Commitments and Contingencies - Land Banking Arrangements (Details)	6 Months Ended
	Jun. 30, 2019 USD ($) Project lot	Dec. 31, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Real estate inventories not owned	$ 240,015,000	$ 315,576,000
Liabilities from inventories not owned	240,015,000	$ 315,576,000
Land, Banking Arrangement
Property, Plant and Equipment [Line Items]
Real estate inventories not owned	240,015,000
Liabilities from inventories not owned	$ 209,800,000
Total number of land banking arrangements consolidated | Project	3
Total number of lots | lot	5,184,000
Total purchase price	$ 452,967,000
Balance of lots still under option and not purchased, number of lots | lot	3,708,000
Forfeited deposits if lots are not purchased	$ 62,338
Minimum | Land, Banking Arrangement
Property, Plant and Equipment [Line Items]
Non-refundable deposit of total purchase price, percentage	15.00%
Maximum | Land, Banking Arrangement
Property, Plant and Equipment [Line Items]
Non-refundable deposit of total purchase price, percentage	25.00%