The number of finished lots purchased through a business acquisition.

No definition available.

Name:	dhi_BusinessAcquisitionNumberOfFinishedLotsAcquired
Namespace Prefix:	dhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of homes acquired by the entity through a business acquisition.

+ References

No definition available.

+ Details

Name:	dhi_BusinessAcquisitionNumberofHomesAcquired
Namespace Prefix:	dhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of lots the entity controls through option contracts as a result of a business acquisition.

+ References

No definition available.

+ Details

Name:	dhi_BusinessAcquisitionNumberofLotsUnderOptionContracts
Namespace Prefix:	dhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The sales order backlog (homes) acquired by the entity through a business acquisition.

+ References

No definition available.

+ Details

Name:	dhi_BusinessAcquisitionSalesOrderBacklogAcquiredHomes
Namespace Prefix:	dhi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_BusinessAcquisitionAxis=dhi_WestportHomesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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Subsequent Event Subsequent Event (Details) $ in Millions	3 Months Ended	12 Months Ended
Subsequent Event Subsequent Event (Details) $ in Millions	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Nov. 09, 2018 Lot Home
Subsequent Event [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired \| $		$ 159.2	$ 4.1	$ 82.2
Westport Homes [Member] \| Subsequent Event [Member]
Subsequent Event [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired \| $	$ 190.0
Business Acquisition, Number of Homes Acquired \| Home					400
Business Acquisition, Number of Finished Lots Acquired \| Lot					3,500
Business Acquisition, Number of Lots Under Option Contracts \| Lot					3,200
Business Acquisition, Sales Order Backlog Acquired (Homes) \| Home					550