Fair Value Disclosures Fair Value Disclosure (Details) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Fair Value Disclosures [Abstract]
Unsecured revolving credit facility	$ 67,500				$ 0				$ 67,500	$ 0
Assets, Fair Value Adjustment											$ 0
Debt Instrument, Unamortized Discount	1,700				2,200				1,700	2,200
Debt Instrument, Unamortized Premium	1,300				1,800				1,300	1,800
Debt Instrument, Unamortized Debt Issuance Costs	4,500				5,900				$ 4,500	$ 5,900
Number of Projects Impaired									2	1	2
Impairment of Real Estate									$ 10,000	$ 2,200	$ 3,500
Impairment of Real Estate Homes	$ 10,000	$ 0	$ 0	$ 0	$ 900	$ 0	$ 1,300	$ 0	10,000	2,200	2,350
Impairment of Real Estate Land									0	0	1,150
Remaining Carrying Value of Inventory Impaired									57,845	5,921	30,225
Other than Temporary Impairment Losses, Investments									$ 1,100	$ 0	0
Liabilities, Fair Value Adjustment											$ 0