Supplemental Guarantor Information (Condensed Consolidated Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Feb. 28, 2015	Feb. 28, 2014
Cash flows from operating activities:
Net cash used in operating activities	$ (48,909)	$ (221,063)
Cash flows from investing activities:
Return of investments in (contributions to) unconsolidated joint ventures	(2,414)	(8,618)
Proceeds from sale of investment in unconsolidated joint venture	0	10,110
Purchases of property and equipment, net	(586)	(1,576)
Intercompany	0	0
Net cash provided by (used in) investing activities	(3,000)	(84)
Cash flows from financing activities:
Change in restricted cash	(749)	(177)
Proceeds from issuance of debt	250,000	0
Payment of debt issuance costs	(2,989)us-gaap_PaymentsOfDebtIssuanceCosts	0us-gaap_PaymentsOfDebtIssuanceCosts
Payments on mortgages and land contracts due to land sellers and other loans	(2,722)	(2,655)
Payments of cash dividends	(2,299)us-gaap_PaymentsOfDividendsCommonStock	(2,094)us-gaap_PaymentsOfDividendsCommonStock
Stock repurchases	(21)	0
Intercompany	0	0
Net cash provided by (used in) financing activities	241,220	(4,926)
Net increase (decrease) in cash and cash equivalents	189,311	(226,073)
Cash and cash equivalents at beginning of period	358,768	532,523
Cash and cash equivalents at end of period	548,079	306,450
KB Home Corporate
Cash flows from operating activities:
Net cash used in operating activities	5,369	25,325
Cash flows from investing activities:
Return of investments in (contributions to) unconsolidated joint ventures	0	0
Proceeds from sale of investment in unconsolidated joint venture		0
Purchases of property and equipment, net	(37)	(70)
Intercompany	(83,524)	(265,597)
Net cash provided by (used in) investing activities	(83,561)	(265,667)
Cash flows from financing activities:
Change in restricted cash	(749)	(177)
Proceeds from issuance of debt	250,000
Payment of debt issuance costs	(2,989)
Payments on mortgages and land contracts due to land sellers and other loans	0	0
Payments of cash dividends	(2,299)	(2,094)
Stock repurchases	(21)
Intercompany	0	0
Net cash provided by (used in) financing activities	243,942	(2,271)
Net increase (decrease) in cash and cash equivalents	165,750	(242,613)
Cash and cash equivalents at beginning of period	303,280	476,847
Cash and cash equivalents at end of period	469,030	234,234
Guarantor Subsidiaries
Cash flows from operating activities:
Net cash used in operating activities	(30,016)	(238,244)
Cash flows from investing activities:
Return of investments in (contributions to) unconsolidated joint ventures	(2,414)	(8,370)
Proceeds from sale of investment in unconsolidated joint venture		0
Purchases of property and equipment, net	(528)	(1,107)
Intercompany	0	0
Net cash provided by (used in) investing activities	(2,942)	(9,477)
Cash flows from financing activities:
Change in restricted cash	0	0
Proceeds from issuance of debt	0
Payment of debt issuance costs	0
Payments on mortgages and land contracts due to land sellers and other loans	(2,722)	(2,655)
Payments of cash dividends	0	0
Stock repurchases	0
Intercompany	66,961	268,173
Net cash provided by (used in) financing activities	64,239	265,518
Net increase (decrease) in cash and cash equivalents	31,281	17,797
Cash and cash equivalents at beginning of period	38,124	39,952
Cash and cash equivalents at end of period	69,405	57,749
Non-Guarantor Subsidiaries
Cash flows from operating activities:
Net cash used in operating activities	(24,262)	(8,144)
Cash flows from investing activities:
Return of investments in (contributions to) unconsolidated joint ventures	0	(248)
Proceeds from sale of investment in unconsolidated joint venture		10,110
Purchases of property and equipment, net	(21)	(399)
Intercompany	0	0
Net cash provided by (used in) investing activities	(21)	9,463
Cash flows from financing activities:
Change in restricted cash	0	0
Proceeds from issuance of debt	0
Payment of debt issuance costs	0
Payments on mortgages and land contracts due to land sellers and other loans	0	0
Payments of cash dividends	0	0
Stock repurchases	0
Intercompany	16,563	(2,576)
Net cash provided by (used in) financing activities	16,563	(2,576)
Net increase (decrease) in cash and cash equivalents	(7,720)	(1,257)
Cash and cash equivalents at beginning of period	17,364	15,724
Cash and cash equivalents at end of period	9,644	14,467
Consolidating Adjustments
Cash flows from operating activities:
Net cash used in operating activities	0	0
Cash flows from investing activities:
Return of investments in (contributions to) unconsolidated joint ventures	0	0
Proceeds from sale of investment in unconsolidated joint venture		0
Purchases of property and equipment, net	0	0
Intercompany	83,524	265,597
Net cash provided by (used in) investing activities	83,524	265,597
Cash flows from financing activities:
Change in restricted cash	0	0
Proceeds from issuance of debt	0
Payment of debt issuance costs	0
Payments on mortgages and land contracts due to land sellers and other loans	0	0
Payments of cash dividends	0	0
Stock repurchases	0
Intercompany	(83,524)	(265,597)
Net cash provided by (used in) financing activities	(83,524)	(265,597)
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	$ 0	$ 0

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3044-108585