Supplemental Guarantor Information (Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands		Feb. 28, 2017	Nov. 30, 2016	Feb. 29, 2016	Nov. 30, 2015
Assets
Cash and Cash Equivalents, at Carrying Value		$ 352,450	$ 593,000	$ 324,856	$ 560,341
Receivables		238,358	231,665
Inventory, Operative Builders		3,423,344	3,403,228
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		64,916	64,016
Deferred tax assets, net		731,885	738,985
Other assets		96,679	91,145
Investments in and Advances to Affiliates, Amount of Equity		0	0
Total assets		4,922,580	5,131,624
Due from Affiliates		0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		680,393	766,327
Mortgages and notes payable		2,504,449	2,640,149
Financial services		1,278	2,003
Due to Affiliate		0	0
Stockholders' equity		1,736,460	1,723,145
Total liabilities and stockholders’ equity		4,922,580	5,131,624
KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value		257,656	463,100	257,361	444,850
Receivables		4,833	4,807
Inventory, Operative Builders		0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		0	0
Deferred tax assets, net		277,977	276,737
Other assets		85,433	79,526
Investments in and Advances to Affiliates, Amount of Equity		55,813	35,965
Total assets		4,336,147	4,419,147
Due from Affiliates		3,654,435	3,559,012
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		134,143	131,530
Mortgages and notes payable		2,450,026	2,548,112
Financial services		0	0
Due to Affiliate		15,518	16,360
Stockholders' equity		1,736,460	1,723,145
Total liabilities and stockholders’ equity		4,336,147	4,419,147
Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		83,677	100,439	57,820	96,741
Receivables		143,517	135,915
Inventory, Operative Builders		3,072,225	3,048,132
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		62,417	61,517
Deferred tax assets, net		309,378	318,077
Other assets		8,728	9,177
Investments in and Advances to Affiliates, Amount of Equity		0	0
Total assets		3,679,942	3,673,257
Due from Affiliates		0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		327,181	397,605
Mortgages and notes payable		28,393	66,927
Financial services		0	0
Due to Affiliate		3,302,230	3,208,725
Stockholders' equity		22,138	0
Total liabilities and stockholders’ equity		3,679,942	3,673,257
Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		11,117	29,461	9,675	18,750
Receivables		90,008	90,943
Inventory, Operative Builders		351,119	355,096
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		2,499	2,499
Deferred tax assets, net		144,530	144,171
Other assets		2,518	2,442
Investments in and Advances to Affiliates, Amount of Equity		0	0
Total assets		709,804	731,259
Due from Affiliates		93,065	97,062
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		219,069	237,192
Mortgages and notes payable		26,030	25,110
Financial services		1,278	2,003
Due to Affiliate		429,752	430,989
Stockholders' equity		33,675	35,965
Total liabilities and stockholders’ equity		709,804	731,259
Homebuilding [Member]
Assets
Cash and Cash Equivalents, at Carrying Value		351,880	592,086	323,076
Total assets		4,907,062	5,121,125
Liabilities and stockholders' equity
Total Liabilities Homebuilding		3,184,842	3,406,476
Homebuilding [Member] | KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value		257,656	463,100
Total assets		625,899	824,170
Liabilities and stockholders' equity
Total Liabilities Homebuilding		2,584,169	2,679,642
Homebuilding [Member] | Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		83,677	100,439
Total assets		3,679,942	3,673,257
Liabilities and stockholders' equity
Total Liabilities Homebuilding		355,574	464,532
Homebuilding [Member] | Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		10,547	28,547
Total assets		601,221	623,698
Liabilities and stockholders' equity
Total Liabilities Homebuilding		245,099	262,302
Financial services [Member]
Assets
Cash and Cash Equivalents, at Carrying Value		570	914	1,780
Receivables		1,859	1,764
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	[1]	13,051	7,771
Other assets		38	50
Total assets		15,518	10,499
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		1,278	2,003
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		15,518	10,499
Consolidating Adjustments
Assets
Cash and Cash Equivalents, at Carrying Value		0	0	$ 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 and Advances to Affiliates, Amount of Equity		(55,813)	(35,965)
Total assets		(3,803,313)	(3,692,039)
Due from Affiliates		(3,747,500)	(3,656,074)
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		0	0
Mortgages and notes payable		0	0
Financial services		0	0
Due to Affiliate		(3,747,500)	(3,656,074)
Stockholders' equity		(55,813)	(35,965)
Total liabilities and stockholders’ equity		(3,803,313)	(3,692,039)
Consolidating Adjustments | Homebuilding [Member]
Assets
Cash and Cash Equivalents, at Carrying Value		0	0
Total assets		0	0
Liabilities and stockholders' equity
Total Liabilities Homebuilding		0	0
Consolidating Adjustments | Financial services [Member]
Assets
Total assets		$ 0	$ 0

[1] Our investments in unconsolidated joint ventures as of February 28, 2017 included a $5.3 million capital contribution we made to KBHS in the 2017 first quarter.