REVENUE - RECEIVABLES AND CONTRACT LIABILITIES BALANCES (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($)
Contract with Customer, Asset [Roll Forward]
Beginning of period, January 1, 2021	$ 111,871
End of period, June 30, 2021	147,168
Increase in receivables during the period	35,297
Contract with Customer, Liability [Roll Forward]
Beginning of period, January 1, 2021	2,060
End of period, June 30, 2021	3,605
Increase in contract liabilities during the period	$ 1,545