Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Supplemental disclosure of non-cash activity:
Decrease in obligations related to land not owned under option agreements	$ 0	$ (2,916)	$ (1,717)
Decrease in debt related to conversion of Mandatory Convertible Subordinated Notes and Tangible Equity Units for common stock	0	0	(2,376)
Sale of interest in REIT for shares of AMH	0	0	26,040
Purchase of AMH shares in exchange for interest in REIT	0	0	(26,040)
Non-cash land acquisitions	8,265	12,904	20,274
Issuance of stock under deferred bonus stock plans	0	0	103
Non-cash capital expenditure	0	674	0
Supplemental disclosure of cash activity:
Interest payments	131,730	117,177	117,501
Income tax payments	1,420	942	212
Tax refunds received	$ 201	0	$ 33,271
Non-cash seller financing		7,800
Lot takedown costs		$ 5,100