SEGMENT AND GEOGRAPHIC REGION INFORMATION (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Sales to clients attributed to the geographic areas based on the origin of sale
Sales to clients	$ 250,026	$ 219,794	$ 221,018	$ 196,662	$ 223,148	$ 239,543	$ 238,650	$ 220,858	$ 887,499	$ 922,200	$ 809,467
Property, plant, and equipment, net	124,838				121,792				124,838	121,792	122,219
United States
Sales to clients attributed to the geographic areas based on the origin of sale
Sales to clients									774,654	797,834	688,914
Property, plant, and equipment, net	80,953				77,230				80,953	77,230	75,228
Canada
Sales to clients attributed to the geographic areas based on the origin of sale
Sales to clients									40,669	44,225	34,267
Property, plant, and equipment, net	29,064				29,110				29,064	29,110	31,435
Europe
Sales to clients attributed to the geographic areas based on the origin of sale
Sales to clients									72,176	80,141	86,286
Property, plant, and equipment, net	$ 14,821				$ 15,452				$ 14,821	$ 15,452	$ 15,556