REAL ESTATE - Highest Tenant Industry Concentrations- Grater than 10% of Annual Base Rent (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) tenant
Concentration Risk [Line Items]
Number of Tenants | tenant	660
Annualized Base Rent | $	$ 94,085
Percentage of Annualized Base Rent	40.30%
Finance
Concentration Risk [Line Items]
Number of Tenants | tenant	130
Annualized Base Rent | $	$ 42,970
Percentage of Annualized Base Rent	18.40%
Real Estate
Concentration Risk [Line Items]
Number of Tenants | tenant	61
Annualized Base Rent | $	$ 26,532
Percentage of Annualized Base Rent	11.40%
Professional, Scientific and Technical Services
Concentration Risk [Line Items]
Number of Tenants | tenant	43
Annualized Base Rent | $	$ 24,583
Percentage of Annualized Base Rent	10.50%