BUSINESS INFORMATION (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) client	Jun. 30, 2016 USD ($) client	Jun. 30, 2017 USD ($) client	Jun. 30, 2016 USD ($) client	Dec. 31, 2016 USD ($)
Business information
Total revenues	$ 172,149	$ 131,725	$ 345,407	$ 258,089
Total assets	$ 627,806		$ 627,806		$ 598,800
Client | Revenue
Business information
Number of clients | client	0	0	0	0
United States
Business information
Total revenues	$ 150,704	$ 106,219	$ 289,106	$ 212,952
Total assets	540,819		540,819		506,748
Europe
Business information
Total revenues	16,637	13,328	38,656	24,122
Total assets	27,477		27,477		31,341
Rest Of World
Business information
Total revenues	4,808	$ 12,178	17,645	$ 21,015
Total assets	$ 59,510		$ 59,510		$ 60,711