OTHER LONG TERM LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Other Liabilities, Noncurrent [Abstract]
Deferred revenue - long-term	$ 19,203	$ 17,434
Deferred Compensation Liability, Classified, Noncurrent	25,781	23,858
Other Accrued Liabilities, Noncurrent	55,170	54,893
Other Liabilities, Noncurrent, Total	$ 100,154	$ 96,185