Supplemental Guarantor Information - Consolidating Condensed Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	Feb. 28, 2019	Feb. 28, 2018
Cash flows from operating activities:
Net income	$ 203,334	$ 243,013	$ 212,515	$ 302,095	$ 137,109	$ 217,211	$ 658,862	$ 656,415
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation							164,380	157,319
Amortization of intangible assets and capitalized contract costs							101,949	47,583
Stock-based compensation							105,553	86,044
Gain on sale of a cost method investment	0			0			(69,373)	0
Gain on sale of business							(2,419)	(99,060)
Deferred income taxes							25,079	(120,428)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(61,102)	(40,046)
Inventories, net							(70,716)	4,011
Uniforms and other rental items in service							(72,336)	(44,050)
Prepaid expenses and other current assets and capitalized contract costs							(85,123)	(17,925)
Accounts payable							79	(580)
Accrued compensation and related liabilities							(3,866)	(2,209)
Accrued liabilities and other							3,614	10,997
Income taxes, current							(23,864)	22,793
Net cash provided by operating activities							670,717	660,864
Cash flows from investing activities:
Capital expenditures							(207,805)	(196,040)
Proceeds from redemption of marketable securities							0	146,302
Purchase of marketable securities and investments							(17,544)	(157,528)
Proceeds from sale of a cost method investment		$ 73,300					73,342	0
Proceeds from sale of business							3,200	127,835
Acquisitions of businesses, net of cash acquired							(7,403)	(12,298)
Other, net							(6,804)	1,746
Net cash used in investing activities							(163,014)	(89,983)
Cash flows from financing activities:
Issuance of commercial paper, net							217,500	137,000
Proceeds from issuance of debt								0
Repayment of debt							0	(550,000)
Proceeds from exercise of stock-based compensation awards							54,274	35,838
Dividends paid							(220,760)	(175,589)
Repurchase of common stock							(608,224)	(37,050)
Other, net							(8,088)	(2,489)
Net cash used in financing activities							(565,298)	(592,290)
Effect of exchange rate changes on cash and cash equivalents							(270)	4,706
Net decrease in cash and cash equivalents							(57,865)	(16,703)
Cash and cash equivalents at beginning of period			138,724			169,266	138,724	169,266
Cash and cash equivalents at end of period	80,859			152,563			80,859	152,563
Eliminations
Cash flows from operating activities:
Net income	(199,324)			(302,562)			(650,444)	(654,978)
Adjustments to reconcile net income to net cash provided by (used in) 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	0
Deferred income taxes							0	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(4,280)	0
Inventories, net							(3,780)	(1,386)
Uniforms and other rental items in service							0	109
Prepaid expenses and other current assets and capitalized contract costs							0	0
Accounts payable							(361)	(159)
Accrued compensation and related liabilities							0	0
Accrued liabilities and other							0	0
Income taxes, current							0	0
Net cash provided by operating activities							(658,865)	(656,414)
Cash flows from investing activities:
Capital expenditures							0	0
Proceeds from redemption of marketable securities								0
Purchase of marketable securities and investments							750	3,000
Proceeds from sale of a cost method investment							0
Proceeds from sale of business							0	0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							658,115	653,414
Net cash used in investing activities							658,865	656,414
Cash flows from financing activities:
Issuance of commercial paper, net							0	0
Proceeds from issuance of debt								0
Repayment of debt								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 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	203,334			302,095			658,862	656,415
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation							0	0
Amortization of intangible assets and capitalized contract costs							0	0
Stock-based compensation							105,553	86,044
Gain on sale of a cost method investment							0
Gain on sale of business							0	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							764,415	742,459
Cash flows from investing activities:
Capital expenditures							0	0
Proceeds from redemption of marketable securities								0
Purchase of marketable securities and investments							0	0
Proceeds from sale of a cost method investment							0
Proceeds from sale of business							0	0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							10,201	(565,726)
Net cash used in investing activities							10,201	(565,726)
Cash flows from financing activities:
Issuance of commercial paper, net							0	0
Proceeds from issuance of debt								0
Repayment of debt								0
Proceeds from exercise of stock-based compensation awards							54,274	35,838
Dividends paid							(220,666)	(175,521)
Repurchase of common stock							(608,224)	(37,050)
Other, net							0	0
Net cash used in financing activities							(774,616)	(176,733)
Effect of exchange rate changes on cash and cash equivalents							0	0
Net 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	62,239			150,250			178,279	286,761
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation							106,577	94,846
Amortization of intangible assets and capitalized contract costs							91,912	37,338
Stock-based compensation							0	0
Gain on sale of a cost method investment							0
Gain on sale of business							(2,419)	(114,581)
Deferred income taxes							16,059	(82,475)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(51,317)	(57,631)
Inventories, net							(64,014)	17,558
Uniforms and other rental items in service							(51,696)	(33,728)
Prepaid expenses and other current assets and capitalized contract costs							(74,606)	1,252
Accounts payable							(205,528)	3,657
Accrued compensation and related liabilities							1,832	(12,519)
Accrued liabilities and other							(274)	(85,980)
Income taxes, current							7,059	25,777
Net cash provided by operating activities							(48,136)	80,275
Cash flows from investing activities:
Capital expenditures							(147,744)	(127,736)
Proceeds from redemption of marketable securities								13,589
Purchase of marketable securities and investments							(1,938)	6,343
Proceeds from sale of a cost method investment							0
Proceeds from sale of business							3,200	127,835
Acquisitions of businesses, net of cash acquired							(7,403)	(12,298)
Other, net							(5,216)	323,643
Net cash used in investing activities							(159,101)	331,376
Cash flows from financing activities:
Issuance of commercial paper, net							217,500	137,000
Proceeds from issuance of debt								0
Repayment of debt								(550,000)
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							0	0
Repurchase of common stock							0	0
Other, net							(8,088)	(2,204)
Net cash used in financing activities							209,412	(415,204)
Effect of exchange rate changes on cash and cash equivalents							0	0
Net decrease in cash and cash equivalents							2,175	(3,553)
Cash and cash equivalents at beginning of period			44,499			48,658	44,499	48,658
Cash and cash equivalents at end of period	46,674			45,105			46,674	45,105
Subsidiary Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	130,863			150,090			453,598	349,416
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation							47,116	52,162
Amortization of intangible assets and capitalized contract costs							3,801	3,824
Stock-based compensation							0	0
Gain on sale of a cost method investment							(69,373)
Gain on sale of business							0	15,521
Deferred income taxes							5,654	(39,692)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							2,522	20,615
Inventories, net							1,395	(15,487)
Uniforms and other rental items in service							(12,329)	(2,748)
Prepaid expenses and other current assets and capitalized contract costs							(10,067)	(19,495)
Accounts payable							204,336	23,201
Accrued compensation and related liabilities							(4,143)	13,106
Accrued liabilities and other							4,567	91,624
Income taxes, current							(24,957)	(930)
Net cash provided by operating activities							602,120	491,117
Cash flows from investing activities:
Capital expenditures							(44,151)	(59,018)
Proceeds from redemption of marketable securities								(1,189)
Purchase of marketable securities and investments							(16,356)	(22,521)
Proceeds from sale of a cost method investment							73,342
Proceeds from sale of business							0	0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							(663,791)	(413,382)
Net cash used in investing activities							(650,956)	(496,110)
Cash flows from financing activities:
Issuance of commercial paper, net							0	0
Proceeds from issuance of debt								2,810
Repayment of debt								0
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							0	0
Repurchase of common stock							0	0
Other, net							0	(10)
Net cash used in financing activities							0	2,800
Effect of exchange rate changes on cash and cash equivalents							0	0
Net decrease in cash and cash equivalents							(48,836)	(2,193)
Cash and cash equivalents at beginning of period			60,310			17,302	60,310	17,302
Cash and cash equivalents at end of period	11,474			15,109			11,474	15,109
Non- Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	6,222			2,222			18,567	18,801
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation							10,687	10,311
Amortization of intangible assets and capitalized contract costs							6,236	6,421
Stock-based compensation							0	0
Gain on sale of a cost method investment							0
Gain on sale of business							0	0
Deferred income taxes							3,366	1,739
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net							(8,027)	(3,030)
Inventories, net							(4,317)	3,326
Uniforms and other rental items in service							(8,311)	(7,683)
Prepaid expenses and other current assets and capitalized contract costs							(450)	318
Accounts payable							1,632	(27,279)
Accrued compensation and related liabilities							(1,555)	(2,796)
Accrued liabilities and other							(679)	5,353
Income taxes, current							(5,966)	(2,054)
Net cash provided by operating activities							11,183	3,427
Cash flows from investing activities:
Capital expenditures							(15,910)	(9,286)
Proceeds from redemption of marketable securities								133,902
Purchase of marketable securities and investments							0	(144,350)
Proceeds from sale of a cost method investment							0
Proceeds from sale of business							0	0
Acquisitions of businesses, net of cash acquired							0	0
Other, net							(6,113)	3,797
Net cash used in investing activities							(22,023)	(15,937)
Cash flows from financing activities:
Issuance of commercial paper, net							0	0
Proceeds from issuance of debt								(2,810)
Repayment of debt								0
Proceeds from exercise of stock-based compensation awards							0	0
Dividends paid							(94)	(68)
Repurchase of common stock							0	0
Other, net							0	(275)
Net cash used in financing activities							(94)	(3,153)
Effect of exchange rate changes on cash and cash equivalents							(270)	4,706
Net decrease in cash and cash equivalents							(11,204)	(10,957)
Cash and cash equivalents at beginning of period			$ 33,915			$ 103,306	33,915	103,306
Cash and cash equivalents at end of period	$ 22,711			$ 92,349			$ 22,711	$ 92,349