Inventory (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Sep. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Inventory Impairments and Land Option Cost Write-Offs [Abstract]
Carrying Value of Communities Impaired	$ 76.4	$ 76.4
Inventory Write-down	$ 8.3	14.0	$ 19.0	$ 3.8
Loss on Contract Termination		$ 64.8	$ 61.3	$ 66.6

Amount of loss from reductions in inventory due to subsequent measurement adjustments, including, but not limited to, physical deterioration, obsolescence, or changes in price levels.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 330
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483080/330-10-50-2

Name:	us-gaap_InventoryWriteDown
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration