Inventory - Summary of Interests in Lot Option Agreements (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014
Real Estate Properties [Line Items]
Deposits and non-refundable preacquisition costs incurred	$ 44,733	$ 43,529
Remaining obligations	380,730	420,534
Land not owned under option agreements	1,443	3,857
Consolidated VIEs
Real Estate Properties [Line Items]
Deposits and non-refundable preacquisition costs incurred	195	941
Remaining obligations	1,248	2,916
Land not owned under option agreements	1,443	3,857
Unconsolidated lot option agreements
Real Estate Properties [Line Items]
Deposits and non-refundable preacquisition costs incurred	44,538	42,588
Remaining obligations	379,482	417,618
Land not owned under option agreements	$ 0	$ 0