INCOME TAXES - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Activity related to unrecognized tax benefits
Gross unrecognized tax benefits at the beginning of the period	$ 32,682	$ 30,232	$ 20,961
Increase in unrecognized tax benefits taken during a prior period			7,293
Increase in unrecognized tax benefits taken during the current period	2,964	3,383	3,408
Lapse in statute of limitations	(1,768)	(933)	(1,430)
Gross unrecognized tax benefits at the end of the period	33,878	32,682	30,232
Interest and penalties accrued	6,900	$ 5,900	$ 4,500
Unrecognized tax benefits that would affect the effective tax rate if recognized	$ 40,700