Real Estate Property Asset Acquisitions (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Real Estate [Line Items]
Acquired in-place leases, net	$ 6,281	$ 8,371
Prepaid expenses, deposits and other	6,683	5,945
TOTAL ASSETS	2,198,250	2,259,864
Accounts payable and accrued expenses	46,616	38,069
Security deposits payable	8,844	6,570
Other liabilities and deferred credits	49,547	46,061
Liabilities	$ 1,395,779	1,415,720
Gateway Marketplace
Real Estate [Line Items]
Land		17,363
Buildings		19,192
Land improvements		1,522
Furniture, fixtures, and equipment		930
Total real estate		39,007
Acquired in-place leases, net		2,920
Prepaid expenses, deposits and other		0
TOTAL ASSETS		41,927
Accounts payable and accrued expenses		203
Security deposits payable		22
Other liabilities and deferred credits		1,034
Liabilities		1,259
Pacific Ridge Apartments
Real Estate [Line Items]
Land		47,971
Buildings		171,813
Land improvements		3,403
Furniture, fixtures, and equipment		3,281
Total real estate		226,468
Acquired in-place leases, net		5,592
Prepaid expenses, deposits and other		424
TOTAL ASSETS		232,484
Accounts payable and accrued expenses		74
Security deposits payable		673
Other liabilities and deferred credits		49
Liabilities		$ 796