Supplemental Guarantor Information (Details 1) (USD $) In Thousands, unless otherwise specified	May 31, 2012	Nov. 30, 2011
Homebuilding:
Cash and cash equivalents	$ 314,258	$ 415,050
Restricted cash	63,182	64,481
Receivables	74,028	66,179
Inventories	1,727,640	1,731,629
Investments in unconsolidated joint ventures	121,408	127,926
Other assets	85,197	75,104
Total homebuilding assets	2,385,713	2,480,369
Financial services	8,292	32,173
Total assets	2,394,005	2,512,542
Homebuilding:
Accounts payable, accrued expenses and other liabilities	436,185	478,820
Mortgages and notes payable	1,582,788	1,583,571
Total Homebuilding liabilities	2,018,973	2,062,391
Financial services	5,501	7,494
Stockholders' equity	369,531	442,657
Total liabilities and stockholders' equity	2,394,005	2,512,542
KB Home Corporate [Member]
Homebuilding:
Cash and cash equivalents	273,312	340,957
Restricted cash	63,182	64,475
Receivables	899	801
Other assets	76,609	67,059
Total homebuilding assets	414,002	473,292
Investments in subsidiaries	12,710	34,235
Total assets	426,712	507,527
Homebuilding:
Accounts payable, accrued expenses and other liabilities	118,224	121,572
Mortgages and notes payable	1,539,389	1,533,477
Total Homebuilding liabilities	1,657,613	1,655,049
Intercompany	(1,600,432)	(1,590,179)
Stockholders' equity	369,531	442,657
Total liabilities and stockholders' equity	426,712	507,527
Guarantor Subsidiaries [Member]
Homebuilding:
Cash and cash equivalents	17,847	32,876
Restricted cash		6
Receivables	29,891	29,250
Inventories	1,229,731	1,256,468
Investments in unconsolidated joint ventures	107,090	113,921
Other assets	846	730
Total homebuilding assets	1,385,405	1,433,251
Total assets	1,385,405	1,433,251
Homebuilding:
Accounts payable, accrued expenses and other liabilities	154,853	181,835
Mortgages and notes payable	39,348	45,925
Total Homebuilding liabilities	194,201	227,760
Intercompany	1,191,204	1,205,491
Total liabilities and stockholders' equity	1,385,405	1,433,251
Non-Guarantor Subsidiaries [Member]
Homebuilding:
Cash and cash equivalents	23,099	41,217
Receivables	43,238	36,128
Inventories	497,909	475,161
Investments in unconsolidated joint ventures	14,318	14,005
Other assets	7,742	7,315
Total homebuilding assets	586,306	573,826
Financial services	8,292	32,173
Total assets	594,598	605,999
Homebuilding:
Accounts payable, accrued expenses and other liabilities	163,108	175,413
Mortgages and notes payable	4,051	4,169
Total Homebuilding liabilities	167,159	179,582
Financial services	5,501	7,494
Intercompany	409,228	384,688
Stockholders' equity	12,710	34,235
Total liabilities and stockholders' equity	594,598	605,999
Consolidating Adjustments [Member]
Homebuilding:
Investments in subsidiaries	(12,710)	(34,235)
Total assets	(12,710)	(34,235)
Homebuilding:
Stockholders' equity	(12,710)	(34,235)
Total liabilities and stockholders' equity	$ (12,710)	$ (34,235)