INCOME TAXES - Unrecognized tax benefits (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Unrecognized tax benefits
Unrecognized tax benefits	$ 2,811
Accrued interest on unrecognized tax benefits	241
Portion that, if recognized, would reduce tax expense and effective tax rate	3,052
Reasonably possible reduction to the balance of unrecognized tax in subsequent year	2,058
Portion that, if recognized, would reduce tax expense and effective tax rate	$ 2,058