Supplemental Guarantor Information - Consolidating Condensed Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Cash flows from operating activities:
Net income	$ 243,013	$ 137,109	$ 455,528	$ 354,320
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation			107,112	107,578
Amortization of intangible assets and capitalized contract costs			67,559	31,261
Stock-based compensation			74,784	55,204
Gain on sale of a cost method investment	(69,373)	0	(69,373)	0
Gain on sale of business			0	(99,060)
Deferred income taxes			19,227	42,162
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(85,748)	(24,800)
Inventories, net			(53,227)	2,595
Uniforms and other rental items in service			(57,684)	(33,294)
Prepaid expenses and other current assets and capitalized contract costs			(58,161)	(18,573)
Accounts payable			(1,955)	(8,706)
Accrued compensation and related liabilities			(20,969)	(36,480)
Accrued liabilities and other			(15,322)	(1,940)
Income taxes, current			(17,204)	8,742
Net cash provided by operating activities			344,567	379,009
Cash flows from investing activities:
Capital expenditures			(137,614)	(132,466)
Proceeds from redemption of marketable securities			0	100,259
Purchase of marketable securities and investments			(14,071)	(99,877)
Proceeds from sale of a cost method investment	73,300		73,342	0
Proceeds from sale of business			0	127,835
Acquisitions of businesses, net of cash acquired			(6,580)	(1,099)
Other, net			(1,717)	(870)
Net cash used in investing activities			(86,640)	(6,218)
Cash flows from financing activities:
Issuance (payments) of commercial paper, net			173,500	(50,500)
Repayment of debt			0	(250,000)
Proceeds from exercise of stock-based compensation awards			32,612	28,558
Repurchase of common stock			(508,129)	(35,697)
Other, net			(5,362)	(1,882)
Net cash used in financing activities			(307,379)	(309,521)
Effect of exchange rate changes on cash and cash equivalents			(793)	3,466
Net (decrease) increase in cash and cash equivalents			(50,245)	66,736
Cash and cash equivalents at beginning of period			138,724	169,266
Cash and cash equivalents at end of period	88,479	236,002	88,479	236,002
Eliminations
Cash flows from operating activities:
Net income	(240,465)	(138,010)	(451,120)	(352,416)
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		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			(2,461)	0
Inventories, net			(1,631)	(1,385)
Uniforms and other rental items in service			0	(357)
Prepaid expenses and other current assets and capitalized contract costs			0	0
Accounts payable			(316)	(160)
Accrued compensation and related liabilities			0	0
Accrued liabilities and other			0	0
Income taxes, current			0	0
Net cash provided by operating activities			(455,528)	(354,318)
Cash flows from investing activities:
Capital expenditures			0	0
Proceeds from redemption of marketable securities				0
Purchase of marketable securities and investments			0	2,000
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			455,528	352,318
Net cash used in investing activities			455,528	354,318
Cash flows from financing activities:
Issuance (payments) of commercial paper, net			0	0
Repayment of debt				0
Proceeds from exercise of stock-based compensation awards			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) increase in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			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	243,013	137,109	455,528	354,320
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			74,784	55,204
Gain on sale of a cost method investment	0		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			530,312	409,524
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
Acquisitions of businesses, net of cash acquired			0	0
Other, net			(54,795)	(402,385)
Net cash used in investing activities			(54,795)	(402,385)
Cash flows from financing activities:
Issuance (payments) of commercial paper, net			0	0
Repayment of debt				0
Proceeds from exercise of stock-based compensation awards			32,612	28,558
Repurchase of common stock			(508,129)	(35,697)
Other, net			0	0
Net cash used in financing activities			(475,517)	(7,139)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net (decrease) increase in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			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	53,428	17,981	116,040	136,511
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation			68,929	65,942
Amortization of intangible assets and capitalized contract costs			61,044	24,522
Stock-based compensation			0	0
Gain on sale of a cost method investment	0		0
Gain on sale of business				(114,581)
Deferred income taxes			10,865	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(52,953)	(42,881)
Inventories, net			(52,989)	17,728
Uniforms and other rental items in service			(39,481)	(29,520)
Prepaid expenses and other current assets and capitalized contract costs			(52,392)	(5,428)
Accounts payable			(98,465)	155,461
Accrued compensation and related liabilities			(16,186)	6,341
Accrued liabilities and other			(1,908)	(26,847)
Income taxes, current			(5,329)	32,963
Net cash provided by operating activities			(62,825)	220,211
Cash flows from investing activities:
Capital expenditures			(92,461)	(90,497)
Proceeds from redemption of marketable securities				12,400
Purchase of marketable securities and investments			(466)	5,510
Proceeds from sale of a cost method investment			0
Proceeds from sale of business				127,835
Acquisitions of businesses, net of cash acquired			(6,580)	(1,099)
Other, net			(2,534)	21,470
Net cash used in investing activities			(102,041)	75,619
Cash flows from financing activities:
Issuance (payments) of commercial paper, net			173,500	(50,500)
Repayment of debt				(250,000)
Proceeds from exercise of stock-based compensation awards			0	0
Repurchase of common stock			0	0
Other, net			(5,362)	(1,862)
Net cash used in financing activities			168,138	(302,362)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net (decrease) increase in cash and cash equivalents			3,272	(6,532)
Cash and cash equivalents at beginning of period			44,499	48,658
Cash and cash equivalents at end of period	47,771	42,126	47,771	42,126
Subsidiary Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	179,702	112,155	322,735	199,326
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation			31,274	34,789
Amortization of intangible assets and capitalized contract costs			2,339	2,547
Stock-based compensation			0	0
Gain on sale of a cost method investment	(69,373)		(69,373)
Gain on sale of business				15,521
Deferred income taxes			5,519	40,555
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(20,151)	20,790
Inventories, net			3,546	(13,863)
Uniforms and other rental items in service			(11,051)	(112)
Prepaid expenses and other current assets and capitalized contract costs			(5,570)	(13,609)
Accounts payable			90,324	(153,831)
Accrued compensation and related liabilities			(6,468)	(39,311)
Accrued liabilities and other			(9,983)	26,373
Income taxes, current			(7,109)	(22,794)
Net cash provided by operating activities			326,032	96,381
Cash flows from investing activities:
Capital expenditures			(37,357)	(36,875)
Proceeds from redemption of marketable securities				0
Purchase of marketable securities and investments			(13,605)	(20,064)
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			(398,963)	26,771
Net cash used in investing activities			(376,583)	(30,168)
Cash flows from financing activities:
Issuance (payments) of commercial paper, net			0	0
Repayment of debt				0
Proceeds from exercise of stock-based compensation awards			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) increase in cash and cash equivalents			(50,551)	66,213
Cash and cash equivalents at beginning of period			60,310	17,302
Cash and cash equivalents at end of period	9,759	83,515	9,759	83,515
Non- Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	7,335	7,874	12,345	16,579
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation			6,909	6,847
Amortization of intangible assets and capitalized contract costs			4,176	4,192
Stock-based compensation			0	0
Gain on sale of a cost method investment	0		0
Gain on sale of business				0
Deferred income taxes			2,843	1,607
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(10,183)	(2,709)
Inventories, net			(2,153)	115
Uniforms and other rental items in service			(7,152)	(3,305)
Prepaid expenses and other current assets and capitalized contract costs			(199)	464
Accounts payable			6,502	(10,176)
Accrued compensation and related liabilities			1,685	(3,510)
Accrued liabilities and other			(3,431)	(1,466)
Income taxes, current			(4,766)	(1,427)
Net cash provided by operating activities			6,576	7,211
Cash flows from investing activities:
Capital expenditures			(7,796)	(5,094)
Proceeds from redemption of marketable securities				87,859
Purchase of marketable securities and investments			0	(87,323)
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			(953)	956
Net cash used in investing activities			(8,749)	(3,602)
Cash flows from financing activities:
Issuance (payments) of commercial paper, net			0	0
Repayment of debt				0
Proceeds from exercise of stock-based compensation awards			0	0
Repurchase of common stock			0	0
Other, net			0	(20)
Net cash used in financing activities			0	(20)
Effect of exchange rate changes on cash and cash equivalents			(793)	3,466
Net (decrease) increase in cash and cash equivalents			(2,966)	7,055
Cash and cash equivalents at beginning of period			33,915	103,306
Cash and cash equivalents at end of period	$ 30,949	$ 110,361	$ 30,949	$ 110,361