INCOME TAXES - Additional Information (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 138,238	$ 179,788
Unrecognized Tax Benefits	1,014	$ 1,021	$ 1,067	$ 1,096
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	410,300
Net operating loss carryforwards subject to annual limitation	12,900
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 450,400