Supplemental Guarantor Information (Condensed Consolidated Statements of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	May 31, 2014		May 31, 2013		May 31, 2014		May 31, 2013
Condensed Consolidated Statements of Operations
Revenues	$ 565,007		$ 524,406		$ 1,015,694		$ 929,625
Homebuilding:
Revenues	562,396		521,788		1,010,663		924,604
Construction and land costs	(456,560)		(442,998)		(825,834)		(786,263)
Selling, general and administrative expenses	(71,544)		(70,099)		(132,818)		(129,196)
Operating income (loss)	34,292		8,691		52,011		9,145
Interest income	115		232		283		436
Interest expense	(8,558)		(14,507)		(19,834)		(29,747)
Intercompany Interest Income (Expense)	0		0		0		0
Equity in income (loss) of unconsolidated joint ventures					1,900		85
Total pretax income (loss)	26,924		(4,173)		37,687		(16,531)
Income tax benefit (expense)	(300)		1,200		(500)		1,100
Equity in Net Income (Loss) of Subsidiaries	0		0		0		0
Net income (loss)	26,624		(2,973)		37,187		(15,431)
KB Home Corporate
Condensed Consolidated Statements of Operations
Revenues	0		0		0		0
Homebuilding:
Revenues	0		0		0		0
Construction and land costs	0		0		0		0
Selling, general and administrative expenses	(15,751)		(19,329)		(31,495)		(34,152)
Operating income (loss)	(15,751)		(19,329)		(31,495)		(34,152)
Interest income	109		228		276		429
Interest expense	(41,671)		(33,103)		(79,679)		(64,951)
Intercompany Interest Income (Expense)	70,709		49,201		130,431		94,558
Total pretax income (loss)	13,396		(3,003)		19,533		(4,116)
Income tax benefit (expense)	(100)		1,000		(200)		300
Equity in Net Income (Loss) of Subsidiaries	13,328		(970)		17,854		(11,615)
Net income (loss)	26,624		(2,973)		37,187		(15,431)
Guarantor Subsidiaries
Condensed Consolidated Statements of Operations
Revenues	552,407		508,015		988,256		901,243
Homebuilding:
Revenues	552,407		508,015		988,256		901,243
Construction and land costs	(446,730)		(430,669)		(804,822)		(765,166)
Selling, general and administrative expenses	(51,803)		(47,188)		(93,775)		(87,997)
Operating income (loss)	53,874		30,158		89,659		48,080
Interest income	5		2		6		3
Interest expense	(1,488)		(1,387)		(2,760)		(2,961)
Intercompany Interest Income (Expense)	(35,437)		(29,292)		(67,533)		(57,424)
Total pretax income (loss)	16,276		(1,086)		21,284		(13,304)
Income tax benefit (expense)	(200)		200		(300)		800
Equity in Net Income (Loss) of Subsidiaries	0		0		0		0
Net income (loss)	16,076		(886)		20,984		(12,504)
Non-Guarantor Subsidiaries
Condensed Consolidated Statements of Operations
Revenues	12,600		16,391		27,438		28,382
Homebuilding:
Revenues	9,989		13,773		22,407		23,361
Construction and land costs	(9,830)		(12,329)		(21,012)		(21,097)
Selling, general and administrative expenses	(3,990)		(3,582)		(7,548)		(7,047)
Operating income (loss)	(3,831)		(2,138)		(6,153)		(4,783)
Interest income	1		2		1		4
Interest expense	0		0		0		0
Intercompany Interest Income (Expense)	(671)		74		(293)		1,031
Total pretax income (loss)	(2,748)		(84)		(3,130)		889
Income tax benefit (expense)	0		0		0		0
Equity in Net Income (Loss) of Subsidiaries	0		0		0		0
Net income (loss)	(2,748)		(84)		(3,130)		889
Consolidating Adjustments
Condensed Consolidated Statements of Operations
Revenues	0		0		0		0
Homebuilding:
Revenues	0		0		0		0
Construction and land costs	0		0		0		0
Selling, general and administrative expenses	0		0		0		0
Operating income (loss)	0		0		0		0
Interest income	0		0		0		0
Interest expense	34,601		19,983		62,605		38,165
Intercompany Interest Income (Expense)	(34,601)		(19,983)		(62,605)		(38,165)
Total pretax income (loss)	0		0		0		0
Income tax benefit (expense)	0		0		0		0
Equity in Net Income (Loss) of Subsidiaries	(13,328)		970		(17,854)		11,615
Net income (loss)	(13,328)		970		(17,854)		11,615
Homebuilding [Member]
Condensed Consolidated Statements of Operations
Revenues	562,396		521,788		1,010,663		924,604
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	(678)		(567)		1,912		(1,002)
Total pretax income (loss)	25,171		(6,151)		34,372		(21,168)
Homebuilding [Member] | KB Home Corporate
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	0		0		0		0
Total pretax income (loss)	13,396		(3,003)		19,533		(4,116)
Homebuilding [Member] | Guarantor Subsidiaries
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	(678)		(567)		1,912		(1,002)
Total pretax income (loss)	16,276		(1,086)		21,284		(13,304)
Homebuilding [Member] | Non-Guarantor Subsidiaries
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	0		0		0		0
Total pretax income (loss)	(4,501)		(2,062)		(6,445)		(3,748)
Homebuilding [Member] | Consolidating Adjustments
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	0		0		0		0
Total pretax income (loss)	0		0		0		0
Financial services [Member]
Condensed Consolidated Statements of Operations
Revenues	2,611		2,618		5,031		5,021
Homebuilding:
Operating income (loss)	1,759		1,982		3,327		3,550
Equity in income (loss) of unconsolidated joint ventures	(6)	[1]	(4)	[1]	(12)	[1]	1,087	[1]
Total pretax income (loss)	1,753		1,978		3,315		4,637
Financial services [Member] | KB Home Corporate
Homebuilding:
Total pretax income (loss)	0		0		0		0
Financial services [Member] | Guarantor Subsidiaries
Homebuilding:
Total pretax income (loss)	0		0		0		0
Financial services [Member] | Non-Guarantor Subsidiaries
Homebuilding:
Total pretax income (loss)	1,753		1,978		3,315		4,637
Financial services [Member] | Consolidating Adjustments
Homebuilding:
Total pretax income (loss)	$ 0		$ 0		$ 0		$ 0

[1] Equity in income of unconsolidated joint ventures for the six months ended May 31, 2013 related to the wind down of KBA Mortgage, LLC (“KBA Mortgage”), our unconsolidated mortgage banking joint venture with a subsidiary of Bank of America, N.A., which ceased offering mortgage banking services in 2011.