Supplemental Guarantor Information (Details 1) (USD $) In Thousands, unless otherwise specified	Feb. 29, 2012	Nov. 30, 2011
Homebuilding:
Cash and cash equivalents	$ 304,171	$ 415,050
Restricted cash	63,890	64,481
Receivables	72,442	66,179
Inventories	1,748,377	1,731,629
Investments in unconsolidated joint ventures	121,307	127,926
Other assets	87,948	75,104
Total homebuilding assets	2,398,135	2,480,369
Financial services	7,938	32,173
Total assets	2,406,073	2,512,542
Homebuilding:
Accounts payable, accrued expenses and other liabilities	418,686	478,820
Mortgages and notes payable	1,587,414	1,583,571
Total Homebuilding liabilities	2,006,100	2,062,391
Financial services	6,105	7,494
Stockholders' equity	393,868	442,657
Total liabilities and stockholders' equity	2,406,073	2,512,542
KB Home Corporate [Member]
Homebuilding:
Cash and cash equivalents	259,419	340,957
Restricted cash	63,884	64,475
Receivables	820	801
Other assets	79,414	67,059
Total homebuilding assets	403,537	473,292
Investments in subsidiaries	(35,592)	34,235
Total assets	367,945	507,527
Homebuilding:
Accounts payable, accrued expenses and other liabilities	113,316	121,572
Mortgages and notes payable	1,539,035	1,533,477
Total Homebuilding liabilities	1,652,351	1,655,049
Intercompany	(1,678,274)	(1,590,179)
Stockholders' equity	393,868	442,657
Total liabilities and stockholders' equity	367,945	507,527
Guarantor Subsidiaries [Member]
Homebuilding:
Cash and cash equivalents	24,385	32,876
Restricted cash	6	6
Receivables	31,369	29,250
Inventories	1,260,358	1,256,468
Investments in unconsolidated joint ventures	107,321	113,921
Other assets	690	730
Total homebuilding assets	1,424,129	1,433,251
Total assets	1,424,129	1,433,251
Homebuilding:
Accounts payable, accrued expenses and other liabilities	147,364	181,835
Mortgages and notes payable	44,281	45,925
Total Homebuilding liabilities	191,645	227,760
Intercompany	1,266,081	1,205,491
Stockholders' equity	(33,597)
Total liabilities and stockholders' equity	1,424,129	1,433,251
Non-Guarantor Subsidiaries [Member]
Homebuilding:
Cash and cash equivalents	20,367	41,217
Receivables	40,253	36,128
Inventories	488,019	475,161
Investments in unconsolidated joint ventures	13,986	14,005
Other assets	7,844	7,315
Total homebuilding assets	570,469	573,826
Financial services	7,938	32,173
Total assets	578,407	605,999
Homebuilding:
Accounts payable, accrued expenses and other liabilities	158,006	175,413
Mortgages and notes payable	4,098	4,169
Total Homebuilding liabilities	162,104	179,582
Financial services	6,105	7,494
Intercompany	412,193	384,688
Stockholders' equity	(1,995)	34,235
Total liabilities and stockholders' equity	578,407	605,999
Consolidating Adjustments [Member]
Homebuilding:
Investments in subsidiaries	35,592	(34,235)
Total assets	35,592	(34,235)
Homebuilding:
Stockholders' equity	35,592	(34,235)
Total liabilities and stockholders' equity	$ 35,592	$ (34,235)