Supplemental Guarantor Information (Condensed Consolidated Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2014	Nov. 30, 2013	May 31, 2013	Nov. 30, 2012
Assets
Cash and Cash Equivalents, at Carrying Value	$ 487,270	$ 532,523	$ 541,206	$ 525,688
Restricted cash	44,237	41,906
Receivables	99,779	75,749
Inventory, Operative Builders	3,006,118	2,298,577
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	67,594	130,192
Other assets	116,558	107,076
Intercompany Receivables	0	0
Investments in and Advances to Affiliates, Amount of Equity	0	0
Total assets	3,828,026	3,193,635
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	542,519	504,458
Mortgages and notes payable	2,573,980	2,150,498
Financial services	1,854	2,593
Intercompany	0	0
Stockholders' equity	709,673	536,086	470,816	376,806
Total liabilities and stockholders’ equity	3,828,026	3,193,635
KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value	412,811	476,847	480,655	457,007
Restricted cash	44,237	41,906
Receivables	1,464	1,472
Inventory, Operative Builders	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	102,898	97,647
Intercompany Receivables	2,779,476	2,129,729
Investments in and Advances to Affiliates, Amount of Equity	39,620	39,955
Total assets	3,380,506	2,787,556
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	137,208	117,875
Mortgages and notes payable	2,512,454	2,111,773
Financial services	0	0
Intercompany	21,171	21,822
Stockholders' equity	709,673	536,086
Total liabilities and stockholders’ equity	3,380,506	2,787,556
Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	67,208	41,316	51,467	54,205
Restricted cash	0	0
Receivables	97,956	74,186
Inventory, Operative Builders	2,963,356	2,263,034
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	67,594	130,192
Other assets	12,334	9,072
Intercompany Receivables	0	0
Investments in and Advances to Affiliates, Amount of Equity	0	0
Total assets	3,208,448	2,517,800
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	311,139	292,220
Mortgages and notes payable	61,526	38,725
Financial services	0	0
Intercompany	2,835,783	2,186,855
Stockholders' equity	0	0
Total liabilities and stockholders’ equity	3,208,448	2,517,800
Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	7,251	14,360	9,084	14,476
Restricted cash	0	0
Receivables	359	91
Inventory, Operative Builders	42,762	35,543
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	1,326	357
Intercompany Receivables	115,848	117,829
Investments in and Advances to Affiliates, Amount of Equity	0	0
Total assets	174,016	175,792
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	94,172	94,363
Mortgages and notes payable	0	0
Financial services	1,854	2,593
Intercompany	38,370	38,881
Stockholders' equity	39,620	39,955
Total liabilities and stockholders’ equity	174,016	175,792
Consolidating Adjustments
Assets
Cash and Cash Equivalents, at Carrying Value	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
Intercompany Receivables	(2,895,324)	(2,247,558)
Investments in and Advances to Affiliates, Amount of Equity	(39,620)	(39,955)
Total assets	(2,934,944)	(2,287,513)
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	0	0
Mortgages and notes payable	0	0
Financial services	0	0
Intercompany	(2,895,324)	(2,247,558)
Stockholders' equity	(39,620)	(39,955)
Total liabilities and stockholders’ equity	(2,934,944)	(2,287,513)
Homebuilding [Member]
Assets
Cash and Cash Equivalents, at Carrying Value	484,472	530,095	538,571
Total assets	3,818,758	3,183,595
Liabilities and stockholders' equity
Total Liabilities Homebuilding	3,116,499	2,654,956
Homebuilding [Member] | KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value	412,811	476,847
Total assets	561,410	617,872
Liabilities and stockholders' equity
Total Liabilities Homebuilding	2,649,662	2,229,648
Homebuilding [Member] | Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	67,208	41,316
Total assets	3,208,448	2,517,800
Liabilities and stockholders' equity
Total Liabilities Homebuilding	372,665	330,945
Homebuilding [Member] | Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value	4,453	11,932
Total assets	48,900	47,923
Liabilities and stockholders' equity
Total Liabilities Homebuilding	94,172	94,363
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	2,798	2,428	2,635
Receivables	764	2,084
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	5,477	5,490
Other assets	229	38
Total assets	9,268	10,040
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	1,854	2,593
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	9,268	10,040
Financial services [Member] | Consolidating Adjustments
Assets
Total assets	$ 0	$ 0