LEASES - RIGHT OF USE ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease assets	$ 3,828	$ 4,048	$ 0
Operating lease liabilities - current	1,165	1,157	$ 0
Operating lease liabilities - long-term	3,445	3,693
Total lease liabilities	$ 4,610	$ 4,850