OTHER ASSETS (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Other Assets Components [Abstract]
Leasing costs (principally commissions)	$ 76,587	$ 72,722
Accumulated amortization of leasing costs	(28,742)	(27,973)
Leasing costs (principally commissions), net of accumulated amortization	47,845	44,749
Straight-line rents receivable	35,276	31,609
Allowance for doubtful accounts on straight-line rents receivable	(134)	(48)
Straight-line rents receivable, net of allowance for doubtful accounts	35,142	31,561
Accounts receivable	5,026	6,004
Allowance for doubtful accounts on accounts receivable	(515)	(577)
Accounts receivable, net of allowance for doubtful accounts	4,511	5,427
Acquired in-place lease intangibles	21,752	20,690
Accumulated amortization of acquired in-place lease intangibles	(9,168)	(8,974)
Acquired in-place lease intangibles, net of accumulated amortization	12,584	11,716
Acquired above market lease intangibles	1,465	1,550
Accumulated amortization of acquired above market lease intangibles	(852)	(794)
Acquired above market lease intangibles, net of accumulated amortization	613	756
Mortgage loans receivable	2,604	4,581
Interest rate swap assets	10,693	6,034
Goodwill	990	990
Prepaid expenses and other assets	5,870	10,215
Other Assets Total	$ 120,852	$ 116,029