Contingencies - Narrative (Details) $ in Thousands	12 Months Ended			15 Months Ended
	Sep. 30, 2015 USD ($) home Community	Sep. 30, 2014 USD ($) home	Sep. 30, 2013 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2012 USD ($)
Loss Contingencies [Line Items]
Limited Product Warranty Length	5 years
Standard Product Warranty Accrual	$ 27,681	$ 16,084	$ 11,663	$ 27,681	$ 15,477
Insurance Recoveries	18,900
InsuranceReimbursements	11,100
InsuranceReceivableNet	$ 7,800			$ 7,800
Company's Liability Under Deferred Prosecution Agreement, Percentage of Company's Adjusted EBITDA	4.00%			4.00%
Loss Contingency, Range of Possible Loss, Maximum	$ 48,000			$ 48,000
Loss Contingency, Damages Paid, Value	22,700
Accrued amounts for litigation and other contingent liabilities	12,600	13,400		12,600
Loss Contingency Accrual, Provision	5,300	$ 5,400	$ 3,500
DPA Liability
Loss Contingencies [Line Items]
Accrued amounts for litigation and other contingent liabilities	$ 7,400			7,400
FLORIDA
Loss Contingencies [Line Items]
Homes Likely to Require More than Minor Repairs | home	532	135
Product Warranty Accrual, Warranties Issued		$ 4,300
Homes Repaired During Period | home	163	11
Product Warranty Accrual, Payments	$ (15,800)	$ 300
Standard Product Warranty Accrual	14,500	$ 4,000		14,500
Number of Homes Requiring More than Minor Repairs Accounted for in Warranty Liability | home		124
Insurance Recoveries	$ 12,700
Specific Warranty Issue
Loss Contingencies [Line Items]
Product Warranty Expense				31,200
Specific Warranty Issue | FLORIDA
Loss Contingencies [Line Items]
Product Warranty Expense				30,600
Specific Warranty Issue | NEW JERSEY
Loss Contingencies [Line Items]
Product Warranty Expense				600
Number of Communities With Water Intrusion Issues | Community	1
Average Age of Specific Issue Warranty	8 years
Performance Bonds
Loss Contingencies [Line Items]
Letters of credit secured using cash collateral	$ 43,100			43,100
Cash collateral in restricted accounts securing letters of credit	$ 201,300			$ 201,300
Minimum
Loss Contingencies [Line Items]
Standard product warranty period	1 year
Maximum
Loss Contingencies [Line Items]
Standard product warranty period	2 years