Supplemental Guarantor Information (Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands		May 31, 2017	Nov. 30, 2016	May 31, 2016	Nov. 30, 2015
Assets
Cash and Cash Equivalents, at Carrying Value		$ 349,372	$ 593,000	$ 276,549	$ 560,341
Receivables		234,712	231,665
Inventory, Operative Builders		3,488,204	3,403,228
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		64,000	64,016
Deferred tax assets, net		711,885	738,985
Other assets		99,996	91,145
Investments in and Advances to Affiliates, Amount of Equity		0	0
Total assets		4,958,795	5,131,624
Due from Affiliates		0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		674,829	766,327
Mortgages and notes payable		2,510,121	2,640,149
Financial services		1,457	2,003
Due to Affiliate		0	0
Stockholders' equity		1,772,388	1,723,145
Total liabilities and stockholders’ equity		4,958,795	5,131,624
KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value		297,258	463,100	195,383	444,850
Receivables		4,293	4,807
Inventory, Operative Builders		0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		0	0
Deferred tax assets, net		275,558	276,737
Other assets		88,133	79,526
Investments in and Advances to Affiliates, Amount of Equity		40,811	35,965
Total assets		4,372,920	4,419,147
Due from Affiliates		3,666,867	3,559,012
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		129,689	131,530
Mortgages and notes payable		2,451,564	2,548,112
Financial services		0	0
Due to Affiliate		19,279	16,360
Stockholders' equity		1,772,388	1,723,145
Total liabilities and stockholders’ equity		4,372,920	4,419,147
Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		42,386	100,439	62,846	96,741
Receivables		145,851	135,915
Inventory, Operative Builders		3,147,848	3,048,132
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		61,499	61,517
Deferred tax assets, net		292,017	318,077
Other assets		8,498	9,177
Investments in and Advances to Affiliates, Amount of Equity		0	0
Total assets		3,698,099	3,673,257
Due from Affiliates		0	0
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		329,052	397,605
Mortgages and notes payable		32,527	66,927
Financial services		0	0
Due to Affiliate		3,336,520	3,208,725
Stockholders' equity		0	0
Total liabilities and stockholders’ equity		3,698,099	3,673,257
Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		9,728	29,461	18,320	18,750
Receivables		84,568	90,943
Inventory, Operative Builders		340,356	355,096
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		2,501	2,499
Deferred tax assets, net		144,310	144,171
Other assets		3,365	2,442
Investments in and Advances to Affiliates, Amount of Equity		0	0
Total assets		695,813	731,259
Due from Affiliates		100,359	97,062
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		216,088	237,192
Mortgages and notes payable		26,030	25,110
Financial services		1,457	2,003
Due to Affiliate		411,427	430,989
Stockholders' equity		40,811	35,965
Total liabilities and stockholders’ equity		695,813	731,259
Homebuilding [Member]
Assets
Cash and Cash Equivalents, at Carrying Value		348,588	592,086	274,849
Total assets		4,947,385	5,121,125
Liabilities and stockholders' equity
Total Liabilities Homebuilding		3,184,950	3,406,476
Homebuilding [Member] | KB Home Corporate
Assets
Cash and Cash Equivalents, at Carrying Value		297,258	463,100
Total assets		665,242	824,170
Liabilities and stockholders' equity
Total Liabilities Homebuilding		2,581,253	2,679,642
Homebuilding [Member] | Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		42,386	100,439
Total assets		3,698,099	3,673,257
Liabilities and stockholders' equity
Total Liabilities Homebuilding		361,579	464,532
Homebuilding [Member] | Non-Guarantor Subsidiaries
Assets
Cash and Cash Equivalents, at Carrying Value		8,944	28,547
Total assets		584,044	623,698
Liabilities and stockholders' equity
Total Liabilities Homebuilding		242,118	262,302
Financial services [Member]
Assets
Cash and Cash Equivalents, at Carrying Value		784	914	1,700
Receivables		1,622	1,764
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	[1]	8,972	7,771
Other assets		32	50
Total assets		11,410	10,499
Liabilities and stockholders' equity
Accounts payable, accrued expenses and other liabilities		1,457	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		11,410	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		(40,811)	(35,965)
Total assets		(3,808,037)	(3,692,039)
Due from Affiliates		(3,767,226)	(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		(3,767,226)	(3,656,074)
Stockholders' equity		(40,811)	(35,965)
Total liabilities and stockholders’ equity		(3,808,037)	(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 May 31, 2017 included a $5.3 million capital contribution we made to KBHS in the 2017 first quarter, and a $5.0 million distribution we received from HCM in the 2017 second quarter.