RECEIVABLES, CONTRACT ASSETS, AND DEFERRED REVENUE- Contract Effective (Details) $ in Thousands	Jun. 30, 2021 USD ($)
Receivables [Abstract]
2021	$ 140,395
2020	131,618
2019	55,282
2018	26,688
2017 and prior	26,533
Unbilled revenue total	$ 380,516
2021	37.00%
2020	34.00%
2019	15.00%
2018	7.00%
2017 and prior	7.00%
Total percentage of unbilled revenue	100.00%