Supplemental Guarantor Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2012
Assets
Cash and cash equivalents	$ 560,341	$ 358,768	$ 532,523	$ 525,688
Restricted cash	9,344	27,235
Receivables	152,682	125,488
Inventory, Operative Builders	3,313,747	3,218,387
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	71,558	79,441
Deferred tax assets, net	782,196	825,232
Other assets	112,774	114,915
Investments in subsidiaries	0	0
Total assets	5,015,371	4,757,550
Due from Affiliates	0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	697,184	582,598
Notes payable	2,625,536	2,576,525
Financial services	1,817	2,517
Due to Affiliate	0	0
Stockholder's equity	1,690,834	1,595,910	536,086	376,806
Total liabilities and Stockholders' equity	5,015,371	4,757,550
KB Home Corporate
Assets
Cash and cash equivalents	444,850	303,280	476,847	457,007
Restricted cash	9,344	27,235
Receivables	39	15
Inventory, Operative Builders	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Deferred tax assets, net	190,770	215,923
Other assets	97,590	99,099
Investments in subsidiaries	39,383	39,356
Total assets	4,409,126	4,267,520
Due from Affiliates	3,627,150	3,582,612
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	136,352	138,298
Notes payable	2,564,762	2,513,165
Financial services	0	0
Due to Affiliate	17,178	20,147
Stockholder's equity	1,690,834	1,595,910
Total liabilities and Stockholders' equity	4,409,126	4,267,520
Guarantor Subsidiaries
Assets
Cash and cash equivalents	98,281	37,112	37,957	49,218
Restricted cash	0	0
Receivables	148,338	120,857
Inventory, Operative Builders	2,979,617	2,847,415
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	69,057	76,940
Deferred tax assets, net	501,454	552,653
Other assets	11,783	13,136
Investments in subsidiaries	0	0
Total assets	3,808,530	3,648,113
Due from Affiliates	0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	442,529	317,550
Notes payable	60,774	63,360
Financial services	0	0
Due to Affiliate	3,305,227	3,267,203
Stockholder's equity	0	0
Total liabilities and Stockholders' equity	3,808,530	3,648,113
Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	17,210	18,376	17,719	19,463
Restricted cash	0	0
Receivables	4,305	4,616
Inventory, Operative Builders	334,130	370,972
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	2,501	2,501
Deferred tax assets, net	89,972	56,656
Other assets	3,401	2,680
Investments in subsidiaries	0	0
Total assets	566,351	576,804
Due from Affiliates	102,103	112,919
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	118,303	126,750
Notes payable	0	0
Financial services	1,817	2,517
Due to Affiliate	406,848	408,181
Stockholder's equity	39,383	39,356
Total liabilities and Stockholders' equity	566,351	576,804
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
Deferred tax assets, net	0	0
Other assets	0	0
Investments in subsidiaries	(39,383)	(39,356)
Total assets	(3,768,636)	(3,734,887)
Due from Affiliates	(3,729,253)	(3,695,531)
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	0	0
Notes payable	0	0
Financial services	0	0
Due to Affiliate	(3,729,253)	(3,695,531)
Stockholder's equity	(39,383)	(39,356)
Total liabilities and Stockholders' equity	(3,768,636)	(3,734,887)
Homebuilding [Member]
Assets
Cash and cash equivalents	559,042	356,366	530,095
Total assets	5,001,343	4,747,064
Liabilities and stockholders' equity
Total Homebuilding	3,322,720	3,159,123
Homebuilding [Member] | KB Home Corporate
Assets
Cash and cash equivalents	444,850	303,280
Total assets	742,593	645,552
Liabilities and stockholders' equity
Total Homebuilding	2,701,114	2,651,463
Homebuilding [Member] | Guarantor Subsidiaries
Assets
Cash and cash equivalents	98,281	37,112
Total assets	3,808,530	3,648,113
Liabilities and stockholders' equity
Total Homebuilding	503,303	380,910
Homebuilding [Member] | Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	15,911	15,974
Total assets	450,220	453,399
Liabilities and stockholders' equity
Total Homebuilding	118,303	126,750
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	1,299	2,402	$ 2,428
Receivables	2,245	1,738
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	10,440	6,149
Other assets	44	197
Total assets	14,028	10,486
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities	1,817	2,517
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	14,028	10,486
Financial services [Member] | Consolidating Adjustments
Assets
Total assets	$ 0	$ 0