OTHER LONG TERM LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Other Liabilities, Noncurrent [Abstract]
Deferred revenue - long-term	$ 22,123	$ 17,434
Deferred Compensation Liability, Classified, Noncurrent	27,826	23,858
Deferred social security taxes	16,983	15,986
Other Accrued Liabilities, Noncurrent	29,469	38,907
Other Liabilities, Noncurrent, Total	$ 96,401	$ 96,185