			224,873	178,279
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation							115,229	106,577
Amortization of intangible assets and capitalized contract costs							97,267	91,912
Stock-based compensation							0	0
Gain on sale of a cost method investment								0
Gain on sale of business								(2,419)
Deferred income taxes							8,319	16,059
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(23,027)	(51,317)
Inventories, net							(25,914)	(64,014)
Uniforms and other rental items in service							(32,368)	(51,696)
Prepaid expenses and other current assets and capitalized contract costs							(77,609)	(74,606)
Accounts payable							24,315	(205,528)
Accrued compensation and related liabilities							(20,168)	1,832
Accrued liabilities and other							(7,377)	(274)
Income taxes, current							(11,863)	7,059
Net cash provided by operating activities							271,677	(48,136)
Cash flows from investing activities:
Capital expenditures							(140,144)	(147,744)
Purchases of investments							(793)	(1,938)
Proceeds from sale of assets							0
Proceeds from sale of a cost method investment								0
Proceeds from sale of business								3,200
Acquisitions of businesses, net of cash acquired							(47,777)	(7,403)
Other, net							31,121	(5,216)
Net cash used in investing activities							(157,593)	(159,101)
Cash flows from financing activities:
(Payments) issuance of commercial paper, net							(112,500)	217,500
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							0	0
Repurchase of common stock							0	0
Other, net							30	(8,088)
Net cash used in financing activities							(112,470)	209,412
Effect of exchange rate changes on cash and cash equivalents							0	0
Net increase (decrease) in cash and cash equivalents							1,614	2,175
Cash and cash equivalents at beginning of period			54,963			44,499	54,963	44,499
Cash and cash equivalents at end of period	56,577			46,674			56,577	46,674
Subsidiary Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	160,400			130,863			497,208	453,598
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation							49,181	47,116
Amortization of intangible assets and capitalized contract costs							3,838	3,801
Stock-based compensation							0	0
Gain on sale of a cost method investment								(69,373)
Gain on sale of business								0
Deferred income taxes							(3,735)	5,654
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(5,536)	2,522
Inventories, net							8,346	1,395
Uniforms and other rental items in service							(4,754)	(12,329)
Prepaid expenses and other current assets and capitalized contract costs							(17,543)	(10,067)
Accounts payable							(9,136)	204,336
Accrued compensation and related liabilities							14,343	(4,143)
Accrued liabilities and other							13,777	4,567
Income taxes, current							(5,733)	(24,957)
Net cash provided by operating activities							540,256	602,120
Cash flows from investing activities:
Capital expenditures							(32,026)	(44,151)
Purchases of investments							(9,668)	(16,356)
Proceeds from sale of assets							0
Proceeds from sale of a cost method investment								73,342
Proceeds from sale of business								0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							(359,185)	(663,791)
Net cash used in investing activities							(400,879)	(650,956)
Cash flows from financing activities:
(Payments) issuance of commercial paper, net							0	0
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							0	0
Repurchase of common stock							0	0
Other, net							0	0
Net cash used in financing activities							0	0
Effect of exchange rate changes on cash and cash equivalents							0	0
Net increase (decrease) in cash and cash equivalents							139,377	(48,836)
Cash and cash equivalents at beginning of period			13,151			60,310	13,151	60,310
Cash and cash equivalents at end of period	152,528			11,474			152,528	11,474
Non- Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	6,022			6,222			22,561	18,567
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation							10,851	10,687
Amortization of intangible assets and capitalized contract costs							6,127	6,236
Stock-based compensation							0	0
Gain on sale of a cost method investment								0
Gain on sale of business								0
Deferred income taxes							429	3,366
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(2,572)	(8,027)
Inventories, net							(212)	(4,317)
Uniforms and other rental items in service							(1,630)	(8,311)
Prepaid expenses and other current assets and capitalized contract costs							(17)	(450)
Accounts payable							(543)	1,632
Accrued compensation and related liabilities							1,033	(1,555)
Accrued liabilities and other							(2,974)	(679)
Income taxes, current							1,670	(5,966)
Net cash provided by operating activities							34,723	11,183
Cash flows from investing activities:
Capital expenditures							(17,209)	(15,910)
Purchases of investments							0	0
Proceeds from sale of assets							13,300
Proceeds from sale of a cost method investment								0
Proceeds from sale of business								0
Acquisitions of businesses, net of cash acquired							(73)	0
Other, net							(33,854)	(6,113)
Net cash used in investing activities							(37,836)	(22,023)
Cash flows from financing activities:
(Payments) issuance of commercial paper, net							0	0
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							(101)	(94)
Repurchase of common stock							0	0
Other, net							0	0
Net cash used in financing activities							(101)	(94)
Effect of exchange rate changes on cash and cash equivalents							19	(270)
Net increase (decrease) in cash and cash equivalents							(3,195)	(11,204)
Cash and cash equivalents at beginning of period			$ 28,531			$ 33,915	28,531	33,915
Cash and cash equivalents at end of period	$ 25,336			$ 22,711			$ 25,336	$ 22,711