LEASES - Lease Costs & Additional Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 831	$ 999	$ 3,095	$ 2,788
Variable lease cost	0	0	0	0
Sublease income	(745)	(1,182)	(2,877)	(3,123)
Lease cost	$ 86		$ 218
Lease income		$ (183)		$ (335)
Weighted-average remaining lease term - operating leases (in years)	9 years 9 months 18 days		9 years 9 months 18 days
Weighted-average discount rate - operating leases (as a percent)	3.19%		3.19%