Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Supplemental disclosure of non-cash activity:
Decrease in obligations related to land not owned under option agreements	$ (2,916)	$ (1,717)	$ (154)
Decrease in debt related to conversion of Mandatory Convertible Subordinated Notes and Tangible Equity Units for common stock	0	(2,376)	(9,402)
Sale of interest in REIT for shares of AMH	0	26,040	0
Purchase of AMH shares in exchange for interest in REIT	0	(26,040)	0
Non-cash land acquisitions	12,904	20,274	11,000
Issuance of stock under deferred bonus stock plans	0	103	68
Non-cash capital expenditure	674	0	0
Supplemental disclosure of cash activity:
Interest payments	117,177	117,501	102,716
Income tax payments	942	212	403
Tax refunds received	0	$ 33,271	$ 6,730
Non-cash Land Acquisitions, Non-cash Seller Financing	7,800
Non-cash Land Acquisitions, Lot Takedown Costs	$ 5,100