Inventory and Capitalized Interest Other Inventory Items - Homes under construction not subject to a sale contract (Details) $ in Millions	Dec. 31, 2020 USD ($) homes	Dec. 31, 2019 USD ($) homes
Other Inventory, Gross [Abstract]
Number of Speculative Homes | homes	1,131	1,459
Speculative Homes Carrying Value | $	$ 186.9	$ 304.0