OTHER ASSETS (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other Assets Components [Abstract]
Leasing costs (principally commissions)	$ 96,473	$ 89,191
Accumulated amortization of leasing costs	(38,166)	(34,963)
Leasing costs (principally commissions), net of accumulated amortization	58,307	54,228
Acquired in-place lease intangibles	26,175	28,834
Accumulated amortization of acquired in-place lease intangibles	(12,870)	(11,918)
Acquired in-place lease intangibles, net of accumulated amortization	13,305	16,916
Acquired above market lease intangibles	1,723	1,721
Accumulated amortization of acquired above market lease intangibles	(1,174)	(1,007)
Acquired above market lease intangibles, net of accumulated amortization	549	714
Straight-line rents receivable	43,033	40,369
Accounts receivable	5,841	5,581
Mortgage loans receivable	1,658	1,679
Interest rate swap assets	0	3,485
Right of use assets - Office Leases (operating)	2,253	2,115
Goodwill	990	990
Prepaid expenses and other assets	19,765	18,545
Total Other Assets	$ 145,701	$ 144,622