Supplemental Guarantor Information (Details 1) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2011	Nov. 30, 2010	Nov. 30, 2009	Nov. 30, 2008
Homebuilding:
Cash and cash equivalents	$ 415,050	$ 904,401
Restricted cash	64,481	115,477
Receivables	66,179	108,048
Inventories	1,731,629	1,696,721
Investments in unconsolidated joint ventures	127,926	105,583
Other assets	75,104	150,076
Total homebuilding assets	2,480,369	3,080,306
Financial services	32,173	29,443
Investments in subsidiaries	0	0
Total assets	2,512,542	3,109,749
Homebuilding:
Accounts payable, accrued expenses and other liabilities	478,820	699,722
Mortgages and notes payable	1,583,571	1,775,529
Total Homebuilding	2,062,391	2,475,251
Financial services	7,494	2,620
Intercompany	0	0
Total stockholder's equity	442,657	631,878	707,224	830,605
Total liabilities and Stockholders' equity	2,512,542	3,109,749
KB Home Corporate[Member]
Homebuilding:
Cash and cash equivalents	340,957	770,603
Restricted cash	64,475	88,714
Receivables	801	4,205
Inventories	0	0
Investments in unconsolidated joint ventures	0	0
Other assets	67,059	68,166
Total homebuilding assets	473,292	931,688
Financial services	0	0
Investments in subsidiaries	34,235	36,279
Total assets	507,527	967,967
Homebuilding:
Accounts payable, accrued expenses and other liabilities	121,572	124,609
Mortgages and notes payable	1,533,477	1,632,362
Total Homebuilding	1,655,049	1,756,971
Financial services	0	0
Intercompany	(1,590,179)	(1,420,882)
Total stockholder's equity	442,657	631,878
Total liabilities and Stockholders' equity	507,527	967,967
Guarantor Subsidiaries [Member]
Homebuilding:
Cash and cash equivalents	32,876	3,619
Restricted cash	6	0
Receivables	29,250	6,271
Inventories	1,256,468	774,102
Investments in unconsolidated joint ventures	113,921	37,007
Other assets	730	72,805
Total homebuilding assets	1,433,251	893,804
Financial services	0	0
Investments in subsidiaries	0	0
Total assets	1,433,251	893,804
Homebuilding:
Accounts payable, accrued expenses and other liabilities	181,835	150,260
Mortgages and notes payable	45,925	112,368
Total Homebuilding	227,760	262,628
Financial services	0	0
Intercompany	1,205,491	631,176
Total stockholder's equity	0	0
Total liabilities and Stockholders' equity	1,433,251	893,804
Non-Guarantor Subsidiaries [Member]
Homebuilding:
Cash and cash equivalents	41,217	130,179
Restricted cash	0	26,763
Receivables	36,128	97,572
Inventories	475,161	922,619
Investments in unconsolidated joint ventures	14,005	68,576
Other assets	7,315	9,105
Total homebuilding assets	573,826	1,254,814
Financial services	32,173	29,443
Investments in subsidiaries	0	0
Total assets	605,999	1,284,257
Homebuilding:
Accounts payable, accrued expenses and other liabilities	175,413	424,853
Mortgages and notes payable	4,169	30,799
Total Homebuilding	179,582	455,652
Financial services	7,494	2,620
Intercompany	384,688	789,706
Total stockholder's equity	34,235	36,279
Total liabilities and Stockholders' equity	605,999	1,284,257
Consolidating Adjustments [Member]
Homebuilding:
Cash and cash equivalents	0	0
Restricted cash	0	0
Receivables	0	0
Inventories	0	0
Investments in unconsolidated joint ventures	0	0
Other assets	0	0
Total homebuilding assets	0	0
Financial services	0	0
Investments in subsidiaries	(34,235)	(36,279)
Total assets	(34,235)	(36,279)
Homebuilding:
Accounts payable, accrued expenses and other liabilities	0	0
Mortgages and notes payable	0	0
Total Homebuilding	0	0
Financial services	0	0
Intercompany	0	0
Total stockholder's equity	(34,235)	(36,279)
Total liabilities and Stockholders' equity	$ (34,235)	$ (36,279)