Inventory (Summary of Interests in Land Option Agreements) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Deposits and Pre-acquisition Costs	$ 303,582	$ 299,437
Remaining Purchase Price	3,331,103	3,221,962
Land options with VIEs
Variable Interest Entity [Line Items]
Deposits and Pre-acquisition Costs	130,537	123,775
Remaining Purchase Price	1,523,601	1,466,585
Other land options
Variable Interest Entity [Line Items]
Deposits and Pre-acquisition Costs	173,045	175,662
Remaining Purchase Price	$ 1,807,502	$ 1,755,377