Supplemental Guarantor Information (Condensed Consolidating Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2013	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2010
Assets
Cash and cash equivalents	$ 532,523	$ 525,688	$ 418,074	$ 908,430
Restricted cash	41,906	42,362
Receivables	75,749	64,821
Inventory, Operative Builders	2,298,577	1,706,571
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	130,192	123,674
Other assets	107,076	95,050
Investments in subsidiaries	0	0
Total assets	3,193,635	2,561,698
Intercompany receivables	0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	504,458	458,889
Mortgages and notes payable	2,150,498	1,722,815
Financial services	2,593	3,188
Intercompany	0	0
Stockholder's equity	536,086	376,806	442,657	631,878
Total liabilities and Stockholders' equity	3,193,635	2,561,698
KB Home Corporate
Assets
Cash and cash equivalents	476,847	457,007	340,957	770,603
Restricted cash	41,906	42,362
Receivables	1,472	121
Inventory, Operative Builders	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	97,647	85,901
Investments in subsidiaries	39,955	38,479
Total assets	2,787,556	2,183,582
Intercompany receivables	2,129,729	1,559,712
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	117,875	134,314
Mortgages and notes payable	2,111,773	1,645,394
Financial services	0	0
Intercompany	21,822	27,068
Stockholder's equity	536,086	376,806
Total liabilities and Stockholders' equity	2,787,556	2,183,582
Guarantor Subsidiaries
Assets
Cash and cash equivalents	41,316	54,205	52,263	25,102
Restricted cash	0	0
Receivables	74,186	64,504
Inventory, Operative Builders	2,263,034	1,688,301
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	130,192	116,793
Other assets	9,072	15,980
Investments in subsidiaries	0	0
Total assets	2,517,800	1,939,783
Intercompany receivables	0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	292,220	221,611
Mortgages and notes payable	38,725	77,421
Financial services	0	0
Intercompany	2,186,855	1,640,751
Stockholder's equity	0	0
Total liabilities and Stockholders' equity	2,517,800	1,939,783
Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	14,360	14,476	24,854	112,725
Restricted cash	0	0
Receivables	91	196
Inventory, Operative Builders	35,543	18,270
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	6,881
Other assets	357	(6,831)
Investments in subsidiaries	0	0
Total assets	175,792	159,104
Intercompany receivables	117,829	122,580
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	94,363	102,964
Mortgages and notes payable	0	0
Financial services	2,593	3,188
Intercompany	38,881	14,473
Stockholder's equity	39,955	38,479
Total liabilities and Stockholders' equity	175,792	159,104
Consolidating Adjustments
Assets
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0
Receivables	0	0
Inventory, Operative Builders	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	0	0
Investments in subsidiaries	(39,955)	(38,479)
Total assets	(2,287,513)	(1,720,771)
Intercompany receivables	(2,247,558)	(1,682,292)
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	0	0
Mortgages and notes payable	0	0
Financial services	0	0
Intercompany	(2,247,558)	(1,682,292)
Stockholder's equity	(39,955)	(38,479)
Total liabilities and Stockholders' equity	(2,287,513)	(1,720,771)
Homebuilding [Member]
Assets
Cash and cash equivalents	530,095	524,765	415,050
Total assets	3,183,595	2,557,243
Liabilities and stockholders' equity
Total Homebuilding	2,654,956	2,181,704
Homebuilding [Member] | KB Home Corporate
Assets
Cash and cash equivalents	476,847	457,007
Total assets	617,872	585,391
Liabilities and stockholders' equity
Total Homebuilding	2,229,648	1,779,708
Homebuilding [Member] | Guarantor Subsidiaries
Assets
Cash and cash equivalents	41,316	54,205
Total assets	2,517,800	1,939,783
Liabilities and stockholders' equity
Total Homebuilding	330,945	299,032
Homebuilding [Member] | Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	11,932	13,553
Total assets	47,923	32,069
Liabilities and stockholders' equity
Total Homebuilding	94,363	102,964
Homebuilding [Member] | Consolidating Adjustments
Assets
Cash and cash equivalents	0	0
Total assets	0	0
Liabilities and stockholders' equity
Total Homebuilding	0	0
Financial services [Member]
Assets
Cash and cash equivalents	2,428	923	3,024
Receivables	2,084	1,859
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	5,490	1,630
Other assets	38	43
Total assets	10,040	4,455
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	2,593	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	10,040	4,455
Financial services [Member] | Consolidating Adjustments
Assets
Total assets	$ 0	$ 0