Contingencies - Litigation and Other Matters (Details) - Credit Facility [Domain] - USD ($) $ in Millions	3 Months Ended	9 Months Ended	63 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Sep. 30, 2014
Loss Contingencies [Line Items]
Accrued amounts for litigation and other contingent liabilities	$ 11.9	$ 11.9	$ 13.4
Pledged Assets Separately Reported, Securities Pledged for Other Debt Obligations, at Fair Value	$ 217.4	$ 217.4
DPA And HUD
Loss Contingencies [Line Items]
Company's liability under Deferred Prosecution Agreement (percent)	4.00%	4.00%
Maximum liability under the DPA and other settlement agreements	$ 48.0	$ 48.0
Portion of liability under DPA that has been paid as of balance sheet date			$ 22.7
bzh_DeferredProsecutionAgreementAccrual	4.6	4.6
Loss Contingency Accrual, Provision	1.7	2.5
Performance Bonds
Loss Contingencies [Line Items]
Letters of credit secured using cash collateral	$ 41.5	$ 41.5