Supplemental Guarantor Information - Consolidating Condensed Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Feb. 28, 2018	Aug. 31, 2017	Feb. 28, 2017	Aug. 31, 2016	Feb. 28, 2018	Feb. 28, 2017
Cash flows from operating activities:
Net income	$ 302,095		$ 118,005		$ 656,415	$ 396,473
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation					157,319	120,493
Amortization of intangible assets					47,583	11,221
Stock-based compensation					86,044	63,578
Gain on sale of business					(99,060)	0
Gain on Shred-it					0	(25,876)
Deferred income taxes					(120,428)	(3,472)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net					(40,046)	(28,646)
Inventories, net					4,011	(23,364)
Uniforms and other rental items in service					(44,050)	(53)
Prepaid expenses and other current assets					(17,925)	(11,387)
Accounts payable					(580)	15,538
Accrued compensation and related liabilities					(2,209)	(5,812)
Accrued liabilities and other					10,997	(6,079)
Income taxes, current					22,793	(18,856)
Net cash provided by operating activities					660,864	483,758
Cash flows from investing activities:
Capital expenditures					(196,040)	(218,621)
Proceeds from redemption of marketable securities					146,302	172,506
Purchase of marketable securities and investments					(157,528)	(125,634)
Proceeds from sale of investment in Shred-it					0	25,876
Proceeds from sale of business					127,835	0
Acquisitions of businesses					(12,298)
Acquisitions of businesses, net of cash acquired					(12,298)	(19,630)
Other, net					1,746	28
Net cash used in investing activities					(89,983)	(165,475)
Cash flows from financing activities:
Payments of commercial paper, net					137,000	99,500
Proceeds from issuance of debt					0	0
Repayment of debt					(550,000)	(250,000)
Prepaid short-term debt financing fees					0	(13,949)
Proceeds from exercise of stock-based compensation awards					35,838	25,114
Dividends paid		$ (175,589)		$ (142,444)	(175,589)	(142,444)
Repurchase of common stock					(37,050)	(20,054)
Other, net					(2,489)	(5,801)
Net cash used in financing activities					(592,290)	(307,634)
Effect of exchange rate changes on cash and cash equivalents					4,706	(2,762)
Net decrease in cash and cash equivalents					(16,703)	7,887
Cash and cash equivalents at beginning of period		169,266		139,357	169,266	139,357
Cash and cash equivalents at end of period	152,563		147,244		152,563	147,244
Eliminations
Cash flows from operating activities:
Net income	(302,562)		(117,593)		(654,978)	(392,917)
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation					0	0
Amortization of intangible assets					0	0
Stock-based compensation					0	0
Gain on sale of business					0
Gain on Shred-it						0
Deferred income taxes						0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net					0	0
Inventories, net					(1,386)	(1,678)
Uniforms and other rental items in service					109	(1,993)
Prepaid expenses and other current assets					0	0
Accounts payable					(159)	114
Accrued compensation and related liabilities					0	0
Accrued liabilities and other					0	0
Income taxes, current					0	0
Net cash provided by operating activities					(656,414)	(396,474)
Cash flows from investing activities:
Capital expenditures					0	0
Proceeds from redemption of marketable securities					0	0
Purchase of marketable securities and investments					3,000	23,608
Proceeds from sale of investment in Shred-it						0
Proceeds from sale of business					0
Acquisitions of businesses					0
Acquisitions of businesses, net of cash acquired						0
Other, net					653,414	372,866
Net cash used in investing activities					656,414	396,474
Cash flows from financing activities:
Payments of commercial paper, net					0	0
Proceeds from issuance of debt					0	0
Repayment of debt					0	0
Prepaid short-term debt financing fees						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
Cash flows from operating activities:
Net income	302,095		118,005		656,415	396,473
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation					0	0
Amortization of intangible assets					0	0
Stock-based compensation					86,044	63,578
Gain on sale of business					0
Gain on Shred-it						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					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					742,459	460,051
Cash flows from investing activities:
Capital expenditures					0	0
Proceeds from redemption of marketable securities					0	0
Purchase of marketable securities and investments					0	0
Proceeds from sale of investment in Shred-it						0
Proceeds from sale of business					0
Acquisitions of businesses					0
Acquisitions of businesses, net of cash acquired						0
Other, net					(565,726)	(322,723)
Net cash used in investing activities					(565,726)	(322,723)
Cash flows from financing activities:
Payments of commercial paper, net					0	0
Proceeds from issuance of debt					0	0
Repayment of debt					0	0
Prepaid short-term debt financing fees						0
Proceeds from exercise of stock-based compensation awards					35,838	25,114
Dividends paid					(175,521)	(142,388)
Repurchase of common stock					(37,050)	(20,054)
Other, net					0	0
Net cash used in financing activities					(176,733)	(137,328)
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
Cash flows from operating activities:
Net income	150,250		37,609		286,761	136,484
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation					94,846	79,459
Amortization of intangible assets					37,338	10,288
Stock-based compensation					0	0
Gain on sale of business					(114,581)
Gain on Shred-it						(23,935)
Deferred income taxes					(82,475)	(11,104)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net					(57,631)	(21,965)
Inventories, net					17,558	(21,588)
Uniforms and other rental items in service					(33,728)	3,662
Prepaid expenses and other current assets					1,252	(6,460)
Accounts payable					3,657	(36,312)
Accrued compensation and related liabilities					(12,519)	(3,243)
Accrued liabilities and other					(85,980)	(10,958)
Income taxes, current					25,777	10,886
Net cash provided by operating activities					80,275	105,214
Cash flows from investing activities:
Capital expenditures					(127,736)	(125,995)
Proceeds from redemption of marketable securities					13,589	0
Purchase of marketable securities and investments					6,343	(5,644)
Proceeds from sale of investment in Shred-it						23,935
Proceeds from sale of business					127,835
Acquisitions of businesses					(12,298)
Acquisitions of businesses, net of cash acquired						(9,097)
Other, net					323,643	166,718
Net cash used in investing activities					331,376	49,917
Cash flows from financing activities:
Payments of commercial paper, net					137,000	99,500
Proceeds from issuance of debt					0	0
Repayment of debt					(550,000)	(250,000)
Prepaid short-term debt financing fees						(13,949)
Proceeds from exercise of stock-based compensation awards					0	0
Dividends paid					0	0
Repurchase of common stock					0	0
Other, net					(2,204)	(5,801)
Net cash used in financing activities					(415,204)	(170,250)
Effect of exchange rate changes on cash and cash equivalents					0	0
Net decrease in cash and cash equivalents					(3,553)	(15,119)
Cash and cash equivalents at beginning of period		48,658		57,893	48,658	57,893
Cash and cash equivalents at end of period	45,105		42,774		45,105	42,774
Subsidiary Guarantors
Cash flows from operating activities:
Net income	150,090		78,059		349,416	244,759
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation					52,162	33,697
Amortization of intangible assets					3,824	262
Stock-based compensation					0	0
Gain on sale of business					15,521
Gain on Shred-it						0
Deferred income taxes					(39,692)	7,406
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net					20,615	(5,959)
Inventories, net					(15,487)	2,079
Uniforms and other rental items in service					(2,748)	(2,753)
Prepaid expenses and other current assets					(19,495)	(5,037)
Accounts payable					23,201	45,593
Accrued compensation and related liabilities					13,106	(3,099)
Accrued liabilities and other					91,624	5,110
Income taxes, current					(930)	(29,632)
Net cash provided by operating activities					491,117	292,426
Cash flows from investing activities:
Capital expenditures					(59,018)	(77,025)
Proceeds from redemption of marketable securities					(1,189)	0
Purchase of marketable securities and investments					(22,521)	(41,180)
Proceeds from sale of investment in Shred-it						0
Proceeds from sale of business					0
Acquisitions of businesses					0
Acquisitions of businesses, net of cash acquired						0
Other, net					(413,382)	(218,390)
Net cash used in investing activities					(496,110)	(336,595)
Cash flows from financing activities:
Payments of commercial paper, net					0	0
Proceeds from issuance of debt					2,810	(2,000)
Repayment of debt					0	0
Prepaid short-term debt financing fees						0
Proceeds from exercise of stock-based compensation awards					0	0
Dividends paid					0	0
Repurchase of common stock					0	0
Other, net					(10)	0
Net cash used in financing activities					2,800	(2,000)
Effect of exchange rate changes on cash and cash equivalents					0	0
Net decrease in cash and cash equivalents					(2,193)	(46,169)
Cash and cash equivalents at beginning of period		17,302		55,392	17,302	55,392
Cash and cash equivalents at end of period	15,109		9,223		15,109	9,223
Non- Guarantors
Cash flows from operating activities:
Net income	2,222		1,925		18,801	11,674
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation					10,311	7,337
Amortization of intangible assets					6,421	671
Stock-based compensation					0	0
Gain on sale of business					0
Gain on Shred-it						(1,941)
Deferred income taxes					1,739	226
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net					(3,030)	(722)
Inventories, net					3,326	(2,177)
Uniforms and other rental items in service					(7,683)	1,031
Prepaid expenses and other current assets					318	110
Accounts payable					(27,279)	6,143
Accrued compensation and related liabilities					(2,796)	530
Accrued liabilities and other					5,353	(231)
Income taxes, current					(2,054)	(110)
Net cash provided by operating activities					3,427	22,541
Cash flows from investing activities:
Capital expenditures					(9,286)	(15,601)
Proceeds from redemption of marketable securities					133,902	172,506
Purchase of marketable securities and investments					(144,350)	(102,418)
Proceeds from sale of investment in Shred-it						1,941
Proceeds from sale of business					0
Acquisitions of businesses					0
Acquisitions of businesses, net of cash acquired						(10,533)
Other, net					3,797	1,557
Net cash used in investing activities					(15,937)	47,452
Cash flows from financing activities:
Payments of commercial paper, net					0	0
Proceeds from issuance of debt					(2,810)	2,000
Repayment of debt					0	0
Prepaid short-term debt financing fees						0
Proceeds from exercise of stock-based compensation awards					0	0
Dividends paid					(68)	(56)
Repurchase of common stock					0	0
Other, net					(275)	0
Net cash used in financing activities					(3,153)	1,944
Effect of exchange rate changes on cash and cash equivalents					4,706	(2,762)
Net decrease in cash and cash equivalents					(10,957)	69,175
Cash and cash equivalents at beginning of period		$ 103,306		$ 26,072	103,306	26,072
Cash and cash equivalents at end of period	$ 92,349		$ 95,247		$ 92,349	$ 95,247