Real Estate Inventories and Capitalized Interest Inventory Impairments (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Inventory Disclosure [Abstract]
Impairment of Real Estate Homes	$ 900	$ 0	$ 1,300	$ 0	$ 2,350	$ 0	$ 0	$ 0	$ 2,200	$ 2,350	$ 0
Impairment of Real Estate Land					$ 1,150	$ 0	$ 0	$ 0	0	1,150	0
Total Inventory Impairments									2,200	3,500	0
Remaining Carrying Value of Inventory Impaired									$ 5,921	$ 30,225	$ 0
Number of Projects Impaired									1	3	0
Number of Projects Reviewed for Impairment									26	27	18
Number of Homebuilding Projects Impaired									1	2