CASH AND RESTRICTED CASH (Details - Balance Sheet) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 64,565	$ 105,102
Restricted cash and cash equivalents	38	56
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period	$ 64,603	$ 105,158	$ 350,554	$ 372,641