OTHER ASSETS (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Other Assets Components [Abstract]
Leasing costs (principally commissions)	$ 101,140	$ 95,914
Accumulated amortization of leasing costs	(38,200)	(38,371)
Leasing costs (principally commissions), net of accumulated amortization	62,940	57,543
Acquired in-place lease intangibles	26,989	28,107
Accumulated amortization of acquired in-place lease intangibles	(13,596)	(13,554)
Acquired in-place lease intangibles, net of accumulated amortization	13,393	14,553
Acquired above market lease intangibles	1,825	1,825
Accumulated amortization of acquired above market lease intangibles	(1,292)	(1,231)
Acquired above market lease intangibles, net of accumulated amortization	533	594
Straight-line rents receivable	45,057	43,079
Accounts receivable	4,510	6,256
Interest rate swap assets	1,178	0
Right of use assets - Office Leases (operating)	2,359	2,131
Receivable for common stock offerings	0	1,942
Goodwill	990	990
Prepaid expenses and other assets	21,293	22,491
Total Other Assets	$ 152,253	$ 149,579