Debt And Lines Of Credit , Narrative - Line of Credit (Details)	1 Months Ended		9 Months Ended	12 Months Ended
	Apr. 30, 2017	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) properties Rate	Dec. 31, 2016 USD ($)	Apr. 25, 2017 USD ($) Rate	Apr. 24, 2017 USD ($)
Line of Credit Facility [Line Items]
Number of Real Estate Properties | properties			192
Long-term Debt			$ 0
Repayments of Debt		$ 62,100,000
Lines of credit				$ 100,095,000
Weighted average interest rate			4.60%	4.50%
Debt weighted average to maturity, length			8 years 4 months 24 days	8 years 6 months
Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity					$ 650,000,000	$ 450,000,000
Line of credit, borrowing capacity					1,000,000,000
Debt Instrument, Maturity Date	Apr. 25, 2021
Line of credit, additional borrowing capacity					350,000,000
Interest rate				2.14%
Lines of credit				$ 100,300,000
Letters of credit outstanding, amount			$ 3,800,000	4,600,000
Line of credit - manufactured home floor plan facility [Member]
Line of Credit Facility [Line Items]
Line of credit, borrowing capacity			12,000,000
Lines of credit			$ 0	2,800,000
Weighted average interest rate | Rate			7.00%
Prime Rate [Member] | Line of credit - manufactured home floor plan facility [Member]
Line of Credit Facility [Line Items]
Basis points | Rate			100.00%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit, borrowing capacity					550,000,000
Debt instrument, face amount				$ 42,300,000
Lines of credit			$ 0
Revolving Credit Facility [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Weighted average interest rate			0.00%	2.10%
Debt weighted average to maturity, length			0 days	3 years 7 months 6 days
Revolving Credit Facility [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of credit variable interest rate | Rate			1.35%
Term Loan [Member]
Line of Credit Facility [Line Items]
Line of credit, borrowing capacity					$ 100,000,000
Term Loan [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Lines of credit				$ 58,000,000
Term Loan [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of credit variable interest rate | Rate			1.30%
Minimum [Member] | Revolving Credit Facility [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					1.35%
Minimum [Member] | Term Loan [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					1.30%
Maximum [Member] | Prime Rate [Member] | Line of credit - manufactured home floor plan facility [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate			6.00%
Maximum [Member] | Revolving Credit Facility [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					2.20%
Maximum [Member] | Term Loan [Member] | Eurodollar [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate | Rate					2.15%