Supplemental Guarantor Information - Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2019	Aug. 31, 2018
Cash flows from operating activities:
Net income	$ 250,812	$ 212,515
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	56,726	52,745
Amortization of intangible assets and capitalized contract costs	35,268	33,550
Stock-based compensation	40,395	46,172
Deferred income taxes	7,910	9,022
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(6,636)	(15,051)
Inventories, net	(1,726)	(34,629)
Uniforms and other rental items in service	(11,305)	(23,019)
Prepaid expenses and other current assets and capitalized contract costs	(41,928)	(46,930)
Accounts payable	13,357	(329)
Accrued compensation and related liabilities	(58,718)	(56,186)
Accrued liabilities and other	(24,082)	(27,556)
Income taxes, current	16,828	12,681
Net cash provided by operating activities	276,901	162,985
Cash flows from investing activities:
Capital expenditures	(64,743)	(64,528)
Proceeds from redemption of marketable securities	0	1,558
Purchase of investments	(9,391)	0
Acquisitions of businesses, net of cash acquired	(3,896)	(7,613)
Other, net	(109)	(202)
Net cash used in investing activities	(78,139)	(70,785)
Cash flows from financing activities:
Issuance of commercial paper, net	26,500	0
Proceeds from exercise of stock-based compensation awards	37,915	27,512
Repurchase of common stock	(256,830)	(139,468)
Other, net	(1,192)	(552)
Net cash used in financing activities	(193,607)	(112,508)
Effect of exchange rate changes on cash and cash equivalents	331	(60)
Net increase (decrease) in cash and cash equivalents	5,486	(20,368)
Cash and cash equivalents at beginning of period	96,645	138,724
Cash and cash equivalents at end of period	102,131	118,356
Eliminations
Cash flows from operating activities:
Net income	(258,665)	(210,655)
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
Deferred income taxes	0	0
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	0	0
Inventories, net	0	(782)
Uniforms and other rental items in service	1,968	(1,379)
Prepaid expenses and other current assets and capitalized contract costs	0	0
Accounts payable	(141)	302
Accrued compensation and related liabilities	0	0
Accrued liabilities and other	0	0
Income taxes, current	0	0
Net cash provided by operating activities	(256,838)	(212,514)
Cash flows from investing activities:
Capital expenditures	0	0
Proceeds from redemption of marketable securities		0
Purchase of investments	0
Acquisitions of businesses, net of cash acquired	0	0
Other, net	256,838	213,504
Net cash used in investing activities	256,838	213,504
Cash flows from financing activities:
Issuance of commercial paper, net	0
Proceeds from exercise of stock-based compensation awards	0	0
Repurchase of common stock	0	0
Other, net	0	(990)
Net cash used in financing activities	0	(990)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) 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
Cintas Corporation | Reportable Legal Entities
Cash flows from operating activities:
Net income	250,812	212,515
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	40,395	46,172
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	291,207	258,687
Cash flows from investing activities:
Capital expenditures	0	0
Proceeds from redemption of marketable securities		0
Purchase of investments	0
Acquisitions of businesses, net of cash acquired	0	0
Other, net	(72,292)	(146,731)
Net cash used in investing activities	(72,292)	(146,731)
Cash flows from financing activities:
Issuance of commercial paper, net	0
Proceeds from exercise of stock-based compensation awards	37,915	27,512
Repurchase of common stock	(256,830)	(139,468)
Other, net	0	0
Net cash used in financing activities	(218,915)	(111,956)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) 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
Corp. 2 | Reportable Legal Entities
Cash flows from operating activities:
Net income	81,688	62,612
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	37,056	33,866
Amortization of intangible assets and capitalized contract costs	31,949	30,156
Stock-based compensation	0	0
Deferred income taxes	8,652	5,388
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(14,317)	(12,891)
Inventories, net	(8,686)	(37,207)
Uniforms and other rental items in service	(11,416)	(10,800)
Prepaid expenses and other current assets and capitalized contract costs	(26,355)	(25,060)
Accounts payable	(8,103)	41,784
Accrued compensation and related liabilities	(58,252)	(41,910)
Accrued liabilities and other	5,833	2,305
Income taxes, current	(9,493)	5,022
Net cash provided by operating activities	28,556	53,265
Cash flows from investing activities:
Capital expenditures	(46,605)	(43,966)
Proceeds from redemption of marketable securities		1,554
Purchase of investments	271
Acquisitions of businesses, net of cash acquired	(3,896)	(7,613)
Other, net	3,368	(4,048)
Net cash used in investing activities	(46,862)	(54,073)
Cash flows from financing activities:
Issuance of commercial paper, net	26,500
Proceeds from exercise of stock-based compensation awards	0	0
Repurchase of common stock	0	0
Other, net	(1,192)	2,909
Net cash used in financing activities	25,308	2,909
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	7,002	2,101
Cash and cash equivalents at beginning of period	54,963	44,499
Cash and cash equivalents at end of period	61,965	46,600
Subsidiary Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	169,106	143,033
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	16,032	15,427
Amortization of intangible assets and capitalized contract costs	1,279	1,278
Stock-based compensation	0	0
Deferred income taxes	(382)	2,122
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	7,965	3,381
Inventories, net	7,359	2,700
Uniforms and other rental items in service	(1,135)	(7,904)
Prepaid expenses and other current assets and capitalized contract costs	(15,462)	(21,838)
Accounts payable	28,923	(37,657)
Accrued compensation and related liabilities	2,120	(10,982)
Accrued liabilities and other	(27,074)	(26,295)
Income taxes, current	25,974	8,474
Net cash provided by operating activities	214,705	71,739
Cash flows from investing activities:
Capital expenditures	(14,916)	(17,979)
Proceeds from redemption of marketable securities		4
Purchase of investments	(9,662)
Acquisitions of businesses, net of cash acquired	0	0
Other, net	(188,490)	(65,509)
Net cash used in investing activities	(213,068)	(83,484)
Cash flows from financing activities:
Issuance of commercial paper, net	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 increase (decrease) in cash and cash equivalents	1,637	(11,745)
Cash and cash equivalents at beginning of period	13,151	60,310
Cash and cash equivalents at end of period	14,788	48,565
Non- Guarantors | Reportable Legal Entities
Cash flows from operating activities:
Net income	7,871	5,010
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	3,638	3,452
Amortization of intangible assets and capitalized contract costs	2,040	2,116
Stock-based compensation	0	0
Deferred income taxes	(360)	1,512
Change in current assets and liabilities, net of acquisitions of businesses:
Accounts receivable, net	(284)	(5,541)
Inventories, net	(399)	660
Uniforms and other rental items in service	(722)	(2,936)
Prepaid expenses and other current assets and capitalized contract costs	(111)	(32)
Accounts payable	(7,322)	(4,758)
Accrued compensation and related liabilities	(2,586)	(3,294)
Accrued liabilities and other	(2,841)	(3,566)
Income taxes, current	347	(815)
Net cash provided by operating activities	(729)	(8,192)
Cash flows from investing activities:
Capital expenditures	(3,222)	(2,583)
Proceeds from redemption of marketable securities		0
Purchase of investments	0
Acquisitions of businesses, net of cash acquired	0	0
Other, net	467	2,582
Net cash used in investing activities	(2,755)	(1)
Cash flows from financing activities:
Issuance of commercial paper, net	0
Proceeds from exercise of stock-based compensation awards	0	0
Repurchase of common stock	0	0
Other, net	0	(2,471)
Net cash used in financing activities	0	(2,471)
Effect of exchange rate changes on cash and cash equivalents	331	(60)
Net increase (decrease) in cash and cash equivalents	(3,153)	(10,724)
Cash and cash equivalents at beginning of period	28,531	33,915
Cash and cash equivalents at end of period	$ 25,378	$ 23,191