Supplemental Guarantor Information (Condensed Consolidated Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2013	Nov. 30, 2012	Aug. 31, 2012	Nov. 30, 2011
Assets
Cash and Cash Equivalents, at Carrying Value	$ 386,465	$ 525,688	$ 423,124	$ 418,074
Restricted cash	41,631	42,362
Receivables	72,345	64,821
Inventories	2,229,720	1,706,571
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	126,549	123,674
Other assets	101,247	95,050
Intercompany Receivables	0	0
Investments in and Advances to Affiliates, Amount of Equity	0	0
Total assets	2,964,841	2,561,698
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	526,913	458,889
Mortgages and notes payable	1,937,057	1,722,815
Financial services	2,865	3,188
Intercompany	0	0
Stockholders' equity	498,006	376,806	372,441	442,657
Total liabilities and stockholders’ equity	2,964,841	2,561,698
KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value	306,955	457,007	360,827	340,957
Restricted cash	41,631	42,362
Receivables	167	121
Inventories	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	91,083	85,901
Intercompany Receivables	2,037,313	1,559,712
Investments in and Advances to Affiliates, Amount of Equity	33,771	11,411
Total assets	2,510,920	2,156,514
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	136,473	134,314
Mortgages and notes payable	1,876,441	1,645,394
Financial services	0	0
Intercompany	0	0
Stockholders' equity	498,006	376,806
Total liabilities and stockholders’ equity	2,510,920	2,156,514
Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	63,968	52,933	43,037	46,375
Restricted cash	0	0
Receivables	70,719	63,600
Inventories	2,046,106	1,572,999
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	124,049	114,292
Other assets	8,718	15,638
Intercompany Receivables	0	0
Investments in and Advances to Affiliates, Amount of Equity	0	0
Total assets	2,313,560	1,819,462
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	258,175	207,641
Mortgages and notes payable	60,616	77,421
Financial services	0	0
Intercompany	1,978,378	1,534,400
Stockholders' equity	16,391	0
Total liabilities and stockholders’ equity	2,313,560	1,819,462
Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	15,542	15,748	19,260	30,742
Restricted cash	0	0
Receivables	1,459	1,100
Inventories	183,614	133,572
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	2,500	9,382
Other assets	1,446	(6,489)
Intercompany Receivables	0	0
Investments in and Advances to Affiliates, Amount of Equity	0	0
Total assets	211,445	156,845
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	132,265	116,934
Mortgages and notes payable	0	0
Financial services	2,865	3,188
Intercompany	58,935	25,312
Stockholders' equity	17,380	11,411
Total liabilities and stockholders’ equity	211,445	156,845
Consolidating Adjustments
Assets
Cash and Cash Equivalents, at Carrying Value	0	0	0	0
Restricted cash	0	0
Receivables	0	0
Inventories	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	0	0
Intercompany Receivables	(2,037,313)	(1,559,712)
Investments in and Advances to Affiliates, Amount of Equity	(33,771)	(11,411)
Total assets	(2,071,084)	(1,571,123)
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	0	0
Mortgages and notes payable	0	0
Financial services	0	0
Intercompany	(2,037,313)	(1,559,712)
Stockholders' equity	(33,771)	(11,411)
Total liabilities and stockholders’ equity	(2,071,084)	(1,571,123)
Homebuilding [Member]
Assets
Cash and Cash Equivalents, at Carrying Value	383,314	524,765	420,392
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	126,549	123,674
Total assets	2,954,806	2,557,243
Liabilities and stockholders' equity
Total Liabilities Homebuilding	2,463,970	2,181,704
Homebuilding [Member] | KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value	306,955	457,007
Total assets	439,836	585,391
Liabilities and stockholders' equity
Total Liabilities Homebuilding	2,012,914	1,779,708
Homebuilding [Member] | Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	63,968	52,933
Total assets	2,313,560	1,819,462
Liabilities and stockholders' equity
Total Liabilities Homebuilding	318,791	285,062
Homebuilding [Member] | Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	12,391	14,825
Total assets	201,410	152,390
Liabilities and stockholders' equity
Total Liabilities Homebuilding	132,265	116,934
Homebuilding [Member] | Consolidating Adjustments
Assets
Cash and Cash Equivalents, at Carrying Value	0	0
Total assets	0	0
Liabilities and stockholders' equity
Total Liabilities Homebuilding	0	0
Financial services [Member]
Assets
Cash and Cash Equivalents, at Carrying Value	3,151	923	2,732
Receivables	1,336	1,859
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	5,496	1,630
Other assets	52	43
Total assets	10,035	4,455
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	2,865	3,188
Financial services [Member] | KB Home Corporate
Assets
Total assets	0	0
Financial services [Member] | Guarantor Subsidiaries
Assets
Total assets	0	0
Financial services [Member] | Non-Guarantor Subsidiaries
Assets
Total assets	10,035	4,455
Financial services [Member] | Consolidating Adjustments
Assets
Total assets	$ 0	$ 0