Supplemental Guarantor Information (Condensed Consolidated Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Nov. 30, 2011
Condensed Consolidated Statements of Cash Flows
Net cash provided by (used in) operating activities	$ (443,486)	$ 34,617	$ (347,545)
Cash flows from investing activities:
Return of investment in (contributions to) unconsolidated joint ventures	(14,359)	989	(67,260)
Proceeds from sale of operating property	0	0	80,600
Purchases of property and equipment, net	(2,391)	(1,749)	(242)
Intercompany	0	0	0
Net cash provided by (used in) investing activities	(16,750)	(760)	13,098
Cash flows from financing activities:
Change in restricted cash	456	22,119	50,996
Proceeds from issuance of senior notes	680,000	694,831	0
Payment of senior notes issuance costs	(16,525)	(12,445)	0
Repayments of Long-term Debt	(225,394)	(592,645)	(100,000)
Payments on mortgages and land contracts due to land sellers and other loans	(66,296)	(26,298)	(89,461)
Proceeds from Issuance or Sale of Equity	109,503	0	0
Issuance of common stock under employee stock plans	2,181	593	1,796
Payments of cash dividends	(8,366)	(10,599)	(19,240)
Repurchases of common stock	(8,488)	(1,799)	0
Intercompany	0	0	0
Net cash provided by (used in) financing activities	467,071	73,757	(155,909)
Net increase (decrease) in cash and cash equivalents	6,835	107,614	(490,356)
Cash and cash equivalents at beginning of year	525,688	418,074	908,430
Cash and cash equivalents at end of year	532,523	525,688	418,074
KB Home Corporate
Condensed Consolidated Statements of Cash Flows
Net cash provided by (used in) operating activities	4,695	11,033	9,443
Cash flows from investing activities:
Return of investment in (contributions to) unconsolidated joint ventures	0	0	0
Proceeds from sale of operating property			0
Purchases of property and equipment, net	(519)	(175)	(200)
Intercompany	(517,703)	5,137	(349,081)
Net cash provided by (used in) investing activities	(518,222)	4,962	(349,281)
Cash flows from financing activities:
Change in restricted cash	456	22,119	24,239
Proceeds from issuance of senior notes	680,000	694,831
Payment of senior notes issuance costs	(16,525)	(12,445)
Repayments of Long-term Debt	(225,394)	(592,645)	(100,000)
Payments on mortgages and land contracts due to land sellers and other loans	0	0	3,397
Proceeds from Issuance or Sale of Equity	109,503
Issuance of common stock under employee stock plans	2,181	593	1,796
Payments of cash dividends	(8,366)	(10,599)	(19,240)
Repurchases of common stock	(8,488)	(1,799)
Intercompany	0	0	0
Net cash provided by (used in) financing activities	533,367	100,055	(89,808)
Net increase (decrease) in cash and cash equivalents	19,840	116,050	(429,646)
Cash and cash equivalents at beginning of year	457,007	340,957	770,603
Cash and cash equivalents at end of year	476,847	457,007	340,957
Guarantor Subsidiaries
Condensed Consolidated Statements of Cash Flows
Net cash provided by (used in) operating activities	(441,236)	4,943	(355,165)
Cash flows from investing activities:
Return of investment in (contributions to) unconsolidated joint ventures	(9,368)	1,922	(78,619)
Proceeds from sale of operating property			80,600
Purchases of property and equipment, net	(1,491)	(1,540)	(649)
Intercompany	0	0	0
Net cash provided by (used in) investing activities	(10,859)	382	1,332
Cash flows from financing activities:
Change in restricted cash	0	0	26,757
Proceeds from issuance of senior notes	0	0
Payment of senior notes issuance costs	0	0
Repayments of Long-term Debt	0	0	0
Payments on mortgages and land contracts due to land sellers and other loans	(66,296)	(26,298)	(89,461)
Proceeds from Issuance or Sale of Equity	0
Issuance of common stock under employee stock plans	0	0	0
Payments of cash dividends	0	0	0
Repurchases of common stock	0	0
Intercompany	(505,502)	(22,915)	(443,698)
Net cash provided by (used in) financing activities	439,206	(3,383)	380,994
Net increase (decrease) in cash and cash equivalents	(12,889)	1,942	27,161
Cash and cash equivalents at beginning of year	54,205	52,263	25,102
Cash and cash equivalents at end of year	41,316	54,205	52,263
Non-Guarantor Subsidiaries
Condensed Consolidated Statements of Cash Flows
Net cash provided by (used in) operating activities	(6,945)	18,641	(1,823)
Cash flows from investing activities:
Return of investment in (contributions to) unconsolidated joint ventures	(4,991)	(933)	11,359
Proceeds from sale of operating property			0
Purchases of property and equipment, net	(381)	(34)	607
Intercompany	0	0	0
Net cash provided by (used in) investing activities	(5,372)	(967)	11,966
Cash flows from financing activities:
Change in restricted cash	0	0	0
Proceeds from issuance of senior notes	0	0
Payment of senior notes issuance costs	0	0
Repayments of Long-term Debt	0	0	0
Payments on mortgages and land contracts due to land sellers and other loans	0	0	(3,397)
Proceeds from Issuance or Sale of Equity	0
Issuance of common stock under employee stock plans	0	0	0
Payments of cash dividends	0	0	0
Repurchases of common stock	0	0
Intercompany	(12,201)	(28,052)	(94,617)
Net cash provided by (used in) financing activities	12,201	(28,052)	(98,014)
Net increase (decrease) in cash and cash equivalents	(116)	(10,378)	(87,871)
Cash and cash equivalents at beginning of year	14,476	24,854	112,725
Cash and cash equivalents at end of year	14,360	14,476	24,854
Consolidating Adjustments
Condensed Consolidated Statements of Cash Flows
Net cash provided by (used in) operating activities	0	0	0
Cash flows from investing activities:
Return of investment in (contributions to) unconsolidated joint ventures	0	0	0
Proceeds from sale of operating property			0
Purchases of property and equipment, net	0	0	0
Intercompany	517,703	(5,137)	349,081
Net cash provided by (used in) investing activities	517,703	(5,137)	349,081
Cash flows from financing activities:
Change in restricted cash	0	0	0
Proceeds from issuance of senior notes	0	0
Payment of senior notes issuance costs	0	0
Repayments of Long-term Debt	0	0	0
Payments on mortgages and land contracts due to land sellers and other loans	0	0	0
Proceeds from Issuance or Sale of Equity	0
Issuance of common stock under employee stock plans	0	0	0
Payments of cash dividends	0	0	0
Repurchases of common stock	0	0
Intercompany	517,703	(5,137)	349,081
Net cash provided by (used in) financing activities	(517,703)	5,137	(349,081)
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	$ 0	$ 0	$ 0