LEASES - NARRATIVE (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease liabilities	$ 4,082	$ 4,850
Operating lease, borrowing rate		3.25%
Right-of-use assets	$ 3,371	$ 4,048	$ 0
Deferred rent			$ 764
ASU 2016-02
Lessee, Lease, Description [Line Items]
Operating lease liabilities		4,900
Right-of-use assets		$ 4,000