Inventory Impairments and Land Option Contract Abandonments (Narratives) (Details)	3 Months Ended
Feb. 28, 2018 USD ($) property lot delivery	Feb. 28, 2017 USD ($) property delivery	Nov. 30, 2017 USD ($) property
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impairment of Real Estate	$ 4,699,000	$ 3,217,000
Number of land parcels or communities evaluated for recoverability \| property	29	39
Carrying Value of Communities or Land Parcels Evaluated for Impairment	$ 200,100,000	$ 366,400,000
Aggregate carrying value of inventory impacted by pretax, noncash inventory impairment charges	$ 178,400,000		$ 177,800,000
Number of communities and various other land parcels impacted by pretax, noncash inventory impairment charges	20		24
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Estimate Input at Average Selling Price	$ 774,100	$ 307,900
Fair Value Estimate Input, Delivery For Period \| delivery	3	4
Fair Value Inputs, Discount Rate	18.00%	17.00%
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Estimate Input at Average Selling Price	$ 774,100	$ 299,800
Fair Value Estimate Input, Delivery For Period \| delivery	3	3
Fair Value Inputs, Discount Rate	18.00%	17.00%
Land Option Contract Abandonment [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Payments to Acquire Land	$ (286,000)	$ (791,000)
West Coast [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impairment of Real Estate	4,699,000	0
West Coast [Member] \| Land Option Contract Abandonment [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Payments to Acquire Land	(208,000)	(791,000)
Central [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impairment of Real Estate	0	0
Central [Member] \| Land Option Contract Abandonment [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Payments to Acquire Land	(78,000)	0
Southeast [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impairment of Real Estate	0	1,874,000
Southeast [Member] \| Land Option Contract Abandonment [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Payments to Acquire Land	$ 0	$ 0

Aggregate carrying value of inventory impacted by pretax, noncash inventory impairment charges.

No definition available.

Name:	kbh_AggregateCarryingValueOfInventoryImpactedByPretaxNoncashInventoryImpairmentCharges
Namespace Prefix:	kbh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying Value of Communities or Land Parcels Evaluated for Impairment

+ References

No definition available.

+ Details

Name:	kbh_CarryingValueofCommunitiesorLandParcelsEvaluatedforImpairment
Namespace Prefix:	kbh_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value estimate input, average selling price

+ References

No definition available.

+ Details

Name:	kbh_FairValueEstimateInputAverageSellingPrice
Namespace Prefix:	kbh_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value estimate input, delivery for period

+ References

No definition available.

+ Details

Name:	kbh_FairValueEstimateInputDeliveryForPeriod
Namespace Prefix:	kbh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of communities and various other land parcels impacted by pretax, noncash inventory impairment charges.

+ References

No definition available.

+ Details

Name:	kbh_NumberOfCommunitiesAndVariousOtherLandParcelsImpactedByPretaxNoncashInventoryImpairmentCharges
Namespace Prefix:	kbh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of land parcels or communities evaluated for recoverability.

+ References

No definition available.

+ Details

Name:	kbh_NumberOfLandParcelsOrCommunitiesEvaluatedForRecoverability
Namespace Prefix:	kbh_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The charge against earnings in the period to reduce the carrying amount of real property to fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2921-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

Name:	us-gaap_ImpairmentOfRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The loss recognized on termination of a contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 912
-SubTopic 275
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84167019&loc=d3e54681-109401

+ Details

Name:	us-gaap_LossOnContractTermination
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=kbh_LandOptionContractAbandonmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=kbh_WestCoastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=kbh_CentralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementGeographicalAxis=kbh_SoutheastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: