CUSTOMER CONTRACTS - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Balance at January 1, 2020	$ 2,596	$ 2,406		$ 2,406
Bad debt expense	898	539	$ 645	1,437	$ 915
Write-Offs, net of Recoveries	(532)	(349)
Balance at March 31, 2020	$ 2,962	$ 2,596		$ 2,962