Summary of Significant Accounting Policies - Inventories and Property (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Land and Other Inventories
Land and other inventories, impairment assessment	$ 943	$ 769	$ 0
Investment in nonconsolidated entities
Investment in nonconsolidated entities	$ 300	$ 1,200
Land Improvements | Minimum
Property and Equipment, net
Estimated useful lives	5 years
Land Improvements | Maximum
Property and Equipment, net
Estimated useful lives	15 years
Building and Improvements | Minimum
Property and Equipment, net
Estimated useful lives	3 years
Building and Improvements | Maximum
Property and Equipment, net
Estimated useful lives	40 years
Machinery, Equipment and Fixtures | Minimum
Property and Equipment, net
Estimated useful lives	3 years
Machinery, Equipment and Fixtures | Maximum
Property and Equipment, net
Estimated useful lives	10 years