OPERATING SEGMENTS - Revenue and Long-lived 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
Revenue, Property and Equipment and Intangible Assets Outside of the United States
Total revenue	$ 124,824	$ 148,414	$ 360,493	$ 424,797
Total long- lived assets	453,768		453,768		$ 449,905
United States
Revenue, Property and Equipment and Intangible Assets Outside of the United States
Total revenue	111,005	138,367	325,379	392,698
Total long- lived assets	398,722		398,722		400,320
Canada
Revenue, Property and Equipment and Intangible Assets Outside of the United States
Total revenue	13,819	$ 10,047	35,114	$ 32,099
Total long- lived assets	$ 55,046		$ 55,046		$ 49,585