CUSTOMER CONTRACTS - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Balance at January 1, 2020	$ 2,406
Bad debt expense	539	$ 270
Write-Offs, net of Recoveries	(349)
Balance at March 31, 2020	$ 2,596