Supplemental Guarantor Information (Condensed Consolidated Statements of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Feb. 28, 2015	Feb. 28, 2014
Condensed Consolidated Statements of Operations
Revenues	$ 580,121us-gaap_Revenues	$ 450,687us-gaap_Revenues
Homebuilding:
Revenues	577,888us-gaap_HomeBuildingRevenue	448,267us-gaap_HomeBuildingRevenue
Construction and land costs	(492,418)us-gaap_ConstructionAndDevelopmentCosts	(369,274)us-gaap_ConstructionAndDevelopmentCosts
Selling, general and administrative expenses	(71,072)	(61,274)
Operating income (loss)	14,398us-gaap_OperatingIncomeLoss	17,719us-gaap_OperatingIncomeLoss
Interest income	103us-gaap_InvestmentIncomeInterest	168us-gaap_InvestmentIncomeInterest
Interest expense	(5,338)us-gaap_InterestExpense	(11,276)us-gaap_InterestExpense
Intercompany Interest Income (Expense)	0kbh_IntercompanyInterestIncomeExpense	0kbh_IntercompanyInterestIncomeExpense
Equity in income (loss) of unconsolidated joint ventures	67	2,584
Total pretax income (loss)	10,499	10,763
Income tax expense	(2,700)us-gaap_IncomeTaxExpenseBenefit	(200)us-gaap_IncomeTaxExpenseBenefit
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net income	7,799us-gaap_NetIncomeLoss	10,563us-gaap_NetIncomeLoss
KB Home Corporate
Condensed Consolidated Statements of Operations
Revenues	0	0
Homebuilding:
Revenues	0	0
Construction and land costs	0	0
Selling, general and administrative expenses	(15,672)	(15,744)
Operating income (loss)	(15,672)	(15,744)
Interest income	101	167
Interest expense	(43,580)	(38,008)
Intercompany Interest Income (Expense)	70,468	59,722
Total pretax income (loss)	11,317	6,137
Income tax expense	200	0
Income (Loss) from Subsidiaries, Net of Tax	(3,718)	4,426
Net income	7,799	10,563
Guarantor Subsidiaries
Condensed Consolidated Statements of Operations
Revenues	534,276	392,178
Homebuilding:
Revenues	534,276	392,178
Construction and land costs	(451,140)	(321,352)
Selling, general and administrative expenses	(48,504)	(37,081)
Operating income (loss)	34,632	33,745
Interest income	1	1
Interest expense	(1,460)	(1,272)
Intercompany Interest Income (Expense)	(28,406)	(30,074)
Total pretax income (loss)	4,420	1,697
Income tax expense	(3,100)	(200)
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net income	1,320	1,497
Non-Guarantor Subsidiaries
Condensed Consolidated Statements of Operations
Revenues	45,845	58,509
Homebuilding:
Revenues	43,612	56,089
Construction and land costs	(41,278)	(47,922)
Selling, general and administrative expenses	(6,896)	(8,449)
Operating income (loss)	(4,562)	(282)
Interest income	1	0
Interest expense	0	0
Intercompany Interest Income (Expense)	(2,360)	(1,644)
Total pretax income (loss)	(5,238)	2,929
Income tax expense	200	0
Income (Loss) from Subsidiaries, Net of Tax	0	0
Net income	(5,038)	2,929
Consolidating Adjustments
Condensed Consolidated Statements of Operations
Revenues	0	0
Homebuilding:
Revenues	0	0
Construction and land costs	0	0
Selling, general and administrative expenses	0	0
Operating income (loss)	0	0
Interest income	0	0
Interest expense	39,702	28,004
Intercompany Interest Income (Expense)	(39,702)	(28,004)
Total pretax income (loss)	0	0
Income tax expense	0	0
Income (Loss) from Subsidiaries, Net of Tax	3,718	(4,426)
Net income	3,718	(4,426)
Homebuilding [Member]
Condensed Consolidated Statements of Operations
Revenues	577,888	448,267
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	(347)	2,590
Total pretax income (loss)	8,816	9,201
Homebuilding [Member] \| KB Home Corporate
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	0	0
Total pretax income (loss)	11,317	6,137
Homebuilding [Member] \| Guarantor Subsidiaries
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	(347)	(703)
Total pretax income (loss)	4,420	1,697
Homebuilding [Member] \| Non-Guarantor Subsidiaries
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	0	3,293
Total pretax income (loss)	(6,921)	1,367
Homebuilding [Member] \| Consolidating Adjustments
Homebuilding:
Equity in income (loss) of unconsolidated joint ventures	0	0
Total pretax income (loss)	0	0
Financial services [Member]
Condensed Consolidated Statements of Operations
Revenues	2,233	2,420
Homebuilding:
Operating income (loss)	1,269	1,568
Equity in income (loss) of unconsolidated joint ventures	414	(6)
Total pretax income (loss)	1,683	1,562
Financial services [Member] \| KB Home Corporate
Homebuilding:
Total pretax income (loss)	0	0
Financial services [Member] \| Guarantor Subsidiaries
Homebuilding:
Total pretax income (loss)	0	0
Financial services [Member] \| Non-Guarantor Subsidiaries
Homebuilding:
Total pretax income (loss)	1,683	1,562
Financial services [Member] \| Consolidating Adjustments
Homebuilding:
Total pretax income (loss)	$ 0	$ 0

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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