Cover Page - USD ($) $ in Millions	12 Months Ended
	Jul. 31, 2019	Sep. 16, 2019	Jan. 31, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Jul. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	THOR INDUSTRIES INC
Entity Central Index Key	0000730263
Current Fiscal Year End Date	--07-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Public Float			$ 3,295
Entity Interactive Data Current	Yes
Entity Address, State or Province	IN
Title of 12(b) Security	Common Stock
Trading Symbol	THO
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		55,063,473