Inventory and Capitalized Interest Other Inventory Items - Homes under construction not subject to a sale contract (Details) $ in Millions	Mar. 31, 2019 USD ($) homes	Dec. 31, 2018 USD ($)
Other Inventory, Gross [Abstract]
Number of Speculative Homes	1,278	1,443
Speculative Homes Carrying Value	$ 270.0	$ 311.0