Investments in Unconsolidated Real Estate Joint Ventures (Summary Balance Sheets for Unconsolidated Joint Ventures) (Details) - Unconsolidated Properties [Member] - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets
Land	$ 87,402	$ 90,859
Buildings, improvements and fixtures	457,969	477,061
Construction in progress	4,495	4,779
Rental property, at cost, total	549,866	572,699
Accumulated depreciation	(133,199)	(132,860)
Total rental property, net	416,667	439,839
Cash and cash equivalents	9,274	19,750
Deferred lease costs and other intangibles, net	5,554	6,772
Prepaids and other assets	26,888	17,789
Total assets	458,383	484,150
Liabilities and Owners’ Equity
Mortgages payable, net	358,923	368,032
Accounts payable and other liabilities	15,627	17,173
Total liabilities	374,550	385,205
Owners’ equity	83,833	98,945
Total liabilities and equity	$ 458,383	$ 484,150