OVERVIEW AND BASIS OF PRESENTATION (TABLES) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 89,046	$ 78,237
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	91,439	$ 78,237	$ 81,594	$ 74,437
Prepaid Expenses and Other Current Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	2,380
Other Noncurrent Assets [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 13