Supplemental Guarantor Information - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2015	May 31, 2016	May 31, 2015	May 31, 2014
Cash flows from operating activities:
Net income		$ 693,520	$ 430,618	$ 374,442
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation		149,691	140,624	168,220
Amortization of intangible assets		15,588	14,458	22,642
Stock-based compensation		79,293	47,002	29,875
Gain on Storage transactions		(15,786)	(38,573)	0
Loss (gain) on Shred-it		24,288	3,851	(108,441)
Gain on Shred-it		(378,359)
Shredding Transaction asset impairment charge		0	0	16,143
Shredding Transaction costs		0	0	26,057
Deferred income taxes		(59,302)	20,866	47,109
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net		(52,762)	(1,443)	(56,231)
Inventories, net		(17,917)	23,785	(11,062)
Uniforms and other rental items in service		(6,306)	(31,994)	(11,435)
Prepaid expenses and other current assets		(965)	(3,202)	(2,177)
Accounts payable		(564)	(33,445)	30,446
Accrued compensation and related liabilities		13,512	3,234	10,931
Accrued liabilities and other		22,714	33,066	54,237
Income taxes, current		(800)	(6,832)	15,213
Net cash provided by operating activities		465,845	580,276	605,969
Cash flows from investing activities:
Capital expenditures		(275,385)	(217,720)	(145,580)
Proceeds from redemption of marketable securities		434,179	161,938	54,196
Purchase of marketable securities and investments		(494,146)	(195,471)	(63,858)
Proceeds from Storage transactions, net of cash contributed		35,338	158,428	0
Proceeds from Shredding transactions, net of cash contributed		580,837	3,344	179,359
Proceeds from sale of stock of an equity method investment		0	29,933	0
Dividends received on equity method investment		0	5,247	0
Acquisitions of businesses, net of cash acquired		(156,579)	(15,495)	(33,441)
Other		4,137	1,383	(5,219)
Net cash provided by (used in) investing activities		128,381	44,987	(14,543)
Cash flows from financing activities:
Proceeds from issuance of debt		0	0	0
Repayment of debt		(16)	(518)	(8,187)
Proceeds from exercise of stock-based compensation awards		28,226	40,230	41,902
Dividends paid		(115,273)	(201,891)	(93,320)
Repurchase of common stock		(780,151)	(551,970)	(370,599)
Other		490	1,589	469
Net cash used in financing activities		(866,724)	(712,560)	(429,735)
Effect of exchange rate changes on cash and cash equivalents		(5,218)	(8,918)	(676)
Net (decrease) increase in cash and cash equivalents		(277,716)	(96,215)	161,015
Cash and cash equivalents at beginning of year		417,073	513,288	352,273
Cash and cash equivalents at end of year	$ 417,073	139,357	417,073	513,288
Shred-it Partnership
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Gain on Storage transactions		(4,300)
Gain on Shred-it			(4,100)	(106,400)
Shredding Transaction asset impairment charge				16,100
Cash flows from investing activities:
Proceeds from Shredding transactions, net of cash contributed		578,300
Dividends received on equity method investment	113,400	0	113,400	0
Eliminations
Cash flows from operating activities:
Net income		(700,704)	(433,022)	(388,081)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation		0	0	0
Amortization of intangible assets		0	0	0
Stock-based compensation		0	0	0
Gain on Storage transactions		0	0
Loss (gain) on Shred-it		0	0	0
Gain on Shred-it		0
Shredding Transaction asset impairment charge				0
Shredding Transaction costs				0
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		6,443	2,272	(1,616)
Uniforms and other rental items in service		759	127	(15)
Prepaid expenses and other current assets		0	0	0
Accounts payable		(16)	4	1
Accrued compensation and related liabilities		0	0	0
Accrued liabilities and other		724	22	21
Income taxes, current		0	0	0
Net cash provided by operating activities		(692,794)	(430,597)	(389,690)
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		10,037	(53,245)	378,548
Proceeds from Storage transactions, net of cash contributed		0	0
Proceeds from Shredding transactions, net of cash contributed		0	0	0
Proceeds from sale of stock of an equity method investment			0
Dividends received on equity method investment			0
Acquisitions of businesses, net of cash acquired		0	0	0
Other		683,481	483,864	11,163
Net cash provided by (used in) investing activities		693,518	430,619	389,711
Cash flows from financing activities:
Proceeds from issuance of debt		0	0	0
Repayment of debt		(724)	(22)	(21)
Proceeds from exercise of stock-based compensation awards		0	0	0
Dividends paid		0	0	0
Repurchase of common stock		0	0	0
Other		0	0	0
Net cash used in financing activities		(724)	(22)	(21)
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
Cash and cash equivalents at end of year	0	0	0	0
Eliminations | Shred-it Partnership
Cash flows from investing activities:
Dividends received on equity method investment			0
Cintas Corporation
Cash flows from operating activities:
Net income		693,520	430,618	374,442
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation		0	0	0
Amortization of intangible assets		0	0	0
Stock-based compensation		79,293	47,002	29,875
Gain on Storage transactions		0	0
Loss (gain) on Shred-it		0	0	0
Gain on Shred-it		0
Shredding Transaction asset impairment charge				0
Shredding Transaction costs				0
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 and other current assets		0	0	0
Accounts payable		0	0	0
Accrued compensation and related liabilities		0	0	0
Accrued liabilities and other		0	0	0
Income taxes, current		0	0	0
Net cash provided by operating activities		772,813	477,620	404,317
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
Proceeds from Storage transactions, net of cash contributed		0	0
Proceeds from Shredding transactions, net of cash contributed		0	0	0
Proceeds from sale of stock of an equity method investment			0
Dividends received on equity method investment			0
Acquisitions of businesses, net of cash acquired		0	0	0
Other		94,344	235,951	13,783
Net cash provided by (used in) investing activities		94,344	235,951	13,783
Cash flows from financing activities:
Proceeds from issuance of debt		0	0	0
Repayment of debt		0	0	0
Proceeds from exercise of stock-based compensation awards		28,226	40,230	41,902
Dividends paid		(115,232)	(201,831)	(93,293)
Repurchase of common stock		(780,151)	(551,970)	(370,599)
Other		0	0	3,890
Net cash used in financing activities		(867,157)	(713,571)	(418,100)
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
Cash and cash equivalents at end of year	0	0	0	0
Cintas Corporation | Shred-it Partnership
Cash flows from investing activities:
Dividends received on equity method investment			0
Corp. 2
Cash flows from operating activities:
Net income		388,049	134,861	162,263
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation		96,885	87,186	110,100
Amortization of intangible assets		14,830	13,972	20,547
Stock-based compensation		0	0	0
Gain on Storage transactions		(12,547)	(31,113)
Loss (gain) on Shred-it		22,470	3,190	(113,511)
Gain on Shred-it		(388,930)
Shredding Transaction asset impairment charge				0
Shredding Transaction costs				0
Deferred income taxes		(83,648)	67	(2)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net		(30,570)	4,370	(53,053)
Inventories, net		(23,917)	22,405	(14,735)
Uniforms and other rental items in service		(10,329)	(24,351)	(11,004)
Prepaid expenses and other current assets		(142)	(345)	(386)
Accounts payable		(461,203)	(322,461)	25,573
Accrued compensation and related liabilities		9,959	3,171	5,778
Accrued liabilities and other		(2,926)	(15,829)	50,008
Income taxes, current		1,342	358	2,621
Net cash provided by operating activities		(480,677)	(124,519)	184,199
Cash flows from investing activities:
Capital expenditures		(151,063)	(110,658)	(123,978)
Proceeds from redemption of marketable securities		0	0	0
Purchase of marketable securities and investments		(3,333)	(1,827)	(151,063)
Proceeds from Storage transactions, net of cash contributed		32,099	93,387
Proceeds from Shredding transactions, net of cash contributed		568,223	3,344	180,000
Proceeds from sale of stock of an equity method investment			0
Dividends received on equity method investment			0
Acquisitions of businesses, net of cash acquired		(130,786)	(15,495)	(13,199)
Other		154,412	42,199	(50,446)
Net cash provided by (used in) investing activities		469,552	124,350	(158,686)
Cash flows from financing activities:
Proceeds from issuance of debt		0	0	0
Repayment of debt		(9,151)	(1,178)	(8,436)
Proceeds from exercise of stock-based compensation awards		0	0	0
Dividends paid		0	0	0
Repurchase of common stock		0	0	0
Other		1,952	1,952	1,952
Net cash used in financing activities		(7,199)	774	(6,484)
Effect of exchange rate changes on cash and cash equivalents		0	0	0
Net (decrease) increase in cash and cash equivalents		(18,324)	605	19,029
Cash and cash equivalents at beginning of year		74,145	73,540	54,511
Cash and cash equivalents at end of year	74,145	55,821	74,145	73,540
Corp. 2 | Shred-it Partnership
Cash flows from investing activities:
Dividends received on equity method investment			113,400
Subsidiary Guarantors
Cash flows from operating activities:
Net income		308,750	281,160	205,009
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation		43,441	43,013	44,856
Amortization of intangible assets		304	60	153
Stock-based compensation		0	0	0
Gain on Storage transactions		0	0
Loss (gain) on Shred-it		0	0	0
Gain on Shred-it		0
Shredding Transaction asset impairment charge				16,143
Shredding Transaction costs				26,057
Deferred income taxes		22,025	18,565	47,373
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net		(20,007)	(7,095)	(1,300)
Inventories, net		2,011	(405)	4,839
Uniforms and other rental items in service		5,104	(5,006)	557
Prepaid expenses and other current assets		(939)	(2,740)	(1,844)
Accounts payable		465,539	289,110	23,246
Accrued compensation and related liabilities		2,982	1,400	4,947
Accrued liabilities and other		24,761	42,551	4,897
Income taxes, current		(1,565)	(6,155)	9,902
Net cash provided by operating activities		852,406	632,719	384,835
Cash flows from investing activities:
Capital expenditures		(111,392)	(92,600)	(9,591)
Proceeds from redemption of marketable securities		0	0	5,659
Purchase of marketable securities and investments		(12,085)	38,731	(242,956)
Proceeds from Storage transactions, net of cash contributed		0	0
Proceeds from Shredding transactions, net of cash contributed		0	0	0
Proceeds from sale of stock of an equity method investment			29,933
Dividends received on equity method investment			5,247
Acquisitions of businesses, net of cash acquired		0	0	0
Other		(929,997)	(764,336)	8,108
Net cash provided by (used in) investing activities		(1,053,474)	(783,025)	(238,780)
Cash flows from financing activities:
Proceeds from issuance of debt		(165)	(2,615)	(2,445)
Repayment of debt		10,224	2,962	(106)
Proceeds from exercise of stock-based compensation awards		0	0	0
Dividends paid		0	0	0
Repurchase of common stock		0	0	0
Other		(730)	(363)	8,951
Net cash used in financing activities		9,329	(16)	6,400
Effect of exchange rate changes on cash and cash equivalents		0	0	0
Net (decrease) increase in cash and cash equivalents		(191,739)	(150,322)	152,455
Cash and cash equivalents at beginning of year		249,203	399,525	247,070
Cash and cash equivalents at end of year	249,203	57,464	249,203	399,525
Subsidiary Guarantors | Shred-it Partnership
Cash flows from investing activities:
Dividends received on equity method investment			0
Non- Guarantors
Cash flows from operating activities:
Net income		3,905	17,001	20,809
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation		9,365	10,425	13,264
Amortization of intangible assets		454	426	1,942
Stock-based compensation		0	0	0
Gain on Storage transactions		(3,239)	(7,460)
Loss (gain) on Shred-it		1,818	661	5,070
Gain on Shred-it		10,571
Shredding Transaction asset impairment charge				0
Shredding Transaction costs				0
Deferred income taxes		2,321	2,234	(262)
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net		(2,185)	1,282	(1,878)
Inventories, net		(2,454)	(487)	450
Uniforms and other rental items in service		(1,840)	(2,764)	(973)
Prepaid expenses and other current assets		116	(117)	53
Accounts payable		(4,884)	(98)	(18,374)
Accrued compensation and related liabilities		571	(1,337)	206
Accrued liabilities and other		155	6,322	(689)
Income taxes, current		(577)	(1,035)	2,690
Net cash provided by operating activities		14,097	25,053	22,308
Cash flows from investing activities:
Capital expenditures		(12,930)	(14,462)	(12,011)
Proceeds from redemption of marketable securities		434,179	161,938	48,537
Purchase of marketable securities and investments		(488,765)	(179,130)	(48,387)
Proceeds from Storage transactions, net of cash contributed		3,239	65,041
Proceeds from Shredding transactions, net of cash contributed		12,614	0	(641)
Proceeds from sale of stock of an equity method investment			0
Dividends received on equity method investment			0
Acquisitions of businesses, net of cash acquired		(25,793)	0	(20,242)
Other		1,897	3,705	12,173
Net cash provided by (used in) investing activities		(75,559)	37,092	(20,571)
Cash flows from financing activities:
Proceeds from issuance of debt		165	2,615	2,445
Repayment of debt		(365)	(2,280)	376
Proceeds from exercise of stock-based compensation awards		0	0	0
Dividends paid		(41)	(60)	(27)
Repurchase of common stock		0	0	0
Other		(732)	0	(14,324)
Net cash used in financing activities		(973)	275	(11,530)
Effect of exchange rate changes on cash and cash equivalents		(5,218)	(8,918)	(676)
Net (decrease) increase in cash and cash equivalents		(67,653)	53,502	(10,469)
Cash and cash equivalents at beginning of year		93,725	40,223	50,692
Cash and cash equivalents at end of year	$ 93,725	$ 26,072	93,725	$ 40,223
Non- Guarantors | Shred-it Partnership
Cash flows from investing activities:
Dividends received on equity method investment			$ 0