Debt And Lines Of Credit , Narrative - Mortgage Notes (Details) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	1 Months Ended		3 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended			1 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Mortgages [Member] properties sites	Dec. 31, 2011 Mortgages [Member]	May 31, 2011 Mortgages [Member] Mortgage - refinancing BoA [Member] properties	Jun. 30, 2011 Mortgages [Member] Mortgage - Kentland acquisition [Member] properties	Mar. 31, 2012 Mortgages [Member] Mortgage - Kentland acquisition [Member]	Jun. 30, 2011 Mortgages [Member] Mortgage - variable financing BoA Kentland and Orange City [Member] properties	Mar. 31, 2012 Mortgages [Member] Mortgage - variable financing BoA Kentland and Orange City [Member]	Mar. 31, 2012 Mortgages [Member] Mortgage - Florida Properties [Member] properties	Dec. 31, 2011 Mortgages [Member] Mortgage - Florida Properties [Member] properties	Mar. 31, 2012 Mortgages [Member] Mortgage - Leisure Village [Member]	Jun. 30, 2011 Kentland [Member] sites	Jun. 30, 2011 Kentland [Member] Mortgages [Member] Mortgage - variable financing BoA Kentland and Orange City [Member] properties	Feb. 29, 2012 Repayment of Debt [Member] Mortgages [Member] Mortgage - variable financing BoA Kentland and Orange City [Member]
Debt Instrument [Line Items]
Debt weighted average to maturity, length	7 years 1 month	7 years 4 months	3 years 2 months	3 years 3 months		4 years 5 months	4 years 2 months	3 years 9 months	3 years 2 months	4 years 8 months	5 years
Debt Instrument, Face Amount					$ 23,600,000			$ 22,900,000		$ 19,000,000	$ 17,000,000
Stated interest rate					5.38%
Number of properties securing a debt instument (in properties)			32		3	12		6		3	3			5
Weighted average interest rate	5.30%	5.30%	3.60%	3.80%		5.70%	5.60%	3.10%	3.09%	2.74%	2.78%
Extinguishment of debt amount					17,900,000							2,700,000			4,500,000
Loans assumed	52,398,000					52,400,000							52,398,000
Total debt	1,287,571,000	1,268,191,000	154,722,000	143,877,000
Number of sites (in sites)			8,453										5,434
Property, net book value			$ 266,500,000