Mortgages and Notes Receivable (Details) (USD $)	9 Months Ended			3 Months Ended	12 Months Ended			9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Mar. 31, 2014 Seller Financing [Member]	Dec. 31, 2010 Seller Financing [Member] transactions	Sep. 30, 2014 Seller Financing [Member]	Dec. 31, 2013 Seller Financing [Member]	Sep. 30, 2014 Mortgage Receivable [Member]	Dec. 31, 2013 Mortgage Receivable [Member]	Dec. 31, 2012 Mortgage Receivable [Member]	Sep. 30, 2014 Promissory Notes [Member]	Sep. 30, 2013 Promissory Notes [Member]	Sep. 30, 2014 Promissory Notes [Member]	Sep. 30, 2013 Promissory Notes [Member]	Dec. 31, 2013 Promissory Notes [Member]
Schedule of mortgages and notes receivable [Abstract]
Mortgages and notes receivable, gross						$ 0	$ 16,454,000	$ 10,300,000	$ 9,435,000	$ 8,600,000	$ 456,000		$ 456,000		$ 822,000
Mortgages and notes receivable, allowance	(255,000)					0		0			(255,000)	(340,000)	(255,000)	(340,000)
Mortgages and notes receivable, net	10,501,000		26,409,000			0	16,454,000	10,300,000	9,435,000		201,000		201,000		520,000
Number of transactions with seller financing					2
Repayment of seller financing	16,974,000	437,000		16,500,000
Deferred gain on sale of real estate				400,000
Mortgages and notes receivable, gross						0	16,454,000	10,300,000	9,435,000	8,600,000	456,000		456,000		822,000
Additional loan commitment to third party										8,400,000
Cumulative funds for future infrastructure disbursed to third party								700,000
Notes receivable allowance, promissory notes [Roll Forward]
Beginning notes receivable allowance	302,000			0		0		0			275,000	376,000	302,000	182,000
Recoveries/write-offs/other											(20,000)	(36,000)	(47,000)	158,000
Total notes receivable allowance	$ 255,000					$ 0		$ 0			$ 255,000	$ 340,000	$ 255,000	$ 340,000