INCOME TAXES, Income Tax Uncertainties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of unrecognized tax benefits [Roll Forward]
Balance at beginning of period	$ 6,637	$ 6,570	$ 5,205
Increases for tax positions of prior years	393	332	943
Decreases for tax positions of prior years	(2,711)	(406)	(120)
Increases for tax positions related to current year	462	141	542
Balance at end of period	4,781	6,637	6,570
Interest and penalties	94	94	$ 138
Accrued interest and penalties	$ 1,882	$ 2,486