RECEIVABLES, CONTRACT ASSETS, AND DEFERRED REVENUE- Contract Effective (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Receivables [Abstract]
2021	$ 168,237
2020	109,904
2019	47,058
2018	22,169
2017 and prior	24,553
Unbilled revenue total	$ 371,921
2021	45.00%
2020	29.00%
2019	13.00%
2018	6.00%
2017 and prior	7.00%
Total percentage of unbilled revenue	100.00%