SEGMENT DISCLOSURE (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) property	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment disclosure
Number of types of commercial real estate properties | property									3
Revenues	$ 52,744	$ 55,384	$ 61,299	$ 66,949	$ 64,622	$ 64,332	$ 68,360	$ 68,617	$ 236,376	$ 265,931	$ 276,948
Interest expense									36,338	34,385	23,630
Property expenses:
General and administrative									5,479	7,961	9,402
EXPENSES									256,979	273,239	273,122
Reportable segments
Property expenses:
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									128,452	133,406	136,294
Reportable segments | Office
Segment disclosure
Revenues									174,004	187,435	188,270
Property expenses:
Operating									68,801	81,217	80,014
General and administrative									981	1,234	771
EXPENSES									69,782	82,451	80,785
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									104,222	104,984	107,485
Reportable segments | Hotel
Segment disclosure
Revenues									38,585	48,379	61,436
Property expenses:
Operating									25,059	32,177	41,585
General and administrative									77	282	389
EXPENSES									25,136	32,459	41,974
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									13,449	15,920	19,462
Reportable segments | Multi-family
Segment disclosure
Revenues									13,566	20,303	18,721
Property expenses:
Operating									7,725	11,309	11,579
General and administrative									393	1,048	589
EXPENSES									8,118	12,357	12,168
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									5,448	7,946	6,553
Reportable segments | Lending division
Segment disclosure
Revenues									10,221	9,814	8,521
Interest expense									414	537	845
Fees to related party									3,464	3,555	3,850
Property expenses:
General and administrative									1,010	1,166	1,032
EXPENSES									4,888	5,258	5,727
INCOME FROM CONTINUING OPERATIONS BEFORE PROVISION FOR INCOME TAXES									$ 5,333	$ 4,556	$ 2,794