Contingencies - Warranty (Details) $ in Thousands	3 Months Ended		9 Months Ended		33 Months Ended
	Jun. 30, 2017 USD ($) home	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) home	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) home
Loss Contingencies [Line Items]
Standard product warranty length, minimum			1 year
Standard product warranty length, maximum			2 years
Limited product warranty length (up to)			10 years
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 25,386	$ 40,903	$ 39,131	$ 27,681
Accruals for warranties issued	3,727	3,567	9,549	9,269
Changes in liability related to warranties existing in prior periods	(1,293)	11,148	6,581	41,801
Payments made	(7,998)	(15,028)	(35,439)	(38,161)
Balance at end of period	19,822	40,590	19,822	40,590	$ 19,822
Insurance recoveries	(600)	11,700	5,600	47,900
Excess insurance recovery				3,600
Specific Warranty Issue | Florida
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period			22,600
Balance at end of period	7,200		7,200		7,200
Product warranty expense	$ (100)	11,000	$ 6,000	$ 39,600	$ 84,600
Homes likely to require more than minor repairs | home	709		709		709
Movement on number of homes likely to be repaired | home			19
Homes have been repaired | home	609		609		609
Product warranty accrual, payments	$ 4,100		$ 21,400
Estimated remaining warranty costs	$ 2,900		$ 2,900		$ 2,900
Settled Litigation | Florida Insurance Settlement
Movement in Standard Product Warranty Accrual [Roll Forward]
Insurance recoveries		$ 15,500