Cover Page	9 Months Ended
	Aug. 31, 2021 $ / shares shares
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Aug. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Registrant Name	KB HOME
Entity Central Index Key	0000795266
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--11-30
Entity Filer Category	Large Accelerated Filer
Entity Common Stock Shares Outstanding	87,477,633
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	001-09195
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-3666267
Entity Address, Address Line One	10990 Wilshire Boulevard
Entity Address, City or Town	Los Angeles
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90024
City Area Code	310
Local Phone Number	231-4000
Common Stock, Par or Stated Value Per Share | $ / shares	$ 1.00
Document Quarterly Report	true
Document Transition Report	false
Grantor Stock Ownership Trust
Document Information [Line Items]
Entity Common Stock Shares Outstanding	6,705,247
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock (par value $1.00 per share)
Trading Symbol	KBH
Security Exchange Name	NYSE
Rights
Document Information [Line Items]
Title of 12(b) Security	Rights to Purchase Series A Participating Cumulative Preferred Stock
Trading Symbol	KBH
Security Exchange Name	NYSE