Basis of Presentation and Summary of Significant Accounting Policies - Business Acquisitions (Details) $ in Millions	Jul. 13, 2018 USD ($) home lot Community
Business Acquisition [Line Items]
Number of single-family communities | Community	27
Venture Homes
Business Acquisition [Line Items]
Purchase price, net of cash acquired	$ 61.3
Number of homes in backlog | home	48
Number of model homes in backlog | home	6
Inventory acquired	$ 55.2
Goodwill and intangible assets, net	11.4
Other assets acquired	0.4
Accounts payable assumed	5.5
Other liabilities assumed	$ 0.2
Minimum | Venture Homes
Business Acquisition [Line Items]
Number of lots owned or controlled | lot	1,100