Income Taxes - Narrative (Details) (USD $)	Mar. 31, 2015	Sep. 30, 2014
Income Tax Disclosure [Line Items]
Uncertain tax positions reasonably possible to reverse in next twelve months	$ 3,200,000
Accrued interest and penalties	400,000	400,000
Limit on operating loss carryforwards and recognition	11,400,000
Limit on operating loss carryforwards and recognition, tax-effected	4,000,000
Total deferred tax assets	477,071,000us-gaap_DeferredTaxAssetsGross
Deferred tax liabilities	(43,496,000)us-gaap_DeferredTaxLiabilities
Net deferred tax assets before valuation allowance	433,575,000bzh_NetDeferredTaxAssetGross
Valuation allowance	433,529,000	445,200,000
Net deferred tax assets	46,000us-gaap_DeferredTaxAssetsLiabilitiesNet
Maximum
Income Tax Disclosure [Line Items]
Limit on operating loss carryforwards and recognition	392,700,000
Limit on operating loss carryforwards and recognition, tax-effected	425,600,000
Certain Components Likely To Be Subject To Annual Limitation
Income Tax Disclosure [Line Items]
Total deferred tax assets	40,905,000
Certain Components Likely To Be Subject To Annual Limitation \| Maximum
Income Tax Disclosure [Line Items]
Net deferred tax assets	40,900,000
Certain Components Likely To Be Subject To Annual Limitation \| Minimum
Income Tax Disclosure [Line Items]
Net deferred tax assets	7,900,000
Subject To Annual Limitation
Income Tax Disclosure [Line Items]
Total deferred tax assets	102,207,000
Generally Not Subject to Annual Limitation
Income Tax Disclosure [Line Items]
Total deferred tax assets	$ 333,959,000

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Net Deferred Tax Asset, Gross - Net deferred tax asset (net of liabilities) before valuation allowance

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Operating Loss Carryforwards and Recognition, Limitations on Use

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Operating Loss Carryforwards And Recognition Limitations On Use, Tax-effected

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

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-Glossary Deferred Tax Asset

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

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-Paragraph 2

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The current portion of the amount recognized for uncertain tax positions as of the balance sheet date.

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-Topic 210

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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-Name Accounting Standards Codification

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-Paragraph 15

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