LEASES - Components of lease expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lease, Cost [Abstract]
Operating lease expense	$ 8,616	$ 9,129	$ 17,766	$ 18,655
Variable lease expense	6,105	5,291	11,989	11,320
Short-term lease expense	544	293	1,046	525
Total lease expense	$ 15,265	$ 14,713	$ 30,801	$ 30,500