OTHER (EXPENSE) INCOME, NET - Components of Other (Expense) Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Other Income and Expenses [Abstract]
Interest and investment income	$ 74	$ 312
Income tax expense	(127)	(206)
Other non-operating income	0	2
Total other (expense) income, net	$ (53)	$ 108