SEGMENT AND GEOGRAPHIC REGION INFORMATION (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Sales to clients attributed to the geographic areas based on the origin of sale
Sales	$ 286,453	$ 268,297	$ 265,943	$ 229,601	$ 230,456	$ 216,898	$ 214,312	$ 200,586	$ 1,050,294	$ 862,252	$ 898,496
Property, plant, and equipment, net	165,019				137,893				165,019	137,893	124,838
United States
Sales to clients attributed to the geographic areas based on the origin of sale
Sales									928,733	752,347	785,651
Property, plant, and equipment, net	123,821				94,896				123,821	94,896	80,953
Canada
Sales to clients attributed to the geographic areas based on the origin of sale
Sales									32,811	36,240	40,669
Property, plant, and equipment, net	25,669				27,938				25,669	27,938	29,064
Europe
Sales to clients attributed to the geographic areas based on the origin of sale
Sales									88,750	73,665	72,176
Property, plant, and equipment, net	$ 15,529				$ 15,059				$ 15,529	$ 15,059	$ 14,821