OTHER ASSETS (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Other Assets Components [Abstract]
Leasing costs (principally commissions)	$ 110,986	$ 95,914
Accumulated amortization of leasing costs	(40,713)	(38,371)
Leasing costs (principally commissions), net of accumulated amortization	70,273	57,543
Acquired in-place lease intangibles	29,606	28,107
Accumulated amortization of acquired in-place lease intangibles	(13,674)	(13,554)
Acquired in-place lease intangibles, net of accumulated amortization	15,932	14,553
Acquired above market lease intangibles	1,815	1,825
Accumulated amortization of acquired above market lease intangibles	(1,399)	(1,231)
Acquired above market lease intangibles, net of accumulated amortization	416	594
Straight-line rents receivable	49,919	43,079
Accounts receivable	5,535	6,064
Interest rate swap assets	511	0
Right of use assets - Office Leases (operating)	2,108	2,131
Receivable for common stock offerings	0	1,942
Goodwill	990	990
Receivable for tenant improvement cost reimbursements	14,762	192
Prepaid expenses and other assets	11,146	22,491
Total Other Assets	$ 171,592	$ 149,579