BUSINESS SEGMENT INFORMATION - Geographic (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment information:
Total revenues	$ 188,757	$ 89,300	$ 371,367	$ 333,077
United States
Segment information:
Total revenues	181,530	82,506	354,459	310,500
International
Segment information:
Total revenues	$ 7,227	$ 6,794	$ 16,908	$ 22,577