Inventory (Summary of Interests in Land Option Agreements) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Deposits and Pre-acquisition Costs	$ 195,717	$ 195,436
Remaining Purchase Price	1,992,161	2,102,563
Land options with VIEs
Variable Interest Entity [Line Items]
Deposits and Pre-acquisition Costs	71,558	68,527
Remaining Purchase Price	842,784	849,901
Other Land Option Agreements Member
Variable Interest Entity [Line Items]
Deposits and Pre-acquisition Costs	124,159	126,909
Remaining Purchase Price	$ 1,149,377	$ 1,252,662