Agreements and Transactions with Related Parties (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Amounts Included in the Consolidated Statements of Income
Asset management fees	$ 7,489	$ 7,422	$ 22,456	$ 21,864
Available Cash Distributions	5,276	5,837	17,803	17,690
Personnel and overhead reimbursements	2,293	3,086	7,318	9,238
Acquisition expenses	1,403	0	2,844	430
Interest expense on deferred acquisition fees and loan from affiliate	47	113	176	246
Operating expenses	16,508	16,458	50,597	49,468
Acquisition Fees Capitalized
Personnel and overhead reimbursements	108	0	221	0
Current acquisition fees	0	563	550	5,500
Deferred acquisition fees	0	450	440	4,182
Transaction fees incurred	$ 108	$ 1,013	$ 1,211	$ 9,682