Inventory - Total Owned Inventory by Segment (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Projects in Progress	$ 1,421,589bzh_InventoryProjectsInProgress	$ 1,204,776bzh_InventoryProjectsInProgress
Land held for future development	270,518us-gaap_LandAvailableForDevelopment	301,048us-gaap_LandAvailableForDevelopment
Land held for sale	64,929us-gaap_InventoryLandHeldForSale	51,672us-gaap_InventoryLandHeldForSale
Total owned inventory	1,757,036us-gaap_InventoryOperativeBuilders	1,557,496us-gaap_InventoryOperativeBuilders
West Segment
Segment Reporting Information [Line Items]
Projects in Progress	576,985	462,508
Land held for future development	230,362	260,898
Land held for sale	10,088	10,026
Total owned inventory	817,435	733,432
East Segment
Segment Reporting Information [Line Items]
Projects in Progress	392,952	353,859
Land held for future development	29,215	29,239
Land held for sale	33,048	34,530
Total owned inventory	455,215	417,628
Southeast Segment
Segment Reporting Information [Line Items]
Projects in Progress	292,380	264,843
Land held for future development	10,941	10,911
Land held for sale	19,931	4,821
Total owned inventory	323,252	280,575
Unallocated and Other
Segment Reporting Information [Line Items]
Projects in Progress	159,272	123,566
Land held for future development	0	0
Land held for sale	1,862	2,295
Total owned inventory	$ 161,134	$ 125,861

Carrying amount as of the balance sheet date of project in progress

No definition available.

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- Definition

Carrying amount as of the balance sheet date of parcels of land held for sale, and on which the entity has no intention or no further intention to perform construction activities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(a))

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph a

-Article 5

+ Details

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- Definition

The net carrying amount as of the balance sheet date of the sum of the various components of an operative builder's inventory, including finished homes. Operative builders primarily consist of entities that develop land, construct residential homes and commercial and industrial buildings thereon, and sell them to home buyers and operators of the commercial and industrial properties.

+ References

+ Details

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- Definition

Carrying amount of land available for development.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a),1(d))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph d

-Article 7

+ Details

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