OTHER ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Assets Components [Abstract]
Leasing costs (principally commissions)	$ 72,722	$ 65,521
Accumulated amortization of leasing costs	(27,973)	(26,340)
Leasing costs (principally commissions), net of accumulated amortization	44,749	39,181
Straight-line rents receivable	31,609	28,369
Allowance for doubtful accounts on straight-line rents receivable	(48)	(76)
Straight-line rents receivable, net of allowance for doubtful accounts	31,561	28,293
Accounts receivable	6,004	6,824
Allowance for doubtful accounts on accounts receivable	(577)	(809)
Accounts receivable, net of allowance for doubtful accounts	5,427	6,015
Acquired in-place lease intangibles	20,690	21,231
Accumulated amortization of acquired in-place lease intangibles	(8,974)	(8,642)
Acquired in-place lease intangibles, net of accumulated amortization	11,716	12,589
Acquired above market lease intangibles	1,550	1,594
Accumulated amortization of acquired above market lease intangibles	(794)	(736)
Acquired above market lease intangibles, net of accumulated amortization	756	858
Mortgage loans receivable	4,581	4,752
Interest rate swap assets	6,034	4,546
Goodwill	990	990
Prepaid expenses and other assets	11,490	7,606
Other Assets Total	$ 117,304	$ 104,830