Reporting Segments and Related Information - Revenue Components of Real Estate Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue from External Customer [Line Items]
Equity in earnings of unconsolidated joint ventures, net	$ 1,181	$ 1,971	$ 2,536	$ 2,847
Total expenses	7,558	10,341	19,634	22,035
Operating results from commercial/industrial and unconsolidated joint ventures	(130)	927	(302)	1,146
Real estate - commercial/industrial
Revenue from External Customer [Line Items]
Commercial/industrial revenues	2,114	6,595	4,434	9,421
Equity in earnings of unconsolidated joint ventures, net	1,181	1,971	2,536	2,847
Commercial/industrial revenues and equity in earnings of unconsolidated joint ventures	3,295	8,566	6,970	12,268
Total expenses	1,747	4,593	3,678	6,385
Operating results from commercial/industrial and unconsolidated joint ventures	$ 1,548	$ 3,973	$ 3,292	$ 5,883