Segment Reporting Segment Reporting, Seasonality (Details) $ in Millions	3 Months Ended								9 Months Ended
	Dec. 31, 2017	Sep. 30, 2017 USD ($)	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016 USD ($)	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017 USD ($) segment
Segment Reporting Information [Line Items]
Number of reportable segments | segment									2
Real Property Operations Segment [Member]
Segment Reporting Information [Line Items]
Expected annual transient RV revenue | $		$ 77.8			$ 58.2				$ 77.8
Transient RV rental revenue recognized as a percentage		36.90%	20.20%	27.20%	18.60%	45.20%	18.70%	17.50%
Scenario, Forecast [Member] | Real Property Operations Segment [Member]
Segment Reporting Information [Line Items]
Transient RV rental revenue recognized as a percentage	15.70%