PROPERTY, PLANT AND EQUIPMENT (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 94,470	$ 77,499
Less: accumulated depreciation and amortization	(57,401)	(54,521)
Property, plant & equipment, net	37,069	22,978
Land and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	1,669	1,267
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	26,692	20,078
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	63,456	53,710
Transportation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	937	760
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 1,716	$ 1,684