Document and Entity Information - USD ($)	12 Months Ended
	Jul. 31, 2018	Sep. 28, 2018	Jan. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	COPART INC
Entity Central Index Key	0000900075
Current Fiscal Year End Date	--07-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Jul. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Trading Symbol	cprt
Entity Common Stock, Shares Outstanding		233,916,190
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Public Float			$ 8,903,622,911