ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Contract assets and liabilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Contract assets:
Unbilled receivables	$ 10,470	$ 8,540	$ 10,735
Contract liabilities:
Customer advances and unearned income	7,708	5,252	7,494
Reserve for audience deficiency	7,050	6,478	$ 6,020
Unearned event income	$ 379	$ 6,118