Inventory (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Properties for sale		$ 62,911	$ 12,649
Properties not available for sale		6,653	2,328
Properties under improvement		35,896	7,717
Inventory	$ 105,460	105,460	22,694
Lower of cost or net realizable value write-downs		$ 272	$ 190
Inventory, Current [Roll Forward]
Inventory as of December 31, 2018	22,694
Purchases and additions to inventory	213,813
Relief of inventory to cost of revenue	(130,965)
Lower of cost or net realizable value write-downs, net	(82)
Inventory as of September 30, 2019	$ 105,460