LEASES - Other information related to operating leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Other information related to operating leases:
Operating lease cost	$ 4,012	$ 1,636	$ 11,178	$ 4,867
Cash paid for amounts included in the measurement of operating lease liabilities	$ 3,724	$ 1,745	$ 10,496	$ 5,295
Weighted average remaining lease term	6 years 10 months 24 days		6 years 10 months 24 days		6 years 6 months
Weighted average discount rate	1.82%		1.82%		3.23%