ENTITY WIDE DISCLOSURES - Geographic Breakdown of Revenues and Total Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 289,577	$ 243,552	$ 876,871	$ 671,358
Total assets	1,182,422		1,182,422		$ 798,991
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	208,009	192,109	651,126	509,592
Total assets	958,541		958,541		682,124
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	33,747	30,194	97,568	93,137
Total assets	65,710		65,710		59,626
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	27,930	10,935	77,971	36,293
Total assets	108,531		108,531		33,271
Other foreign countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	19,891	$ 10,314	50,206	$ 32,336
Total assets	$ 49,640		$ 49,640		$ 23,970