Basis of Presentation (Details) $ in Millions	3 Months Ended	6 Months Ended
	Dec. 31, 2020 USD ($) Home	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Noncontrolling Interest, Ownership Percentage by Parent		64.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		36.00%
Payments related to business acquisitions | $	$ 23.0	$ 24.2	$ 5.6
Business Acquisition, Number of Homes Acquired	90
Business Acquisition, Number of Finished Lots Acquired	95
Business Acquisition, Number of Lots Under Option Contracts	840
Business Acquisition, Sales Order Backlog Acquired	125