Supplemental Guarantor Information (Condensed Consolidating Statements of Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Nov. 30, 2015	Aug. 31, 2015	May. 31, 2015	Feb. 28, 2015	Nov. 30, 2014	Aug. 31, 2014	May. 31, 2014	Feb. 28, 2014	Nov. 30, 2015	Nov. 30, 2014	Nov. 30, 2013
Net income (loss)	$ 44,017	$ 23,254	$ 9,573	$ 7,799	$ 852,801	$ 28,361	$ 26,624	$ 10,563	$ 84,643	$ 918,349	$ 39,963
Other Comprehensive Income (Loss), before Reclassifications, before Tax									6,149	(1,888)	10,442
Other Comprehensive Income (Loss), before Tax									6,149	(1,888)	10,442
Income tax expense related to items of other comprehensive income									(2,460)	(1,604)	0
Other comprehensive income (loss), net of tax									3,689	(3,492)	10,442
Comprehensive income									88,332	914,857	50,405
KB Home Corporate
Net income (loss)									84,643	918,349	39,963
Other Comprehensive Income (Loss), before Reclassifications, before Tax									6,149	(1,888)	10,442
Other Comprehensive Income (Loss), before Tax									6,149	(1,888)
Income tax expense related to items of other comprehensive income									(2,460)	(1,604)
Other comprehensive income (loss), net of tax									3,689	(3,492)	10,442
Comprehensive income									88,332	914,857	50,405
Guarantor Subsidiaries
Net income (loss)									70,719	596,269	51,239
Other Comprehensive Income (Loss), before Reclassifications, before Tax									0	0	0
Other Comprehensive Income (Loss), before Tax									0	0
Income tax expense related to items of other comprehensive income									0	0
Other comprehensive income (loss), net of tax									0	0	0
Comprehensive income									70,719	596,269	51,239
Non-Guarantor Subsidiaries
Net income (loss)									(11,500)	53,142	(10,793)
Other Comprehensive Income (Loss), before Reclassifications, before Tax									0	0	0
Other Comprehensive Income (Loss), before Tax									0	0
Income tax expense related to items of other comprehensive income									0	0
Other comprehensive income (loss), net of tax									0	0	0
Comprehensive income									(11,500)	53,142	(10,793)
Consolidating Adjustments
Net income (loss)									(59,219)	(649,411)	(40,446)
Other Comprehensive Income (Loss), before Reclassifications, before Tax									0	0	0
Other Comprehensive Income (Loss), before Tax									0	0
Income tax expense related to items of other comprehensive income									0	0
Other comprehensive income (loss), net of tax									0	0	0
Comprehensive income									$ (59,219)	$ (649,411)	$ (40,446)