Supplemental Guarantor Information (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 31, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Aug. 31, 2010	May 31, 2012	May 31, 2011	May 31, 2010
Cash flows from operating activities:
Net income	$ 78,614	$ 76,035	$ 74,350	$ 68,638	$ 70,776	$ 59,070	$ 55,866	$ 61,277	$ 297,637	$ 246,989	$ 215,620
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation									155,831	150,886	152,059
Amortization of deferred charges									38,334	42,581	41,082
Stock-based compensation									20,312	15,203	15,349
Deferred income taxes									56,727	47,908	13,295
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net									(24,261)	(48,986)	5,222
Inventories, net									(2,330)	(78,824)	30,293
Uniforms and other rental items in service									(60,279)	(58,180)	4,164
Prepaid expenses									(1,496)	360	3,715
Accounts payable									(12,557)	29,215	8,939
Accrued compensation and related liabilities									11,625	12,493	18,393
Accrued liabilities									(20,371)	(2,167)	47,528
Income taxes, current									10,690	(16,592)	9,995
Net cash provided by operating activities									469,862	340,886	565,654
Cash flows from investing activities:
Capital expenditures									(160,802)	(182,592)	(111,078)
Proceeds from redemption of marketable securities									665,016	139,056	34,712
Purchase of marketable securities and investments									(585,655)	(78,307)	(81,269)
Acquisitions of businesses, net of cash acquired									(24,864)	(171,552)	(50,444)
Other									2,011	(5,198)	497
Net cash used in investing activities									(104,294)	(298,593)	(207,582)
Cash flows from financing activities:
Proceeds from issuance of debt									0	1,002,281	0
Repayment of debt									(1,323)	(502,208)	(603)
Exercise of stock-based compensation awards									3,341	0	0
Dividends paid									(70,820)	(71,812)	(73,960)
Repurchase of common stock									(392,328)	(443,690)	(969)
Other									555	(4,609)	(977)
Net cash used in financing activities									(460,575)	(20,038)	(76,509)
Effect of exchange rate changes on cash and cash equivalents									(3,274)	4,570	(27)
Net (decrease) increase in cash and cash equivalents									(98,281)	26,825	281,536
Cash and cash equivalents at beginning of year				438,106				411,281	438,106	411,281	129,745
Cash and cash equivalents at end of year	339,825				438,106				339,825	438,106	411,281
Cintas Corporation [Member]
Cash flows from operating activities:
Net income									297,637	246,989	215,620
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation									0	0	0
Amortization of deferred charges									0	0	0
Stock-based compensation									20,312	15,203	15,349
Deferred income taxes									0	0	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net									0	0	0
Inventories, net									0	0	0
Uniforms and other rental items in service									0	0	0
Prepaid expenses									0	0	0
Accounts payable									0	0	0
Accrued compensation and related liabilities									0	0	0
Accrued liabilities									0	0	0
Income taxes, current									0	0	0
Net cash provided by operating activities									317,949	262,192	230,969
Cash flows from investing activities:
Capital expenditures									0	0	0
Proceeds from redemption of marketable securities									0	0	0
Purchase of marketable securities and investments									0	0	0
Acquisitions of businesses, net of cash acquired									0	0	0
Other									141,350	253,387	(156,082)
Net cash used in investing activities									141,350	253,387	(156,082)
Cash flows from financing activities:
Proceeds from issuance of debt									0	0
Repayment of debt									0	0	0
Exercise of stock-based compensation awards									3,341
Dividends paid									(70,800)	(71,801)	(73,950)
Repurchase of common stock									(392,328)	(443,690)	(969)
Other									488	(88)	32
Net cash used in financing activities									(459,299)	(515,579)	(74,887)
Effect of exchange rate changes on cash and cash equivalents									0	0	0
Net (decrease) increase in cash and cash equivalents									0	0	0
Cash and cash equivalents at beginning of year				0				0	0	0	0
Cash and cash equivalents at end of year	0				0				0	0	0
Corp. 2 [Member]
Cash flows from operating activities:
Net income									165,559	105,914	46,146
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation									102,613	103,039	105,981
Amortization of deferred charges									33,114	37,615	37,723
Stock-based compensation									0	0	0
Deferred income taxes									0	(4,886)	(1,745)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net									(15,280)	(39,060)	21,442
Inventories, net									(5,635)	(59,223)	49,396
Uniforms and other rental items in service									(34,401)	(45,149)	2,379
Prepaid expenses									(2,154)	223	667
Accounts payable									(143,189)	(392,210)	19,707
Accrued compensation and related liabilities									8,659	12,957	10,022
Accrued liabilities									16,929	(2,740)	2,489
Income taxes, current									(4,357)	4,265	(2,134)
Net cash provided by operating activities									121,858	(279,255)	292,073
Cash flows from investing activities:
Capital expenditures									(116,954)	(99,739)	(62,236)
Proceeds from redemption of marketable securities									0	0	0
Purchase of marketable securities and investments									(2,740)	(16,897)	(24,826)
Acquisitions of businesses, net of cash acquired									(19,323)	(133,378)	(25,686)
Other									20,090	54,296	(184,047)
Net cash used in investing activities									(118,927)	(195,718)	(296,795)
Cash flows from financing activities:
Proceeds from issuance of debt									0	1,000,500
Repayment of debt									(843)	(501,316)	(754)
Exercise of stock-based compensation awards									0
Dividends paid									0	0	0
Repurchase of common stock									0	0	0
Other									1,508	(4,576)	767
Net cash used in financing activities									665	494,608	13
Effect of exchange rate changes on cash and cash equivalents									184	417	217
Net (decrease) increase in cash and cash equivalents									3,780	20,052	(4,492)
Cash and cash equivalents at beginning of year				54,957				34,905	54,957	34,905	39,397
Cash and cash equivalents at end of year	58,737				54,957				58,737	54,957	34,905
Subsidiary Guarantors [Member]
Cash flows from operating activities:
Net income									230,677	134,424	149,996
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation									40,613	36,032	37,149
Amortization of deferred charges									393	543	879
Stock-based compensation									0	0	0
Deferred income taxes									56,411	51,996	12,668
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net									(4,985)	(2,079)	14,594
Inventories, net									4,685	(8,112)	(16,803)
Uniforms and other rental items in service									(19,286)	(11,671)	5,655
Prepaid expenses									950	2,085	3,101
Accounts payable									661,243	393,185	(70,957)
Accrued compensation and related liabilities									1,466	(1,577)	7,435
Accrued liabilities									(30,586)	(6,318)	45,418
Income taxes, current									4,712	(8,858)	16,455
Net cash provided by operating activities									946,293	579,650	205,590
Cash flows from investing activities:
Capital expenditures									(26,270)	(68,274)	(42,422)
Proceeds from redemption of marketable securities									0	23,206	8,361
Purchase of marketable securities and investments									(416,100)	(55,438)	161,621
Acquisitions of businesses, net of cash acquired									(65)	(1,831)	0
Other									(588,518)	(504,637)	(34,494)
Net cash used in investing activities									(1,030,953)	(606,974)	93,066
Cash flows from financing activities:
Proceeds from issuance of debt									(786)	1,781
Repayment of debt									324	(876)	(35,933)
Exercise of stock-based compensation awards									0
Dividends paid									0	0	0
Repurchase of common stock									0	0	0
Other									(574)	0	0
Net cash used in financing activities									(1,036)	905	(35,933)
Effect of exchange rate changes on cash and cash equivalents									1,700	0	0
Net (decrease) increase in cash and cash equivalents									(83,996)	(26,419)	262,723
Cash and cash equivalents at beginning of year				313,283				339,702	313,283	339,702	76,979
Cash and cash equivalents at end of year	229,287				313,283				229,287	313,283	339,702
Non-Guarantors [Member]
Cash flows from operating activities:
Net income									437,579	103,964	17,902
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation									12,605	11,815	8,929
Amortization of deferred charges									4,827	4,423	2,480
Stock-based compensation									0	0	0
Deferred income taxes									316	798	2,372
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net									(3,996)	(7,847)	(2,512)
Inventories, net									1,590	(2,957)	(913)
Uniforms and other rental items in service									(1,477)	(7,179)	(3,681)
Prepaid expenses									(292)	(1,948)	(53)
Accounts payable									(530,611)	28,244	43,498
Accrued compensation and related liabilities									1,500	1,113	936
Accrued liabilities									(6,732)	6,875	(417)
Income taxes, current									10,335	(11,999)	(4,326)
Net cash provided by operating activities									(74,356)	125,302	64,215
Cash flows from investing activities:
Capital expenditures									(17,578)	(14,579)	(6,420)
Proceeds from redemption of marketable securities									665,016	115,850	26,351
Purchase of marketable securities and investments									(579,654)	(61,438)	(34,137)
Acquisitions of businesses, net of cash acquired									(5,476)	(36,343)	(24,758)
Other									28	(99,797)	84
Net cash used in investing activities									62,336	(96,307)	(38,880)
Cash flows from financing activities:
Proceeds from issuance of debt									0	0
Repayment of debt									0	0	0
Exercise of stock-based compensation awards									0
Dividends paid									(20)	(11)	(10)
Repurchase of common stock									0	0	0
Other									(867)	55	(1,776)
Net cash used in financing activities									(887)	44	(1,786)
Effect of exchange rate changes on cash and cash equivalents									(5,158)	4,153	(244)
Net (decrease) increase in cash and cash equivalents									(18,065)	33,192	23,305
Cash and cash equivalents at beginning of year				69,866				36,674	69,866	36,674	13,369
Cash and cash equivalents at end of year	51,801				69,866				51,801	69,866	36,674
Eliminations [Member]
Cash flows from operating activities:
Net income									(833,815)	(344,302)	(214,044)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation									0	0	0
Amortization of deferred charges									0	0	0
Stock-based compensation									0	0	0
Deferred income taxes									0	0	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net									0	0	(28,302)
Inventories, net									(2,970)	(8,532)	(1,387)
Uniforms and other rental items in service									(5,115)	5,819	(189)
Prepaid expenses									0	0	0
Accounts payable									0	(4)	16,691
Accrued compensation and related liabilities									0	0	0
Accrued liabilities									18	16	38
Income taxes, current									0	0	0
Net cash provided by operating activities									(841,882)	(347,003)	(227,193)
Cash flows from investing activities:
Capital expenditures									0	0	0
Proceeds from redemption of marketable securities									0	0	0
Purchase of marketable securities and investments									412,839	55,466	(183,927)
Acquisitions of businesses, net of cash acquired									0	0	0
Other									429,061	291,553	375,036
Net cash used in investing activities									841,900	347,019	191,109
Cash flows from financing activities:
Proceeds from issuance of debt									786	0
Repayment of debt									(804)	(16)	36,084
Exercise of stock-based compensation awards									0
Dividends paid									0	0	0
Repurchase of common stock									0	0	0
Other									0	0	0
Net cash used in financing activities									(18)	(16)	36,084
Effect of exchange rate changes on cash and cash equivalents									0	0	0
Net (decrease) increase in cash and cash equivalents									0	0	0
Cash and cash equivalents at beginning of year				0				0	0	0	0
Cash and cash equivalents at end of year	$ 0				$ 0				$ 0	$ 0	$ 0