LEASES - Ground Leases as Lessee (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Leased Assets [Line Items]
Finance ground lease assets	$ 25,607	$ 16,063
Ground lease
Operating Leased Assets [Line Items]
Finance ground lease assets	$ 25,600
Options to extend lease terms	99 years
Weighted average remaining non-cancelable lease term	96 years
Ground lease | Minimum
Operating Leased Assets [Line Items]
Ground lease remaining term	63 years
Ground lease | Maximum
Operating Leased Assets [Line Items]
Ground lease remaining term	99 years