REVENUE RECOGNITION - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Contract Assets and Liabilities
Contract Asset - current	$ 1,900
Change in contract asset - current	513
Contract Asset - current	$ 2,413	$ 1,900
% of change in contract asset - current	27.00%
Contract asset, noncurrent	$ 802
Change in contract Asset - noncurrent	103
Contract asset, noncurrent	$ 905	802
% of change in contract Asset - noncurrent	13.00%
Contract liability- current	$ (13,787)
Change in contract liabilities - current	(1,257)
Contract liability- current	$ (15,044)	(13,787)
% of change in contract liabilities - current	(9.00%)
Contract liability- noncurrent	$ 0
Change in contract liabilities - noncurrent	(5,450)
Contract liability- noncurrent	$ (5,450)	0
% of change in contract liabilities - Noncurrent	100.00%
Net contract liability	$ (11,085)
Change in net contract liability	(6,091)
Net contract liability	$ (17,176)	(11,085)
% of change in net contract liability	(55.00%)
Revenue recognized related to contract liability	$ 12,100
Amortization of contract assets	1,800
Revenue recognized in the period related to performance obligations that were satisfied or partially satisfied in previous periods	$ 0	$ 0