Real Estate Property Asset Acquisitions (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Real Estate [Line Items]
Acquired in-place leases, net	$ 26,207	$ 31,224
Prepaid expenses, deposits and other	8,702	7,225
TOTAL ASSETS	2,817,309	2,790,333
Accounts payable and accrued expenses	59,262	62,576
Security deposits payable	6,590	8,316
Other liabilities and deferred credits	91,300	68,110
Liabilities	$ 1,563,903	1,496,661
La Jolla Commons
Real Estate [Line Items]
Land		82,759
Buildings		361,471
Land improvements		1,359
Furniture, fixtures, and equipment		30,822
Total real estate		476,411
Acquired in-place leases, net		40,082
Prepaid expenses, deposits and other		13
TOTAL ASSETS		516,506
Accounts payable and accrued expenses		3,578
Security deposits payable		443
Other liabilities and deferred credits		3,817
Liabilities		$ 7,838