INCOME TAXES - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Reconciliation [Abstract]
Income tax at Federal statutory rate	$ 22,348	$ 20,260	$ 20,796
State income taxes, net of Federal income taxes	2,288	(244)	2,742
Stock Options	(1,529)	(222)	(1,293)
GILTI	0	2,507	1,027
FDII	(1,400)	(1,922)	0
Deemed Repatriation	0	0	(970)
Patent Box Decree (related to prior years)	0	(1,948)	0
Foreign Tax Credits	0	(1,125)	(1,136)
Other	87	(499)	(709)
Total income tax provision	$ 21,794	$ 16,807	$ 20,457