Supplemental Guarantor Information - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Cash flows from operating activities:
Net income	$ 140,377	$ 345,100	$ 278,468	$ 445,281
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation			79,590	73,130
Amortization of intangible assets			7,460	7,764
Stock-based compensation			39,582	40,241
Gain on Storage transactions			0	(15,786)
Gain on Shred-it			(25,876)	(349,738)
Deferred income taxes			(3,833)	(98,423)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(44,920)	(39,418)
Inventories, net			(14,616)	(19,841)
Uniforms and other rental items in service			(4,315)	(10,893)
Prepaid expenses and other current assets			(1,952)	(2,369)
Accounts payable			15,451	19,368
Accrued compensation and related liabilities			(18,936)	(22,771)
Accrued liabilities and other			(4,866)	1,041
Income taxes, current			484	237,451
Net cash provided by operating activities			301,721	265,037
Cash flows from investing activities:
Capital expenditures			(155,173)	(121,817)
Proceeds from redemption of marketable securities			172,968	212,081
Purchase of marketable securities and investments			(118,270)	(271,341)
Proceeds from Storage transactions			0	35,338
Proceeds from sale of investment in Shred-it			25,876	578,257
Acquisitions of businesses, net of cash acquired			(17,778)	(121,237)
Other, net			332	1,987
Net cash (used in) provided by investing activities			(92,045)	313,268
Cash flows from financing activities:
Proceeds from issuance of commercial paper, net			66,000	0
Proceeds from issuance of debt			0	0
Repayment of debt			(250,000)	(16)
Prepaid short-term debt financing fees			(13,495)	0
Proceeds from exercise of stock-based compensation awards			19,225	17,444
Repurchase of common stock			(19,230)	(402,293)
Other, net			(5,572)	646
Net cash used in financing activities			(203,072)	(384,219)
Effect of exchange rate changes on cash and cash equivalents			(2,388)	(4,374)
Net increase in cash and cash equivalents			4,216	189,712
Cash and cash equivalents at beginning of period			139,357	417,073
Cash and cash equivalents at end of period	143,573	606,785	143,573	606,785
Eliminations
Cash flows from operating activities:
Net income	(140,059)	(345,873)	(275,324)	(447,677)
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation			0	0
Amortization of intangible assets			0	0
Stock-based compensation			0	0
Gain on Storage transactions				0
Gain on Shred-it			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			(1,856)	2,594
Uniforms and other rental items in service			(1,398)	(193)
Prepaid expenses and other current assets			0	0
Accounts payable			110	(10)
Accrued compensation and related liabilities			0	0
Accrued liabilities and other			0	724
Income taxes, current			0	0
Net cash provided by operating activities			(278,468)	(444,562)
Cash flows from investing activities:
Capital expenditures			0	0
Proceeds from redemption of marketable securities			0	0
Purchase of marketable securities and investments			17,733	4,010
Proceeds from Storage transactions				0
Proceeds from sale of investment in Shred-it			0	0
Acquisitions of businesses, net of cash acquired			0	0
Other, net			260,735	441,276
Net cash (used in) provided by investing activities			278,468	445,286
Cash flows from financing activities:
Proceeds from issuance of commercial paper, net			0
Proceeds from issuance of debt			0	0
Repayment of debt			0	(724)
Prepaid short-term debt financing fees			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	(724)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net 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
Cash flows from operating activities:
Net income	140,377	345,100	278,468	445,281
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation			0	0
Amortization of intangible assets			0	0
Stock-based compensation			39,582	40,241
Gain on Storage transactions				0
Gain on Shred-it			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			0	0
Accounts payable			0	0
Accrued compensation and related liabilities			2,819	0
Accrued liabilities and other			139,766	0
Income taxes, current			0	0
Net cash provided by operating activities			460,635	485,522
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 Storage transactions				0
Proceeds from sale of investment in Shred-it			0	0
Acquisitions of businesses, net of cash acquired			0	0
Other, net			(460,630)	(100,673)
Net cash (used in) provided by investing activities			(460,630)	(100,673)
Cash flows from financing activities:
Proceeds from issuance of commercial paper, net			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			19,225	17,444
Repurchase of common stock			(19,230)	(402,293)
Other, net			0	0
Net cash used in financing activities			(5)	(384,849)
Effect of exchange rate changes on cash and cash equivalents			0	0
Net 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
Cash flows from operating activities:
Net income	55,004	273,530	98,875	305,340
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation			52,259	46,231
Amortization of intangible assets			6,847	7,248
Stock-based compensation			0	0
Gain on Storage transactions				(12,547)
Gain on Shred-it			(23,935)	(362,237)
Deferred income taxes			(9,578)	(93,097)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(36,939)	(24,824)
Inventories, net			(14,038)	(20,021)
Uniforms and other rental items in service			754	(6,851)
Prepaid expenses and other current assets			412	128
Accounts payable			23,367	(388,996)
Accrued compensation and related liabilities			(12,734)	(18,569)
Accrued liabilities and other			3,711	685
Income taxes, current			(1,635)	231,042
Net cash provided by operating activities			87,366	(336,468)
Cash flows from investing activities:
Capital expenditures			(85,207)	(67,463)
Proceeds from redemption of marketable securities			0	0
Purchase of marketable securities and investments			(4,560)	(3,437)
Proceeds from Storage transactions				32,099
Proceeds from sale of investment in Shred-it			23,935	565,643
Acquisitions of businesses, net of cash acquired			(7,245)	(96,465)
Other, net			177,446	(60,133)
Net cash (used in) provided by investing activities			104,369	370,244
Cash flows from financing activities:
Proceeds from issuance of commercial paper, net			66,000
Proceeds from issuance of debt			0	0
Repayment of debt			(250,000)	(309)
Prepaid short-term debt financing fees			(13,495)
Proceeds from exercise of stock-based compensation awards			0	0
Repurchase of common stock			0	0
Other, net			(5,572)	976
Net cash used in financing activities			(203,067)	667
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase in cash and cash equivalents			(11,332)	34,443
Cash and cash equivalents at beginning of period			57,893	74,632
Cash and cash equivalents at end of period	46,561	109,075	46,561	109,075
Subsidiary Guarantors
Cash flows from operating activities:
Net income	79,185	76,731	166,700	144,586
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation			22,412	22,231
Amortization of intangible assets			175	337
Stock-based compensation			0	0
Gain on Storage transactions				0
Gain on Shred-it			0	0
Deferred income taxes			5,395	(6,913)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(6,813)	(13,014)
Inventories, net			2,871	(2,049)
Uniforms and other rental items in service			(4,182)	(2,319)
Prepaid expenses and other current assets			(2,411)	(2,534)
Accounts payable			(10,857)	403,502
Accrued compensation and related liabilities			(8,935)	(3,520)
Accrued liabilities and other			(148,384)	976
Income taxes, current			1,460	6,309
Net cash provided by operating activities			17,431	547,592
Cash flows from investing activities:
Capital expenditures			(60,837)	(47,537)
Proceeds from redemption of marketable securities			0	0
Purchase of marketable securities and investments			(28,751)	(7,549)
Proceeds from Storage transactions				0
Proceeds from sale of investment in Shred-it			0	0
Acquisitions of businesses, net of cash acquired			0	0
Other, net			21,190	(278,564)
Net cash (used in) provided by investing activities			(68,398)	(333,650)
Cash flows from financing activities:
Proceeds from issuance of commercial paper, net			0
Proceeds from issuance of debt			(2,000)	(55)
Repayment of debt			0	1,053
Prepaid short-term debt financing fees			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			(2,000)	998
Effect of exchange rate changes on cash and cash equivalents			0	0
Net increase in cash and cash equivalents			(52,967)	214,940
Cash and cash equivalents at beginning of period			55,392	248,716
Cash and cash equivalents at end of period	2,425	463,656	2,425	463,656
Non- Guarantors
Cash flows from operating activities:
Net income	5,870	(4,388)	9,749	(2,249)
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation			4,919	4,668
Amortization of intangible assets			438	179
Stock-based compensation			0	0
Gain on Storage transactions				(3,239)
Gain on Shred-it			(1,941)	12,499
Deferred income taxes			350	1,587
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net			(1,168)	(1,580)
Inventories, net			(1,593)	(365)
Uniforms and other rental items in service			511	(1,530)
Prepaid expenses and other current assets			47	37
Accounts payable			2,831	4,872
Accrued compensation and related liabilities			(86)	(682)
Accrued liabilities and other			41	(1,344)
Income taxes, current			659	100
Net cash provided by operating activities			14,757	12,953
Cash flows from investing activities:
Capital expenditures			(9,129)	(6,817)
Proceeds from redemption of marketable securities			172,968	212,081
Purchase of marketable securities and investments			(102,692)	(264,365)
Proceeds from Storage transactions				3,239
Proceeds from sale of investment in Shred-it			1,941	12,614
Acquisitions of businesses, net of cash acquired			(10,533)	(24,772)
Other, net			1,591	81
Net cash (used in) provided by investing activities			54,146	(67,939)
Cash flows from financing activities:
Proceeds from issuance of commercial paper, net			0
Proceeds from issuance of debt			2,000	55
Repayment of debt			0	(36)
Prepaid short-term debt financing fees			0
Proceeds from exercise of stock-based compensation awards			0	0
Repurchase of common stock			0	0
Other, net			0	(330)
Net cash used in financing activities			2,000	(311)
Effect of exchange rate changes on cash and cash equivalents			(2,388)	(4,374)
Net increase in cash and cash equivalents			68,515	(59,671)
Cash and cash equivalents at beginning of period			26,072	93,725
Cash and cash equivalents at end of period	$ 94,587	$ 34,054	$ 94,587	$ 34,054