SEGMENT AND GEOGRAPHIC INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEGMENT AND GEOGRAPHIC INFORMATION
Revenue									$ 527,113	$ 518,920	$ 519,289
Long-lived assets:	$ 188,455				$ 186,101				188,455	186,101	178,972
United States
SEGMENT AND GEOGRAPHIC INFORMATION
Long-lived assets:	155,428				151,770				155,428	151,770	145,210
Canada
SEGMENT AND GEOGRAPHIC INFORMATION
Long-lived assets:	30,412				31,843				30,412	31,843	30,823
Mexico and Other
SEGMENT AND GEOGRAPHIC INFORMATION
Long-lived assets:	2,615				2,488				2,615	2,488	2,939
Product
SEGMENT AND GEOGRAPHIC INFORMATION
Revenue	$ 134,663	$ 181,913	$ 106,021	$ 101,019	$ 127,264	$ 181,505	$ 105,623	$ 100,859	523,616	515,251	515,674
Product | United States
SEGMENT AND GEOGRAPHIC INFORMATION
Revenue									478,790	471,561	472,222
Product | Canada, Mexico, and Other
SEGMENT AND GEOGRAPHIC INFORMATION
Revenue									$ 44,826	$ 43,690	$ 43,452