INCOME TAXES - Reconciliation of Unrecognized Income Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, beginning balance	$ 5,048	$ 8,651	$ 8,020
Additions for tax positions of prior years	247	208	459
Additions for tax positions of current years	368	393	1,248
Expiration of the statute of limitations	(1,202)	(3,182)	(1,024)
Reductions for tax positions of prior years	(103)	(217)	(52)
Settlements	0	(805)	0
Unrecognized tax benefits, ending balance	$ 4,358	$ 5,048	$ 8,651