LEASES - Lessee Expenses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessee operating leases
Contractual lease expense	$ 100	$ 200
Variable lease expense	100	200
Total lease expense	2,301	4,598
Operating lease right-of-use asset amortization		400
Operating lease liabilities amortization		200
Ground Leases
Lessee operating leases
Contractual lease expense	2,139	4,278
Variable lease expense	143	282
Ground Leases | Other operating expense
Lessee operating leases
Total lease expense	2,282	4,560
Office Space | General and administrative expense
Lessee operating leases
Contractual lease expense	$ 19	$ 38